Composite films of gelatin hydroxyapatite/bioactive glass for tissue-engineering application

Cross-linked gelatin/hydroxyapatite/bioactive glass (G/HA/CEL2) films with different compositions (100:0:0 (G1); 30:70:0 (G2); 30:0:70 (G3); 30:35:35 (G4) (%, w/w/w)) were prepared as scaffold materials for tissue-engineering applications, particularly in the field of bone repair. A bioactive glass with 45% SiO₂, 3% P₂O₅, 26% CaO, 7% MgO, 15% Na ₂O and 4% K₂O molar composition was selected (CEL2). Genipin was used as a cross-linker for the gelatin component. Samples were characterized in terms of their bioactivity, thermal properties, mechanical behaviour and cell compatibility. After only 3 days of incubation in simulated body fluid (SBF) at 37°C, calcium phosphate crystals precipitated on G3 and G4 surfaces, due to the high CEL2 bioactivity. Cross-linking increased the thermal stability of the gelatine component as indicated by thermal analysis (denaturation temperature was 92.3°C and 97.6°C for not cross-linked and cross-linked gelatin, respectively). Furthermore, tensile modulus of samples increased with increasing the inorganic phase amount (from 4.72 ± 0.23 MPa for G1 to 6.46 ± 0.05 MPa for G4). The adhesion and proliferation of human primary osteoblasts on composite films was evaluated. Cell viability was high with respect to the control for all samples and the presence of hydroxyapatite exerted an important role in the ability of mineralization.