Research advances of nanomaterials for the acceleration of fracture healing.

The bone fracture cases have been increasing yearly, accompanied by the increased number of patients experiencing non-union or delayed union after their bone fracture. Although clinical materials facilitate fracture healing (e.g., metallic and composite materials), they cannot fulfill the requirements due to the slow degradation rate, limited osteogenic activity, inadequate osseointegration ability, and suboptimal mechanical properties. Since early 2000, nanomaterials successfully mimic the nanoscale features of bones and offer unique properties, receiving extensive attention. This paper reviews the achievements of nanomaterials in treating bone fracture (e.g., the intrinsic properties of nanomaterials, nanomaterials for bone defect filling, and nanoscale drug delivery systems in treating fracture delayed union). Furthermore, we discuss the perspectives on the challenges and future directions of developing nanomaterials to accelerate fracture healing.