In vitro/ in vivo evaluation of double crosslinked bone glue with different degrees

Successful bone fragment fixation is a crucial factor in bone fracture healing, the fixation of crushed bone fragments could hinder bone fracture healing. Thus, ideal bone glues to effectively adhere and splice comminuted bone fragments are needed in clinical. Herein, an osteoinductive and biodegradable double cross-linked bone glue (GelMA-oDex-AMBGN) was constructed through Schiff's base reaction between commercial GelMA (with different substitution degrees of amino groups) and Odex mixed with amine-modified mesoporous bioactive glass nanoparticles (AMBGN), followed by crosslink with blue light irradiation. The GelMA-oDex-AMBGN bone glue successfully adhered and spliced the comminuted bone fragments of isolated rat skulls. GelMA-oDex-AMBGN promoted the proliferation of 3T3 cells and enhanced the expression of osteogenic proteins Runx2 and OCN in vitro. In rat cranial critical-sized defect models, GelMA-oDex-AMBGNs with different substitution degrees significantly increased the new bone contents at the fracture defect sites and promoted bone tissue regeneration in vivo. In conclusion, the double cross-linked bone glue (GelMA-oDex-AMBGN) was successfully constructed and can induce bone regeneration. Additionally, there was no significant difference in osteogenic activity among GelMA-oDex-AMBGNs with different substitution degrees and the equal content of AMBGN.