Self-setting silica-gelatin hybrid 3D printed scaffolds with tunable composition and enhanced physicochemical and biological properties

Abstract Silica-based materials can stimulate bone regeneration; however, pure silica materials have shown some disadvantages, such as low degradability and brittleness, which can be overcome by developing hybrid materials. For bone tissue engineering, the organic co-network should contain adhesion sequences to enhance cell adhesion, be bound to the silica network and in lower proportion than silica. With this purpose, the tetraethyl orthosilicate (TEOS) sol-gel reaction was used to create hybrid ink for 3D printing with gelatin as polymer, and 3-glycidyloxypropyl(trimethoxysilane) (GPTMS) as cross-linking agent. By adjusting the TEOS, GPTMS and gelatin proportions, four different hybrid inks were obtained with a wide variety of physicochemical properties and all demonstrating a high printability and shape fidelity. As result of this silica-gelatin hybrids, scaffolds had faster degradation rate, higher water uptake and improved mechanical properties, when compared to the pure silica scaffolds. All these properties were achieved without losing any apatite formation capacity due to gelatin presence, and improving initial cell adhesion and proliferation in two of the developed inks. The silica-gelatin hybrid inks showed promise in the development of tailored 3D printed scaffolds. Graphical Abstract