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Eckstein KN, Hergert JE, Uzcategui AC, Schoonraad SA, Bryant SJ, McLeod RR, Ferguson VL. Controlled Mechanical Property Gradients Within a Digital Light Processing Printed Hydrogel-Composite Osteochondral Scaffold. Ann Biomed Eng 2024:10.1007/s10439-024-03516-x. [PMID: 38684606 DOI: 10.1007/s10439-024-03516-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 04/07/2024] [Indexed: 05/02/2024]
Abstract
Tissue engineered scaffolds are needed to support physiological loads and emulate the micrometer-scale strain gradients within tissues that guide cell mechanobiological responses. We designed and fabricated micro-truss structures to possess spatially varying geometry and controlled stiffness gradients. Using a custom projection microstereolithography (μSLA) system, using digital light projection (DLP), and photopolymerizable poly(ethylene glycol) diacrylate (PEGDA) hydrogel monomers, three designs with feature sizes < 200 μm were formed: (1) uniform structure with 1 MPa structural modulus ( E ) designed to match equilibrium modulus of healthy articular cartilage, (2) E = 1 MPa gradient structure designed to vary strain with depth, and (3) osteochondral bilayer with distinct cartilage ( E = 1 MPa) and bone ( E = 7 MPa) layers. Finite element models (FEM) guided design and predicted the local mechanical environment. Empty trusses and poly(ethylene glycol) norbornene hydrogel-infilled composite trusses were compressed during X-ray microscopy (XRM) imaging to evaluate regional stiffnesses. Our designs achieved target moduli for cartilage and bone while maintaining 68-81% porosity. Combined XRM imaging and compression of empty and hydrogel-infilled micro-truss structures revealed regional stiffnesses that were accurately predicted by FEM. In the infilling hydrogel, FEM demonstrated the stress-shielding effect of reinforcing structures while predicting strain distributions. Composite scaffolds made from stiff μSLA-printed polymers support physiological load levels and enable controlled mechanical property gradients which may improve in vivo outcomes for osteochondral defect tissue regeneration. Advanced 3D imaging and FE analysis provide insights into the local mechanical environment surrounding cells in composite scaffolds.
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Affiliation(s)
- Kevin N Eckstein
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 427 UCB, Boulder, CO, 80309, USA
| | - John E Hergert
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO, USA
| | - Asais Camila Uzcategui
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO, USA
| | - Sarah A Schoonraad
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - Stephanie J Bryant
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - Robert R McLeod
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO, USA
- Department of Electrical, Computer & Energy Engineering, University of Colorado at Boulder, Boulder, CO, USA
| | - Virginia L Ferguson
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 427 UCB, Boulder, CO, 80309, USA.
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO, USA.
- BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO, USA.
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2
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Blackman SA, Miles D, Suresh J, Calve S, Bryant SJ. Cell- and Serum-Derived Proteins Act as DAMPs to Activate RAW 264.7 Macrophage-like Cells on Silicone Implants. ACS Biomater Sci Eng 2024; 10:1418-1434. [PMID: 38319825 DOI: 10.1021/acsbiomaterials.3c01393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Protein adsorption after biomaterial implantation is the first stage of the foreign body response (FBR). However, the source(s) of the adsorbed proteins that lead to damaged associated molecular patterns (DAMPs) and induce inflammation have not been fully elucidated. This study examined the effects of different protein sources, cell-derived (from a NIH/3T3 fibroblast cell lysate) and serum-derived (from fetal bovine serum), which were compared to implant-derived proteins (after a 30 min subcutaneous implantation in mice) on activation of RAW 264.7 cells cultured in minimal (serum-free) medium. Both cell-derived and serum-derived protein sources when preadsorbed to either tissue culture polystyrene or medical-grade silicone induced RAW 264.7 cell activation. The combination led to an even higher expression of pro-inflammatory cytokine genes and proteins. Implant-derived proteins on silicone explants induced a rapid inflammatory response that then subsided more quickly and to a greater extent than the studies with in vitro cell-derived or serum-derived protein sources. Proteomic analysis of the implant-derived proteins identified proteins that included cell-derived and serum-derived, but also other proteinaceous sources (e.g., extracellular matrix), suggesting that the latter or nonproteinaceous sources may help to temper the inflammatory response in vivo. These findings indicate that both serum-derived and cell-derived proteins adsorbed to implants can act as DAMPs to drive inflammation in the FBR, but other protein sources may play an important role in controlling inflammation.
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Affiliation(s)
- Samuel A Blackman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
| | - Dalton Miles
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
| | - Joshita Suresh
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
| | - Sarah Calve
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, Colorado 80309-0427, United States
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
- Materials Science and Engineering Program, University of Colorado Boulder, 4001 Discovery Drive, Boulder, Colorado 80300-0613, United States
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3
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Schoonraad SA, Jaimes AA, Singh AJX, Croland KJ, Bryant SJ. Osteogenic effects of covalently tethered rhBMP-2 and rhBMP-9 in an MMP-sensitive PEG hydrogel nanocomposite. Acta Biomater 2023; 170:53-67. [PMID: 37634836 PMCID: PMC10831697 DOI: 10.1016/j.actbio.2023.08.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023]
Abstract
While bone morphogenic protein-2 (BMP-2) is one of the most widely studied BMPs in bone tissue engineering, BMP-9 has been purported to be a highly osteogenic BMP. This work investigates the individual osteogenic effects of recombinant human (rh) BMP-2 and rhBMP-9, when tethered into a hydrogel, on encapsulated human mesenchymal stem cells (MSCs). A matrix-metalloproteinase (MMP)-sensitive hydrogel nanocomposite, comprised of poly(ethylene glycol) crosslinked with MMP-sensitive peptides, tethered RGD, and entrapped hydroxyapatite nanoparticles was used. The rhBMPs were functionalized with free thiols and then covalently tethered into the hydrogel by a thiol-norbornene photoclick reaction. rhBMP-2 retained its full bioactivity post-thiolation, while the bioactivity of rhBMP-9 was partially reduced. Nonetheless, both rhBMPs were highly effective at enhancing osteogenesis over 12-weeks in a chemically-defined medium. Expression of ID1 and osterix, early markers of osteogenesis; collagen type I, a main component of the bone extracellular matrix (ECM); and osteopontin, bone sialoprotein II and dentin matrix protein I, mature osteoblast markers, increased with increasing concentrations of tethered rhBMP-2 or rhBMP-9. When comparing the two BMPs, rhBMP-9 led to more rapid collagen deposition and greater mineralization long-term. In summary, rhBMP-2 retained its bioactivity post-thiolation while rhBMP-9 is more susceptible to thiolation. Despite this shortcoming with rhBMP-9, both rhBMPs when tethered into this hydrogel, enhanced osteogenesis of MSCs, leading to a mature osteoblast phenotype surrounded by a mineralized ECM. STATEMENT OF SIGNIFICANCE: Osteoinductive hydrogels are a promising vehicle to deliver mesenchymal stem cells (MSCs) for bone regeneration. This study examines the in vitro osteoinductive capabilities when tethered bone morphogenic proteins (BMPs) are incorporated into a degradable biomimetic hydrogel with cell adhesive ligands, matrix metalloproteinase sensitive crosslinks for cell-mediated degradation, and hydroxyapatite nanoparticles. This study demonstrates that BMP-2 is readily thiolated and tethered without loss of bioactivity while bioactivity of BMP-9 is more susceptible to immobilization. Nonetheless, when either BMP2 or BMP9 are tethered into this hydrogel, osteogenesis of human MSCs is enhanced, bone extracellular matrix is deposited, and a mature osteoblast phenotype is achieved. This bone-biomimetic hydrogel is a promising design for stem cell-mediated bone regeneration.
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Affiliation(s)
- Sarah A Schoonraad
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, CO 80309-0613, United States
| | - Alan A Jaimes
- Department of Biochemistry, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, United States
| | - Arjun J X Singh
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, United States
| | - Kiera J Croland
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, United States
| | - Stephanie J Bryant
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, CO 80309-0613, United States; Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, United States; BioFrontiers Institute, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, United States.
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Grey EL, McClendon J, Suresh J, Alper S, Janssen WJ, Bryant SJ. Thiol-Michael Addition Microparticles: Their Synthesis, Characterization, and Uptake by Macrophages. ACS Biomater Sci Eng 2023; 9:4223-4240. [PMID: 37379254 PMCID: PMC10619202 DOI: 10.1021/acsbiomaterials.3c00441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
Polymeric microparticles are promising biomaterial platforms for targeting macrophages in the treatment of disease. This study investigates microparticles formed by a thiol-Michael addition step-growth polymerization reaction with tunable physiochemical properties and their uptake by macrophages. The hexafunctional thiol monomer dipentaerythritol hexa-3-mercaptopropionate (DPHMP) and tetrafunctional acrylate monomer di(trimethylolpropane) tetraacrylate (DTPTA) were reacted in a stepwise dispersion polymerization, achieving tunable monodisperse particles over a size range (1-10 μm) relevant for targeting macrophages. An off-stoichiometry thiol-acrylate reaction afforded facile secondary chemical functionalization to create particles with different chemical moieties. Uptake of the microparticles by RAW 264.7 macrophages was highly dependent on treatment time, particle size, and particle chemistry with amide, carboxyl, and thiol terminal chemistries. The amide-terminated particles were non-inflammatory, while the carboxyl- and thiol-terminated particles induced pro-inflammatory cytokine production in conjunction with particle phagocytosis. Finally, a lung-specific application was explored through time-dependent uptake of amide-terminated particles by human alveolar macrophages in vitro and mouse lungs in vivo without inducing inflammation. The findings demonstrate a promising microparticulate delivery vehicle that is cyto-compatible, is non-inflammatory, and exhibits high rates of uptake by macrophages.
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Affiliation(s)
- Emerson L. Grey
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, USA
| | - Jazalle McClendon
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, CO 80206, USA
| | - Joshita Suresh
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, USA
| | - Scott Alper
- Department of Immunology and Genomic Medicine, Center for Genes, Environment and Health, National Jewish Health, 1400 Jackson St, Denver, CO 80206, USA
| | - William J. Janssen
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, 1400 Jackson St, Denver, CO 80206, USA
- Department of Medicine, University of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, Aurora, CO 80045, USA
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, USA
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, CO 80309-0613, USA
- BioFrontiers Institute, University of Colorado, 3415 Colorado Ave, Boulder, CO 80309-0596, USA
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5
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Maples MM, Schneider MC, Bryant SJ. Impact of Inter- and Intra-Donor Variability by Age on the Gel-to-Tissue Transition in MMP-Sensitive PEG Hydrogels for Cartilage Regeneration. ACS Appl Bio Mater 2023. [PMID: 37367934 DOI: 10.1021/acsabm.3c00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Matrix metalloproteinase (MMP)-sensitive hydrogels are promising for cartilage tissue engineering due to cell-mediated control over hydrogel degradation. However, any variability in MMP, tissue inhibitors of matrix metalloproteinase (TIMP), and/or extracellular matrix (ECM) production among donors will impact neotissue formation in the hydrogels. The goal for this study was to investigate the impact of inter- and intra-donor variability on the hydrogel-to-tissue transition. Transforming growth factor β3 was tethered into the hydrogel to maintain the chondrogenic phenotype and support neocartilage production, allowing the use of chemically defined medium. Bovine chondrocytes were isolated from two donor groups, skeletally immature juvenile and skeletally mature adult donors (inter-donor variability) and three donors within each group (intra-donor group variability). While the hydrogel supported neocartilaginous growth by all donors, donor age impacted MMP, TIMP, and ECM synthesis rates. Of the MMPs and TIMPs studied, MMP-1 and TIMP-1 were the most abundantly produced by all donors. Adult chondrocytes secreted higher levels of MMPs, which was accompanied by higher production of TIMPs. Juvenile chondrocytes exhibited more rapid ECM growth. By day 29, juvenile chondrocytes had surpassed the gel-to-tissue transition. On the contrary, the adult donors had a percolated polymer network indicating that despite higher levels of MMPs the gel-to-transition had not yet been achieved. The intra-donor group variability of MMP, TIMP, and ECM production was higher in adult chondrocytes but did not impact the extent of the gel-to-tissue transition. In summary, age-dependent inter-donor variations in MMPs and TIMPs significantly impact the timing of the gel-to-tissue transition in MMP-sensitive hydrogels.
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Affiliation(s)
- Mollie M Maples
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0596, United States
| | - Margaret C Schneider
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0596, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0596, United States
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309-0596, United States
- BioFrontiers Institute, University of Colorado, Boulder, Colorado 80309-0596, United States
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6
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Wilmoth RL, Sharma S, Ferguson VL, Bryant SJ. The effects of prostaglandin E2 on gene expression of IDG-SW3-derived osteocytes in 2D and 3D culture. Biochem Biophys Res Commun 2022; 630:8-15. [PMID: 36126467 DOI: 10.1016/j.bbrc.2022.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 09/02/2022] [Indexed: 11/20/2022]
Abstract
Prostaglandin E2 (PGE2) is a key signaling molecule produced by osteocytes in response to mechanical loading, but its effect on osteocytes is less understood. This work examined the effect of PGE2 on IDG-SW3-derived osteocytes in standard 2D culture (collagen-coated tissue culture polystyrene) and in a 3D degradable poly(ethylene glycol) hydrogel. IDG-SW3 cells were differentiated for 35 days into osteocytes in 2D and 3D cultures. 3D culture led to a more mature osteocyte phenotype with 100-fold higher Sost expression. IDG-SW3-derived osteocytes were treated with PGE2 and assessed for expression of genes involved in PGE2, anabolic, and catabolic signaling. In 2D, PGE2 had a rapid (1 h) and sustained (24 h) effect on many PGE2 signaling genes, a rapid stimulatory effect on Il6, and a sustained inhibitory effect on Tnfrsf11b and Bglap. Comparing culture environment without PGE2, osteocytes had higher expression of all four EP receptors and Sost but lower expression of Tnfrsf11b, Bglap, and Gja1 in 3D. Osteocytes were more responsive to PGE2 in 3D. With increasing PGE2, 3D led to increased Gja1 and decreased Sost expressions and a higher Tnfrsf11b/Tnfsf11 ratio, indicating an anabolic response. Further analysis in 3D revealed that EP4, the receptor implicated in PGE2 signaling in bone, was not responsible for the PGE2-induced gene expression changes in osteocytes. In summary, osteocytes are highly responsive to PGE2 when cultured in an in vitro 3D hydrogel model suggesting that autocrine and paracrine PGE2 signaling in osteocytes may play a role in bone homeostasis.
