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Rohrer L, Kato S, Browne SA, Striedinger-Melo K, Healy K, Pomerantz JH. Acrylated Hyaluronic-Acid Based Hydrogel for the Treatment of Craniofacial Volumetric Muscle Loss. Tissue Eng Part A 2024. [PMID: 38534963 DOI: 10.1089/ten.tea.2023.0241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024] Open
Abstract
Current treatment options for craniofacial volumetric muscle loss (VML) have disadvantages and cannot fully restore normal function. Bio-inspired semisynthetic acrylated hyaluronic acid (AcHyA) hydrogel, which fills irregularly shaped defects, resembles an extracellular matrix, and induces a minimal inflammatory response, has shown promise in experimental studies of extremity VML. We therefore sought to study AcHyA hydrogel in the treatment of craniofacial VML. For this, we used a novel model of masseter VML in the rat. Following the creation of a 5 mm × 5 mm injury to the superficial masseter and administration of AcHyA to the wound, masseters were explanted between 2 and 16 weeks postoperatively and were analyzed for evidence of muscle regeneration including fibrosis, defect size, and fiber cross-sectional area (FCSA). At 8 and 16 weeks, masseters treated with AcHyA showed significantly less fibrosis than nonrepaired controls and a smaller decrease in defect size. The mean FCSA among fibers near the defect was significantly greater among hydrogel-repaired than control masseters at 8 weeks, 12 weeks, and 16 weeks. These results show that the hydrogel mitigates the fibrotic healing response and wound contracture. Our findings also suggest that hydrogel-based treatments have potential use as a treatment for the regeneration of craniofacial VML and demonstrate a system for evaluating subsequent iterations of materials in VML injuries.
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Affiliation(s)
- Lucas Rohrer
- School of Medicine, University of California San Francisco, San Francisco, California, USA
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, California, USA
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of California San Francisco, San Francisco, California, USA
| | - Shinji Kato
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, California, USA
| | - Shane A Browne
- Department of Bioengineering, University of California Berkeley, Berkeley, California, USA
| | - Katharine Striedinger-Melo
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, California, USA
| | - Kevin Healy
- Department of Bioengineering, University of California Berkeley, Berkeley, California, USA
| | - Jason H Pomerantz
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, California, USA
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of California San Francisco, San Francisco, California, USA
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2
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Jiang W, Han L, Li G, Yang Y, Shen Q, Fan B, Wang Y, Yu X, Sun Y, He S, Du H, Miao J, Wang Y, Jia L. Baits-trap chip for accurate and ultrasensitive capture of living circulating tumor cells. Acta Biomater 2023; 162:226-239. [PMID: 36940769 DOI: 10.1016/j.actbio.2023.03.019] [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: 12/19/2022] [Revised: 02/17/2023] [Accepted: 03/13/2023] [Indexed: 03/22/2023]
Abstract
Accurate analysis of living circulating tumor cells (CTCs) plays a crucial role in cancer diagnosis and prognosis evaluation. However, it is still challenging to develop a facile method for accurate, sensitive, and broad-spectrum isolation of living CTCs. Herein, inspired by the filopodia-extending behavior and clustered surface-biomarker of living CTCs, we present a unique baits-trap chip to achieve accurate and ultrasensitive capture of living CTCs from peripheral blood. The baits-trap chip is designed with the integration of nanocage (NCage) structure and branched aptamers. The NCage structure could "trap" the extended filopodia of living CTCs and resist the adhesion of filopodia-inhibited apoptotic cells, thus realizing the accurate capture (∼95% accuracy) of living CTCs independent of complex instruments. Using an in-situ rolling circle amplification (RCA) method, branched aptamers were easily modified onto the NCage structure, and served as "baits" to enhance the multi-interactions between CTC biomarker and chips, leading to ultrasensitive (99%) and reversible cell capture performance. The baits-trap chip successfully detects living CTCs in broad-spectrum cancer patients and achieves high diagnostic sensitivity (100%) and specificity (86%) of early prostate cancer. Therefore, our baits-trap chip provides a facile, accurate, and ultrasensitive strategy for living CTC isolation in clinical. STATEMENT OF SIGNIFICANCE: A unique baits-trap chip integrated with precise nanocage structure and branched aptamers was developed for the accurate and ultrasensitive capture of living CTCs. Compared with the current CTC isolation methods that are unable to distinguish CTC viability, the nanocage structure could not only "trap" the extended-filopodia of living CTCs, but also resist the adhesion of filopodia-inhibited apoptotic cells, thus realizing the accurate capture of living CTCs. Additionally, benefiting from the "baits-trap" synergistic effects generated by aptamer modification and nanocage structure, our chip achieved ultrasensitive, reversible capture of living CTCs. Moreover, this work provided a facile strategy for living CTC isolation from the blood of patients with early-stage and advanced cancer, exhibiting high consistency with the pathological diagnosis.
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Affiliation(s)
- Wenning Jiang
- Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116023, P. R. China
| | - Lulu Han
- Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116023, P. R. China.
| | - Guorui Li
- Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116023, P. R. China
| | - Ying Yang
- Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116023, P. R. China
| | - Qidong Shen
- Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116023, P. R. China
| | - Bo Fan
- Department of Urology, The Second Hospital Affiliated of Dalian Medical University, Dalian 116023, P. R. China
| | - Yuchao Wang
- Department of Urology, The Second Hospital Affiliated of Dalian Medical University, Dalian 116023, P. R. China
| | - Xiaomin Yu
- Department of Oncology, The Dalian Municipal Central Hospital Affiliated of Dalian University of Technology, Dalian 116033, P.R. China
| | - Yan Sun
- Department of Oncology, The Dalian Municipal Central Hospital Affiliated of Dalian University of Technology, Dalian 116033, P.R. China
| | - Shengxiu He
- Department of Oncology, The Dalian Municipal Central Hospital Affiliated of Dalian University of Technology, Dalian 116033, P.R. China
| | - Huakun Du
- Department of Oncology, The Dalian Municipal Central Hospital Affiliated of Dalian University of Technology, Dalian 116033, P.R. China
| | - Jian Miao
- Hepatobiliary Pancreatic Surgery II, The Second Hospital Affiliated of Dalian Medical University, Dalian 116023, P. R. China
| | - Yuefeng Wang
- Hepatobiliary Pancreatic Surgery II, The Second Hospital Affiliated of Dalian Medical University, Dalian 116023, P. R. China
| | - Lingyun Jia
- Liaoning Key Laboratory of Molecular Recognition and Imaging, School of Bioengineering, Dalian University of Technology, Dalian 116023, P. R. China.
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3
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Ramasubramanian A, Muckom R, Sugnaux C, Fuentes C, Ekerdt BL, Clark DS, Healy KE, Schaffer DV. High-Throughput Discovery of Targeted, Minimally Complex Peptide Surfaces for Human Pluripotent Stem Cell Culture. ACS Biomater Sci Eng 2021; 7:1344-1360. [PMID: 33750112 DOI: 10.1021/acsbiomaterials.0c01462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human pluripotent stem cells harbor an unlimited capacity to generate therapeutically relevant cells for applications in regenerative medicine. However, to utilize these cells in the clinic, scalable culture systems that activate defined receptors and signaling pathways to sustain stem cell self-renewal are required; and synthetic materials offer considerable promise to meet these needs. De novo development of materials that target novel pathways has been stymied by a limited understanding of critical receptor interactions maintaining pluripotency. Here, we identify peptide agonists for the human pluripotent stem cell (hPSC) laminin receptor and pluripotency regulator, α6-integrin, through unbiased, library-based panning strategies. Biophysical characterization of adhesion suggests that identified peptides bind hPSCs through α6-integrin with sub-μM dissociation constants similar to laminin. By harnessing a high-throughput microculture platform, we developed predictive guidelines for presenting these integrin-targeting peptides alongside canonical binding motifs at optimal stoichiometries to generate nascent culture surfaces. Finally, when presented as self-assembled monolayers, predicted peptide combinations supported hPSC expansion, highlighting how unbiased screens can accelerate the discovery of targeted biomaterials.
