Injectable PGS-based osteoadhesive incorporating PDA-modified inorganic nanoparticles for fracture repair

The repair of bone fractures remains a significant challenge due to the scarcity of biomaterials that can simultaneously ensure robust adhesion and facilitate effective bone regeneration. In this study, we have developed an injectable, bioinspired bone fixation system utilizing poly(glycerol sebacate) (PGS) crosslinked with isophorone diisocyanate (IPDI). This system incorporates polydopamine (PDA)-modified nano-hydroxyapatite (nHA) or nano-bioactive glass (nBG) to integrate adhesive fixation with the potential osteoconductive functions of inorganic components. PDA modification affected nanoparticle dispersion and surface wettability in adhesive formulations, while phosphoric acid pretreatment was explored to alter the bone–adhesive interface. The developed adhesive formulations exhibited injectability, measurable adhesion strength, composition-dependent mass-loss behavior, and favorable in vitro cytocompatibility under the tested conditions. In a rat tibial fracture model, the composite adhesive expedited fracture healing, as evidenced by radiographic imaging, micro-CT reconstruction, histological analysis, biomechanical evaluation, and the expression of osteogenic proteins. This injectable fixation strategy combines mechanical stabilization with bioactive regeneration, offering a promising approach for minimally invasive fracture repair and the development of next-generation orthopedic biomaterials.