Degradable Nanohydroxyapatite-Reinforced Superglue for Rapid Bone Fixation and Promoted Osteogenesis

Bone glue with robust adhesion is crucial for treating complicated bone fractures, but it remains a formidable challenge to develop a "true" bone glue with high adhesion strength, degradability, bioactivity, and satisfactory operation time in clinical scenarios. Herein, inspired by the hydroxyapatite and collagen matrix composition of natural bone, we constructed a nanohydroxyapatite (nHAP) reinforced osteogenic backbone-degradable superglue (O-BDSG) by in situ radical ring-opening polymerization. nHAP significantly enhances adhesive cohesion by synergistically acting as noncovalent connectors between polymer chains and increasing the molecular weight of the polymer matrix. Moreover, nHAP endows the glue with bioactivity to promote osteogenesis. The as-prepared glue presented a 9.79 MPa flexural adhesion strength for bone, 4.7 times that without nHAP, and significantly surpassed commercial cyanoacrylate (0.64 MPa). O-BDSG exhibited degradability with 51% mass loss after 6 months of implantation. In vivo critical defect and tibia fracture models demonstrated the promoted osteogenesis of the O-BDSG, with a regenerated bone volume of 75% and mechanical function restoration to 94% of the native tibia after 8 weeks. The glue can be flexibly adapted to clinical scenarios with a curing time window of about 3 min. This work shows promising prospects for clinical application in orthopedic surgery and may inspire the design and development of bone adhesives.