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Affiliation(s)
- Anusuya Ramasubramanian
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Riya Muckom
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Caroline Sugnaux
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Christina Fuentes
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Barbara L Ekerdt
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Douglas S Clark
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Kevin E Healy
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States.,Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - David V Schaffer
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States.,Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
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4
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The impact of antifouling layers in fabricating bioactive surfaces. Acta Biomater 2021; 126:45-62. [PMID: 33727195 DOI: 10.1016/j.actbio.2021.03.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/18/2021] [Accepted: 03/09/2021] [Indexed: 12/18/2022]
Abstract
Bioactive surfaces modified with functional peptides are critical for both fundamental research and practical application of implant materials and tissue repair. However, when bioactive molecules are tethered on biomaterial surfaces, their functions can be compromised due to unwanted fouling (mainly nonspecific protein adsorption and cell adhesion). In recent years, researchers have continuously studied antifouling strategies to obtain low background noise and effectively present the function of bioactive molecules. In this review, we describe several commonly used antifouling strategies and analyzed their advantages and drawbacks. Among these strategies, antifouling molecules are widely used to construct the antifouling layer of various bioactive surfaces. Subsequently, we summarize various structures of antifouling molecules and their surface grafting methods and characteristics. Application of these functionalized surfaces in microarray, biosensors, and implants are also introduced. Finally, we discuss the primary challenges associated with antifouling layers in fabricating bioactive surfaces and provide prospects for the future development of this field. STATEMENT OF SIGNIFICANCE: The nonspecific protein adsorption and cell adhesion will cause unwanted background "noise" on the surface of biological materials and detecting devices and compromise the performance of functional molecules and, therefore, impair the performance of materials and the sensitivity of devices. In addition, the selection of antifouling surfaces with proper chain length and high grafting density is also of great importance and requires further studies. Otherwise, the surface-tethered bioactive molecules may not function in their optimal status or even fail to display their functions. Based on these two critical issues, we summarize antifouling molecules with different structures, variable grafting methods, and diverse applications in biomaterials and biomedical devices reported in literature. Overall, we expect to shed some light on choosing the appropriate antifouling molecules in fabricating bioactive surfaces.
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5
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Dienes J, Browne S, Farjun B, Amaral Passipieri J, Mintz EL, Killian G, Healy KE, Christ GJ. Semisynthetic Hyaluronic Acid-Based Hydrogel Promotes Recovery of the Injured Tibialis Anterior Skeletal Muscle Form and Function. ACS Biomater Sci Eng 2021; 7:1587-1599. [PMID: 33660968 DOI: 10.1021/acsbiomaterials.0c01751] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Volumetric muscle loss (VML) injuries are characterized by a degree of tissue loss that exceeds the endogenous regenerative capacity of muscle, resulting in permanent structural and functional deficits. Such injuries are a consequence of trauma, as well as a host of congenital and acquired diseases and disorders. Despite significant preclinical research with diverse biomaterials, as well as early clinical studies with implantation of decellularized extracellular matrices, there are still significant barriers to more complete restoration of muscle form and function following repair of VML injuries. In fact, identification of novel biomaterials with more advantageous regenerative profiles is a critical limitation to the development of improved therapeutics. As a first step in this direction, we evaluated a novel semisynthetic hyaluronic acid-based (HyA) hydrogel that embodies material features more favorable for robust muscle regeneration. This HyA-based hydrogel is composed of an acrylate-modified HyA (AcHyA) macromer, an AcHyA macromer conjugated with the bsp-RGD(15) peptide sequence to enhance cell adhesion, a high-molecular-weight heparin to sequester growth factors, and a matrix metalloproteinase-cleavable cross-linker to allow for cell-dependent remodeling. In a well-established, clinically relevant rat tibialis anterior VML injury model, we report observations of robust functional recovery, accompanied by volume reconstitution, muscle regeneration, and native-like vascularization following implantation of the HyA-based hydrogel at the site of injury. These findings have important implications for the development and clinical application of the improved biomaterials that will be required for stable and complete functional recovery from diverse VML injuries.
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Affiliation(s)
- Jack Dienes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Shane Browne
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States.,Department of Material Science and Engineering, University of California, Berkeley, Berkeley 94720, United States
| | - Bruna Farjun
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Juliana Amaral Passipieri
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Ellen L Mintz
- Pathology Department, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Grant Killian
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, United States
| | - Kevin E Healy
- Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States.,Department of Material Science and Engineering, University of California, Berkeley, Berkeley 94720, United States
| | - George J Christ
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, United States.,Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia 22908, United States
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6
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da Silva LP, Jha AK, Correlo VM, Marques AP, Reis RL, Healy KE. Gellan Gum Hydrogels with Enzyme-Sensitive Biodegradation and Endothelial Cell Biorecognition Sites. Adv Healthc Mater 2018; 7. [PMID: 29388392 DOI: 10.1002/adhm.201700686] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 12/04/2017] [Indexed: 12/13/2022]
Abstract
The survival of a biomaterial or tissue engineered construct is mainly hampered by the deficient microcirculation in its core, and limited nutrients and oxygen availability to the implanted or colonizing host cells. Aiming to address these issues, we herein propose bioresponsive gellan gum (GG) hydrogels that are biodegradable by metalloproteinase 1 (MMP-1) and enable endothelial cells adhesion and proliferation. GG is chemically functionalized with divinyl sulfone (DVS) and then biofunctionalized with thiol cell-adhesive peptides (T1 or C16) to confer GG endothelial cell biorecognition cues. Biodegradable hydrogels are then formed by Michael type addition of GGDVS or/and peptide-functionalized GGDVS with a dithiol peptide crosslinker sensitive to MMP-1. The mechanical properties (6 to 5580 Pa), swelling (17 to 11), MMP-1-driven degradation (up to 70%), and molecules diffusion coefficients of hydrogels are tuned by increasing the polymer amount and crosslinking density. Human umbilical cord vein endothelial cells depict a polarized elongated morphology when encapsulated within T1-containing hydrogels, in contrast to the round morphology observed in C16-containing hydrogels. Cell organization is favored as early as 1 d of cell culture within the T1-modified hydrogels with higher concentration of peptide, while cell proliferation is higher in T1-modified hydrogels with higher modulus. In conclusion, biodegradable and bioresponsive GGDVS hydrogels are promising endothelial cell responsive materials that can be used for vascularization strategies.