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Affiliation(s)
- Rachel L Wilmoth
- Mechanical Engineering, University of Colorado, 1111 Engineering Dr, Boulder, CO, 80309, USA
| | - Sadhana Sharma
- Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO, 80309, USA
| | - Virginia L Ferguson
- Mechanical Engineering, University of Colorado, 1111 Engineering Dr, Boulder, CO, 80309, USA; BioFrontiers Institute, University of Colorado, 3415 Colorado Ave, Boulder, CO, 80309, USA; Materials Science and Engineering, University of Colorado, 4001 Discovery Dr., Boulder, CO, 80309, USA
| | - Stephanie J Bryant
- Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, CO, 80309, USA; BioFrontiers Institute, University of Colorado, 3415 Colorado Ave, Boulder, CO, 80309, USA; Materials Science and Engineering, University of Colorado, 4001 Discovery Dr., Boulder, CO, 80309, USA.
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7
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Muralidharan A, Crespo-Cuevas V, Ferguson VL, McLeod RR, Bryant SJ. Effects of Kinetic Chain Length on the Degradation of Poly(β-amino ester)-Based Networks and Use in 3D Printing by Projection Microstereolithography. Biomacromolecules 2022; 23:3272-3285. [PMID: 35793134 DOI: 10.1021/acs.biomac.2c00362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Poly(β-amino ester)-diacrylates (PBAE-dAs) are promising resins for three-dimensional (3D) printing. This study investigated the degradation of two PBAEs with different chemistries and kinetic chain lengths. PBAE-dA monomers were synthesized from benzhydrazide and poly(ethylene glycol) (A6) or butanediol (B6) diacrylate and then photopolymerized with pentaerythritol tetrakis(3-mercaptopropionate), which formed thiol-polyacrylate kinetic chains. This tetrathiol acts as a cross-linker and chain-transfer agent that controls the polyacrylate kinetic chain length. A6 networks exhibited bulk degradation, while B6 networks exhibited surface degradation, which transitioned to a combined surface and bulk degradation. Increasing the tetrathiol concentration shortened the polyacrylate kinetic chain and time-to-reverse gelation but degradation mode was unaffected. Hydrolysis occurred primarily through the β-amino ester. As network hydrophilicity increased, the slower degrading ester in the thiol-polyacrylate chains contributed to degradation. Overall, this work demonstrates control over network degradation rate, mode of degradation, and time-to-reverse gelation in PBAE networks and their application in 3D printing.
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Affiliation(s)
- Archish Muralidharan
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, Colorado 80309, United States
| | - Victor Crespo-Cuevas
- Department of Mechanical Engineering, University of Colorado, 1111 Engineering Dr, Boulder, Colorado 80309, United States
| | - Virginia L Ferguson
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, Colorado 80309, United States.,Department of Mechanical Engineering, University of Colorado, 1111 Engineering Dr, Boulder, Colorado 80309, United States.,BioFrontiers Institute, University of Colorado, 3415 Colorado Ave, Boulder, Colorado 80309, United States
| | - Robert R McLeod
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, Colorado 80309, United States.,Department of Electrical, Computer and Energy Engineering, University of Colorado, 1111 Engineering Dr, Boulder, Colorado 80309, United States
| | - Stephanie J Bryant
- Materials Science & Engineering Program, University of Colorado, 4001 Discovery Dr, Boulder, Colorado 80309, United States.,BioFrontiers Institute, University of Colorado, 3415 Colorado Ave, Boulder, Colorado 80309, United States.,Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, Boulder, Colorado 80309, United States
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8
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Saleh LS, Amer LD, Thompson BJ, Danhorn T, Knapp JR, Gibbings SL, Thomas S, Barthel L, O'Connor BP, Janssen WJ, Alper S, Bryant SJ. Mapping Macrophage Polarization and Origin during the Progression of the Foreign Body Response to a Poly(ethylene glycol) Hydrogel Implant. Adv Healthc Mater 2022; 11:e2102209. [PMID: 34967497 PMCID: PMC9081184 DOI: 10.1002/adhm.202102209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/04/2021] [Indexed: 11/10/2022]
Abstract
Poly(ethylene glycol) (PEG) hydrogels hold promise for in vivo applications but induce a foreign body response (FBR). While macrophages are key in the FBR, many questions remain. This study investigates temporal changes in the transcriptome of implant-associated monocytes and macrophages. Proinflammatory pathways are upregulated in monocytes compared to control monocytes but subside by day 28. Macrophages are initially proinflammatory but shift to a profibrotic state by day 14, coinciding with fibrous capsule emergence. Next, this study assesses the origin of macrophages responsible for fibrous encapsulation using wildtype, C-C Motif Chemokine Receptor 2 (CCR2)-/- mice that lack recruited macrophages, and Macrophage Fas-Induced Apoptosis (MaFIA) mice that enable macrophage ablation. Subpopulations of recruited and tissue-resident macrophages are identified. Fibrous encapsulation proceeds in CCR2-/- mice similar to wildtype mice. However, studies in MaFIA mice indicate that macrophages are necessary for fibrous capsule formation. These findings suggest that macrophage origin impacts the FBR progression and provides evidence that tissue-resident macrophages and not the recruited macrophages may drive fibrosis in the FBR to PEG hydrogels. This study demonstrates that implant-associated monocytes and macrophages have temporally distinct transcriptomes in the FBR and that profibrotic pathways associated with macrophages may be enriched in tissue-resident macrophages.
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Affiliation(s)
- Leila S. Saleh
- Department of Chemical and Biological Engineering University of Colorado at Boulder 3415 Colorado Ave Boulder CO 80309 USA
| | - Luke D. Amer
- Department of Chemical and Biological Engineering University of Colorado at Boulder 3415 Colorado Ave Boulder CO 80309 USA
| | - Brittany J. Thompson
- Materials Science and Engineering Program University of Colorado at Boulder 3415 Colorado Ave Boulder CO 80309 USA
| | - Thomas Danhorn
- Center for Genes Environment and Health National Jewish Health 1400 Jackson St Denver CO 80206 USA
| | - Jennifer R. Knapp
- Center for Genes Environment and Health National Jewish Health 1400 Jackson St Denver CO 80206 USA
| | | | - Stacey Thomas
- Division of Pulmonary Sciences and Critical Care Medicine University of Colorado Denver Aurora CO 80045 USA
| | - Lea Barthel
- Division of Pulmonary Sciences and Critical Care Medicine University of Colorado Denver Aurora CO 80045 USA
| | - Brian P. O'Connor
- Center for Genes Environment and Health National Jewish Health 1400 Jackson St Denver CO 80206 USA
- Department of Immunology and Genomic Medicine National Jewish Health Denver CO 80206 USA
| | - William J. Janssen
- Division of Pulmonary Sciences and Critical Care Medicine University of Colorado Denver Aurora CO 80045 USA
- Division of Pulmonary Sleep, and Critical Care Medicine National Jewish Health Denver CO 80206 USA
| | - Scott Alper
- Center for Genes Environment and Health National Jewish Health 1400 Jackson St Denver CO 80206 USA
- Department of Immunology and Genomic Medicine National Jewish Health Denver CO 80206 USA
- Department of Immunology and Microbiology University of Colorado School of Medicine Aurora CO 80045 USA
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering University of Colorado at Boulder 3415 Colorado Ave Boulder CO 80309 USA
- Materials Science and Engineering Program University of Colorado at Boulder 3415 Colorado Ave Boulder CO 80309 USA
- BioFrontiers Institute University of Colorado at Boulder Boulder CO 80309 USA
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9
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Barthold JE, McCreery K, Martinez J, Bellerjeau C, Ding Y, Bryant SJ, Whiting G, Neu CP. Particulate ECM biomaterial ink is 3D printed and naturally crosslinked to form structurally-layered and lubricated cartilage tissue mimics. Biofabrication 2022; 14. [PMID: 35203071 DOI: 10.1088/1758-5090/ac584c] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 02/24/2022] [Indexed: 11/11/2022]
Abstract
Articular cartilage is a layered tissue with a complex, heterogenous structure and lubricated surface which is challenging to reproduce using traditional tissue engineering methods. 3D printing techniques have enabled engineering of complex scaffolds for cartilage regeneration, but constructs fail to replicate the unique zonal layers, and limited cytocompatible crosslinkers exist. To address the need for mechanically robust, layered scaffolds, we developed an extracellular matrix particle-based biomaterial ink (pECM biomaterial ink) which can be extruded, polymerizes via disulfide bonding, and restores surface lubrication. Our cartilage pECM biomaterial ink utilizes functionalized hyaluronan, a naturally occurring glycosaminoglycan, crosslinked directly to decellularized tissue particles (ø 40-100 µm). We experimentally determined that hyaluronan functionalized with thiol groups (t-HA) forms disulfide bonds with the ECM particles to form a 3D network. We show that two inks can be co-printed to create a layered cartilage scaffold with bulk compressive and surface (friction coefficient, adhesion, and roughness) mechanics approaching values measured on native cartilage. We demonstrate that our printing process enables the addition of macropores throughout the construct, increasing the viability of introduced cells by 10%. The delivery of these 3D printed scaffolds to a defect is straightforward, customizable to any shape, and adheres to surrounding tissue.
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Affiliation(s)
- Jeanne E Barthold
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado, 80309-0401, UNITED STATES
| | - Kaitlin McCreery
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado, 80309-0401, UNITED STATES
| | - Jaylene Martinez
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado, 80309-0401, UNITED STATES
| | - Charlotte Bellerjeau
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado, 80309-0401, UNITED STATES
| | - Yifu Ding
- Department of Mechanical Engineering Campmode, University of Colorado at Boulder, Campus Box 427, 1111 Engineering Drive, Boulder, Colorado, 80309, UNITED STATES
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, 3415 Colorado Ave, USA, Boulder, Colorado, 80309, UNITED STATES
| | - Gregory Whiting
- Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado, 80309-0401, UNITED STATES
| | - Corey P Neu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado, 80309-0401, UNITED STATES
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10
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Muralidharan A, McLeod RR, Bryant SJ. Hydrolytically degradable Poly (β-amino ester) resins with tunable degradation for 3D printing by projection micro-stereolithography. Adv Funct Mater 2022; 32:2106509. [PMID: 35813039 PMCID: PMC9268535 DOI: 10.1002/adfm.202106509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Applications of 3D printing that range from temporary medical devices to environmentally responsible manufacturing would benefit from printable resins that yield polymers with controllable material properties and degradation behavior. Towards this goal, poly(β-amino ester) (PBAE)-diacrylate resins were investigated due to the wide range of available chemistries and tunable material properties. PBAE-diacrylate resins were synthesized from hydrophilic and hydrophobic chemistries and with varying electron densities on the ester bond to provide control over degradation. Hydrophilic PBAE-diacrylates led to degradation behaviors characteristic of bulk degradation while hydrophobic PBAE-diacrylates led to degradation behaviors dominated initially by surface degradation and then transitioned to bulk degradation. Depending on chemistry, the crosslinked PBAE-polymers exhibited a range of degradation times under accelerated conditions, from complete mass loss in 90 min to minimal mass loss at 45 days. Patterned features with 55 μm resolution were achieved across all resins, but their fidelity was dependent on PBAE-diacrylate molecular weight, reactivity, and printing parameters. In summary, simple chemical modifications in the PBAE-diacrylate resins coupled with projection microstereolithography enables high resolution 3D printed parts with similar architectures and initial properties, but widely different degradation rates and behaviors.
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Affiliation(s)
- Archish Muralidharan
- Materials Science and Engineering Program, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Robert R. McLeod
- Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA; Materials Science and Engineering Program, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
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11
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Vernerey FJ, Lalitha Sridhar S, Muralidharan A, Bryant SJ. Mechanics of 3D Cell-Hydrogel Interactions: Experiments, Models, and Mechanisms. Chem Rev 2021; 121:11085-11148. [PMID: 34473466 DOI: 10.1021/acs.chemrev.1c00046] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hydrogels are highly water-swollen molecular networks that are ideal platforms to create tissue mimetics owing to their vast and tunable properties. As such, hydrogels are promising cell-delivery vehicles for applications in tissue engineering and have also emerged as an important base for ex vivo models to study healthy and pathophysiological events in a carefully controlled three-dimensional environment. Cells are readily encapsulated in hydrogels resulting in a plethora of biochemical and mechanical communication mechanisms, which recapitulates the natural cell and extracellular matrix interaction in tissues. These interactions are complex, with multiple events that are invariably coupled and spanning multiple length and time scales. To study and identify the underlying mechanisms involved, an integrated experimental and computational approach is ideally needed. This review discusses the state of our knowledge on cell-hydrogel interactions, with a focus on mechanics and transport, and in this context, highlights recent advancements in experiments, mathematical and computational modeling. The review begins with a background on the thermodynamics and physics fundamentals that govern hydrogel mechanics and transport. The review focuses on two main classes of hydrogels, described as semiflexible polymer networks that represent physically cross-linked fibrous hydrogels and flexible polymer networks representing the chemically cross-linked synthetic and natural hydrogels. In this review, we highlight five main cell-hydrogel interactions that involve key cellular functions related to communication, mechanosensing, migration, growth, and tissue deposition and elaboration. For each of these cellular functions, recent experiments and the most up to date modeling strategies are discussed and then followed by a summary of how to tune hydrogel properties to achieve a desired functional cellular outcome. We conclude with a summary linking these advancements and make the case for the need to integrate experiments and modeling to advance our fundamental understanding of cell-matrix interactions that will ultimately help identify new therapeutic approaches and enable successful tissue engineering.
