Highly porous gelatin-silica hybrid scaffolds with textured surfaces using new direct foaming/freezing technique

Highly porous gelatin-silica hybrid scaffolds with high porosity, large pores and large interconnections, as well as tailored surface textures were produced using a newly developed direct foaming/freezing. Two different types of precursors as the silica source, 3-glycidoxyproyltrimethoxysilane (denoted as "GS") and sol-gel derived silica (denoted as "SS"), were used for producing the porous GLA-GS and GLA-GS-SS hybrid scaffolds. In this method, air bubbles could be vigorously incorporated into the GLA-GS and GLA-GS-SS mixtures and then stabilized by rapid freezing of the foamed mixtures at -70 °C. Both the porous GLA-GS and GLA-GS-SS hybrid scaffolds produced herein had a highly porous structure (porosity > 90 vol%, pore size = 200-500 μm, interconnection size = 100-200 μm) with a uniform distribution of the silica phase in the gelatin matrix. In addition, surface textures with a rugged morphology could be created after immersion of the porous GLA-GS and GLA-GS-SS hybrid scaffolds in ethanol at -20 °C for 24 h. The porous GLA-GS and GLA-GS-SS hybrid scaffolds showed much higher mechanical properties than the porous GLA scaffold, while preserving excellent in vitro biocompatibility, demonstrating potential application as the bone scaffold.