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Affiliation(s)
- Lucília P. da Silva
- 3B's Research Group - Biomaterials; Biodegradables and Biomimetics; Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine; University of Minho; Avepark Barco 4805-017 Guimarães Portugal
- ICVS/3B's - PT Government Associate Laboratory; Braga/Guimarães 4710-057/4806-909 Portugal
- Department of Bioengineering; University of California; Berkeley CA 94720-1762 USA
- Department of Materials Science and Engineering; University of California; Berkeley CA 94720-1760 USA
| | - Amit K. Jha
- Department of Bioengineering; University of California; Berkeley CA 94720-1762 USA
- Department of Materials Science and Engineering; University of California; Berkeley CA 94720-1760 USA
| | - Vitor M. Correlo
- 3B's Research Group - Biomaterials; Biodegradables and Biomimetics; Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine; University of Minho; Avepark Barco 4805-017 Guimarães Portugal
- ICVS/3B's - PT Government Associate Laboratory; Braga/Guimarães 4710-057/4806-909 Portugal
- The Discoveries Centre for Regenerative and Precision Medicine; Headquarters at University of Minho; Avepark, Barco 4805-017 Guimarães Portugal
| | - Alexandra P. Marques
- 3B's Research Group - Biomaterials; Biodegradables and Biomimetics; Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine; University of Minho; Avepark Barco 4805-017 Guimarães Portugal
- ICVS/3B's - PT Government Associate Laboratory; Braga/Guimarães 4710-057/4806-909 Portugal
- The Discoveries Centre for Regenerative and Precision Medicine; Headquarters at University of Minho; Avepark, Barco 4805-017 Guimarães Portugal
| | - Rui L. Reis
- 3B's Research Group - Biomaterials; Biodegradables and Biomimetics; Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine; University of Minho; Avepark Barco 4805-017 Guimarães Portugal
- ICVS/3B's - PT Government Associate Laboratory; Braga/Guimarães 4710-057/4806-909 Portugal
- The Discoveries Centre for Regenerative and Precision Medicine; Headquarters at University of Minho; Avepark, Barco 4805-017 Guimarães Portugal
| | - Kevin E. Healy
- Department of Bioengineering; University of California; Berkeley CA 94720-1762 USA
- Department of Materials Science and Engineering; University of California; Berkeley CA 94720-1760 USA
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7
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Yannas IV, Tzeranis D, So PT. Surface biology of collagen scaffold explains blocking of wound contraction and regeneration of skin and peripheral nerves. Biomed Mater 2015; 11:014106. [PMID: 26694657 PMCID: PMC5775477 DOI: 10.1088/1748-6041/11/1/014106] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We review the details of preparation and of the recently elucidated mechanism of biological (regenerative) activity of a collagen scaffold (dermis regeneration template, DRT) that has induced regeneration of skin and peripheral nerves (PN) in a variety of animal models and in the clinic. DRT is a 3D protein network with optimized pore size in the range 20-125 µm, degradation half-life 14 ± 7 d and ligand densities that exceed 200 µM α1β1 or α2β1 ligands. The pore has been optimized to allow migration of contractile cells (myofibroblasts, MFB) into the scaffold and to provide sufficient specific surface for cell-scaffold interaction; the degradation half-life provides the required time window for satisfactory binding interaction of MFB with the scaffold surface; and the ligand density supplies the appropriate ligands for specific binding of MFB on the scaffold surface. A dramatic change in MFB phenotype takes place following MFB-scaffold binding which has been shown to result in blocking of wound contraction. In both skin wounds and PN wounds the evidence has shown clearly that contraction blocking by DRT is followed by induction of regeneration of nearly perfect organs. The biologically active structure of DRT is required for contraction blocking; well-matched collagen scaffold controls of DRT, with structures that varied from that of DRT, have failed to induce regeneration. Careful processing of collagen scaffolds is required for adequate biological activity of the scaffold surface. The newly understood mechanism provides a relatively complete paradigm of regenerative medicine that can be used to prepare scaffolds that may induce regeneration of other organs in future studies.
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Affiliation(s)
- I V Yannas
- Departments of Mechanical and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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8
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Tzeranis DS, Soller EC, Buydash MC, So PTC, Yannas IV. In Situ Quantification of Surface Chemistry in Porous Collagen Biomaterials. Ann Biomed Eng 2015; 44:803-15. [PMID: 26369635 DOI: 10.1007/s10439-015-1445-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 09/01/2015] [Indexed: 01/28/2023]
Abstract
Cells inside a 3D matrix (such as tissue extracellular matrix or biomaterials) sense their insoluble environment through specific binding interactions between their adhesion receptors and ligands present on the matrix surface. Despite the critical role of the insoluble matrix in cell regulation, there exist no widely-applicable methods for quantifying the chemical stimuli provided by a matrix to cells. Here, we describe a general-purpose technique for quantifying in situ the density of ligands for specific cell adhesion receptors of interest on the surface of a 3D matrix. This paper improves significantly the accuracy of the procedure introduced in a previous publication by detailed marker characterization, optimized staining, and improved data interpretation. The optimized methodology is utilized to quantify the ligands of integrins α 1 β 1, α 2 β 1 on two kinds of matched porous collagen scaffolds, which are shown to possess significantly different ligand density, and significantly different ability to induce peripheral nerve regeneration in vivo. Data support the hypothesis that cell adhesion regulates contractile cell phenotypes, recently shown to be inversely related to organ regeneration. The technique provides a standardized way to quantify the surface chemistry of 3D matrices, and a means for introducing matrix effects in quantitative biological models.
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Affiliation(s)
- Dimitrios S Tzeranis
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,Department of Mechanical Engineering, National Technical University of Athens, 15780, Zografou, Greece.
| | - Eric C Soller
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Melissa C Buydash
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Peter T C So
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Ioannis V Yannas
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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9
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A Review of Cell Adhesion Studies for Biomedical and Biological Applications. Int J Mol Sci 2015; 16:18149-84. [PMID: 26251901 PMCID: PMC4581240 DOI: 10.3390/ijms160818149] [Citation(s) in RCA: 519] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 06/21/2015] [Accepted: 06/24/2015] [Indexed: 01/13/2023] Open
Abstract
Cell adhesion is essential in cell communication and regulation, and is of fundamental importance in the development and maintenance of tissues. The mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. The essential function of cell adhesion has created tremendous interests in developing methods for measuring and studying cell adhesion properties. The study of cell adhesion could be categorized into cell adhesion attachment and detachment events. The study of cell adhesion has been widely explored via both events for many important purposes in cellular biology, biomedical, and engineering fields. Cell adhesion attachment and detachment events could be further grouped into the cell population and single cell approach. Various techniques to measure cell adhesion have been applied to many fields of study in order to gain understanding of cell signaling pathways, biomaterial studies for implantable sensors, artificial bone and tooth replacement, the development of tissue-on-a-chip and organ-on-a-chip in tissue engineering, the effects of biochemical treatments and environmental stimuli to the cell adhesion, the potential of drug treatments, cancer metastasis study, and the determination of the adhesion properties of normal and cancerous cells. This review discussed the overview of the available methods to study cell adhesion through attachment and detachment events.
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10
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Prestwich GD, Healy KE. Why regenerative medicine needs an extracellular matrix. Expert Opin Biol Ther 2014; 15:3-7. [DOI: 10.1517/14712598.2015.975200] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Popelka Š, Houska M, Havlíková J, Proks V, Kučka J, Šturcová A, Bačáková L, Rypáček F. Poly(ethylene oxide) brushes prepared by the “grafting to” method as a platform for the assessment of cell receptor–ligand binding. Eur Polym J 2014. [DOI: 10.1016/j.eurpolymj.2014.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Jha AK, Jackson WM, Healy KE. Controlling osteogenic stem cell differentiation via soft bioinspired hydrogels. PLoS One 2014; 9:e98640. [PMID: 24937602 PMCID: PMC4060996 DOI: 10.1371/journal.pone.0098640] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 05/05/2014] [Indexed: 11/18/2022] Open
Abstract
Osteogenic differentiation of human mesenchymal stem cells (hMSCs) is guided by various physical and biochemical factors. Among these factors, modulus (i.e., rigidiy) of the ECM has gained significant attention as a physical osteoinductive signal that can contribute to endochondral ossification of a cartilaginous skeletal template. However, MSCs also participate in intramembranous bone formation, which occurs de novo from within or on a more compliant tissue environment. To further understand the role of the matrix interactions in this process, we evaluated osteogenic differentiation of hMSCs cultured on low moduli (102, 390 or 970 Pa) poly(N-isopropylacrylamide) (p(NIPAAm)) based semi-interpenetrating networks (sIPN) modified with the integrin engaging peptide bsp-RGD(15) (0, 105 or 210 µM). Cell adhesion, proliferation, and osteogenic differentiation of hMSCs, as measured by alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), bone sialoprotein-2 (iBSP), and osteocalcien (OCN) protein expression, was highest on substrates with the highest modulus and peptide concentrations. However, within this range of substrate stiffness, many osteogenic cellular functions were enhanced by increasing either the modulus or the peptide density. These findings suggest that within a compliant and low modulus substrate, a high affinity adhesive ligand serves as a substitute for a rigid matrix to foster osteogenic differentiation.
