1
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Tutoni GG, McDonald SM, Zhong R, Lu A, Huang TJ, Becker ML. Microfluidic Assembly of Degradable, Stereocomplexed Hydrogel Microparticles. J Am Chem Soc 2024; 146:14705-14714. [PMID: 38749060 DOI: 10.1021/jacs.4c02317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Hydrogel microparticles (HMPs) have been investigated widely for their use in tissue engineering and drug delivery applications. However, translation of these highly tunable systems has been hindered by covalent cross-linking methods within microparticles. Stereocomplexation, a stereospecific form of physical cross-linking, provides a robust yet degradable alternative for creating translationally relevant HMPs. Herein, 4-arm polyethylene glycol (PEG) stars were used as macromolecular initiators from which oligomeric poly(l-lactic acid) (PLLA) was polymerized with a degree of polymerization (DPn) of 20 on each arm. Similarly, complementary propargyl-containing ABA cross-linkers with enantiomeric poly(d-lactic acid) (PDLA) segments (DPn = 20) on each arm. Droplets of these gel precursors were formed via a microfluidic organic-in-oil-in-water system where microparticles self-assembled via stereocomplexation and were stabilized after precipitation in deionized water. By varying the flow rate of the dispersed phase, well-defined microparticles with diameters of 33.7 ± 0.5, 62.4 ± 0.6, and 105.7 ± 0.8 μm were fabricated. Gelation due to stereocomplexation was confirmed via wide-angle X-ray scattering in which HMPs exhibited the signature diffraction pattern of stereocomplexed PLA at 2θ = 12.2, 21.2, 24.2°. Differential scanning calorimetry also confirmed stereocomplexation by the appearance of a crystallization exotherm (Tc = 37 °C) and a high-temperature endotherm (Tm = 159 °C) that does not appear in the homocrystallization of PLLA or the hydrogel precursors. Additionally, the propargyl handle present on the cross-linker allows for pre- or post-assembly thiol-yne "click" functionalization as demonstrated by the addition of thiol-containing fluorophores to the HMPs.
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Affiliation(s)
- Gianna G Tutoni
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Samantha M McDonald
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Ruoyu Zhong
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, United States
| | - Annette Lu
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tony Jun Huang
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, United States
| | - Matthew L Becker
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, United States
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States
- Department of Orthopedic Surgery, Duke University, Durham, North Carolina 27708, United States
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2
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Tigner TJ, Dampf G, Tucker A, Huang YC, Jagrit V, Clevenger AJ, Mohapatra A, Raghavan SA, Dulin JN, Alge DL. Clickable Granular Hydrogel Scaffolds for Delivery of Neural Progenitor Cells to Sites of Spinal Cord Injury. Adv Healthc Mater 2024:e2303912. [PMID: 38470994 DOI: 10.1002/adhm.202303912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 02/27/2024] [Indexed: 03/14/2024]
Abstract
Spinal cord injury (SCI) is a serious condition with limited treatment options. Neural progenitor cell (NPC) transplantation is a promising treatment option, and the identification of novel biomaterial scaffolds that support NPC engraftment and therapeutic activity is a top research priority. The objective of this study is to evaluate in situ assembled poly (ethylene glycol) (PEG)-based granular hydrogels for NPC delivery in a murine model of SCI. Microgel precursors are synthesized by using thiol-norbornene click chemistry to react four-armed PEG-amide-norbornene with enzymatically degradable and cell adhesive peptides. Unreacted norbornene groups are utilized for in situ assembly into scaffolds using a PEG-di-tetrazine linker. The granular hydrogel scaffolds exhibit good biocompatibility and do not adversely affect the inflammatory response after SCI. Moreover, when used to deliver NPCs, the granular hydrogel scaffolds supported NPC engraftment, do not adversely affect the immune response to the NPC grafts, and successfully support graft differentiation toward neuronal or astrocytic lineages as well as axonal extension into the host tissue. Collectively, these data establish PEG-based granular hydrogel scaffolds as a suitable biomaterial platform for NPC delivery and justify further testing, particularly in the context of more severe SCI.