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Affiliation(s)
- Franck J Vernerey
- Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado 80309-0428, United States.,Materials Science and Engineering Program, University of Colorado at Boulder, 4001 Discovery Drive, Boulder, Colorado 80309-613, United States
| | - Shankar Lalitha Sridhar
- Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado 80309-0428, United States
| | - Archish Muralidharan
- Materials Science and Engineering Program, University of Colorado at Boulder, 4001 Discovery Drive, Boulder, Colorado 80309-613, United States
| | - Stephanie J Bryant
- Materials Science and Engineering Program, University of Colorado at Boulder, 4001 Discovery Drive, Boulder, Colorado 80309-613, United States.,Department of Chemical and Biological Engineering, University of Colorado at Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States.,BioFrontiers Institute, University of Colorado at Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
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12
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Schoonraad SA, Fischenich KM, Eckstein KN, Crespo-Cuevas V, Savard LM, Muralidharan A, Tomaschke AA, Uzcategui AC, Randolph MA, McLeod RR, Ferguson VL, Bryant SJ. Biomimetic and mechanically supportive 3D printed scaffolds for cartilage and osteochondral tissue engineering using photopolymers and digital light processing. Biofabrication 2021; 13. [PMID: 34479218 DOI: 10.1088/1758-5090/ac23ab] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 09/03/2021] [Indexed: 02/08/2023]
Abstract
Successful 3D scaffold designs for musculoskeletal tissue engineering necessitate full consideration of the form and function of the tissues of interest. When designing structures for engineering cartilage and osteochondral tissues, one must reconcile the need to develop a mechanically robust system that maintains the health of cells embedded in the scaffold. In this work, we present an approach that decouples the mechanical and biochemical needs and allows for the independent development of the structural and cellular niches in a scaffold. Using the highly tuned capabilities of digital light processing-based stereolithography, structures with complex architectures are achieved over a range of effective porosities and moduli. The 3D printed structure is infilled with mesenchymal stem cells and soft biomimetic hydrogels, which are specifically formulated with extracellular matrix analogs and tethered growth factors to provide selected biochemical cues for the guided differentiation towards chondrogenesis and osteogenesis. We demonstrate the ability to utilize these structures to (a) infill a focal chondral defect and mitigate macroscopic and cellular level changes in the cartilage surrounding the defect, and (b) support the development of a stratified multi-tissue scaffold for osteochondral tissue engineering.
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Affiliation(s)
- Sarah A Schoonraad
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Kristine M Fischenich
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Kevin N Eckstein
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Victor Crespo-Cuevas
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Lea M Savard
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Archish Muralidharan
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Andrew A Tomaschke
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Asais Camila Uzcategui
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Mark A Randolph
- Department of Orthopaedic Surgery, Laboratory for Musculoskeletal Tissue Engineering, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, United States of America
| | - Robert R McLeod
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, United States of America.,Department of Electrical, Computer and Energy Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Virginia L Ferguson
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, United States of America.,Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America.,BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO 80309, United States of America
| | - Stephanie J Bryant
- Materials Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, United States of America.,BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO 80309, United States of America.,Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO 80309, United States of America
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13
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Sharma S, Monteleone N, Kopyeva I, Bryant SJ. The effects of processing variables on electrospun poly(ethylene glycol) fibrous hydrogels formed from the
thiol‐norbornene
click reaction. J Appl Polym Sci 2021. [DOI: 10.1002/app.50786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Sadhana Sharma
- Department of Chemical and Biological Engineering University of Colorado‐Boulder Boulder Colorado USA
| | - Nicholas Monteleone
- Department of Chemical and Biological Engineering University of Colorado‐Boulder Boulder Colorado USA
| | - Irina Kopyeva
- Department of Chemical and Biological Engineering University of Colorado‐Boulder Boulder Colorado USA
- Current address: Department of Bioengineering University of Washington Seattle Washington USA
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering University of Colorado‐Boulder Boulder Colorado USA
- Materials Science and Engineering Program University of Colorado‐Boulder Boulder Colorado USA
- BioFrontiers Institute University of Colorado‐Boulder Boulder Colorado USA
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14
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Richardson BM, Walker CJ, Maples MM, Randolph MA, Bryant SJ, Anseth KS. Mechanobiological Interactions between Dynamic Compressive Loading and Viscoelasticity on Chondrocytes in Hydrazone Covalent Adaptable Networks for Cartilage Tissue Engineering. Adv Healthc Mater 2021; 10:e2002030. [PMID: 33738966 PMCID: PMC8785214 DOI: 10.1002/adhm.202002030] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/17/2021] [Indexed: 12/17/2022]
Abstract
Mechanobiological cues influence chondrocyte biosynthesis and are often used in tissue engineering applications to improve the repair of articular cartilage in load-bearing joints. In this work, the biophysical effects of an applied dynamic compression on chondrocytes encapsulated in viscoelastic hydrazone covalent adaptable networks (CANs) is explored. Here, hydrazone CANs exhibit viscoelastic loss tangents ranging from (9.03 ± 0.01) 10-4 to (1.67 ± 0.09) 10-3 based on the molar percentages of alkyl-hydrazone and benzyl-hydrazone crosslinks. Notably, viscoelastic alkyl-hydrazone crosslinks improve articular cartilage specific gene expression showing higher SOX9 expression in free swelling hydrogels and dynamic compression reduces hypertrophic chondrocyte markers (COL10A1, MMP13) in hydrazone CANs. Interestingly, dynamic compression also improves matrix biosynthesis in elastic benzyl-hydrazone controls but reduces biosynthesis in viscoelastic alkyl-hydrazone CANs. Additionally, intermediate levels of viscoelastic adaptability demonstrate the highest levels of matrix biosynthesis in hydrazone CANs, demonstrating on average 70 ± 4 µg of sulfated glycosaminoglycans per day and 31 ± 3 µg of collagen per day over one month in dynamic compression bioreactors. Collectively, the results herein demonstrate the role of matrix adaptability and viscoelasticity on chondrocytes in hydrazone CANs during dynamic compression, which may prove useful for tissue engineering applications in load-bearing joints.
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Affiliation(s)
- Benjamin M Richardson
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
- The BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
| | - Cierra J Walker
- The BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
- Materials Science and Engineering Program, University of Colorado Boulder, 4001 Discovery Drive, Boulder, CO, 80303, USA
| | - Mollie M Maples
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
- The BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
| | - Mark A Randolph
- Department of Orthopedic Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, WAC 435, Boston, MA, 02114, USA
- Division of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, 15 Parkman St, WACC 453, Boston, MA, 02114, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
- The BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
- Materials Science and Engineering Program, University of Colorado Boulder, 4001 Discovery Drive, Boulder, CO, 80303, USA
| | - Kristi S Anseth
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
- The BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80303, USA
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15
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Anderson AJ, Grey E, Bongiardina NJ, Bowman CN, Bryant SJ. Synthesis and Characterization of Click Nucleic Acid Conjugated Polymeric Microparticles for DNA Delivery Applications. Biomacromolecules 2021; 22:1127-1136. [PMID: 33621070 PMCID: PMC8669756 DOI: 10.1021/acs.biomac.0c01563] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microparticle-mediated nucleic acid delivery is a popular strategy to achieve therapeutic outcomes via antisense gene therapy. However, current methods used to fabricate polymeric microparticles suffer from suboptimal properties such as particle polydispersity and low encapsulation efficiency. Here, a new particulate delivery system based on step-growth thiol-Michael dispersion polymerization is reported in which a low polydispersity microparticle is functionalized with a synthetic nucleic acid mimic, namely, click nucleic acids (CNA). CNA oligomers, exhibiting an average length of approximately four nucleic acid repeat units per chain for both adenine and thymine bases, were successfully conjugated to excess thiols present in the microparticles. Effective DNA loading was obtained by simple mixing, and up to 6 ± 2 pmol of complementary DNA/mg of particle was achieved, depending on the length of DNA used. In addition, DNA loading was orders of magnitude less for noncomplementary sequences and sequences containing an alternating base mismatch. The DNA release properties were evaluated, and it was found that release could be triggered by sudden changes in temperature but was unaffected over a range of pH. Finally, phagocytosis of loaded microparticles was observed by confocal microscopy and corroborated by an increase in cellular metabolic activity up to 90%. Overall, this work suggests that CNA functionalized microparticles could be a promising platform for controlled DNA delivery.
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Affiliation(s)
- Alex J Anderson
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Emerson Grey
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
| | - Nicholas J Bongiardina
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
| | - Christopher N Bowman
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
- BioFrontiers Institute, University of Colorado, Boulder, Colorado 80303, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States
- Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303, United States
- BioFrontiers Institute, University of Colorado, Boulder, Colorado 80303, United States
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16
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Uzcategui AC, Higgins CI, Hergert JE, Tomaschke AE, Crespo-Cuevas V, Ferguson VL, Bryant SJ, McLeod RR, Killgore JP. Microscale Photopatterning of Through-thickness Modulus in a Monolithic and Functionally Graded 3D Printed Part. Small Sci 2021; 1:2000017. [PMID: 34458889 PMCID: PMC8388578 DOI: 10.1002/smsc.202000017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
3D printing is transforming traditional processing methods for applications ranging from tissue engineering to optics. To fulfill its maximum potential, 3D printing requires a robust technique for producing structures with precise three-dimensional (x, y and z) control of mechanical properties. Previous efforts to realize such spatial control of modulus within 3D printed parts have largely focused on low-resolution (mm to cm scale) multi-material processes and grayscale approaches that spatially vary the modulus in the x-y plane and energy dose-based (E = I 0 t exp) models that do not account for the resin's sub-linear response to irradiation intensity. Here, we demonstrate a novel approach for through-thickness (z) voxelated control of mechanical properties within a single-material, monolithic part. Control over the local modulus is enabled by a predictive model that incorporates the observed non-reciprocal dose response of the material. The model is validated by an application of atomic force microscopy to map the through-thickness modulus on multi-layered 3D parts. Overall, both smooth gradations (30 MPa change over ≈75 μm) and sharp step-changes (30 MPa change over ≈5 μm) in modulus are realized in poly(ethylene glycol) diacrylate based 3D constructs, paving the way for advancements in tissue engineering, stimuli-responsive 4D printing and graded metamaterials.
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Affiliation(s)
- Asais Camila Uzcategui
- Materials Science and Engineering, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Callie I. Higgins
- Applied Chemicals and Materials Division (647), National Institute of Standards and Technology (NIST), Boulder, CO 80305
| | - John E. Hergert
- Materials Science and Engineering, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Andrew E. Tomaschke
- Department of Mechanical Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA
| | - Victor Crespo-Cuevas
- Department of Mechanical Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA
| | - Virginia L. Ferguson
- Department of Mechanical Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA; Materials Science and Engineering, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA; Materials Science and Engineering, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Robert R. McLeod
- Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA; Materials Science and Engineering, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Jason P. Killgore
- Applied Chemicals and Materials Division (647), National Institute of Standards and Technology (NIST), Boulder, CO 80305
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17
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Schoonraad SA, Trombold ML, Bryant SJ. The Effects of Stably Tethered BMP-2 on MC3T3-E1 Preosteoblasts Encapsulated in a PEG Hydrogel. Biomacromolecules 2021; 22:1065-1079. [PMID: 33555180 DOI: 10.1021/acs.biomac.0c01085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bone morphogenetic protein-2 (BMP-2) is a clinically used osteoinductive growth factor. With a short half-life and side effects, alternative delivery approaches are needed. This work examines thiolation of BMP-2 for chemical attachment to a poly(ethylene glycol) hydrogel using thiol-norbornene click chemistry. BMP-2 retained bioactivity post-thiolation and was successfully tethered into the hydrogel. To assess tethered BMP-2 on osteogenesis, MC3T3-E1 preosteoblasts were encapsulated in matrix metalloproteinase (MMP)-sensitive hydrogels containing RGD and either no BMP-2, soluble BMP-2 (5 nM), or tethered BMP-2 (40-200 nM) and cultured in a chemically defined medium containing dexamethasone for 7 days. The hydrogel culture supported MC3T3-E1 osteogenesis regardless of BMP-2 presentation, but tethered BMP-2 augmented the osteogenic response, leading to significant increases in osteomarkers, Bglap and Ibsp. The ratio, Ibsp-to-Dmp1, highlighted differences in the extent of differentiation, revealing that without BMP-2, MC3T3-E1 cells showed a higher expression of Dmp1 (low ratio), but an equivalent expression with tethered BMP-2 and more abundant bone sialoprotein. In addition, this work identified that dexamethasone contributed to Ibsp expression but not Bglap or Dmp1 and confirmed that tethered BMP-2 induced the BMP canonical signaling pathway. This work presents an effective method for the modification and incorporation of BMP-2 into hydrogels to enhance osteogenesis.
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Affiliation(s)
- Sarah A Schoonraad
- Materials Science & Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
| | - Michael L Trombold
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Stephanie J Bryant
- Materials Science & Engineering Program, University of Colorado, Boulder, Colorado 80309, United States.,Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, United States.,Biofrontiers Institute, University of Colorado, Boulder, Colorado 80309, United States
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18
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Anderson AJ, Culver HR, Prieto TR, Martinez PJ, Sinha J, Bryant SJ, Bowman CN. Messenger RNA enrichment using synthetic oligo(T) click nucleic acids. Chem Commun (Camb) 2020; 56:13987-13990. [PMID: 33094748 PMCID: PMC7891491 DOI: 10.1039/d0cc05815g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Enrichment of mRNA is a key step in a number of molecular biology techniques, particularly in the rapidly growing field of transcriptomics. Currently, mRNA is isolated using oligo(thymine) DNA (oligo(dT)) immobilized on solid supports, which binds to the poly(A) tail of mRNA to pull the mRNA out of solution through the use of magnets or centrifugal filters. Here, a simple method to isolate mRNA by complexing it with synthetic click nucleic acids (CNAs) is described. Oligo(T) CNA bound efficiently to mRNA, and because of the insolubility of CNA in water, >90% of mRNA was readily removed from solution using this method. Simple washing, buffer exchange, and heating steps enabled mRNA's enrichment from total RNA, with a yield of 3.1 ± 1.5% of the input total RNA by mass, comparable to the yield from commercially available mRNA enrichment beads. Further, the integrity and activity of mRNA after CNA-facilitated pulldown and release was evaluated through two assays. In vitro translation of EGFP mRNA confirmed the translatability of mRNA into functional protein and RT-qPCR was used to amplify enriched mRNA from total RNA extracts and compare gene expression to results obtained using commercially available products.
