Fig. 1.

Schematic diagram of MAHS preparation and function for osteogenesis and bone regeneration. (a) Illustration of miRNA nano-delivery system. PEI-capped AuNPs are synthesized through a convenient one-pot method. miRNAs were incubated with AuNPs to form stable complexes “miR/NP”. (b) 3D porous hydrogel scaffold consisting of gelatin and alginate is generated layer by layer through a 3D plotting technique, then crosslinked with Ca²⁺ and varying concentrations of GTA. The lyophilized scaffold is subsequently immersed in miR/NP-containing PBS to load miR/NP through water absorption by the dried hydrogels. Finally, MAHSs with different crosslinking degree are applied for osteogenesis in vitro and bone formation in vivo, and this study focuses on the balance between the scaffold degradation rate and miRNA release profile.