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Affiliation(s)
- Amit K. Jha
- Department of Bioengineering, University of California, Berkeley, California, United States of America
| | - Wesley M. Jackson
- Department of Bioengineering, University of California, Berkeley, California, United States of America
| | - Kevin E. Healy
- Department of Bioengineering, University of California, Berkeley, California, United States of America
- Department of Materials Science and Engineering, University of California, Berkeley, California, United States of America
- * E-mail:
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13
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Surface Modification of Poly Ethylene Glycol to Resist Nonspecific Adsorption of Proteins. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2013. [DOI: 10.1016/s1872-2040(13)60638-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Rafat M, Rotenstein LS, Hu JL, Auguste DT. Engineered endothelial cell adhesion via VCAM1 and E-selectin antibody-presenting alginate hydrogels. Acta Biomater 2012; 8:2697-703. [PMID: 22504076 DOI: 10.1016/j.actbio.2012.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 03/14/2012] [Accepted: 04/04/2012] [Indexed: 11/19/2022]
Abstract
Materials that adhere to the endothelial cell (EC) lining of blood vessels may be useful for treating vascular injury. Cell adhesion molecules (CAMs), such as endothelial leukocyte adhesion molecule-1 (E-selectin) and vascular cell adhesion molecule-1 (VCAM1), modulate EC-leukocyte interactions. In this study, we mimicked cell-cell interactions by seeding cells on alginate hydrogels modified with antibodies against E-selectin and VCAM1, which are upregulated during inflammation. ECs were activated with interleukin-1α to increase CAM expression and subsequently seeded onto hydrogels. The strength of cell adhesion onto gels was assessed via a centrifugation assay. Strong, cooperative EC adhesion was observed on hydrogels presenting a 1:1 ratio of anti-VCAM1:anti-E-selectin. Cell adhesion was stronger on dual functionalized gels than on gels modified with anti-VCAM1, anti-E-selectin or the arginine-glycine-aspartic acid (RGD) peptide alone. Anti-VCAM1:anti-E-selectin-modified hydrogels may be engineered to adhere the endothelium cooperatively.
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Affiliation(s)
- Marjan Rafat
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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15
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Klim JR, Fowler AJ, Courtney AH, Wrighton PJ, Sheridan RTC, Wong ML, Kiessling LL. Small-molecule-modified surfaces engage cells through the αvβ3 integrin. ACS Chem Biol 2012; 7:518-25. [PMID: 22201290 DOI: 10.1021/cb2004725] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Integrins play myriad and vital roles in development and disease. They connect a cell with its surroundings and transmit chemical and mechanical signals across the plasma membrane to the cell's interior. Dissecting their roles in cell behavior is complicated by their overlapping ligand specificity and shared downstream signaling components. In principle, immobilized synthetic peptides can mimic extracellular matrix proteins by supporting integrin-mediated adhesion, but most short peptide sequences lack selectivity for one integrin over others. In contrast, synthetic integrin antagonists can be highly selective. We hypothesized that this selectivity could be exploited if antagonists, when immobilized, could support cellular adhesion and activate signaling by engaging specific cell-surface integrins. To investigate this possibility, we designed a bifunctional (RGD)-based peptidomimetic for surface presentation. Our conjugate combines a high affinity integrin ligand with a biotin moiety; the former engages the α(v)β(3) integrin, and the latter allows for presentation on streptavidin-coated surfaces. Surfaces decorated with this ligand promote both cellular adhesion and integrin activation. Moreover, the selectivity of these surfaces for the α(v)β(3) integrin can be exploited to capture a subset of cells from a mixed population. We anticipate that surfaces displaying highly selective small molecule ligands can reveal the contributions of specific integrin heterodimers to cell adhesion and signaling.
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Affiliation(s)
- Joseph R. Klim
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Anthony J. Fowler
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Adam H. Courtney
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Paul J. Wrighton
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Rachael T. C. Sheridan
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Margaret L. Wong
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Laura L. Kiessling
- Cell
and Molecular Biology Program, ‡Department of Chemistry, and §Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
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16
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Rafat M, Rotenstein LS, You JO, Auguste DT. Dual functionalized PVA hydrogels that adhere endothelial cells synergistically. Biomaterials 2012; 33:3880-6. [PMID: 22364701 DOI: 10.1016/j.biomaterials.2012.02.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 02/06/2012] [Indexed: 10/28/2022]
Abstract
Cell adhesion molecules govern leukocyte-endothelial cell (EC) interactions that are essential in regulating leukocyte recruitment, adhesion, and transmigration in areas of inflammation. In this paper, we synthesized hydrogel matrices modified with antibodies against vascular cell adhesion molecule-1 (VCAM1) and endothelial leukocyte adhesion molecule-1 (E-Selectin) to mimic leukocyte-EC interactions. Adhesion of human umbilical vein ECs to polyvinyl alcohol (PVA) hydrogels was examined as a function of the relative antibody ratio (anti-VCAM1:anti-E-Selectin) and substrate elasticity. Variation of PVA backbone methacrylation was used to affect hydrogel matrix stiffness, ranging from 130 to 720 kPa. Greater EC adhesion was observed on hydrogels presenting 1:1 anti-VCAM1:anti-E-Selectin than on gels presenting either arginine-glycine-asparagine (RGD) peptide, anti-VCAM1, or anti-E-Selectin alone. Engineered cell adhesion - based on complementing the EC surface presentation - may be used to increase the strength of EC-matrix interactions. Hydrogels with tunable and synergistic adhesion may be useful in vascular remodeling.
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Affiliation(s)
- Marjan Rafat
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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17
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Cell adhesion to plasma electrolytic oxidation (PEO) titania coatings, assessed using a centrifuging technique. J Mech Behav Biomed Mater 2011; 4:2103-12. [DOI: 10.1016/j.jmbbm.2011.07.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 07/12/2011] [Accepted: 07/18/2011] [Indexed: 10/18/2022]
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18
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Little LE, Dane KY, Daugherty PS, Healy KE, Schaffer DV. Exploiting bacterial peptide display technology to engineer biomaterials for neural stem cell culture. Biomaterials 2010; 32:1484-94. [PMID: 21129772 DOI: 10.1016/j.biomaterials.2010.10.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 10/15/2010] [Indexed: 12/16/2022]
Abstract
Stem cells are often cultured on substrates that present extracellular matrix (ECM) proteins; however, the heterogeneous and poorly defined nature of ECM proteins presents challenges both for basic biological investigation of cell-matrix investigations and translational applications of stem cells. Therefore, fully synthetic, defined materials conjugated with bioactive ligands, such as adhesive peptides, are preferable for stem cell biology and engineering. However, identifying novel ligands that engage cellular receptors can be challenging, and we have thus developed a high throughput approach to identify new adhesive ligands. We selected an unbiased bacterial peptide display library for the ability to bind adult neural stem cells (NSCs), and 44 bacterial clones expressing peptides were identified and found to bind to NSCs with high avidity. Of these clones, four contained RGD motifs commonly found in integrin binding domains, and three exhibited homology to ECM proteins. Three peptide clones were chosen for further analysis, and their synthetic analogs were adsorbed on tissue culture polystyrene (TCPS) or grafted onto an interpenetrating polymer network (IPN) for cell culture. These three peptides were found to support neural stem cell self-renewal in defined medium as well as multi-lineage differentiation. Therefore, bacterial peptide display offers unique advantages to isolate bioactive peptides from large, unbiased libraries for applications in biomaterials engineering.