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Affiliation(s)
- Thomas J Tigner
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Gabrielle Dampf
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Ashley Tucker
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Yu-Chi Huang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Vipin Jagrit
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
| | - Abigail J Clevenger
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Arpita Mohapatra
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Shreya A Raghavan
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
| | - Jennifer N Dulin
- Department of Biology, Texas A&M University, College Station, TX, 77843-3258, USA
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, 77843-3474, USA
| | - Daniel L Alge
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843-3120, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, 77843-3003, USA
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3
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Tanner GI, Schiltz L, Narra N, Figueiredo ML, Qazi TH. Granular Hydrogels Improve Myogenic Invasion and Repair after Volumetric Muscle Loss. Adv Healthc Mater 2024:e2303576. [PMID: 38329892 DOI: 10.1002/adhm.202303576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/26/2023] [Indexed: 02/10/2024]
Abstract
Skeletal muscle injuries including volumetric muscle loss (VML) lead to excessive tissue scarring and permanent functional disability. Despite its high prevalence, there is currently no effective treatment for VML. Bioengineering interventions such as biomaterials that fill the VML defect to support cell and tissue growth are a promising therapeutic strategy. However, traditional biomaterials developed for this purpose lack the pore features needed to support cell infiltration. The present study investigates for the first time, the impact of granular hydrogels on muscle repair - hypothesizing that their flowability will permit conformable filling of the defect site and their inherent porosity will support the invasion of native myogenic cells, leading to effective muscle repair. Small and large microparticle fragments are prepared from photocurable hyaluronic acid polymer via extrusion fragmentation and facile size sorting. In assembled granular hydrogels, particle size and degree of packing significantly influence pore features, rheological behavior, and injectability. Using a mouse model of VML, it is demonstrated that, in contrast to bulk hydrogels, granular hydrogels support early-stage (satellite cell invasion) and late-stage (myofiber regeneration) muscle repair processes. Together, these results highlight the promising potential of injectable and porous granular hydrogels in supporting endogenous repair after severe muscle injury.
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Affiliation(s)
- Gabrielle I Tanner
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Leia Schiltz
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Niharika Narra
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Marxa L Figueiredo
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Taimoor H Qazi
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
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4
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Ataie Z, Horchler S, Jaberi A, Koduru SV, El-Mallah JC, Sun M, Kheirabadi S, Kedzierski A, Risbud A, Silva ARAE, Ravnic DJ, Sheikhi A. Accelerating Patterned Vascularization Using Granular Hydrogel Scaffolds and Surgical Micropuncture. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307928. [PMID: 37824280 DOI: 10.1002/smll.202307928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Indexed: 10/14/2023]
Abstract
Bulk hydrogel scaffolds are common in reconstructive surgery. They allow for the staged repair of soft tissue loss by providing a base for revascularization. Unfortunately, they are limited by both slow and random vascularization, which may manifest as treatment failure or suboptimal repair. Rapidly inducing patterned vascularization within biomaterials has profound translational implications for current clinical treatment paradigms and the scaleup of regenerative engineering platforms. To address this long-standing challenge, a novel microsurgical approach and granular hydrogel scaffold (GHS) technology are co-developed to hasten and pattern microvascular network formation. In surgical micropuncture (MP), targeted recipient blood vessels are perforated using a microneedle to accelerate cell extravasation and angiogenic outgrowth. By combining MP with an adjacent GHS with precisely tailored void space architecture, microvascular pattern formation as assessed by density, diameter, length, and intercapillary distance is rapidly guided. This work opens new translational opportunities for microvascular engineering, advancing reconstructive surgery, and regenerative medicine.
