Mineralized self-assembled silk fibroin/cellulose interpenetrating network aerogel for bone tissue engineering

The preparation of bioactive materials with biomolecules as templates to control the nucleation and growth of nano-hydroxyapatite (n-HA) crystals is a vital research field in bone tissue engineering. However, meeting the performance requirements of possessing appropriate surface roughness, high porosity, structural stability, adequate mechanical strength, biodegradability and biocompatibility at the same time is the core issue that restricts the development of these biomimetic materials in biosciences as well as medical clinical translation. In this work, a mineralized self-assembled silk fibroin (SF)/cellulose interpenetrating network composite aerogel (M-S-C) material was prepared by freeze-drying using sol-gel and in situ mineralization strategy. The effects of the main factors, such as the surface properties of SF macromolecules and the change of mineralization time, on the n-HA self-assembly process and the property of M-S-C under defined conditions were explored. The properties of M-S-C, including the physicochemical properties, morphology, mechanical property, degradation behavior and in vitro cytotoxicity, were investigated to evaluate its application prospects in bone tissue engineering. M-S-C exhibits the microstructure required for an ideal cancellous bone repair material, porosity up to 99.2%, high thermal stability, moderately adjustable compressive strength (12.7–22.4 MPa), and appreciable in vitro degradation rate. Moreover, M-S-C extracts can significantly accelerate the proliferation of human embryonic kidney cells. This mineralized interpenetrating polymer network aerogel material with excellent comprehensive performance shows potential for application in bone repair and regeneration. • Silk fibroin provides nucleation sites for nano-hydroxyapatite during mineralization through surface charge effects. • Silk fibroin controls the structure, orientation and assembly of hydroxyapatite crystals during mineralization. • Mineralized interpenetrating network aerogel exhibits high porosity and remarkable compressive strength. • Mineralized composite aerogel extracts can significantly promote the proliferation of HEK-293 T cells.