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Affiliation(s)
- Lauren E Little
- Department of Chemical Engineering, University of California at Berkeley, Berkeley, CA 94720, United States
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19
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Tzeranis DS, Roy A, So PTC, Yannas IV. An optical method to quantify the density of ligands for cell adhesion receptors in three-dimensional matrices. J R Soc Interface 2010; 7 Suppl 5:S649-61. [PMID: 20671067 PMCID: PMC3024575 DOI: 10.1098/rsif.2010.0321.focus] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 07/09/2010] [Indexed: 12/21/2022] Open
Abstract
The three-dimensional matrix that surrounds cells is an important insoluble regulator of cell phenotypes. Examples of such insoluble surfaces are the extracellular matrix (ECM), ECM analogues and synthetic polymeric biomaterials. Cell-matrix interactions are mediated by cell adhesion receptors that bind to chemical entities (adhesion ligands) on the surface of the matrix. There are currently no established methods to obtain quantitative estimates of the density of adhesion ligands recognized by specific cell adhesion receptors. This article presents a new optical-based methodology for measuring ligands of adhesion receptors on three-dimensional matrices. The study also provides preliminary quantitative results for the density of adhesion ligands of integrins alpha(1)beta(1) and alpha(2)beta(1) on the surface of collagen-based scaffolds, similar to biomaterials that are used clinically to induce regeneration in injured skin and peripheral nerves. Preliminary estimates of the surface density of the ligands of these two major collagen-binding receptors are 5775 +/- 2064 ligands microm(-2) for ligands of alpha(1)beta(1) and 17 084 +/- 5353 ligands microm(-2) for ligands of alpha(2)beta(1). The proposed methodology can be used to quantify the surface chemistry of insoluble surfaces that possess biological activity, such as native tissue ECM and biomaterials, and therefore can be used in cell biology, biomaterials science and regenerative medical studies for quantitative description of a matrix and its effects on cells.
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Affiliation(s)
- Dimitrios S. Tzeranis
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Amit Roy
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Peter T. C. So
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ioannis V. Yannas
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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20
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Kurkuri MD, Driever C, Johnson G, McFarland G, Thissen H, Voelcker NH. Multifunctional Polymer Coatings for Cell Microarray Applications. Biomacromolecules 2009; 10:1163-72. [DOI: 10.1021/bm801417s] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mahaveer D. Kurkuri
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Bedford Park SA 5042, Australia, CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168, Australia, CSIRO Molecular and Health Technologies, Riverside Corporate Park, 11 Julius Avenue, North Ryde NSW 2113, Australia, and CSIRO Food Futures Flagship, Riverside Corporate Park, 5 Julius Avenue, North Ryde NSW 2113, Australia
| | - Chantelle Driever
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Bedford Park SA 5042, Australia, CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168, Australia, CSIRO Molecular and Health Technologies, Riverside Corporate Park, 11 Julius Avenue, North Ryde NSW 2113, Australia, and CSIRO Food Futures Flagship, Riverside Corporate Park, 5 Julius Avenue, North Ryde NSW 2113, Australia
| | - Graham Johnson
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Bedford Park SA 5042, Australia, CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168, Australia, CSIRO Molecular and Health Technologies, Riverside Corporate Park, 11 Julius Avenue, North Ryde NSW 2113, Australia, and CSIRO Food Futures Flagship, Riverside Corporate Park, 5 Julius Avenue, North Ryde NSW 2113, Australia
| | - Gail McFarland
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Bedford Park SA 5042, Australia, CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168, Australia, CSIRO Molecular and Health Technologies, Riverside Corporate Park, 11 Julius Avenue, North Ryde NSW 2113, Australia, and CSIRO Food Futures Flagship, Riverside Corporate Park, 5 Julius Avenue, North Ryde NSW 2113, Australia
| | - Helmut Thissen
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Bedford Park SA 5042, Australia, CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168, Australia, CSIRO Molecular and Health Technologies, Riverside Corporate Park, 11 Julius Avenue, North Ryde NSW 2113, Australia, and CSIRO Food Futures Flagship, Riverside Corporate Park, 5 Julius Avenue, North Ryde NSW 2113, Australia
| | - Nicolas H. Voelcker
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Bedford Park SA 5042, Australia, CSIRO Molecular and Health Technologies, Bayview Avenue, Clayton VIC 3168, Australia, CSIRO Molecular and Health Technologies, Riverside Corporate Park, 11 Julius Avenue, North Ryde NSW 2113, Australia, and CSIRO Food Futures Flagship, Riverside Corporate Park, 5 Julius Avenue, North Ryde NSW 2113, Australia
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21
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Wan J, Thomas MS, Guthrie S, Vullev VI. Surface-bound proteins with preserved functionality. Ann Biomed Eng 2009; 37:1190-205. [PMID: 19308733 DOI: 10.1007/s10439-009-9673-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Accepted: 03/09/2009] [Indexed: 12/28/2022]
Abstract
Biocompatibility of materials strongly depends on their surface properties. Therefore, surface derivatization in a controllable manner provides means for achieving interfaces essential for a broad range of chemical, biological, and medical applications. Bioactive interfaces, while manifesting the activity for which they are designed, should suppress all nonspecific interaction between the supporting substrates and the surrounding media. This article describes a procedure for chemical derivatization of glass and silicon surfaces with polyethylene glycol (PEG) layers covalently functionalized with proteins. While the proteins introduce the functionality to the surfaces, the PEGs provide resistance against nonspecific interactions. For formation of aldehyde-functionalized surfaces, we coated the substrates with acetals (i.e., protected aldehydes). To avoid deterioration of the surfaces, we did not use strong mineral acids for the deprotection of the aldehydes. Instead, we used a relatively weak Lewis acid for conversion of the acetals into aldehydes. Introduction of alpha,omega-bifunctional polymers into the PEG layers, bound to the aldehydes, allowed us to covalently attach green fluorescent protein and bovine carbonic anhydrase to the surfaces. Spectroscopic studies indicated that the surface-bound proteins preserve their functionalities. The surface concentrations of the proteins, however, did not manifest linear proportionality to the molar fractions of the bifunctional PEGs used for the coatings. This finding suggests that surface-loading ratios cannot be directly predicted from the compositions of the solutions of competing reagents used for chemical derivatization.
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Affiliation(s)
- Jiandi Wan
- Department of Bioengineering, University of California, Riverside, A-220 Bourns Hall, Riverside, CA 92521, USA
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22
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Irwin EF, Saha K, Rosenbluth M, Gamble LJ, Castner DG, Healy KE. Modulus-dependent macrophage adhesion and behavior. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2009; 19:1363-82. [PMID: 18854128 DOI: 10.1163/156856208786052407] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Macrophage attachment and activation to implanted materials is crucial in determining the extent of acute and chronic inflammation, and biomaterials degradation. In an effort to improve implant performance, considerable attention has centered on altering material surface chemistry to modulate macrophage behavior. In this work, the influence of the modulus of a material on the behavior of model macrophages (i.e., human promonocytic THP-1 cells) was investigated. We synthesized interpenetrating polymer network (IPN) coatings with varying moduli to test the hypothesis that lower moduli surfaces attenuate THP-1 cell attachment and activation. The surface chemistry and moduli of the IPN coatings were characterized using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. THP-1 cells preferentially attached to stiffer coatings of identical surface chemistry, confirming that fewer macrophages attach to lower moduli surfaces. The secretion of human TNF-alpha, IL-10, IL-8 and IL-1beta from THP-1 cells attached to the IPNs was measured to assess the concentration of both pro- and anti-inflammatory cytokines. The global amount of TNF-alpha released did not vary for IPN surfaces of different moduli; however, the amount of the pro-inflammatory cytokine IL-8 released demonstrated a biphasic response, where lower (approx. 1.4 kPa) and very high (approx. 348 kPa) moduli IPN surfaces attenuated IL-8 secretion. The different trends for TNF-alpha and IL-8 secretion highlight the complexity of the wound healing response, suggesting that there may not be a unique surface chemistry and substratum modulus combination that minimizes the pro-inflammatory cytokines produced by activated macrophages.
