Chitosan/gelatin blends for biomedical applications

Blends between chitosan (CS) and gelatin (G)with various compositions (CS/G 0/100 20/80, 40/60, 60/40, 100/0 w/w) were produced as candidate materials for biomedical applications. Dehydro-thermal crosslinking was adopted to promote the formation of amide and ester bonds between the macromolecules ((CS/G)-t). The effect of composition and crosslinking on the physico-chemical properties of the samples was evaluated by scanning electron microscopy, thermogravimetry, contact angle measurements, dissolution and swelling tests. Mechanical properties of (CS/G)-t samples were also determined through stress-strain and creep-recovery tests. The elastic moduli of dry blend samples showed a positive deviation from the additive law of the in-series model, because of interactions and/or chemical bonds between components. The comparison between the elastic moduli of wet samples and those of different human tissues showed that (CS/G)-t substrates can be suitable for soft-tissue reconstruction. (CS/G)-t two-dimensional scaffolds were fabricated by micro-molding, based on the use of a polydimethylsiloxane mould to create patterns with microscale resolution on cast films. Biocompatibility of (CS/G)-t samples was studied by means of cell tests using NIH-3T3 fibroblasts. Finally, the evaluation of the affinity of (CS/G)-t samples towards neuroblastoma cells adhesion and proliferation was performed, showing promising results for the blend containing 80 wt % gelatin.