In vitro study of alginate-gelatin scaffolds incorporated with silica NPs as injectable, biodegradable hydrogels.

Porous substrates composed of biodegradable polymers and nanoparticles have found extensive use as three-dimensional (3D) scaffolds to regenerate damaged tissues through the incorporation of cells or growth factors. Here, injectable thermally responsive hydrogels based on SiO 2 nanoparticles (NPs), alginate, and gelatin biopolymers, with possible utilization for cartilage tissue engineering, are introduced. The nanocomposites contain different amounts of SiO 2 NPs for reinforcement and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/ N -hydroxysuccinimide (NHS) for chemical crosslinking of polymer chains in the 3D hydrogel network. The cross-sectional structure of the hydrogels containing 0.25, 1.5, and 3.0% SiO 2 NPs was observed by FE-SEM, confirming porous morphology with interconnected pores. Based on the rheometer analyses, by increasing the amount of SiO 2 NPs, the mechanical strength of the gels can be found. In addition, in vitro biodegradation studies show that the hydrogels without SiO 2 are more unstable than the hydrogels containing SiO 2 NPs. In vitro biocompatibility of the products tested by MTT assay indicates that cell viability and attachment depend on the presence of SiO 2 NPs.