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Affiliation(s)
- E F Irwin
- Department of Bioengineering, University of California-Berkeley, Berkeley, CA 94720, USA
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23
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He X, Ma J, Jabbari E. Effect of grafting RGD and BMP-2 protein-derived peptides to a hydrogel substrate on osteogenic differentiation of marrow stromal cells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:12508-12516. [PMID: 18837524 DOI: 10.1021/la802447v] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Osteogenic differentiation and mineralization of bone marrow stromal (BMS) cells depends on the cells' interactions with bioactive peptides associated with the matrix proteins. The RGD peptides of ECM proteins interact with BMS cells through integrin surface receptors to facilitate cell spreading and adhesion. The BMP peptide corresponding to residues 73-92 of bone morphogenetic protein-2 promotes differentiation and mineralization of BMS cells. The objective of this work was to investigate the effects of RGD and BMP peptides, grafted to a hydrogel substrate, on osteogenic differentiation and mineralization of BMS cells. RGD peptide was acrylamide-terminated by reacting acrylic acid with the N-terminal amine group of the peptide to produce the functionalized Ac-GRGD peptide. The PEGylated BMP peptide was reacted with 4-carboxybenzenesulfonazide to produce an azide functionalized Az-mPEG-BMP peptide. Poly (lactide-co-ethylene oxide- co-fumarate) (PLEOF) macromer was cross-linked with Ac-GRGD peptide and propargyl acrylate to produce an RGD conjugated hydrogel. Az-mPEG-BMP peptide was grafted to the hydrogel by "click chemistry". The RGD and BMP peptide density on the hydrogel surface was 1.62+/-0.37 and 5.2+/-0.6 pmol/cm2, respectively. BMS cells were seeded on the hydrogels and the effect of RGD and BMP peptides on osteogenesis was evaluated by measuring ALPase activity and calcium content with incubation time. BMS cells cultured on RGD conjugated, BMP peptide grafted, and RGD+BMP peptide modified hydrogels showed 3, 2.5, and 5-fold increase in ALPase activity after 14 days incubation. BMS cells seeded on RGD+BMP peptides modified hydrogel showed 4.9- and 11.8-fold increase in calcium content after 14 and 21 days, respectively, which was significantly higher than RGD conjugated or BMP grafted hydrogels. These results demonstrate that RGD and BMP peptides, grafted to a hydrogel substrate, act synergistically to enhance osteogenic differentiation and mineralization of BMS cells. These findings are potentially useful in developing engineered scaffolds for bone regeneration.
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Affiliation(s)
- Xuezhong He
- Biomimetic Materials Laboratory, Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA
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24
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Fraser SA, Ting YH, Mallon KS, Wendt AE, Murphy CJ, Nealey PF. Sub-micron and nanoscale feature depth modulates alignment of stromal fibroblasts and corneal epithelial cells in serum-rich and serum-free media. J Biomed Mater Res A 2008; 86:725-35. [PMID: 18041718 DOI: 10.1002/jbm.a.31519] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Topographic features are generally accepted as being capable of modulating cell alignment. Of particular interest is the potential that topographic feature geometry induces cell alignment indirectly through impacting adsorbed proteins from the cell culture medium on the surface of the substrate. However, it has also been reported that micron-scale feature depth significantly impacts the level of alignment of cellular populations on topography, despite being orders of magnitude larger than the average adsorbed protein layer (nm). In order to better determine the impact of biomimetic length scale topography and adsorbed protein interaction on cellular morphology we have systematically investigated the effect of combinations of sub-micron to nanoscale feature depth and lateral pitch on corneal epithelial cell alignment. In addition we have used the unique properties of a serum-free media alternative in direct comparison to serum-rich medium to investigate the role of culture medium protein composition on cellular alignment to topographically patterned surfaces. Our observation that increasing groove depth elicited larger populations of corneal epithelial cells to align regardless of culture medium composition and of cell orientation with respect to the topography, suggests that these cells can sense changes in topographic feature depths independent of adsorbed proteins localized along ridge edges and tops. However, our data also suggests a strong combinatory effect of topography with culture medium composition, and also a cell type dependency in determining the level of cell elongation and alignment to nanoscale topographic features.
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Affiliation(s)
- Sarah A Fraser
- Department of Chemical Engineering, School of Engineering, University of Wisconsin, Madison, Madison, Wisconsin 53706, USA
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25
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Harbers GM, Emoto K, Greef C, Metzger SW, Woodward HN, Mascali JJ, Grainger DW, Lochhead MJ. A functionalized poly(ethylene glycol)-based bioassay surface chemistry that facilitates bio-immobilization and inhibits non-specific protein, bacterial, and mammalian cell adhesion. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2008; 19:4405-4414. [PMID: 18815622 PMCID: PMC2546567 DOI: 10.1021/cm070509u] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This paper describes a new bioassay surface chemistry that effectively inhibits non-specific biomolecular and cell binding interactions, while providing a capacity for specific immobilization of desired biomolecules. Poly(ethylene glycol) (PEG) as the primary component in nonfouling film chemistry is well-established, but the multicomponent formulation described here is unique in that it (1) is applied in a single, reproducible, solution-based coating step; (2) can be applied to diverse substrate materials without the use of special primers; and (3) is readily functionalized to provide specific attachment chemistries. Surface analysis data are presented, detailing surface roughness, polymer film thickness, and film chemistry. Protein non-specific binding assays demonstrate significant inhibition of serum, fibrinogen, and lysozyme adsorption to coated glass, indium tin oxide, and tissue culture polystyrene dishes. Inhibition of S. aureus and K. pneumoniae microbial adhesion in a microfluidic flow cell, and inhibition of fibroblast cell adhesion from serum-based cell culture is shown. Effective functionalization of the coating is demonstrated by directing fibroblast adhesion to polymer surfaces activated with an RGD peptide. Batch-to-batch reproducibility data are included. The in situ cross-linked PEG-based coating chemistry is unique in its formulation, and its surface properties are attractive for a broad range of in vitro bioassay applications.
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Affiliation(s)
- Gregory M. Harbers
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872 USA
| | - Kazunori Emoto
- Accelr8 Technology Corporation, 7000 N. Broadway, Suite 3-307, Denver, CO 80221 USA
| | - Charles Greef
- Accelr8 Technology Corporation, 7000 N. Broadway, Suite 3-307, Denver, CO 80221 USA
| | - Steven W. Metzger
- Accelr8 Technology Corporation, 7000 N. Broadway, Suite 3-307, Denver, CO 80221 USA
| | - Heather N. Woodward
- Accelr8 Technology Corporation, 7000 N. Broadway, Suite 3-307, Denver, CO 80221 USA
| | - James J. Mascali
- Accelr8 Technology Corporation, 7000 N. Broadway, Suite 3-307, Denver, CO 80221 USA
| | - David W. Grainger
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872 USA
| | - Michael J. Lochhead
- Accelr8 Technology Corporation, 7000 N. Broadway, Suite 3-307, Denver, CO 80221 USA
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26
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Little L, Healy KE, Schaffer D. Engineering biomaterials for synthetic neural stem cell microenvironments. Chem Rev 2008; 108:1787-96. [PMID: 18476674 DOI: 10.1021/cr078228t] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Lauren Little
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1760, USA
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27
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Abstract
Although biochemical signals that modulate stem cell self-renewal and differentiation were extensively studied, only recently were the mechanical properties of a stem cell's microenvironment shown to regulate its behavior. It would be desirable to have independent control over biochemical and mechanical cues, to analyze their relative and combined effects on stem-cell function. We developed a synthetic, interfacial hydrogel culture system, termed variable moduli interpenetrating polymer networks (vmIPNs), to assess the effects of soluble signals, adhesion ligand presentation, and material moduli from 10-10,000 Pa on adult neural stem-cell (aNSC) behavior. The aNSCs proliferated when cultured in serum-free growth media on peptide-modified vmIPNs with moduli of >/=100 Pa. In serum-free neuronal differentiation media, a peak level of the neuronal marker, beta-tubulin III, was observed on vmIPNs of 500 Pa, near the physiological stiffness of brain tissue. Furthermore, under mixed differentiation conditions with serum, softer gels ( approximately 100-500 Pa) greatly favored neurons, whereas harder gels ( approximately 1,000-10,000 Pa) promoted glial cultures. In contrast, cell spreading, self-renewal, and differentiation were inhibited on substrata with moduli of approximately 10 Pa. This work demonstrates that the mechanical and biochemical properties of an aNSC microenvironment can be tuned to regulate the self-renewal and differentiation of aNSCs.