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Affiliation(s)
- Zaman Ataie
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Summer Horchler
- Division of Plastic Surgery, Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, 17033, USA
| | - Arian Jaberi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Srinivas V Koduru
- Division of Plastic Surgery, Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, 17033, USA
| | - Jessica C El-Mallah
- Division of Plastic Surgery, Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, 17033, USA
| | - Mingjie Sun
- Division of Plastic Surgery, Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, 17033, USA
| | - Sina Kheirabadi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Alexander Kedzierski
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Aneesh Risbud
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Dino J Ravnic
- Division of Plastic Surgery, Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, 17033, USA
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Amir Sheikhi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
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5
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Widener AE, Roberts A, Phelps EA. Granular Hydrogels for Harnessing the Immune Response. Adv Healthc Mater 2023:e2303005. [PMID: 38145369 PMCID: PMC11196388 DOI: 10.1002/adhm.202303005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/13/2023] [Indexed: 12/26/2023]
Abstract
This review aims to understand the current progress in immune-instructive granular hydrogels and identify the key features used as immunomodulatory strategies. Published work is systematically reviewed and relevant information about granular hydrogels used throughout these studies is collected. The base polymer, microgel generation technique, polymer crosslinking chemistry, particle size and shape, annealing strategy, granular hydrogel stiffness, pore size and void space, degradability, biomolecule presentation, and drug release are cataloged for each work. Several granular hydrogel parameters used for immune modulation: porosity, architecture, bioactivity, drug release, cell delivery, and modularity, are identified. The authors found in this review that porosity is the most significant factor influencing the innate immune response to granular hydrogels, while incorporated bioactivity is more significant in influencing adaptive immune responses. Here, the authors' findings and summarized results from each section are presented and suggestions are made for future studies to better understand the benefits of using immune-instructive granular hydrogels.
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Affiliation(s)
- Adrienne E Widener
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr., Gainesville, 32611, USA
| | - Abilene Roberts
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr., Gainesville, 32611, USA
| | - Edward A Phelps
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr., Gainesville, 32611, USA
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6
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Wilson KL, Joseph NI, Onweller LA, Anderson AR, Darling NJ, David-Bercholz J, Segura T. SDF-1 Bound Heparin Nanoparticles Recruit Progenitor Cells for Their Differentiation and Promotion of Angiogenesis after Stroke. Adv Healthc Mater 2023:e2302081. [PMID: 38009291 PMCID: PMC11128481 DOI: 10.1002/adhm.202302081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/22/2023] [Indexed: 11/28/2023]
Abstract
Angiogenesis after stroke is correlated with enhanced tissue repair and functional outcomes. The existing body of research in biomaterials for stroke focuses on hydrogels for the delivery of stem cells, growth factors, or small molecules or drugs. Despite the ability of hydrogels to enhance all these delivery methods, no material has significantly regrown vasculature within the translatable timeline of days to weeks after stroke. Here, two novel biomaterial formulations of granular hydrogels are developed for tissue regeneration after stroke: highly porous microgels (i.e., Cryo microgels) and microgels bound with heparin-norbornene nanoparticles with covalently bound SDF-1α. The combination of these materials results in perfused vessels throughout the stroke core in only 10 days, in addition to increased neural progenitor cell recruitment, maintenance, and increased neuronal differentiation.
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Affiliation(s)
- Katrina L. Wilson
- Department of Biomedical Engineering, Duke University, Durham NC 27708-0281, USA
| | - Neica I. Joseph
- Department of Biomedical Engineering, Duke University, Durham NC 27708-0281, USA
| | - Lauren A. Onweller
- Department of Biomedical Engineering, Duke University, Durham NC 27708-0281, USA
| | - Alexa R. Anderson
- Department of Biomedical Engineering, Duke University, Durham NC 27708-0281, USA
| | - Nicole J. Darling
- Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA
| | | | - Tatiana Segura
- Department of Biomedical Engineering, Duke University, Durham NC 27708-0281, USA
- Department of Neurology, Duke University, Durham, NC, 27708-0281 USA
- Department of Dermatology, Duke University, Durham, NC, 27708-0281 USA
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7
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Nelson BR, Kirkpatrick BE, Skillin NP, Di Caprio N, Lee JS, Hibbard LP, Hach GK, Khang A, White TJ, Burdick JA, Bowman CN, Anseth KS. Facile Physicochemical Reprogramming of PEG-Dithiolane Microgels. Adv Healthc Mater 2023:e2302925. [PMID: 37984810 PMCID: PMC11102926 DOI: 10.1002/adhm.202302925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/06/2023] [Indexed: 11/22/2023]
Abstract
Granular biomaterials have found widespread applications in tissue engineering, in part because of their inherent porosity, tunable properties, injectability, and 3D printability. However, the assembly of granular hydrogels typically relies on spherical microparticles and more complex particle geometries have been limited in scope, often requiring templating of individual microgels by microfluidics or in-mold polymerization. Here, we use dithiolane-functionalized synthetic macromolecules to fabricate photopolymerized microgels via batch emulsion, and then harness the dynamic disulfide crosslinks to rearrange the network. Through unconfined compression between parallel plates in the presence of photoinitiated radicals, we transform the isotropic microgels are transformed into disks. Characterizing this process, we find that the areas of the microgel surface in contact with the compressive plates are flattened while the curvature of the uncompressed microgel boundaries increases. When cultured with C2C12 myoblasts, cells localize to regions of higher curvature on the disk-shaped microgel surfaces. This altered localization affects cell-driven construction of large supraparticle scaffold assemblies, with spherical particles assembling without specific junction structure while disk microgels assemble preferentially on their curved surfaces. These results represent a unique spatiotemporal process for rapid reprocessing of microgels into anisotropic shapes, providing new opportunities to study shape-driven mechanobiological cues during and after granular hydrogel assembly.
