Ultralong hydroxyapatite nanowires-incorporated dipeptide hydrogel with enhanced mechanical strength and superior in vivo osteogenesis activity

Abstract

Self-assembling peptide hydrogels have attracted considerable interest in tissue engineering for their biocompatibility, biodegradability, low immunogenicity, facile modification, and similarity to the native extracellular matrix. However, they still suffer from weak mechanical strength and lack of specific bioactivity. Ultralong hydroxyapatite nanowires (UHANWs) are synthesized to work as a reinforcement agent similar to the steel bars in the reinforced concrete to co-assemble with dipeptide nanofibers, endowing the hybrid hydrogel with enhancing and controllable mechanical properties. Furthermore, additional factors BMP-2 can be introduced into the hydrogel to improve its bioactivity. The experimental results show that the incorporation of UHANWs into the hydrogel matrix leads to an obvious increase in the storage modulus of scaffolds, exhibiting good biocompatibility and bioactivity. The hybrid hydrogels can facilitate the proliferation and osteogenetic differentiation of cells on their surface. The in vivo evaluation reveals that bone defects implanted with the as-designed hydrogel scaffolds show enhanced bone regeneration activity, implying their great potential in biomedical fields.