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28
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Patel S, Tsang J, Harbers GM, Healy KE, Li S. Regulation of endothelial cell function by GRGDSP peptide grafted on interpenetrating polymers. J Biomed Mater Res A 2007; 83:423-33. [PMID: 17455217 DOI: 10.1002/jbm.a.31320] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vascular endothelium plays an important role in preventing thrombogenesis. Bioactive molecules such as fibronectin-derived peptide Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) can be used to modify the surface of cardiovascular implants such as vascular grafts to promote endothelialization. Here we conjugated GRGDSP peptide to the nonfouling surface of an interpenetrating polymer network (IPN), and investigated the effects of the immobilized GRGDSP molecules on EC functions under static and flow conditions at well-defined GRGDSP surface densities (approximately 0 to 3 pmol/cm2). EC adhesion and spreading increased with GRGDSP surface density, reached a plateau at 1.5 pmol/cm2, and increased further beyond 2.8 pmol/cm2. Cell adhesion and spreading on GRGDSP induced two waves of extracellular signal-regulated kinase (ERK) activation, and 0.2 pmol/cm2 density of GRGDSP was sufficient to activate ERK. EC proliferation rate was not sensitive to GRGDSP surface density, suggesting that cell spreading at low-density of GRGDSP is sufficient to maintain EC proliferation. EC migration on lower-density GRGDSP-IPN surfaces was faster under static condition. With the increase of GRGDSP density, the speed and persistence of EC migration dropped quickly (0.2-0.8 pmol/cm2) and reached a plateau, followed by a slower and gradual decrease (1.5-3.0 pmol/cm2). These data suggest that the changes of EC functions were more sensitive to the increase of GRGDSP density at lower range. Under flow condition with shear stress at 12 dyn/cm2, EC migration was inhibited on GRGDSP-IPN surfaces, which may be attributed to the assembly of large focal adhesions induced by shear stress, suggesting a catch-bond characteristic for RGD-integrin binding. This study provides a rational base for surface engineering of cardiovascular implants.
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Affiliation(s)
- Shyam Patel
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720, USA
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29
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Ho JE, Chung EH, Wall S, Schaffer DV, Healy KE. Immobilized sonic hedgehog N‐terminal signaling domain enhances differentiation of bone marrow‐derived mesenchymal stem cells. J Biomed Mater Res A 2007; 83:1200-1208. [PMID: 17600327 DOI: 10.1002/jbm.a.31355] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The signaling domain of Sonic hedgehog (Shh), a potent upstream regulator of cell fate that has been implicated in osteoblast differentiation from undifferentiated mesenchymal cells in its endogenous form, was investigated in an immobilized form as a means for accelerating differentiation of uncommitted cells to the osteoblast phenotype. A recombinant cysteine-modified N-terminal Shh (mShh) was synthesized, purified, and immobilized onto interpenetrating polymer network (IPN) surfaces also grafted with a bone sialoprotein-derived peptide containing the Arg-Gly-Asp (RGD) sequence (bsp-RGD (15)), at calculated densities of 2.42 and 10 pmol/cm2, respectively. The mitogenic effect of mShh was dependent on the mode of presentation, as surfaces with immobilized mShh and bsp-RGD (15) had no effect on the growth rate of rat bone marrow-derived mesenchymal stem cells (BMSCs), while soluble mShh enhanced cell growth compared to similar surface without mShh supplementation. In conjunction with media supplemented with bone morphogenetic protein-2 and -4, mShh and bsp-RGD (15)-grafted IPN surfaces enhanced the alkaline phosphatase activity of BMSCs compared with tissue culture polystyrene and bsp-RGD (15)-grafted IPN surfaces supplemented with soluble mShh, indicating enhanced osteoblast differentiation. The adhesive peptide bsp-RGD (15) was necessary for cell attachment and proliferation, as well as differentiation in response to immobilized mShh. The addition of immobilized Shh substantially improved the differentiation of uncommitted BMSCs to the osteoblast lineage, and therefore warrants further testing in vivo to examine the effect of the stated biomimetic system on peri-implant bone formation and implant fixation.
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Affiliation(s)
- James E Ho
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720-1762
- Department of Materials Science and Engineering, University of California at Berkeley, 370 Hearst Memorial Mining Building, Berkeley, California 94720-1760
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California
| | - Eugene H Chung
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720-1762
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California
| | - Samuel Wall
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720-1762
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California
| | - David V Schaffer
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California
- Department of Chemical Engineering and the Helen Wills Neuroscience Institute, University of California at Berkeley, 201 Gilman Hall, Berkeley, California 94720-1462
| | - Kevin E Healy
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720-1762
- Department of Materials Science and Engineering, University of California at Berkeley, 370 Hearst Memorial Mining Building, Berkeley, California 94720-1760
- UCSF/UCB Joint Graduate Group in Bioengineering, University of California, Berkeley, California
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30
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Saha K, Irwin EF, Kozhukh J, Schaffer DV, Healy KE. Biomimetic interfacial interpenetrating polymer networks control neural stem cell behavior. J Biomed Mater Res A 2007; 81:240-9. [PMID: 17236216 DOI: 10.1002/jbm.a.30986] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Highly-regulated signals surrounding stem cells, such as growth factors at specific concentrations and matrix mechanical stiffness, have been implicated in modulating stem cell proliferation and maturation. However, tight control of proliferation and lineage commitment signals is rarely achieved during growth outside the body, since the spectrum of biochemical and mechanical signals that govern stem cell renewal and maturation are not fully understood. Therefore, stem cell control can potentially be enhanced through the development of material platforms that more precisely orchestrate signal presentation to stem cells. Using a biomimetic interfacial interpenetrating polymer network (IPN), we define a robust synthetic and highly-defined platform for the culture of adult neural stem cells. IPNs modified with two cell-binding ligands, CGGNGEPRGDTYRAY from bone sialoprotein [bsp-RGD(15)] and CSRARKQAASIKVAVSADR from laminin [lam-IKVAV(19)], were assayed for their ability to regulate self-renewal and differentiation in a dose-dependent manner. IPNs with >5.3 pmol/cm(2) bsp-RGD(15) supported both self-renewal and differentiation, whereas IPNs with lam-IKVAV(19) failed to support stem cell adhesion and did not influence differentiation. The IPN platform is highly tunable to probe stem cell signal transduction mechanisms and to control stem cell behavior in vitro.
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Affiliation(s)
- Krishanu Saha
- Department of Chemical Engineering, University of California at Berkeley, Berkeley, CA, USA
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Li J, Wang X, Wang C, Chen B, Dai Y, Zhang R, Song M, Lv G, Fu D. The Enhancement Effect of Gold Nanoparticles in Drug Delivery and as Biomarkers of Drug-Resistant Cancer Cells. ChemMedChem 2007; 2:374-8. [PMID: 17206735 DOI: 10.1002/cmdc.200600264] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The enhancement effect of 3-mercaptopropionic acid capped gold nanoparticles (NPs) in drug delivery and as biomarkers of drug-resistant cancer cells has been demonstrated through fluorescence microscopy and electrochemical studies. The results of cell viability experiments and confocal fluorescence microscopy studies illustrate that these functionalized Au NPs could play an important role in efficient drug delivery and biomarking of drug-resistant leukemia K562/ADM cells. This could be explored as a novel strategy to inhibit multidrug resistance in targeted tumor cells and as a sensitive method for the early diagnosis of certain cancers. Our observations also indicate that the interaction between the functionalized Au NPs and biologically active molecules on the surface of leukemia cells may contribute the observed enhancement in cellular drug uptake.
