Bioactive Porous Protein Scaffolds Enabled by High Internal Phase Emulsion Templates

Abstract

Bioactive porous scaffolds fabricated by high internal phase emulsions (HIPEs) have gained increasing interest in tissue engineering. However, most of them are constructed by hydrophobic synthetic polymers and hardly possess both appropriate pore size and high porosity. Here, we report the preparation of porous protein scaffolds templated from oil-in-water (O/W) HIPEs costabilized by all-biomass materials including aminated gelatin (AG) and aminated gelatin nanoparticles (AGNPs). Specifically, AG was first synthesized and then used to prepare relatively monodispersed AGNPs. Subsequently, AG and AGNPs were used to costabilize HIPEs and dialdehyde starch (DAS) was added as a cross-linker. In the HIPEs, AG and AGNPs were adsorbed into the oil/water interface to form thick packing layers, and the resulting hydrogen bond and chemical cross-linking network structure significantly improved its stability. The pore structure, pore interconnectivity, swelling ratio, and degradation rate of the scaffolds could be tailored readily by altering the AGNP concentration. A monolithic scaffold (AG@AGNPs 0.5), templated from the HIPE costabilized by 5 wt % AG and 0.5 wt % AGNPs, presented an appropriate pore size (37.8 ± 14.8 μm), high porosity (91.7 ± 5.3%), and interconnected porous morphology, which provides the basis for cell adhesion and proliferation. Furthermore, the scaffold showed a low hemolysis rate, low cytotoxicity, and biological toxicity. Adipose-derived stem cells (ADSCs) adhere and proliferate well on the scaffolds. All of these results confirm that the present bioactive scaffold possesses great promise in the field of tissue engineering.