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Affiliation(s)
- Benjamin R Nelson
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Bruce E Kirkpatrick
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
- Medical Scientist Training Program, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Nathaniel P Skillin
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
- Medical Scientist Training Program, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Nikolas Di Caprio
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Joshua S Lee
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Lea Pearl Hibbard
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Grace K Hach
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Alex Khang
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Timothy J White
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Jason A Burdick
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Christopher N Bowman
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Kristi S Anseth
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, 80303, USA
- Materials Science and Engineering Program, University of Colorado Boulder, Boulder, CO, 80303, USA
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8
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Liu Y, Suarez-Arnedo A, Riley L, Miley T, Xia J, Segura T. Spatial Confinement Modulates Macrophage Response in Microporous Annealed Particle (MAP) Scaffolds. Adv Healthc Mater 2023; 12:e2300823. [PMID: 37165945 PMCID: PMC10592513 DOI: 10.1002/adhm.202300823] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/17/2023] [Indexed: 05/12/2023]
Abstract
Macrophages are essential in the initiation, maintenance, and transition of inflammatory processes such as foreign body response and wound healing. Mounting evidence suggests that physical factors also modulate macrophage activation. 2D in vitro systems demonstrate that constraining macrophages to small areas or channels modulates their phenotypes and changes their responses to known inflammatory agents such as lipopolysaccharide. However, how dimensionality and pore size affect macrophage phenotype is less explored. In this work, the change in macrophage M1/M2 polarization when confined in microporous annealed particle (MAP) scaffolds is studied. Particles sizes (40, 70, and 130 µm) are selected using outputs from software LOVAMAP that analyzes the characteristics of 3D pores in MAP gels. As the size of building block particle correlates with pore size inside the scaffolds, the three types of scaffold allow us to study how the degree of spatial confinement modulates the behavior of embedded macrophages. Spatially confining macrophages in scaffolds with pore size on the scale of cells leads to a reduced level of the inflammatory response, which is correlated with a change in cell morphology and motility.
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Affiliation(s)
- Yining Liu
- Department of Biomedical Engineering, Duke University
| | | | - Lindsay Riley
- Department of Biomedical Engineering, Duke University
| | - Tasman Miley
- Department of Biomedical Engineering, Duke University
| | - Jingyi Xia
- Department of Biomedical Engineering, Duke University
| | - Tatiana Segura
- Department of Biomedical Engineering, Duke University
- Clinical Science Departments of Neurology and Dermatology, Duke University
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9
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Riley L, Wei G, Bao Y, Cheng P, Wilson KL, Liu Y, Gong Y, Segura T. Void Volume Fraction of Granular Scaffolds. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2303466. [PMID: 37267936 PMCID: PMC10592564 DOI: 10.1002/smll.202303466] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/18/2023] [Indexed: 06/04/2023]
Abstract
Void volume fraction (VVF) is a global measurement frequently used to characterize the void space of granular scaffolds, yet there is no gold standard by which to measure VVF in practice. To study the relationship between VVF and particles of varying size, form, and composition, a library of 3D simulated scaffolds is used. Results reveal that relative to particle count, VVF is a less predictable metric across replicate scaffolds. Simulated scaffolds are used to explores the relationship between microscope magnification and VVF, and recommendations are offered for optimizing the accuracy of approximating VVF using 2D microscope images. Lastly, VVF of hydrogel granular scaffolds is measured while varying four input parameters: image quality, magnification, analysis software, and intensity threshold. Results show that VVF is highly sensitive to these parameters. Overall, random packing produces variation in VVF among granular scaffolds comprising the same particle populations. Furthermore, while VVF is used to compare the porosity of granular materials within a study, VVF is a less reliable metric across studies that use different input parameters. VVF, a global measurement, cannot describe the dimensions of porosity within granular scaffolds, and the work supports the notion that more descriptors are necessary to sufficiently characterize void space.