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Affiliation(s)
- Jingyuan Li
- State Key Lab of Bioelectronics (Chien-Shiung WU Laboratory), Southeast University, Nanjing, PR China
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Barber TA, Ho JE, De Ranieri A, Virdi AS, Sumner DR, Healy KE. Peri-implant bone formation and implant integration strength of peptide-modified p(AAM-co-EG/AAC) interpenetrating polymer network-coated titanium implants. J Biomed Mater Res A 2007; 80:306-20. [PMID: 16960836 DOI: 10.1002/jbm.a.30927] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Interpenetrating polymer networks (IPNs) of poly (acrylamide-co-ethylene glycol/acrylic acid) functionalized with an -Arg-Gly-Asp- (RGD) containing 15 amino acid peptides, derived from rat bone sialoprotein (bsp-RGD(15), were grafted to titanium implants in an effort to modulate bone formation in the peri-implant region in the rat femoral ablation model. Bone-implant contact (BIC) and bone formation within the medullary canal were determined using microcomputed tomography at 2 and 4 weeks postimplantation. BIC for bsp-RGD(15)-IPN implants was enhanced relative to hydroxyapatite tricalcium phosphate (HA-TCP) coated implants, but was similar to all other groups. Aggregate bone formation neither indicated a dose-dependent effect of bsp-RGD(15) nor a meaningful trend. Mechanical testing of implant fixation revealed that only the HA-TCP coated implants supported significant (>1 MPa) interfacial shear strength, despite exhibiting lower overall BIC, an indication that bone ingrowth into the rougher coating was the primary mode of implant fixation. While no evidence was found to support the hypothesis that bsp-RGD(15)-modified IPN coated implants significantly impacted bone-implant bonding, these results point to the lack of correlation between in vitro studies employing primary osteoblasts and in vivo wound healing in the peri-implant region.
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Affiliation(s)
- Thomas A Barber
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720, USA
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Schuler M, Trentin D, Textor M, Tosatti SGP. Biomedical interfaces: titanium surface technology for implants and cell carriers. Nanomedicine (Lond) 2006; 1:449-63. [PMID: 17716147 DOI: 10.2217/17435889.1.4.449] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Titanium and its alloys have become key materials for biomedical applications, mainly owing to their compatibility with human tissues and their mechanical strength. Effects of surface topography on cell and tissue response have been investigated extensively in the past, while (bio)chemical surface modification and its combination with designed topographies have remained largely unexplored. The following report describes some of the strategies used or intended to modify titanium surfaces, based on biological principles, with a focus on ultrathin biomimetic adlayers. One of the visions behind such approaches is to achieve improved healing and integration responses after implantation for patients, especially for those suffering from deficiencies, for example, diabetes or osteoporosis, two diseases that have increased drastically in our society during the last century.
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Affiliation(s)
- Martin Schuler
- Laboratory for Surface Science and Technology, BioInterfaceGroup, Department of Materials, ETH Zurich, Zurich, Switzerland.
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Barber TA, Gamble LJ, Castner DG, Healy KE. In vitro characterization of peptide-modified p(AAm-co-EG/AAc) IPN-coated titanium implants. J Orthop Res 2006; 24:1366-76. [PMID: 16732610 DOI: 10.1002/jor.20165] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Interpenetrating polymer networks (IPNs) of poly(acrylamide-co-ethylene glycol/acrylic acid) [p(AAm-co-EG/AAc)] functionalized with an -Arg-Gly-Asp- containing peptide derived from rat bone sialoprotein [bsp-RGD(15)] were grafted to titanium implants in an effort to modulate osteoblast behavior in vitro. Surface characterization data were consistent with the presence of an IPN, and ligand density measurements established that the range of peptide density on the modified implants spanned three orders of magnitude (0.01-20 pmol/cm2). In vitro biological characterization of the modified implants employing the primary rat calvarial osteoblast (RCO) model resulted in the identification of a critical ligand density (0.01<Gammacrit<0.1 pmol/cm2) for maximal support of the osteoblast phenotype. After 14 and 21 days, mineralization was greater on the 0.1 and 10 pmol/cm2 bsp-RGD(15) modified implants compared to the base titanium and other control surfaces. The observed effects were attributed to specific interactions with bsp-RGD(15) and support the concept that peptide-modified implants can enhance the kinetics of differentiation of the cells they contact. These results suggest that in vivo biological performance evaluation of these biomimetic implant surfaces is merited.
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Affiliation(s)
- Thomas A Barber
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720, USA
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Harbers GM, Healy KE. The effect of ligand type and density on osteoblast adhesion, proliferation, and matrix mineralization. J Biomed Mater Res A 2006; 75:855-69. [PMID: 16121356 DOI: 10.1002/jbm.a.30482] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Polystyrene surfaces grafted with a nonfouling interfacial interpenetrating polymer network (IPN) of poly(acrylamide-co-ethylene glycol/acrylic acid) [p(AAm-co-EG/AAc)] were modified with several peptide ligands adapted from bone sialoprotein (BSP). IPNs were modified with both single ligands and ligand blends to study the correlation between a simple metric, ligand-receptor adhesion strength, and the extent of matrix mineralization for osteoblast like cells (rat calvarial osteoblasts). The ligands studied included RGD cell-binding [CGGNGEPRGDTYRAY (l-RGD), CGGEPRGDTYRA (s2-RGD), CGPRGDTYG (lc-RGD), cyclic(CGPRGDTYG) (c-RGD), and CGGPRGDT (s-RGD)], heparin binding (CGGFHRRIKA), and collagen binding (CGGDGEAG) peptides, with the appropriate controls. Adhesion strength scaled with ligand density (1-20 pmol/cm(2)) and was dependent on ligand type with the following trend: l-RGD > s2-RGD approximately c-RGD >> s-RGD approximately lc-RGD >>> FHRRIKA approximately DGEA. Independent of ligand density, % matrix mineralization varied with ligand type resulting in the following trend: lc-RGD > s2-RGD > l-RGD approximately c-RGD >> s-RGD >>> FHRRIKA. The Tyr (Y) residue immediately following the RGD cell-binding domain proved to be critical for stable cell proliferation and mineralization, since removal of this residue resulted in erratic cell attachment and mineralization behavior. The minimum BSP sequence necessary for strong adhesion and extensive mineralization was CGGEPRGDTYRA; the minimal sequence suitable for extensive mineralization but lacking strong adhesion was CGPRGDTYG. The cyclic peptide (c-RGD) had much greater adhesion strength compared to its linear counterpart (lc-RGD). The calculated characteristic adhesion strength (F(70)) obtained using a centrifuge adhesion assay proved to be a poor metric for predicting % mineralized area; however, in general, surfaces possessing a F(70) > 100g promoted extensive matrix mineralization. Percent mineralization and number of mineralized nodules scaled with number of cells seeded suggesting a critical dependence on the initial number of osteoprogenitors in culture. This study demonstrates matrix mineralization dependence on ligand type, ligand density, and adhesion strength. The high-throughput character of these surfaces allowed efficient investigation of multiple ligands at multiple densities providing an excellent tool for studying ligand-receptor interactions under normal cell culture conditions with serum present.
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Affiliation(s)
- Gregory M Harbers
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3107, USA
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Barber TA, Harbers GM, Park S, Gilbert M, Healy KE. Ligand density characterization of peptide-modified biomaterials. Biomaterials 2005; 26:6897-905. [PMID: 16045984 DOI: 10.1016/j.biomaterials.2005.04.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 04/15/2005] [Indexed: 11/17/2022]
Abstract
A simple fluorescence based characterization method was developed to assess ligand density on peptide-modified biomaterials. The method exploits the exquisite sensitivity of proteolysis for the purpose of liberating a fluorescently labeled probe fragment from an immobilized peptide. The released fragment can then be detected in solution using high-throughput fluorometry. In silico screening tools identified the enzyme chymotrypsin as a promising candidate for releasing a detectable probe fragment from the fluorescently labeled peptide, Ac-CGGNGEPRGDTYRAYK(FITC)GG-NH(2). After chymotrypsin digestion of the peptide in solution was first characterized using mass spectrometry and HPLC, a basic enzyme mediated release protocol was developed and implemented to generate peptide-binding isotherms on various peptide-modified biomaterials. The new method is sensitive, has good signal-to-noise ratio (S/N), and is easily standardized. Furthermore, the technique can be applied independent of material chemistry and geometry, making it a suitable alternative to radiolabeling for a wide range of biomaterial applications.
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Affiliation(s)
- Thomas A Barber
- Department of Bioengineering, University of California at Berkeley, 94720, USA
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