A novel injectable hydrogel prepared from phenylboronic acid modified gelatin and oxidized-dextran for bone tissue engineering

Complicated fractures have always been challenging in orthopaedics. Designing a multifunctional biomaterial that can contribute to the treatment of fractures using a simple operation remains challenging. Here, we developed a trinity hydrogel system consisting of hydrogel prepared from phenylboronic acid modified gelatin and oxidized-dextran, lithium and cobalt co-doped mesoporous bioactive glass nanoparticles (MBGNs), and irisin. This hydrogel material exhibits considerable injectability, fat-to-shape, and self-healing characteristics. In addition, compared to hydrogel prepared from gelatin and oxidized-dextran, the hydrogel material presented a noticeable enhancement in compression stress and adhesion strength towards porcine bone fragments, which enables it more effectively splice bone fragments during surgery. Based on the various interactions between irisin and the hydrogel network, the system exhibited a clear sustained release of irisin. Based on the results of in vitro cell tests, the hydrogel material showed good cytocompatibility. And it also considerably enhanced the in vitro pro-osteogenic and pro-angiogenic capacities of bone marrow mesenchymal stromal cells (BMSCs) and human umbilical vein endothelial cells (HUVECs). In vivo experimental results indicated that this hydrogel considerably improved the repair of cranial defects in rats. The current study provides a feasible strategy for the treatment of bone fractures and stimulation of fracture healing.