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Affiliation(s)
- Lindsay Riley
- Department of Biomedical Engineering, Duke University
| | - Grace Wei
- Department of Biology, Duke University
| | - Yijun Bao
- Department of Biomedical Engineering, Duke University
| | | | | | - Yining Liu
- Department of Biomedical Engineering, Duke University
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University
| | - Tatiana Segura
- Department of Biomedical Engineering, Duke University
- Department of Medicine, Neurology, Dermatology, Duke University
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10
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Wilson KL, Onweller LA, Joseph NI, David-Bercholz J, Darling NJ, Segura T. SDF-1 Bound Heparin Nanoparticles Recruit Progenitor Cells for Their Differentiation and Promotion of Angiogenesis After Stroke. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.05.547800. [PMID: 37461490 PMCID: PMC10349963 DOI: 10.1101/2023.07.05.547800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Angiogenesis after stroke is correlated with enhanced tissue repair and functional outcomes. The existing body of research in biomaterials for stroke focuses on hydrogels for the delivery of stem cells, growth factors, or small molecules or drugs. Despite the ability of hydrogels to enhance all these delivery methods, no material has significantly regrown vasculature within the translatable timeline of days to weeks after stroke. Here we developed 2 novel biomaterials for tissue regeneration after stroke, a highly porous granular hydrogel termed Cryo microgels, and heparin-norbornene nanoparticles with covalently bound SDF-1α. The combination of these materials resulted in fully revascularized vessels throughout the stroke core in only 10 days, as well as increased neural progenitor cell migration and maintenance and increased neurons.
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11
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Namjoo AR, Abrbekoh FN, Saghati S, Amini H, Saadatlou MAE, Rahbarghazi R. Tissue engineering modalities in skeletal muscles: focus on angiogenesis and immunomodulation properties. Stem Cell Res Ther 2023; 14:90. [PMID: 37061717 PMCID: PMC10105969 DOI: 10.1186/s13287-023-03310-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/28/2023] [Indexed: 04/17/2023] Open
Abstract
Muscular diseases and injuries are challenging issues in human medicine, resulting in physical disability. The advent of tissue engineering approaches has paved the way for the restoration and regeneration of injured muscle tissues along with available conventional therapies. Despite recent advances in the fabrication, synthesis, and application of hydrogels in terms of muscle tissue, there is a long way to find appropriate hydrogel types in patients with congenital and/or acquired musculoskeletal injuries. Regarding specific muscular tissue microenvironments, the applied hydrogels should provide a suitable platform for the activation of endogenous reparative mechanisms and concurrently deliver transplanting cells and therapeutics into the injured sites. Here, we aimed to highlight recent advances in muscle tissue engineering with a focus on recent strategies related to the regulation of vascularization and immune system response at the site of injury.