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Affiliation(s)
- Alex J Anderson
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303, USA.
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19
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Wilmoth RL, Ferguson VL, Bryant SJ. A 3D, Dynamically Loaded Hydrogel Model of the Osteochondral Unit to Study Osteocyte Mechanobiology. Adv Healthc Mater 2020; 9:e2001226. [PMID: 33073541 PMCID: PMC7677224 DOI: 10.1002/adhm.202001226] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/18/2020] [Indexed: 12/15/2022]
Abstract
Osteocytes are mechanosensitive cells that orchestrate signaling in bone and cartilage across the osteochondral unit. The mechanisms by which osteocytes regulate osteochondral homeostasis and degeneration in response to mechanical cues remain unclear. This study introduces a novel 3D hydrogel bilayer composite designed to support osteocyte differentiation and bone matrix deposition in a bone-like layer and to recapitulate key aspects of the osteochondral unit's complex loading environment. The bilayer hydrogel is fabricated with a soft cartilage-like layer overlaying a stiff bone-like layer. The bone-like layer contains a stiff 3D-printed hydrogel structure infilled with a soft, degradable, cellular hydrogel. The IDG-SW3 cells embedded within the soft hydrogel mature into osteocytes and produce a mineralized collagen matrix. Under dynamic compressive strains, near-physiological levels of strain are achieved in the bone layer (≤ 0.08%), while the cartilage layer bears the majority of the strains (>99%). Under loading, the model induces an osteocyte response, measured by prostaglandin E2, that is frequency, but not strain, dependent: a finding attributed to altered fluid flow within the composite. Overall, this new hydrogel platform provides a novel approach to study osteocyte mechanobiology in vitro in an osteochondral tissue-mimetic environment.
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Affiliation(s)
- Rachel L Wilmoth
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, CO, 80309-0427, USA
| | - Virginia L Ferguson
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, Boulder, CO, 80309-0427, USA
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80309-0596, USA
- Materials Science and Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, CO, 80309, USA
| | - Stephanie J Bryant
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80309-0596, USA
- Materials Science and Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, CO, 80309, USA
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Ave, Boulder, CO, 80309-0596, USA
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20
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Chu S, Maples MM, Bryant SJ. Cell encapsulation spatially alters crosslink density of poly(ethylene glycol) hydrogels formed from free-radical polymerizations. Acta Biomater 2020; 109:37-50. [PMID: 32268243 PMCID: PMC7649065 DOI: 10.1016/j.actbio.2020.03.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 03/10/2020] [Accepted: 03/24/2020] [Indexed: 11/26/2022]
Abstract
Photopolymerizable poly(ethylene glycol) (PEG) hydrogels are a promising platform for chondrocyte encapsulation and cartilage tissue engineering. This study demonstrates that during the process of encapsulation, chondrocytes alter the formation of PEG hydrogels leading to a reduction in the bulk and local hydrogel crosslink density. Freshly isolated chondrocytes were shown to interact with hydrogel precursors, in part through thiol-mediated events between dithiol crosslinkers and cell surface free thiols, depleting crosslinker concentration and causing a reduction in the bulk hydrogel crosslink density. This effect was more pronounced with increasing cell density at the time of encapsulation. Encapsulation of chondrocytes in fluorescently labeled hydrogels exhibited a gradient in hydrogel density around the cell, which was abrogated by treatment of the cells with the antioxidant estradiol prior to encapsulation. This gradient led to spatial variations in the degradation behavior of a hydrolytically degradable PEG hydrogel, creating regions devoid of hydrogel surrounding cells. Collectively, findings from this study indicate that the antioxidant defense mechanisms in chondrocytes alter the resultant properties of PEG hydrogels formed by free-radical polymerizations. These interactions will have a significant impact on tissue engineering, affecting the local microenvironment around cells and how tissue grows within the hydrogels. STATEMENT OF SIGNIFICANCE: Cell encapsulations in synthetic hydrogels formed by free-radical polymerizations offer numerous benefits for tissue engineering. Herein, we studied cartilage cells and identified that during encapsulation, cells interfered with hydrogel formation through two distinct mechanisms. Thiol-mediated events between monomers led to monomer depletion and a lower crosslinked hydrogel. Cells' antioxidant defense mechanisms interfered with free-radicals and inhibited hydrogel formation near the cell. These cell-mediated effects led to softer hydrogels and created unique hydrogel degradations patterns causing rapid degradation around the cells. The latter has benefits for tissue engineering, where these regions provide space for tissue growth. Overall, this study demonstrates that cells play a key role in how the hydrogel structure forms when cells are present.
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Affiliation(s)
- Stanley Chu
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, United States
| | - Mollie M Maples
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, United States; Materials Science and Engineering Program, University of Colorado, Boulder, CO, United States; Biofrontiers Institute, University of Colorado, Boulder, CO, United States.
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21
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Anderson AJ, Culver HR, Bryant SJ, Bowman CN. Viscoelastic and Thermoreversible Networks Crosslinked by Non-covalent Interactions Between "Clickable" Nucleic Acids Oligomers and DNA. Polym Chem 2020; 11:2959-2968. [PMID: 34992679 PMCID: PMC8729761 DOI: 10.1039/d0py00165a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2023]
Abstract
An approach to efficient and scalable production of oligonucleotide-based gel networks is presented. Specifically, a new class of xenonucleic acid (XNA) synthesized through a scalable and efficient thiol-ene polymerization mechanism, "Clickable" Nucleic Acids (CNAs), were conjugated to a multifunctional poly(ethylene glycol), PEG. In the presence of complementary single stranded DNA (ssDNA), the macromolecular conjugate assembled into a crosslinked 3D gel capable of achieving storage moduli on the order of 1 kPa. Binding studies between the PEG-CNA macromolecule and complementary ssDNA indicate that crosslinking is due to the CNA/DNA interaction. Gel formation was specific to the base sequence and length of the ssDNA crosslinker. The gels were fully thermoreversible, completely melting at temperatures above 60°C and re-forming upon cooling over multiple cycles and with no apparent hysteresis. Shear stress relaxation experiments revealed that relaxation dynamics are dependent on crosslinker length, which is hypothesized to be an effect of the polydisperse CNA chains. Arrhenius analysis of characteristic relaxation times was only possible for shorter crosslinker lengths, and the activation energy for these gels was determined to be 110 ± 20 kJ/mol. Overall, the present work demonstrates that CNA is capable of participating in stimuli-responsive interactions that would be expected from XNAs, and that these interactions support 3D gels that have potential uses in biological and materials science applications.
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Affiliation(s)
- Alex J Anderson
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303
| | - Heidi R Culver
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303
- Material Science and Engineering Program, University of Colorado, Boulder, CO 80303
- BioFrontiers Institute, University of Colorado, Boulder, CO 80303
| | - Christopher N Bowman
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80303
- Material Science and Engineering Program, University of Colorado, Boulder, CO 80303
- BioFrontiers Institute, University of Colorado, Boulder, CO 80303
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22
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Higgins CI, Killgore JP, DelRio FW, Bryant SJ, McLeod RR. Photo-tunable hydrogel mechanical heterogeneity informed by predictive transport kinetics model. Soft Matter 2020; 16:4131-4141. [PMID: 32202291 PMCID: PMC7489306 DOI: 10.1039/d0sm00052c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Understanding the three-dimensional (3D) mechanical and chemical properties of distinctly different, adjacent biological tissues is crucial to mimicking their complex properties with materials. 3D printing is a technique often employed to spatially control the distribution of the biomaterials, such as hydrogels, of interest, but it is difficult to print both mechanically robust (high modulus and toughness) and biocompatible (low modulus) hydrogels in a single structure. Moreover, due to the fast diffusion of mobile species during printing and nonequilibrium swelling conditions of low-solids-content hydrogels, it is challenging to form the high-fidelity structures required to mimic tissues. Here a predictive transport and swelling model is presented to model these effects and then is used to compensate for these effects during printing. This model is validated experimentally by photopatterning spatially distinct hydrogel elastic moduli using a single photo-tunable poly(ethylene glycol) (PEG) pre-polymer solution by sequentially patterning and in-diffusing fresh pre-polymer for further polymerization.
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Affiliation(s)
- Callie I Higgins
- Applied Chemicals and Materials Division, Material Measurement Laboratory, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.
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23
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Schneider MC, Lalitha Sridhar S, Vernerey FJ, Bryant SJ. Spatiotemporal neocartilage growth in matrix-metalloproteinase-sensitive poly(ethylene glycol) hydrogels under dynamic compressive loading: an experimental and computational approach. J Mater Chem B 2020; 8:2775-2791. [PMID: 32155233 PMCID: PMC7695218 DOI: 10.1039/c9tb02963j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Enzyme-sensitive hydrogels containing encapsulated chondrocytes are a promising platform for cartilage tissue engineering. However, the growth of neotissue is closely coupled to the degradation of the hydrogel and is further complicated due to the encapsulated cells serving as the enzyme source for hydrogel degradation. To better understand these coupled processes, this study combined experimental and computational methods to analyze the transition from hydrogel to neotissue in a biomimetic MMP-sensitive poly(ethylene glycol) (PEG) hydrogel with encapsulated chondrocytes. A physics-based computational model that describes spatial heterogeneities in cell distribution was used. Experimentally, cell-laden hydrogels were cultured for six weeks under free swelling or subjected daily to one-hour of dynamic compressive loading. Extracellular matrix (ECM) synthesis rates were used as model inputs, and the model was fit to the experimentally determined construct modulus over time for the free swelling condition. Experimentally, ECM accumulation comprising collagen II and aggrecan increased over time concomitant with hydrogel degradation observed by a loss in PEG. Simulations demonstrated rapid degradation in regions of high cell density (i.e., cell clusters) reaching complete degradation by day 13, which facilitated localized ECM growth. Regions of low cell density degraded more slowly, had limited ECM, and led to the decrease in construct modulus during the first two weeks. The primary difference between the two culture environments was greater ECM accumulation in the clusters under free swelling, which facilitated a faster recovery in construct modulus. By 6 weeks the compressive modulus increased 2.5-fold to 107 kPa under free swelling, but dropped 1.6-fold to 26 kPa under loading. In summary, this biomimetic MMP-sensitive hydrogel supports neocartilage growth by facilitating rapid ECM growth within cell clusters, which was followed by slower growth in the rest of the hydrogel. Subtle temporal differences in hydrogel degradation and ECM accumulation, however, had a significant impact on the evolving mechanical properties.
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Affiliation(s)
- Margaret C Schneider
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave., Boulder, Colorado 80309-0596, USA.
| | - Shankar Lalitha Sridhar
- Department of Mechanical Engineering, University of Colorado, 1111 Engineering Dr., Boulder, Colorado 80309-0596, USA.
| | - Franck J Vernerey
- Department of Mechanical Engineering, University of Colorado, 1111 Engineering Dr., Boulder, Colorado 80309-0596, USA. and Materials Science and Engineering Program, University of Colorado, 3415 Colorado Ave., Boulder, Colorado 80309-0596, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave., Boulder, Colorado 80309-0596, USA. and Materials Science and Engineering Program, University of Colorado, 3415 Colorado Ave., Boulder, Colorado 80309-0596, USA and Biofrontiers Institute, University of Colorado, 3415 Colorado Ave., Boulder, Colorado 80309-0596, USA
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24
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Aisenbrey EA, Bilousova G, Payne K, Bryant SJ. Dynamic mechanical loading and growth factors influence chondrogenesis of induced pluripotent mesenchymal progenitor cells in a cartilage-mimetic hydrogel. Biomater Sci 2020; 7:5388-5403. [PMID: 31626251 DOI: 10.1039/c9bm01081e] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human induced pluripotent stem cells (iPSCs) have emerged as a promising alternative to bone-marrow derived mesenchymal stem/stromal cells for cartilage tissue engineering. However, the effect of biochemical and mechanical cues on iPSC chondrogenesis remains understudied. This study evaluated chondrogenesis of induced pluripotent mesenchymal progenitor cells (iPS-MPs) encapsulated in a cartilage-mimetic hydrogel under different culture conditions: free swelling versus dynamic compressive loading and different growth factors (TGFβ3 and/or BMP2). Human iPSCs were differentiated into iPS-MPs and chondrogenesis was evaluated by gene expression (qPCR) and protein expression (immunohistochemistry) after three weeks. In pellet culture, both TGFβ3 and BMP2 were required to promote chondrogenesis. However, the hydrogel in growth factor-free conditions promoted chondrogenesis, but rapidly progressed to hypertrophy. Dynamic loading in growth factor-free conditions supported chondrogenesis, but delayed the transition to hypertrophy. Findings were similar with TGFβ3, BMP2, and TGFβ3 + BMP2. Dynamic loading with TGFβ3, regardless of BMP2, was the only condition that promoted a stable chondrogenic phenotype (aggrecan + collagen II) accompanied by collagen X down-regulation. Positive TGFβRI expression with load-enhanced Smad2/3 signaling and low SMAD1/5/8 signaling was observed. In summary, this study reports a promising cartilage-mimetic hydrogel for iPS-MPs that when combined with appropriate biochemical and mechanical cues induces a stable chondrogenic phenotype.
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Affiliation(s)
- Elizabeth A Aisenbrey
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, 3415 Colorado Ave, Boulder, CO 80309, USA.
