Preparation and properties of homogeneous oxidized sodium alginate/silica/polyacrylamide–gelatin composite hydrogel based on interpenetrating network technology

To address the functional defect of alginate hydrogel in tissue engineering applications, we adopted the interpenetrating polymer network technology as well as the incorporation of SiO 2 nanoparticles and the surface coverage of gelatin to fabricate homogeneous oxidized sodium alginate/silica/polyacrylamide–gelatin (OSA/SiO 2 /PAM-GT) composite hydrogels, using hydroxyapatite/D-glucono-δ-lactone (HAP/GDL) complex as the gelling system. Specially, the effect of SiO 2 nanoparticles on the microstructure, mechanical properties, in vitro swelling, biodegradability, biomineralization and biocompatibility of the composite hydrogels was investigated. The resultant OSA/SiO 2 /PAM-GT composite hydrogels exhibited relatively regular 3D morphology with well-developed pore structure with HAP/GDL as the cross-linking agents. The incorporation of SiO 2 nanoparticles could effectively regulate the pore structure, mechanical properties, swelling ratio, in vitro biodegradability and biomineralization of OSA/SiO 2 /PAM-GT composite hydrogels. Meanwhile, the OSA/SiO 2 /PAM-GT composite hydrogels could also support the adhesion, proliferation and differentiation of MG-63 cells, which could be applied to the tissue engineering field.