(P 15) A Novel Thermoresponsive Copolymer As a Suitable Substrate for Tissue Reconstruction

Introduction: For the reconstruction of tissues and organs, thermoresponsive polymers like Poly(N-isopropylacrylamide(NIPAAm)) play an important role in the detachment of cell layers with undamaged cell-cell and cell-ECM interactions. PIPAAm coated surfaces were usually prepared using electron beam irradiation or plasma polymerisation, both of which are not usually available for every researcher. We aimed to prepare a thermoresponsive copolymer that is easy to prepare and favours cell growth. In this study, a copolymer of NIPAAm and Methyl Methacrylate was prepared and its cytocompatibility was assessed. Methods: Cytotoxicity and cytocompatibility of the copolymer was analysed in comparison to tissue culture polystyrene using cell lines. To demonstrate thermoresponsiveness, both primary and continuous cell lines were detached from copolymer under its lower critical solution temperature. To analyse specific cytocompatibility at molecular level, secretome of a corneal cell line cultured on both substrates is being studied. Results: Copolymerisation and hydrophilic/hydrophobic transition at different temperatures was confirmed using fourier transform infrared spectroscopy and differential scanning calorimetry, respectively. Tritiated thymidine uptake assay and MTT assay results showed that copolymer favoured cell attachment, growth and proliferation. Actin staining demonstrated good cytoskeletal organisation and subsequent cell spreading on copolymer. The cell sheet detachment from the copolymer confirmed its thermoresponsiveness and its use in creating tissue structures. Secretome analysis revealed unique protein expressions on both substrates. Conclusion: Our study proved that a copolymer of NIPAAM can be easily prepared with minimum facilities and the good cytocompatibility along with thermoresponsiveness make the copolymer a suitable candidate as a tissue engineering substrate.