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25
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Ding Y, Johnson R, Sharma S, Ding X, Bryant SJ, Tan W. Tethering transforming growth factor β1 to soft hydrogels guides vascular smooth muscle commitment from human mesenchymal stem cells. Acta Biomater 2020; 105:68-77. [PMID: 31982589 DOI: 10.1016/j.actbio.2020.01.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 01/10/2020] [Accepted: 01/21/2020] [Indexed: 12/15/2022]
Abstract
Mesenchymal stem cells (MSCs) hold great promise for vascular smooth muscle regeneration. However, most studies have mainly relied on extended supplementation of sophisticated biochemical regimen to drive MSC differentiation towards vascular smooth muscle cells (vSMCs). Herein we demonstrate a concomitant method that exploits the advantages of biomimetic matrix stiffness and tethered transforming growth factor β1 (TGF-β1) to guide vSMC commitment from human MSCs. Our designed poly(ethylene glycol) hydrogels, presenting a biomimetic stiffness and tethered TGF-β1, provide an instructive environment to potently upregulate smooth muscle marker expression in vitro and in vivo. Importantly, it significantly enhances the functional contractility of vSMCs derived from MSCs within 3 days. Interestingly, compared to non-tethered one, tethered TGF-β1 enhanced the potency of vSMC commitment on hydrogels. We provide compelling evidence that combining stiffness and tethered TGF-β1 on poly(ethylene glycol) hydrogels can be a promising approach to drastically enhance maturation and function of vSMCs from stem cell differentiation in vitro and in vivo. STATEMENT OF SIGNIFICANCE: A fast, reliable and safe regeneration of vascular smooth muscle cells (vSMCs) from stem cell differentiation is promising for vascular tissue engineering and regenerative medicine applications, but remains challenging. Herein, a photo-click hydrogel platform is devised to recapitulate the stiffness of vascular tissue and appropriate presentation of transforming growth factor β1 (TGF-β1) to guide vSMC commitment from mesenchymal stem cells (MSCs). We demonstrate that such concomitant method drastically enhanced regeneration of mature, functional vSMCs from MSCs in vitro and in vivo within only a 3-days span. This work is not only of fundamental scientific importance, revealing how physiochemical factors and the manner of their presentation direct stem cell differentiation, but also attacks the long-standing difficulty in regenerating highly functional vSMCs within a short period.
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26
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Aziz AH, Wilmoth RL, Ferguson VL, Bryant SJ. IDG-SW3 Osteocyte Differentiation and Bone Extracellular Matrix Deposition Are Enhanced in a 3D Matrix Metalloproteinase-Sensitive Hydrogel. ACS Appl Bio Mater 2020; 3:1666-1680. [PMID: 32719827 DOI: 10.1021/acsabm.9b01227] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Osteocytes reside within a heavily mineralized matrix making them difficult to study in vivo and to extract for studies in vitro. IDG-SW3 cells are capable of producing mineralized collagen matrix and transitioning from osteoblasts to mature osteocytes, thus offering an alternative to study osteoblast to late osteocyte differentiation in vitro. The goal for this work was to develop a 3D degradable hydrogel to support IDG-SW3 differentiation and deposition of bone ECM. In 2D, the genes Mmp2 and Mmp13 increased during IDG-SW3 differentiation and were used as targets to create a MMP-sensitive poly(ethylene glycol) hydrogel containing the peptide crosslink GCGPLG-LWARCG and RGD to promote cell attachment. IDG-SW3 differentiation in the MMP-sensitive hydrogels improved over non-degradable hydrogels and standard 2D culture. Alkaline phosphatase activity at day 14 was higher, Dmp1 and Phex were 8.1-fold and 3.8-fold higher, respectively, and DMP1 protein expression was more pronounced in the MMP-sensitive hydrogels compared to non-degradable hydrogels. Cell-encapsulation density (cells/ml precursor) influenced formation of dendrite-like cellular process and mineral and collagen deposition with 80×106 performing better than 2×106 or 20×106, while connexin 43 was not affected by cell density. The cell density effects were more pronounced in the MMP-sensitive hydrogels over non-degradable hydrogels. This study identified that high cell encapsulation density and a hydrogel susceptible to cell-mediated degradation enhanced mineralized collagen matrix and osteocyte differentiation. Overall, a promising hydrogel is presented that supports IDG-SW3 cell maturation from osteoblasts to osteocytes in 3D.
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Affiliation(s)
- Aaron H Aziz
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO USA.,BioFrontiers Institute, University of Colorado, Boulder, CO 80309 USA
| | - Rachel L Wilmoth
- Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309 USA
| | - Virginia L Ferguson
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309 USA.,Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309 USA.,Material Science and Engineering, University of Colorado, Boulder, CO 80309 USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO USA.,BioFrontiers Institute, University of Colorado, Boulder, CO 80309 USA.,Material Science and Engineering, University of Colorado, Boulder, CO 80309 USA
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27
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Saleh LS, Vanderheyden C, Frederickson A, Bryant SJ. Prostaglandin E2 and Its Receptor EP2 Modulate Macrophage Activation and Fusion in Vitro. ACS Biomater Sci Eng 2020; 6:2668-2681. [PMID: 33463295 DOI: 10.1021/acsbiomaterials.9b01180] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The foreign body response (FBR) has impaired progress of new implantable medical devices through its hallmark of chronic inflammation and foreign body giant cell (FBGC) formation leading to fibrous encapsulation. Macrophages are known to drive the FBR, but efforts to control macrophage polarization remain challenging. The goal for this study was to investigate whether prostaglandin E2 (PGE2), and specifically its receptors EP2 and/or EP4, attenuate classically activated (i.e., inflammatory) macrophages and macrophage fusion into FBGCs in vitro. Lipopolysaccharide (LPS)-stimulated macrophages exhibited a dose-dependent decrease in gene expression and protein production of tumor necrosis factor alpha (TNF-α) when treated with PGE2. This attenuation was primarily by the EP4 receptor, as the addition of the EP2 antagonist PF 04418948 to PGE2-treated LPS-stimulated cells did not recover TNF-α production while the EP4 antagonist ONO AE3 208 did. However, direct stimulation of EP2 with the agonist butaprost to LPS-stimulated macrophages resulted in a ∼60% decrease in TNF-α secretion after 4 h and corresponded with an increase in gene expression for Cebpb and Il10, suggesting a polarization shift toward alternative activation through EP2 alone. Further, fusion of macrophages into FBGCs induced by interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) was inhibited by PGE2 via EP2 signaling and by an EP2 agonist, but not an EP4 agonist. The attenuation by PGE2 was confirmed to be primarily by the EP2 receptor. Mrc1, Dcstamp, and Retlna expressions increased upon IL-4/GM-CSF stimulation, but only Retnla expression with the EP2 agonist returned to levels that were not different from controls. This study identified that PGE2 attenuates classically activated macrophages and macrophage fusion through distinct EP receptors, while targeting EP2 is able to attenuate both. In summary, this study identified EP2 as a potential therapeutic target for reducing the FBR to biomaterials.
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Affiliation(s)
- Leila S Saleh
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80309, United States
| | - Casey Vanderheyden
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80309, United States
| | - Andrew Frederickson
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80309, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80309, United States.,BioFrontiers Institute, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80309, United States.,Material Science and Engineering Program, University of Colorado, 3415 Colorado Avenue, Boulder, Colorado 80309, United States
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28
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Richardson BM, Walker CJ, Macdougall LJ, Hoye JW, Randolph MA, Bryant SJ, Anseth KS. Viscoelasticity of hydrazone crosslinked poly(ethylene glycol) hydrogels directs chondrocyte morphology during mechanical deformation. Biomater Sci 2020; 8:3804-3811. [DOI: 10.1039/d0bm00860e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Adaptable dynamic covalent crosslinks temporally modulate the biophysical transmission of physiologically relevant compressive strains to encapsulated chondrocytes for cartilage tissue engineering.
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Affiliation(s)
- Benjamin M. Richardson
- Department of Chemical and Biological Engineering
- University of Colorado Boulder
- Boulder
- USA
- The BioFrontiers Institute
| | - Cierra J. Walker
- The BioFrontiers Institute
- University of Colorado Boulder
- Boulder
- USA
- Materials Science and Engineering Program
| | | | - Jack W. Hoye
- Department of Chemical and Biological Engineering
- University of Colorado Boulder
- Boulder
- USA
| | - Mark A. Randolph
- Department of Orthopedic Surgery
- Massachusetts General Hospital
- Harvard Medical School
- Boston
- USA
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering
- University of Colorado Boulder
- Boulder
- USA
- The BioFrontiers Institute
| | - Kristi S. Anseth
- Department of Chemical and Biological Engineering
- University of Colorado Boulder
- Boulder
- USA
- The BioFrontiers Institute
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29
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Amer LD, Saleh LS, Walker C, Thomas S, Janssen WJ, Alper S, Bryant SJ. Inflammation via myeloid differentiation primary response gene 88 signaling mediates the fibrotic response to implantable synthetic poly(ethylene glycol) hydrogels. Acta Biomater 2019; 100:105-117. [PMID: 31568879 DOI: 10.1016/j.actbio.2019.09.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/20/2019] [Accepted: 09/26/2019] [Indexed: 12/19/2022]
Abstract
Synthetic hydrogels, such as poly(ethylene glycol) (PEG), are promising for a range of in vivo applications. However, like all non-biological biomaterials, synthetic hydrogels including PEG elicit a foreign body response (FBR). The FBR is thought to be initiated by adsorbed protein that is recognized by and subsequently activates inflammatory cells, notably macrophages, and culminates with fibrotic encapsulation. However, the molecular mechanisms that drive the FBR are not well understood. Toll-like receptors (TLRs) are key receptors that recognize pathogens, but also recognize altered host proteins that display damage-associated molecular patterns (DAMPs). Thus TLRs may play a role in the FBR. Here, we investigated myeloid differentiation primary response gene 88 (MyD88), a signaling adaptor protein that mediates inflammatory cytokine production induced by most TLRs. An in vitro model was used consisting of macrophages cultured on the surface of synthetic hydrogels, specifically PEG, with pre-adsorbed serum proteins. Our in vitro findings demonstrate that MyD88-dependent signaling is the predominant inflammatory pathway in macrophage activation to synthetic hydrogels. When stimulated with TLR agonists to mimic additional DAMPs present in vivo, MyD88-dependent signaling was also the predominant pathway in macrophage activation. An in vivo model of PEG hydrogels implanted subcutaneously in wild-type and MyD88-/- mice also demonstrated that MyD88 is the key contributor to the recruitment of inflammatory cells and formation of the fibrous capsule surrounding the implanted hydrogel. Taken together, findings from this study identify MyD88-mediated inflammation as being a critical pathway involved not only in the inflammatory response, but in formation of the fibrous capsule to PEG hydrogels. STATEMENT OF SIGNIFICANCE: Synthetic hydrogels are promising for in vivo applications but, like all non-biological biomaterials, synthetic hydrogels elicit a foreign body response (FBR). The molecular mechanisms that drive the FBR are not well understood. This work identifies the myeloid differentiation primary response gene 88 (MyD88) as a central mediator to macrophage activation in response to a poly(ethylene glycol) hydrogel with pre-adsorbed proteins in vitro. Moreover, MyD88 was also central to the recruitment of inflammatory cells, which included neutrophils, monocytes, and macrophages, to implanted PEG hydrogels and to fibrous encapsulation. These findings demonstrate that MyD88-mediated inflammation is responsible in part for the formation of the fibrous capsule of the FBR.
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Affiliation(s)
- Luke D Amer
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309, United States; BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States
| | - Leila S Saleh
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309, United States
| | - Cierra Walker
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States; Material Science and Engineering Program, University of Colorado, Boulder, CO 80309, United States
| | - Stacey Thomas
- Division of Pulmonary, Sleep and Critical Care Medicine, National Jewish Health, Denver, CO 80206, United States
| | - William J Janssen
- Division of Pulmonary, Sleep and Critical Care Medicine, National Jewish Health, Denver, CO 80206, United States; Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, United States
| | - Scott Alper
- Department of Biomedical Research and Center for Genes, Environment and Health, National Jewish Health, Denver, CO 80206, United States; Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309, United States; BioFrontiers Institute, University of Colorado, Boulder, CO 80309, United States; Material Science and Engineering Program, University of Colorado, Boulder, CO 80309, United States.
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30
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Muralidharan A, Uzcategui AC, McLeod RR, Bryant SJ. Stereolithographic 3D Printing for Deterministic Control over Integration in Dual-Material Composites. Adv Mater Technol 2019; 4:1900592. [PMID: 33043126 PMCID: PMC7546532 DOI: 10.1002/admt.201900592] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Indexed: 05/20/2023]
Abstract
This work introduces a rapid and facile approach to predictably control integration between two materials with divergent properties. Programmed integration between photopolymerizable soft and stiff hydrogels was investigated for their promise in applications such as tissue engineering where heterogeneous properties are often desired. Spatial control afforded by grayscale 3D printing was leveraged to define regions at the interface that permit diffusive transport of a second material in-filled into the 3D printed part. The printing parameters (i.e., effective exposure dose) for the resin were correlated directly to mesh size to achieve controlled diffusion. Applying this information to grayscale exposures led to a range of distances over which integration was achieved with high fidelity. A prescribed finite distance of integration between soft and stiff hydrogels led to a 33% increase in strain to failure under tensile testing and eliminated failure at the interface. The feasibility of this approach was demonstrated in a layer-by-layer 3D printed part fabricated by stereolithography, which was subsequently infilled with a soft hydrogel containing osteoblastic cells. In summary, this approach holds promise for applications where integration of multiple materials and living cells is needed by allowing precise control over integration and reducing mechanical failure at contrasting material interfaces.