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Affiliation(s)
- Atieh Rezaei Namjoo
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Sepideh Saghati
- Department of Tissue Engineering, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hassan Amini
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
- General and Vascular Surgery Department, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Reza Rahbarghazi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Department of Applied Cell Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
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12
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Cao S, Bo R, Zhang Y. Polymeric Scaffolds for Regeneration of Central/Peripheral Nerves and Soft Connective Tissues. ADVANCED NANOBIOMED RESEARCH 2023. [DOI: 10.1002/anbr.202200147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Shunze Cao
- Applied Mechanics Laboratory Department of Engineering Mechanics Laboratory for Flexible Electronics Technology Tsinghua University Beijing 100084 China
| | - Renheng Bo
- Applied Mechanics Laboratory Department of Engineering Mechanics Laboratory for Flexible Electronics Technology Tsinghua University Beijing 100084 China
| | - Yihui Zhang
- Applied Mechanics Laboratory Department of Engineering Mechanics Laboratory for Flexible Electronics Technology Tsinghua University Beijing 100084 China
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Yazdani N, Willits RK. Mimicking the neural stem cell niche: An engineer’s view of cell: material interactions. FRONTIERS IN CHEMICAL ENGINEERING 2023. [DOI: 10.3389/fceng.2022.1086099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Neural stem cells have attracted attention in recent years to treat neurodegeneration. There are two neurogenic regions in the brain where neural stem cells reside, one of which is called the subventricular zone (SVZ). The SVZ niche is a complicated microenvironment providing cues to regulate self-renewal and differentiation while maintaining the neural stem cell’s pool. Many scientists have spent years understanding the cellular and structural characteristics of the SVZ niche, both in homeostasis and pathological conditions. On the other hand, engineers focus primarily on designing platforms using the knowledge they acquire to understand the effect of individual factors on neural stem cell fate decisions. This review provides a general overview of what we know about the components of the SVZ niche, including the residing cells, extracellular matrix (ECM), growth factors, their interactions, and SVZ niche changes during aging and neurodegenerative diseases. Furthermore, an overview will be given on the biomaterials used to mimic neurogenic niche microenvironments and the design considerations applied to add bioactivity while meeting the structural requirements. Finally, it will discuss the potential gaps in mimicking the microenvironment.
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Salthouse D, Novakovic K, Hilkens CMU, Ferreira AM. Interplay between biomaterials and the immune system: Challenges and opportunities in regenerative medicine. Acta Biomater 2023; 155:1-18. [PMID: 36356914 DOI: 10.1016/j.actbio.2022.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/17/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022]
Abstract
The use of biomaterials for tissue engineering and regenerative medicine applications has increased dramatically over recent years. However, the clinical uptake of a wide variety of biomaterials remains limited due to adverse effects commonly exhibited by patients, which are caused by the host immune response. Despite this, current in vitro evaluation standards (ISO-10993) for assessing the host response to biomaterials have limitations in predicting the likelihood of in vivo biomaterial acceptance. Furthermore, endotoxin contamination of biomaterials is rarely considered, despite its ability to significantly affect the performance of biomaterials and engineered tissues. This review highlights the importance of the immune response to biomaterials and discusses existing challenges and opportunities in the development and standardised assessment of the immune response to biomaterials, including the importance of endotoxin levels. In addition, the properties of biomaterials that impact the host immune response and the exploitation of immunomodulatory biomaterials in regenerative medicine are explored. Finally, a standardised in vitro pathway of evaluating the immune response to biomaterials (hydrogels) and their regenerative potential is proposed, aiming to ensure safety and consistency, while reducing costs and the use of animals in the biomaterials research for tissue engineering and regenerative medicine. STATEMENT OF SIGNIFICANCE: This review presents a critical analysis of the role of the interactions between the immune system and biomaterials in determining the therapeutic success of biomaterial-based approaches. No such review addressing the lack of understanding of biomaterial-immune system interactions during the developmental and pre-clinical stages of biomaterials, including the impact of the endotoxin levels of biomaterials on the immune response, is published. As there is a lack of in vitro regulations to evaluate the immune response to biomaterials, a standardised in vitro pathway to evaluate the immune response to biomaterials (hydrogels) and their immunomodulatory and regenerative potential for use in tissue engineering/regenerative medicine applications is presented. The aim of the proposed pathway of biomaterial evaluation is to ensure safety and consistency in the biomaterials research community, while reducing costs and animal use (through the concept of the 3R's - reduction, refinement, and replacement of animals).
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Affiliation(s)
- Daniel Salthouse
- School of Engineering, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Katarina Novakovic
- School of Engineering, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Catharien M U Hilkens
- Translational & Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ana Marina Ferreira
- School of Engineering, Newcastle University, Newcastle Upon Tyne, United Kingdom.
