Developing a pure silica ink for 3D printing through sol-gel reaction and mild conditions

Silica 3D printable materials are interesting in bone tissue engineering as they allow the development of custom-made scaffolds with high bioactivity and osteogenic properties. However, all pure silica scaffolds nowadays require using a sintering step, which reduces the specific surface and porosity of the scaffolds, while limiting their biological activity and drug encapsulation. In this study, we developed a pure silica 3D printable material using mild temperatures (50-70 & DEG;C) through the sol-gel reaction of tetraethyl orthosilicate (TEOS). The pure silica ink had a printing window of several hours and could be stored without a substantial loss of printability. Moreover, the inks showed a high shape fidelity and a proportionate contraction, without losing the printed shape. The scaffolds also maintained high bioactivity and biocompatibility, proving that the sol-gel reaction and printing parameters did not negatively affect those properties. Therefore, pure silica could be 3D printed showing potential for their use in bone regeneration. Sol-gel pure silica materials could be 3D printed to obtain scaffolds.The nature of the reaction and the discovered parameters allow a long printing window, of up to 36 h.This sol-gel pure silica ink can be stored at -20 & DEG;C for a month without losing printability and printing window.These sol-gel pure silica 3D printed scaffolds maintained the bioactivity and biocompatibility seen in other silica-based materials.