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Affiliation(s)
- Archish Muralidharan
- Materials Science and Engineering Program, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Asais C. Uzcategui
- Materials Science and Engineering Program, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Robert R. McLeod
- Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA
- Materials Science and Engineering Program, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Boulder, CO 80309, USA
- Materials Science and Engineering Program, University of Colorado, Boulder, USA, Boulder, CO 80309, USA
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31
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Yu Y, Rodriguez-Fontan F, Eckstein K, Muralidharan A, Uzcategui AC, Fuchs JR, Weatherford S, Erickson CB, Bryant SJ, Ferguson VL, Hadley Miller N, Li G, Payne KA. Rabbit Model of Physeal Injury for the Evaluation of Regenerative Medicine Approaches. Tissue Eng Part C Methods 2019; 25:701-710. [PMID: 31552802 DOI: 10.1089/ten.tec.2019.0180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Physeal injuries can lead to bony repair tissue formation, known as a bony bar. This can result in growth arrest or angular deformity, which is devastating for children who have not yet reached their full height. Current clinical treatment involves resecting the bony bar and replacing it with a fat graft to prevent further bone formation and growth disturbance, but these treatments frequently fail to do so and require additional interventions. Novel treatments that could prevent bone formation but also regenerate the injured physeal cartilage and restore normal bone elongation are warranted. To test the efficacy of these treatments, animal models that emulate human physeal injury are necessary. The rabbit model of physeal injury quickly establishes a bony bar, which can then be resected to test new treatments. Although numerous rabbit models have been reported, they vary in terms of size and location of the injury, tools used to create the injury, and methods to assess the repair tissue, making comparisons between studies difficult. The study presented here provides a detailed method to create a rabbit model of proximal tibia physeal injury using a two-stage procedure. The first procedure involves unilateral removal of 25% of the physis in a 6-week-old New Zealand white rabbit. This consistently leads to a bony bar, significant limb length discrepancy, and angular deformity within 3 weeks. The second surgical procedure involves bony bar resection and treatment. In this study, we tested the implantation of a fat graft and a photopolymerizable hydrogel as a proof of concept that injectable materials could be delivered into this type of injury. At 8 weeks post-treatment, we measured limb length, tibial angle, and performed imaging and histology of the repair tissue. By providing a detailed, easy to reproduce methodology to perform the physeal injury and test novel treatments after bony bar resection, comparisons between studies can be made and facilitate translation of promising therapies toward clinical use. Impact Statement This study provides details to create a rabbit model of physeal injury that can facilitate comparisons between studies and test novel regenerative medicine approaches. Furthermore, this model mimics the human, clinical situation that requires a bony bar resection followed by treatment. In addition, identification of a suitable treatment can be seen in the correction of the growth deformity, allowing this model to facilitate the development of novel physeal cartilage regenerative medicine approaches.
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Affiliation(s)
- Yangyi Yu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | | | - Kevin Eckstein
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado
| | - Archish Muralidharan
- Material Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado
| | - Asais Camila Uzcategui
- Material Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado
| | - Joseph R Fuchs
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Shane Weatherford
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Christopher B Erickson
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Stephanie J Bryant
- Material Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado.,Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado.,BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado
| | - Virginia L Ferguson
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado.,Material Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado.,BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado
| | - Nancy Hadley Miller
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Guangheng Li
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Karin A Payne
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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Faulón Marruecos D, Saleh LS, Kim HH, Bryant SJ, Schwartz DK, Kaar JL. Stabilization of Fibronectin by Random Copolymer Brushes Inhibits Macrophage Activation. ACS Appl Bio Mater 2019; 2:4698-4702. [DOI: 10.1021/acsabm.9b00815] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Schneider MC, Chu S, Randolph MA, Bryant SJ. An in vitro and in vivo comparison of cartilage growth in chondrocyte-laden matrix metalloproteinase-sensitive poly(ethylene glycol) hydrogels with localized transforming growth factor β3. Acta Biomater 2019; 93:97-110. [PMID: 30914256 DOI: 10.1016/j.actbio.2019.03.046] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 03/20/2019] [Accepted: 03/21/2019] [Indexed: 12/25/2022]
Abstract
While matrix-assisted autologous chondrocyte implantation has emerged as a promising therapy to treat focal chondral defects, matrices that support regeneration of hyaline cartilage remain challenging. The goal of this work was to investigate the potential of a matrix metalloproteinase (MMP)-sensitive poly(ethylene glycol) (PEG) hydrogel containing the tethered growth factor, transforming growth factor β3 (TGF-β3), and compare cartilage regeneration in vitro and in vivo. The in vitro environment comprised chemically-defined medium while the in vivo environment utilized the subcutaneous implant model in athymic mice. Porcine chondrocytes were isolated and expanded in 2D culture for 10 days prior to encapsulation. The presence of tethered TGF-β3 reduced cell spreading. Chondrocyte-laden hydrogels were analyzed for total sulfated glycosaminoglycan and collagen contents, MMP activity, and spatial deposition of aggrecan, decorin, biglycan, and collagens type II and I. The total amount of extracellular matrix (ECM) deposited in the hydrogel constructs was similar in vitro and in vivo. However, the in vitro environment was not able to support long-term culture up to 64 days of the engineered cartilage leading to the eventual breakdown of aggrecan. The in vivo environment, on the other hand, led to more elaborate ECM, which correlated with higher MMP activity, and an overall higher quality of engineered tissue that was rich in aggrecan, decorin, biglycan and collagen type II with minimal collagen type I. Overall, the MMP-sensitive PEG hydrogel containing tethered TGF-β3 is a promising matrix for hyaline cartilage regeneration in vivo. STATEMENT OF SIGNIFICANCE: Regenerating hyaline cartilage remains a significant clinical challenge. The resultant repair tissue is often fibrocartilage, which long-term cannot be sustained. The goal of this study was to investigate the potential of a synthetic hydrogel matrix containing peptide crosslinks that can be degraded by enzymes secreted by encapsulated cartilage cells (i.e., chondrocytes) and tethered growth factors, specifically TGF-β3, to provide localized chondrogenic cues to the cells. This hydrogel led to hyaline cartilage-like tissue growth in vitro and in vivo, with minimal formation of fibrocartilage. However, the tissue formed in vitro, could not be maintained long-term. In vivo this hydrogel shows great promise as a potential matrix for use in regenerating hyaline cartilage.
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Aisenbrey EA, Tomaschke AA, Schoonraad SA, Fischenich KM, Wahlquist JA, Randolph MA, Ferguson VL, Bryant SJ. Assessment and prevention of cartilage degeneration surrounding a focal chondral defect in the porcine model. Biochem Biophys Res Commun 2019; 514:940-945. [PMID: 31088681 DOI: 10.1016/j.bbrc.2019.05.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 05/04/2019] [Indexed: 10/26/2022]
Abstract
Focal defects in articular cartilage are unable to self-repair and, if left untreated, are a leading risk factor for osteoarthritis. This study examined cartilage degeneration surrounding a defect and then assessed whether infilling the defect prevents degeneration. We created a focal chondral defect in porcine osteochondral explants and cultured them ex vivo with and without dynamic compressive loading to decouple the role of loading. When compared to a defect in a porcine knee four weeks post-injury, this model captured loss in sulfated glycosaminoglycans (sGAGs) along the defect's edge that was observed in vivo, but this loss was not load dependent. Loading, however, reduced the indentation modulus of the surrounding cartilage. After infilling with in situ polymerized hydrogels that were soft (100 kPa) or stiff (1 MPa) and which produced swelling pressures of 13 and 310 kPa, respectively, sGAG loss was reduced. This reduction correlated with increased hydrogel stiffness and swelling pressure, but was not affected by loading. This ex vivo model recapitulates sGAG loss surrounding a defect and, when infilled with a mechanically supportive hydrogel, degeneration is minimized.
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Affiliation(s)
- Elizabeth A Aisenbrey
- Department of Chemical and Biological Engineering, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Andrew A Tomaschke
- Department of Mechanical Engineering, 1111 Engineering Dr, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Sarah A Schoonraad
- Materials Science and Engineering Program, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Kristine M Fischenich
- Department of Mechanical Engineering, 1111 Engineering Dr, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Joseph A Wahlquist
- Department of Mechanical Engineering, 1111 Engineering Dr, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Mark A Randolph
- Department of Orthopaedic Surgery, Laboratory for Musculoskeletal Tissue Engineering, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Virginia L Ferguson
- Department of Mechanical Engineering, 1111 Engineering Dr, University of Colorado at Boulder, Boulder, CO, 80309, USA; Materials Science and Engineering Program, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA; BioFrontiers Institute, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA; Materials Science and Engineering Program, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA; BioFrontiers Institute, 3415 Colorado Ave, University of Colorado at Boulder, Boulder, CO, 80309, USA.
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Aziz AH, Eckstein K, Ferguson VL, Bryant SJ. The effects of dynamic compressive loading on human mesenchymal stem cell osteogenesis in the stiff layer of a bilayer hydrogel. J Tissue Eng Regen Med 2019; 13:946-959. [PMID: 30793536 DOI: 10.1002/term.2827] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 11/26/2018] [Accepted: 02/13/2019] [Indexed: 02/05/2023]
Abstract
Bilayer hydrogels with a soft cartilage-like layer and a stiff bone-like layer embedded with human mesenchymal stem cells (hMSCs) are promising for osteochondral tissue engineering. The goals of this work were to evaluate the effects of dynamic compressive loading (2.5% applied strain, 1 Hz) on osteogenesis in the stiff layer and spatially map local mechanical responses (strain, stress, hydrostatic pressure, and fluid velocity). A bilayer hydrogel was fabricated from soft (24 kPa) and stiff (124 kPa) poly (ethylene glycol) hydrogels. With hMSCs embedded in the stiff layer, osteogenesis was delayed under loading evident by lower OSX and OPN expressions, alkaline phosphatase activity, and collagen content. At Day 28, mineral deposits were present throughout the stiff layer without loading but localized centrally and near the interface under loading. Local strains mapped by particle tracking showed substantial equivalent strain (~1.5%) transferring to the stiff layer. When hMSCs were cultured in stiff single-layer hydrogels subjected to similar strains, mineralization was inhibited. Finite element analysis revealed that hydrostatic pressures ≥~600 Pa correlated to regions lacking mineralization in both hydrogels. Fluid velocities were low (~1-10 nm/s) in the hydrogels with no apparent correlation to mineralization. Mineralization was recovered by inhibiting ERK1/2, indicating cell-mediated inhibition. These findings suggest that high strains (~1.5%) combined with higher hydrostatic pressures negatively impact osteogenesis, but in a manner that depends on the magnitude of each mechanical response. This work highlights the importance of local mechanical responses in mediating osteogenesis of hMSCs in bilayer hydrogels being studied for osteochondral tissue engineering.
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Affiliation(s)
- Aaron H Aziz
- Chemical and Biological Engineering, University of Colorado, Boulder, Colorado.,BioFrontiers Institute, University of Colorado, Boulder, Colorado
| | - Kevin Eckstein
- Mechanical Engineering, University of Colorado, Boulder, Colorado
| | - Virginia L Ferguson
- BioFrontiers Institute, University of Colorado, Boulder, Colorado.,Mechanical Engineering, University of Colorado, Boulder, Colorado.,Material Science and Engineering, University of Colorado, Boulder, Colorado
| | - Stephanie J Bryant
- Chemical and Biological Engineering, University of Colorado, Boulder, Colorado.,BioFrontiers Institute, University of Colorado, Boulder, Colorado.,Material Science and Engineering, University of Colorado, Boulder, Colorado
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Aziz AH, Bryant SJ. A comparison of human mesenchymal stem cell osteogenesis in poly(ethylene glycol) hydrogels as a function of MMP-sensitive crosslinker and crosslink density in chemically defined medium. Biotechnol Bioeng 2019; 116:1523-1536. [PMID: 30776309 DOI: 10.1002/bit.26957] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/28/2018] [Accepted: 02/14/2019] [Indexed: 12/13/2022]
Abstract
This study investigated osteogenesis of human mesenchymal stem cells encapsulated in matrix-metalloproteinase (MMP)-sensitive poly(ethylene glycol) (PEG) hydrogels in chemically defined medium (10 ng/ml bone morphogenic factor-2). Thiol-norbornene photoclick hydrogels were formed with CRGDS and crosslinkers of PEG dithiol (nondegradable), CVPLS-LYSGC (P1) or CRGRIGF-LRTDC (P2; dash indicates cleavage site) at two crosslink densities. Exogenous MMP-2 degraded P1 and P2 hydrogels similarly. MMP-14 degraded P1 hydrogels more rapidly than P2 hydrogels. Cell spreading was greatest in P1 low crosslinked hydrogels and to a lesser degree in P2 low crosslinked hydrogels, but not evident in nondegradable and high crosslinked MMP-sensitive hydrogels. Early osteogenesis (Alkaline phosphatase [ALP] activity) was accelerated in hydrogels that facilitated cell spreading. Contrarily, late osteogenesis (mineralization) was independent of cell spreading. Mineralized matrix was present in P1 hydrogels, but only present in P2 high crosslinked hydrogels and not yet present in nondegradable hydrogels. Overall, the low crosslinked P1 hydrogels exhibited an accelerated early and late osteogenesis with the highest ALP activity (Day 7), greatest calcium content (Day 14), and greatest collagen content (Day 28), concomitant with increased compressive modulus over time. Collectively, this study demonstrates that in chemically defined medium, hydrogel degradability is critical to accelerating early osteogenesis, but other factors are important in late osteogenesis.
