title: Pre-crosslinked polymeric collagen in 3-D models of mechanically stiff tissues: blended collagen polymer hydrogels for rapid layer fabrication.
abstract: Currently one factor hindering the development of collagen hydrogel constructs for tissue engineering is the mismatch between initial cellularity and mechanical strength. The main advantage of collagen hydrogel tissue constructs is their ability to support interstitially seeded cells. However, cells are sensitive to their environment, in particular, substrate stiffness, which cannot easily be replicated within hydrogels without cytotoxic cross-linking treatment. In this study, pre-crosslinked polymeric collagen fibrils are introduced as a starting material, thereby avoiding artificial cross-linking. Shear aggregation of this material in solution results in fibril alignment, but cell addition is only possible when polymeric collagen is blended with its monomeric counterparts to slow the aggregation of collagen fibrils. The hydrogel can then be brought to physiological collagen density by plastic compression. Interstitially seeded fibroblasts were supported for 14days. Although compression of blended gels resulted in some cell death due to increased rate of fluid expulsion, not normally seen in conventional collagen hydrogels, the surviving cell population recovers during subsequent culture. Importantly, the compression process can be controlled and customized to limit cell damage. This is the first report of native polymeric collagen used in a tissue engineering context, for the rapid production of a stiff collagen-cell constructs.
authors.affiliation: UCL Institute of Orthopaedics and Musculoskeletal Sciences, UCL Tissue Repair and Engineering Centre, University College London, Stanmore Campus, London HA7 4LP, UK.
authors.forename: Josephine P F
authors.initials: JPF
authors.lastname: Wong
authors.affiliation: UCL Institute of Orthopaedics and Musculoskeletal Sciences, UCL Tissue Repair and Engineering Centre, University College London, Stanmore Campus, London HA7 4LP, UK; Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon, Lisbon, Portugal.
authors.forename: Danielle
authors.initials: D
authors.lastname: Baptista
authors.affiliation: UCL Institute of Orthopaedics and Musculoskeletal Sciences, UCL Tissue Repair and Engineering Centre, University College London, Stanmore Campus, London HA7 4LP, UK. Electronic address: r.a.brown@ucl.ac.uk.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Brown
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis*; D049109:Cell Proliferation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry*; D055119:Elastic Modulus; D024022:Fibrillar Collagens / Q000737:chemistry*; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology*; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry; D033081:Shear Strength
chemical_list: D003432:Cross-Linking Reagents; D024022:Fibrillar Collagens; D020100:Hydrogels; D011108:Polymers
keywords: Collagen hydrogel; Fibroblasts; Plastic compression; Polymeric collagen; Stiff tissue mimics