Synthesis and photopolymerisation of maleic polyvinyl alcohol based hydrogels for bone tissue engineering

The novel synthesis of photopolymerisable polyvinyl alcohol (PVA) was achieved by reacting maleic anhydride with the hydroxyl groups of PVA. The incorporation of photopolymerisable double bonds onto the PVA polymeric chain was confirmed by both ¹H NMR and ¹³C NMR spectroscopy. Hydrogel blends were prepared by mixing maleic PVA and polyethylene glycol dimethacrylate (PEGDMA) precursors at different concentrations and molecular weights. It was observed that the increase in crosslinking with the introduction of maleic PVA crosslinks resulted in higher compressive properties and storage modulus values. These values fall below those reported for bone; however, if these scaffolds were used in conjunction with fixation devices and with the sustained release of dexamethasone it would allow for faster regeneration of bone defects. Drug release results showed that the release profile of the hydrogels was between 11 and 16 days. This was as a result of altering the swelling and pore sizes of the hydrogels by varying the precursor concentrations. Preliminary in vitro cytotoxicity evaluations were performed using the MTT assay as an end point, showing that these novel hydrogels are non-toxic to mouse embryonic fibroblast cell line.