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Affiliation(s)
- Aaron H Aziz
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado.,BioFrontiers Institute, University of Colorado, Boulder, Colorado
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado.,BioFrontiers Institute, University of Colorado, Boulder, Colorado.,Material Science and Engineering, University of Colorado, Boulder, Colorado
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Pascual-Garrido C, Aisenbrey EA, Rodriguez-Fontan F, Payne KA, Bryant SJ, Goodrich LR. Photopolymerizable Injectable Cartilage Mimetic Hydrogel for the Treatment of Focal Chondral Lesions: A Proof of Concept Study in a Rabbit Animal Model. Am J Sports Med 2019; 47:212-221. [PMID: 30481048 DOI: 10.1177/0363546518808012] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND In this study, we investigate the in vitro and in vivo chondrogenic capacity of a novel photopolymerizable cartilage mimetic hydrogel, enhanced with extracellular matrix analogs, for cartilage regeneration. PURPOSE To (1) determine whether mesenchymal stem cells (MSCs) embedded in a novel cartilage mimetic hydrogel support in vitro chondrogenesis, (2) demonstrate that the proposed hydrogel can be delivered in situ in a critical chondral defect in a rabbit model, and (3) determine whether the hydrogel with or without MSCs supports in vivo chondrogenesis in a critical chondral defect. STUDY DESIGN Controlled laboratory study. METHODS Rabbit bone marrow-derived MSCs were isolated, expanded, encapsulated in the hydrogel, and cultured in chondrogenic differentiation medium for 9 weeks. Compressive modulus was evaluated at day 1 and at weeks 3, 6, and 9. Chondrogenic differentiation was investigated via quantitative polymerase reaction, safranin-O staining, and immunofluorescence. In vivo, a 3 mm-wide × 2-mm-deep chondral defect was created bilaterally on the knee trochlea of 10 rabbits. Each animal had 1 defect randomly assigned to be treated with hydrogel with or without MSCs, and the contralateral knee was left untreated. Hence, each rabbit served as its own matched control. Three groups were established: group A, hydrogel (n = 5); group B, hydrogel with MSCs (n = 5); and group C, control (n = 10). Repair tissue was evaluated at 6 months after intervention. RESULTS In vitro, chondrogenesis and the degradable behavior of the hydrogel by MSCs were confirmed. In vivo, the hydrogel could be delivered intraoperatively in a sterile manner. Overall, the hydrogel group had the highest scores on the modified O'Driscoll scoring system (group A, 17.4 ± 4.7; group B, 13 ± 3; group C, 16.7 ± 2.9) ( P = .11) and showed higher safranin-O staining (group A, 49.4% ± 20%; group B, 25.8% ± 16.4%; group C, 36.9% ± 25.2%) ( P = .27), although significance was not detected for either parameter. CONCLUSION This study provides the first evidence of the ability to photopolymerize this novel hydrogel in situ and assess its ability to provide chondrogenic cues for cartilage repair in a small animal model. In vitro chondrogenesis was evident when MSCs were encapsulated in the hydrogel. CLINICAL RELEVANCE Cartilage mimetic hydrogel may offer a tissue engineering approach for the treatment of osteochondral lesions.
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Affiliation(s)
- Cecilia Pascual-Garrido
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Elizabeth A Aisenbrey
- Department of Chemical & Biological Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | | | - Karin A Payne
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Stephanie J Bryant
- Department of Chemical & Biological Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | - Laurie R Goodrich
- Department of Clinical Sciences and Orthopaedic Research Center, Colorado State University, Fort Collins, Colorado, USA
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Uzcategui AC, Muralidharan A, Ferguson VL, Bryant SJ, McLeod RR. Understanding and Improving Mechanical Properties in 3D printed Parts Using a Dual-Cure Acrylate-Based Resin for Stereolithography. Adv Eng Mater 2018; 20:1800876. [PMID: 30766445 PMCID: PMC6370025 DOI: 10.1002/adem.201800876] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Indexed: 05/20/2023]
Abstract
Application of 3D printed structures via stereolithography (SLA) is limited by imprecise dimensional control and inferior mechanical properties. These challenges is attributed to poor understanding ofpolymerization behavior during the printing process and inadequate post-processing methods. The former via a modified version of Jacob's working curve equation that incorporates the resin's sub-linear response to irradiation intensity is addressed by the authors. This new model provides a more accurate approach to select 3D printing parameters given a desired z-resolution and conversion profile along the depth of the printed part. The authors use this improved model to motivate a novel material design that can be post-processed to be indistinguishable from the polymer at 100% conversion. This approach employs a dual initiating system in which photo-initiated printing is followed by a thermal post-cure to achieve uniform conversion. The authors show that this approach enables fast printing times (10 s per layer), exceptional horizontal resolution (1-10 microns), precise control over vertical resolution, and decreased surface corrugations on a 10's of microns scale. The techniques described herein use an acrylate-based SLA resin, but the approach can be extended to other monomer systems to simultaneously achieve predictable properties and dimensions that are critical for application of additive manufacturing in load-bearing applications.
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Affiliation(s)
| | - Archish Muralidharan
- Materials Science and Engineering University of Colorado Boulder Boulder, CO 80309, USA
| | - Virginia L Ferguson
- Department of Mechanical Engineering University of Colorado Boulder Boulder, CO 80309, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering University of Colorado Boulder Boulder, CO 80309, USA
| | - Robert R McLeod
- Department of Electrical Computer and Energy Engineering University of Colorado Boulder Boulder, CO 80309, USA
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Aisenbrey EA, Bryant SJ. The role of chondroitin sulfate in regulating hypertrophy during MSC chondrogenesis in a cartilage mimetic hydrogel under dynamic loading. Biomaterials 2018; 190-191:51-62. [PMID: 30391802 DOI: 10.1016/j.biomaterials.2018.10.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/18/2018] [Accepted: 10/21/2018] [Indexed: 01/29/2023]
Abstract
Mesenchymal stem cells (MSCs) are promising for cartilage regeneration, but readily undergo terminal differentiation. The aim of this study was two-fold: a) investigate physiochemical cues from a cartilage-mimetic hydrogel under dynamic compressive loading on MSC chondrogenesis and hypertrophy and b) identify whether Smad signaling and p38 MAPK signaling mediate hypertrophy during MSC chondrogenesis. Human MSCs were encapsulated in photoclickable poly(ethylene glycol) hydrogels containing chondroitin sulfate and RGD, cultured under dynamic compressive loading or free swelling for three weeks, and evaluated by qPCR and immunohistochemistry. Loading inhibited hypertrophy in the cartilage-mimetic hydrogel indicated by a reduction in pSmad 1/5/8, Runx2, and collagen X proteins, while maintaining chondrogenesis by pSmad 2/3 and collagen II proteins. Inhibiting pSmad 1/5/8 under free swelling culture significantly reduced collagen X protein, similar to the loading condition. Chondroitin sulfate was necessary for load-inhibited hypertrophy and correlated with enhanced S100A4 expression, which is downstream of the osmotic responsive transcription factor NFAT5. Inhibiting p38 MAPK under loading reduced S100A4 expression, and upregulated Runx2 and collagen X protein. Findings from this study indicate that chondroitin sulfate with dynamic loading create physiochemical cues that support MSC chondrogenesis and attenuate hypertrophy through Smad 1/5/8 inhibition and p38 MAPK upregulation.
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Affiliation(s)
- Elizabeth A Aisenbrey
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309-0596, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309-0596, USA; BioFrontiers Institute, University of Colorado, Boulder, CO 80309-0596, USA; Material Science and Engineering Program, University of Colorado, Boulder, CO 80309-0596, USA.
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40
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Aisenbrey EA, Bryant SJ. A MMP7-sensitive photoclickable biomimetic hydrogel for MSC encapsulation towards engineering human cartilage. J Biomed Mater Res A 2018; 106:2344-2355. [PMID: 29577606 PMCID: PMC6030485 DOI: 10.1002/jbm.a.36412] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/30/2018] [Accepted: 03/15/2018] [Indexed: 12/28/2022]
Abstract
Cartilage tissue engineering strategies that use in situ forming degradable hydrogels for mesenchymal stem cell (MSC) delivery are promising for treating chondral defects. Hydrogels that recapitulate aspects of the native tissue have the potential to encourage chondrogenesis, permit cellular mediated degradation, and facilitate tissue growth. This study investigated photoclickable poly(ethylene glycol) hydrogels, which were tailored to mimic the cartilage microenvironment by incorporating extracellular matrix analogs, chondroitin sulfate and RGD, and crosslinks sensitive to matrix metalloproteinase 7 (MMP7). Human MSCs were encapsulated in the hydrogel, cultured up to nine weeks, and assessed by mRNA expression, protein production and biochemical analysis. Chondrogenic genes, SOX9, ACAN, and COL2A1, significantly increased with culture time, and the ratios of COL2A1:COL10A1 and SOX9:RUNX2 reached values of ∼20-100 by week 6. The encapsulated MSCs degraded the hydrogel, which was nearly undetectable by week 9. There was substantial deposition of aggrecan and collagen II, which correlated with degradation of the hydrogel. Minimal collagen X was detectable, but collagen I was prevalent. After week 1, extracellular matrix elaboration was accompanied by a ∼twofold increase in compressive modulus with culture time. The MMP7-sensitive cartilage mimetic hydrogel supported MSC chondrogenesis and promoted macroscopic neocartilaginous matrix elaboration representative of fibrocartilage. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2344-2355, 2018.
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Affiliation(s)
- Elizabeth A Aisenbrey
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309
| | - Stephanie J. Bryant
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309
- Material Science and Engineering Program, University of Colorado, Boulder, CO 80309
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41
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Jansen LE, Amer LD, Chen EYT, Nguyen TV, Saleh LS, Emrick T, Liu WF, Bryant SJ, Peyton SR. Zwitterionic PEG-PC Hydrogels Modulate the Foreign Body Response in a Modulus-Dependent Manner. Biomacromolecules 2018; 19:2880-2888. [PMID: 29698603 PMCID: PMC6190668 DOI: 10.1021/acs.biomac.8b00444] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Reducing the foreign body response (FBR) to implanted biomaterials will enhance their performance in tissue engineering. Poly(ethylene glycol) (PEG) hydrogels are increasingly popular for this application due to their low cost, ease of use, and the ability to tune their compliance via molecular weight and cross-linking densities. PEG hydrogels can elicit chronic inflammation in vivo, but recent evidence has suggested that extremely hydrophilic, zwitterionic materials and particles can evade the immune system. To combine the advantages of PEG-based hydrogels with the hydrophilicity of zwitterions, we synthesized hydrogels with comonomers PEG and the zwitterion phosphorylcholine (PC). Recent evidence suggests that stiff hydrogels elicit increased immune cell adhesion to hydrogels, which we attempted to reduce by increasing hydrogel hydrophilicity. Surprisingly, hydrogels with the highest amount of zwitterionic comonomer elicited the highest FBR. Lowering the hydrogel modulus (165 to 3 kPa), or PC content (20 to 0 wt %), mitigated this effect. A high density of macrophages was found at the surface of implants associated with a high FBR, and mass spectrometry analysis of the proteins adsorbed to these gels implicated extracellular matrix, immune response, and cell adhesion protein categories as drivers of macrophage recruitment. Overall, we show that modulus regulates macrophage adhesion to zwitterionic-PEG hydrogels, and demonstrate that chemical modifications to hydrogels should be studied in parallel with their physical properties to optimize implant design.
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Affiliation(s)
- Lauren E. Jansen
- University of Massachusetts, Amherst, Department of Chemical Engineering
| | - Luke D. Amer
- University of Colorado Boulder, Department of Chemical and Biological Engineering
| | - Esther Y-T Chen
- University of California, Irvine, Department of Biomedical Engineering
| | - Thuy V. Nguyen
- University of Massachusetts, Amherst, Department of Chemical Engineering
| | - Leila S. Saleh
- University of Colorado Boulder, Department of Chemical and Biological Engineering
| | - Todd Emrick
- University of Massachusetts, Amherst, Department of Polymer Science and Engineering
| | - Wendy F. Liu
- University of California, Irvine, Department of Biomedical Engineering
| | - Stephanie J. Bryant
- University of Colorado Boulder, Department of Chemical and Biological Engineering
| | - Shelly R. Peyton
- University of Massachusetts, Amherst, Department of Chemical Engineering
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Ding Y, Xu X, Sharma S, Floren M, Stenmark K, Bryant SJ, Neu CP, Tan W. Biomimetic soft fibrous hydrogels for contractile and pharmacologically responsive smooth muscle. Acta Biomater 2018; 74:121-130. [PMID: 29753912 DOI: 10.1016/j.actbio.2018.05.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 01/22/2023]
Abstract
The ability to assess changes in smooth muscle contractility and pharmacological responsiveness in normal or pathological-relevant vascular tissue environments is critical to enable vascular drug discovery. However, major challenges remain in both capturing the complexity of in vivo vascular remodeling and evaluating cell contractility in complex, tissue-like environments. Herein, we developed a biomimetic fibrous hydrogel with tunable structure, stiffness, and composition to resemble the native vascular tissue environment. This hydrogel platform was further combined with the combinatory protein array technology as well as advanced approaches to measure cell mechanics and contractility, thus permitting evaluation of smooth muscle functions in a variety of tissue-like microenvironments. Our results demonstrated that biomimetic fibrous structure played a dominant role in smooth muscle function, while the presentation of adhesion proteins co-regulated it to various degrees. Specifically, fibre networks enabled cell infiltration and upregulated expression of actomyosin proteins in contrast to flat hydrogels. Remarkably, fibrous structure and physiologically relevant stiffness of hydrogels cooperatively enhanced smooth muscle contractility and pharmacological responses to vasoactive drugs at both the single cell and intact tissue levels. Together, this study is the first to demonstrate alterations of human vascular smooth muscle contractility and pharmacological responsiveness in biomimetic soft, fibrous environments with a cellular array platform. The integrated platform produced here could enable investigations for pathobiology and pharmacological interventions by developing a broad range of patho-physiologically relevant in vitro tissue models. STATEMENT OF SIGNIFICANCE Engineering functional smooth muscle in vitro holds the great potential for diseased tissue replacement and drug testing. A central challenge is recapitulating the smooth muscle contractility and pharmacological responses given its significant phenotypic plasticity in response to changes in environment. We present a biomimetic fibrous hydrogel with tunable structure, stiffness, and composition that enables the creation of functional smooth muscle tissues in the native-like vascular tissue microenvironment. Such fibrous hydrogel is further combined with the combinatory protein array technology to construct a cellular array for evaluation of smooth muscle phenotype, contraction, and cell mechanics. The integrated platform produced here could be promising for developing a broad range of normal or diseased in vitro tissue models.
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Affiliation(s)
- Yonghui Ding
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Xin Xu
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Sadhana Sharma
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Michael Floren
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA; Cardiovascular Pulmonary Research Laboratories, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kurt Stenmark
- Cardiovascular Pulmonary Research Laboratories, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA; BioFrontiers Institute, Material Science and Engineering Program, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Corey P Neu
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Wei Tan
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA.
