Event Abstract Back to Event In vitro fabrication of extracellular matrix-rich tissue equivalents Kyriakos Spanoudes1, 2*, Yves Bayon3*, Abhay Pandit2* and Dimitrios I. Zeugolis1, 2* 1 National University of Ireland Galway, Regenerative, Modular and Developmental Engineering Laboratory (REMODEL), Ireland 2 National University of Ireland Galway, Centre for Research in Medical Devices (CURAM), Ireland 3 Covidien, Sofradim Production, France Introduction: Tendon tissue engineering is becoming increasingly important, as current surgical treatment modalities based on tissue grafts and non-degradable polymers have numerous drawbacks, including disease transmission, foreign body response and scar tissue formation[1]. Injectable cell based therapies are characterised by poor cell localisation at the site of injection[2]. Herein, we hypothesise that provision of a more relevant microenvironment with anisotropic topography and macromolecular crowding will maintain tenogenic phenotype in vitro[3],[4] and facilitate the fabrication of an extracellular matrix-rich tendon equivalent, promoting functional repair and regeneration in vivo. Materials and Methods: Glycomer™ 631, co-polymer of glycolide (60%), trimethylene carbonate (26%) and dioxanone (14%) was dissolved in hexafluoro-isopropanol (HFIP) at 100mg/ml concentration. Using a rotating collector (3000 RPM) anisotropic electro-spun fibres were produced. Human patellar tendon tenocytes were expanded up to passage 3 in DMEM media, supplemented with 10% foetal bovine serum and 1% penicillin / streptomycin. 50,000 cells / cm2 were subsequently cultured for up to 28 days under the influence of Carragennan 75 μg/ml (crowder). Fibre orientation and fibre diameter distribution were assessed with Scanning Electron Microscopy (SEM). The influence of electro-spun fibres on cell viability and metabolic activity was assessed using Live/Dead® and alamarBlue® assays respectively. Cell morphometric analysis was carried out using DAPI and rhodamine conjugated phalloidin and subsequent image analysis (ImageJ). Tendon specific extracellular matrix (ECM) deposition was assessed with immunocytochemistry. Results: The scaffold obtained by electrospinning Glycomer™ 631 at 3000RPM, is characterised by high degree of alignment, a fibre diameter distributed at the submicron level and adequate mechanical and thermal properties (Figure 1). Macromolecular crowding enhances tendon-specific matrix deposition from cells. This allows the fabrication of an ECM-rich tendon equivalent in vitro, where tenocytes obtain and maintain their physiological bidirectional morphology (Figure 2). Conclusion: These in vitro data indicate that anisotropic electro-spun Glycomer™ 631 scaffolds along with macromolecular crowding provide a suitable microenvironment for tenocyte growth, facilitating the in vitro fabrication of a matrix-rich tendon equivalent. Further mechanical analysis, protein and gene assays and in vivo studies are under way. Irish Research Council