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Emiroglu DB, Bekcic A, Dranseikiene D, Zhang X, Zambelli T, deMello AJ, Tibbitt MW. Building block properties govern granular hydrogel mechanics through contact deformations. SCIENCE ADVANCES 2022; 8:eadd8570. [PMID: 36525484 PMCID: PMC9757745 DOI: 10.1126/sciadv.add8570] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Granular hydrogels have been increasingly exploited in biomedical applications, including wound healing and cardiac repair. Despite their utility, design guidelines for engineering their macroscale properties remain limited, as we do not understand how the properties of granular hydrogels emerge from collective interactions of their microgel building blocks. In this work, we related building block features (stiffness and size) to the macroscale properties of granular hydrogels using contact mechanics. We investigated the mechanics of the microgel packings through dynamic oscillatory rheology. In addition, we modeled the system as a collection of two-body interactions and applied the Zwanzig and Mountain formula to calculate the plateau modulus and viscosity of the granular hydrogels. The calculations agreed with the dynamic mechanical measurements and described how microgel properties and contact deformations define the rheology of granular hydrogels. These results support a rational design framework for improved engineering of this fascinating class of materials.
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Affiliation(s)
- Dilara Börte Emiroglu
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Aleksandar Bekcic
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Dalia Dranseikiene
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Xinyu Zhang
- Laboratory of Biosensors and Bioelectronics, Department of Information Technology and Electrical Engineering, ETHZurich, 8093 Zurich, Switzerland
| | - Tomaso Zambelli
- Laboratory of Biosensors and Bioelectronics, Department of Information Technology and Electrical Engineering, ETHZurich, 8093 Zurich, Switzerland
| | - Andrew J. deMello
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Mark W. Tibbitt
- Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
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Anderson AR, Nicklow E, Segura T. Particle fraction is a bioactive cue in granular scaffolds. Acta Biomater 2022; 150:111-127. [PMID: 35917913 PMCID: PMC10329855 DOI: 10.1016/j.actbio.2022.07.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/15/2022] [Accepted: 07/26/2022] [Indexed: 11/27/2022]
Abstract
Microporous annealed particle (MAP) hydrogels are porous 3D scaffolds generated by interlinking randomly packed microgels (µgels). Particle fraction, hydrogel stiffness, microparticle shape, and crosslinking chemistry are paramount to the microstructure that microgels make within MAP scaffolds. Of these parameters, control over the particle fraction in MAP scaffolds varies greatly by user and drying technique, leading to inconsistent microarchitectures. These inconsistencies have biological ramifications, as the particle fraction of MAP scaffolds determines the void space within the material which strongly impacts cell growth. Here, we describe a method of freeze-drying microgels that leads to consistent and user-defined particle fractions by weighing the dried microgel powder and reconstituting at known volumes. Though freeze-drying hydrogels typically leads to ice crystal and cryogel formation, we report on mediums that result in freeze-dried microgels that retain their original properties when rehydrated. By rehydrating lyophilized microgels to form MAP scaffolds, we demonstrate that particle fraction controls the bulk scaffold stiffness, but not local microgel stiffness. Further, the particle fraction in MAP scaffolds directly affects cell growth and macromolecular diffusion. Using controlled particle fractions in MAP scaffolds, we can now reproducibly assess mechanical properties, diffusion of macromolecules, and cell responses within user-defined microarchitectures. STATEMENT OF SIGNIFICANCE: The porosity of biomaterials is one key characteristic that influences cell infiltration and growth. Granular hydrogels are a class of biomaterials that are comprised of small, building block components that boast a porous architecture in the void space between the particles. Controlling the composition of these granular materials is key to guiding cell responses. In this work, we demonstrate methods for controlling the fraction of the material containing hydrogel versus void space. As a result, we can now reproducibly study the effect of particle fraction on cell responses, mechanical properties, and mass transport in granular hydrogels.
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Affiliation(s)
- Alexa R Anderson
- Department of Biomedical Engineering, Duke University, 534 Research Drive, Durham NC 27708-0281, United States
| | - Ethan Nicklow
- Department of Biomedical Engineering, Duke University, 534 Research Drive, Durham NC 27708-0281, United States
| | - Tatiana Segura
- Department of Biomedical Engineering, Duke University, 534 Research Drive, Durham NC 27708-0281, United States; Clinical Science Departments of Neurology and Dermatology, Duke University, 534 Research Drive, Durham NC 27708-0281, United States.
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