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Abstract
The foreign body response (FBR) occurs ubiquitously to essentially all non-biological materials that are implanted into higher organisms. The FBR is characterized by inflammation followed by fibrosis and is mediated largely by macrophages. While many current medical devices tolerate the FBR, the FBR is responsible for many asceptic device failures and is hindering advancements of new devices that rely on device-host communication to function. To this end, in vitro and in vivo models are critical to studying how a biomaterial, via its chemistry and properties, affect the FBR. This short review highlights the main in vitro and in vivo models that are used to study the FBR. In vitro models that capture macrophage interrogation of a biomaterial and evaluation of macrophage attachment, polarization and fusion are described. In vivo models using rodents, which provide a relatively simple model of the complex FBR process, and human-relevant nonhuman primate models are described. Collectively, the combination of in vitro and in vivo models will help advance our fundmental understanding of the FBR and enable new biomaterials to be developed that can effectively modulate the FBR to achieve a desire device-host outcome.
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Affiliation(s)
- Leila S Saleh
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA.,BioFrontiers Institute, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA.,Material Science and Engineering Program, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA
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Anderson AJ, Peters EB, Neumann A, Wagner J, Fairbanks B, Bryant SJ, Bowman CN. Cytocompatibility and Cellular Internalization of PEGylated "Clickable" Nucleic Acid Oligomers. Biomacromolecules 2018; 19:2535-2541. [PMID: 29698604 DOI: 10.1021/acs.biomac.8b00162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The recently developed synthetic oligonucleotides referred to as "click" nucleic acids (CNAs) are promising due to their relatively simple synthesis based on thiol-X reactions with numerous potential applications in biotechnology, biodetection, gene silencing, and drug delivery. Here, the cytocompatibility and cellular uptake of rhodamine tagged, PEGylated CNA copolymers (PEG-CNA-RHO) were evaluated. NIH 3T3 fibroblast cells treated for 1 h with 1, 10, or 100 μg/mL PEG-CNA-RHO maintained an average cell viability of 86%, which was not significantly different from the untreated control. Cellular uptake of PEG-CNA-RHO was detected within 30 s, and the amount internalized increased over the course of 1 h. Moreover, these copolymers were internalized within cells to a higher degree than controls consisting of either rhodamine tagged PEG or the rhodamine alone. Uptake was not affected by temperature (i.e., 4 or 37 °C), suggesting a passive uptake mechanism. Subcellular colocalization analysis failed to indicate significant correlations between the internalized PEG-CNA-RHO and the organelles examined (mitochondria, endoplasmic reticulum, endosomes and lysosomes). These results indicate that CNA copolymers are cytocompatible and are readily internalized by cells, supporting the idea that CNAs are a promising alternative to DNA in antisense therapy applications.
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Carles-Carner M, Saleh LS, Bryant SJ. The effects of hydroxyapatite nanoparticles embedded in a MMP-sensitive photoclickable PEG hydrogel on encapsulated MC3T3-E1 pre-osteoblasts. Biomed Mater 2018; 13:045009. [PMID: 29611815 PMCID: PMC5988492 DOI: 10.1088/1748-605x/aabb31] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study investigated the effects of introducing hydroxyapatite nanoparticles into a matrix metalloproteinase (MMP) sensitive poly(ethylene glycol) (PEG) hydrogel containing cell adhesion peptides of RGD for bone tissue engineering. MC3T3-E1 pre-osteoblasts were encapsulated in the biomimetic PEG hydrogel, which was formed from the photoclick thiol-norbornene reaction system, cultured for up to 28 d in growth medium or osteogenic differentiation medium, and evaluated by cellular morphology and differentiation by alkaline phosphatase (ALP) activity and bone-like extracellular matrix deposition for mineral and collagen. Hydroxyapatite nanoparticles were incorporated during hydrogel formation and cell encapsulation at 0%, 0.1% or 1% (w/w). Incorporation of hydroxyapatite nanoparticles did not affect the hydrogel properties as measured by compressive modulus and equilibrium swelling. In growth medium, encapsulated MC3T3-E1 cells remained largely round regardless of hydroxyapatite concentration. ALP activity increased by 25% at day 14 and total collagen content increased by 55% at day 28 with increasing hydroxyapatite concentration from 0% to 1%. In differentiation medium, cell spreading was evident regardless of hydroxyapatite indicating that the MC3T3-E1 cells were able to degrade the hydrogel. For the 1% hydroxyapatite condition, ALP activity was 27% higher at day 14 and total collagen content was 22% higher at day 28 in differentiation medium when compared to growth medium. Mineral deposits were more abundant and spatial elaboration of collagen type I was more evident in the 1% (w/w) hydroxyapatite condition with differentiation medium when compared to all other conditions. Overall, osteogenesis was observed in the hydrogels with hydroxyapatite nanoparticles in growth medium but was enhanced in differentiation medium. In summary, a biomimetic hydrogel comprised of MMP-sensitive crosslinks, RGD cell adhesion peptides, and 1% (w/w) hydroxyapatite nanoparticles is promising for bone tissue engineering.
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Affiliation(s)
- Maria Carles-Carner
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80309, United States of America
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46
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Patel D, Sharma S, Screen HRC, Bryant SJ. Effects of cell adhesion motif, fiber stiffness, and cyclic strain on tenocyte gene expression in a tendon mimetic fiber composite hydrogel. Biochem Biophys Res Commun 2018; 499:642-647. [PMID: 29601813 PMCID: PMC5916510 DOI: 10.1016/j.bbrc.2018.03.203] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 03/27/2018] [Indexed: 12/11/2022]
Abstract
We recently developed a fiber composite consisting of tenocytes seeded onto discontinuous fibers embedded within a hydrogel, designed to mimic physiological tendon micromechanics of tension and shear. This study examined if cell adhesion peptide (DGEA or YRGDS), fiber modulus (50 or 1300 kPa) and/or cyclic strain (5% strain, 1 Hz) influenced bovine tenocyte gene expression. Ten genes were analyzed and none were sensitive to peptide or fiber modulus in the absence of cyclic tensile strain. Genes associated with tendon (SCX and TNMD), collagens (COL1A1, COL3A1, COL11A1), and matrix remodelling (MMP1, MMP2, and TIMP3) were insensitive to cyclic strain. Contrarily, cyclic strain up-regulated IL6 by 30-fold and MMP3 by 10-fold in soft YRGDS fibers. IL6 expression in soft YRGDS fibers was 5.7 and 3.3-fold greater than in soft DGEA fibers and stiff RGD fibers, respectively, under cyclic strain. Our findings suggest that changes in the surrounding matrix can influence catabolic genes in tenocytes when cultured in a complex strain environment mimicking that of tendon, while having minimal effects on tendon and homeostatic genes. A fiber composite material exhibits multimodal shear and tension micromechanics. Gene expression of tenocytes is insensitive to fiber stiffness or YRGDS vs DGEA. Tendon marker and collagen genes are insensitive to fiber environment under strain. MMP3 and IL6 genes are sensitive to fiber stiffness and peptide under cyclic strain. Healthy tenocytes rapidly respond to their environment by a catabolic response.
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Affiliation(s)
- Dharmesh Patel
- School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, UK
| | - Sadhana Sharma
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Hazel R C Screen
- School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, UK
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309, USA; Material Science and Engineering Program, University of Colorado-Boulder, Boulder, CO 80309, USA; BioFrontiers Institute, University of Colorado-Boulder, Boulder, CO 80309, USA.
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Abstract
Implantation of cell-laden scaffolds is a promising strategy for regenerating tissue that has been damaged due to injury or disease. However, the act of implantation initiates an acute inflammatory response. If the scaffold is non-biologic (i.e., a modified biologic scaffold or synthetic-based scaffold), inflammation will be prolonged through the foreign body response (FBR), which eventually forms a fibrous capsule and walls off the implant from the surrounding host tissue. This host response, from a cellular perspective, can create a harsh environment leading to long-lasting effects on the tissue engineering outcome. At the same time, cells embedded within the scaffold can respond to this environment and influence the interrogating immune cells (e.g., macrophages). This crosstalk, depending on the type of cell, can dramatically influence the host response. This review provides an overview of the FBR and highlights important and recent advancements in the host response to cell-laden scaffolds with a focus on the impact of the communication between immune cells and cells embedded within a scaffold. Understanding this complex interplay between the immune cells, notably macrophages, and the tissue engineering cells is a critically important component to a successful in vivo tissue engineering therapy.
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Affiliation(s)
- Leila S Saleh
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA.,BioFrontiers Institute, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA.,Material Science and Engineering Program, University of Colorado, 3415 Colorado Avenue, Boulder, CO 80303, USA
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48
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Aisenbrey EA, Tomaschke A, Kleinjan E, Muralidharan A, Pascual-Garrido C, McLeod RR, Ferguson VL, Bryant SJ. A Stereolithography-Based 3D Printed Hybrid Scaffold for In Situ Cartilage Defect Repair. Macromol Biosci 2018; 18:10.1002/mabi.201700267. [PMID: 29266791 PMCID: PMC5959280 DOI: 10.1002/mabi.201700267] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 10/05/2017] [Indexed: 11/12/2022]
Abstract
Damage to articular cartilage can over time cause degeneration to the tissue surrounding the injury. To address this problem, scaffolds that prevent degeneration and promote neotissue growth are needed. A new hybrid scaffold that combines a stereolithography-based 3D printed support structure with an injectable and photopolymerizable hydrogel for delivering cells to treat focal chondral defects is introduced. In this proof of concept study, the ability to a) infill the support structure with an injectable hydrogel precursor solution, b) incorporate cartilage cells during infilling using a degradable hydrogel that promotes neotissue deposition, and c) minimize damage to the surrounding cartilage when the hybrid scaffold is placed in situ in a focal chondral defect in an osteochondral plug that is cultured under mechanical loading is demonstrated. With the ability to independently control the properties of the structure and the injectable hydrogel, this hybrid scaffold approach holds promise for treating chondral defects.
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Affiliation(s)
- Elizabeth A Aisenbrey
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Andrew Tomaschke
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Eric Kleinjan
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309, USA
| | - Archish Muralidharan
- Material Science and Engineering Program, University of Colorado, Boulder, CO, 80309, USA
| | | | - Robert R McLeod
- Department of Electrical, Computing and Energy Engineering, Material Science and Engineering Program, University of Colorado, Boulder, CO, 80309, USA
| | - Virginia L Ferguson
- Department of Mechanical Engineering, Material Science and Engineering Program, BioFrontiers Institute, University of Colorado, Boulder, CO, 80309, USA
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering, Material Science and Engineering Program, BioFrontiers Institute, University of Colorado, Boulder, CO, 80309, USA
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Bryant SJ, Vernerey FJ. Programmable Hydrogels for Cell Encapsulation and Neo-Tissue Growth to Enable Personalized Tissue Engineering. Adv Healthc Mater 2018; 7. [PMID: 28975716 DOI: 10.1002/adhm.201700605] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 06/12/2017] [Indexed: 12/11/2022]
Abstract
Biomimetic and biodegradable synthetic hydrogels are emerging as a promising platform for cell encapsulation and tissue engineering. Notably, synthetic-based hydrogels offer highly programmable macroscopic properties (e.g., mechanical, swelling and transport properties) and degradation profiles through control over several tunable parameters (e.g., the initial network structure, degradation kinetics and behavior, and polymer properties). One component to success is the ability to maintain structural integrity as the hydrogel transitions to neo-tissue. This seamless transition is complicated by the fact that cellular activity is highly variable among donors. Thus, computational models provide an important tool in tissue engineering due to their unique ability to explore the coupled processes of hydrogel degradation and neo-tissue growth across multiple length scales. In addition, such models provide new opportunities to develop predictive computational tools to overcome the challenges with designing hydrogels for different donors. In this report, programmable properties of synthetic-based hydrogels and their relation to the hydrogel's structural properties and their evolution with degradation are reviewed. This is followed by recent progress on the development of computational models that describe hydrogel degradation with neo-tissue growth when cells are encapsulated in a hydrogel. Finally, the potential for predictive models to enable patient-specific hydrogel designs for personalized tissue engineering is discussed.
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Affiliation(s)
- Stephanie J. Bryant
- Department of Chemical and Biological Engineering; University of Colorado; 3415 Colorado Ave; Boulder CO 80309-0596 USA
| | - Franck J. Vernerey
- Department of Mechanical Engineering; University of Colorado; 1111 Engineering Dr.; Boulder CO 80309-0428 USA
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Pascual-Garrido C, Rodriguez-Fontan F, Aisenbrey EA, Payne KA, Chahla J, Goodrich LR, Bryant SJ. Current and novel injectable hydrogels to treat focal chondral lesions: Properties and applicability. J Orthop Res 2018; 36:64-75. [PMID: 28975658 PMCID: PMC5839960 DOI: 10.1002/jor.23760] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/22/2017] [Indexed: 02/04/2023]
Abstract
Focal chondral lesions and early osteoarthritis (OA) are responsible for progressive joint pain and disability in millions of people worldwide, yet there is currently no surgical joint preservation treatment available to fully restore the long term functionality of cartilage. Limitations of current treatments for cartilage defects have prompted the field of cartilage tissue engineering, which seeks to integrate engineering and biological principles to promote the growth of new cartilage to replace damaged tissue. Toward improving cartilage repair, hydrogel design has advanced in recent years to improve their utility. Injectable hydrogels have emerged as a promising scaffold due to their wide range of properties, the ability to encapsulate cells within the material, and their ability to provide cues for cell differentiation. Some of these advances include the development of improved control over in situ gelation (e.g., light), new techniques to process hydrogels (e.g., multi-layers), and better incorporation of biological signals (e.g., immobilization, controlled release, and tethering). This review summarises the innovative approaches to engineer injectable hydrogels toward cartilage repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:64-75, 2018.
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Affiliation(s)
| | | | - Elizabeth A. Aisenbrey
- Department of Chemical & Biological Engineering, University of Colorado Denver, Boulder, CO
| | - Karin A. Payne
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO
| | | | - Laurie R. Goodrich
- Department of Clinical Sciences and Orthopaedic Research Center, Colorado State University, Fort Collins, CO
| | - Stephanie J. Bryant
- Department of Chemical & Biological Engineering, University of Colorado Denver, Boulder, CO
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