Gold nanorods modified by endogenous protein with light-irradiation enhance bone repair via multiple osteogenic signal pathways

Fracture is one of the most common clinical diseases that reduce the quality of patients' lives significantly. In this study, we prepared gold nanorods modified by endogenous proteins which collected from the autologous blood of individual mice for enhanced photothermal therapy (PTT) to treat fracture. Due to the outermost layer being endogenous proteins, we find that GNRs neither activate the immune cells in vitro nor cause any rejection immune responses after entering the body as compared with PEG modification. In addition, the internal bleeding and edema of the fracture site result in a rapid enrichment of GNRs after intravenous injection. Under near infrared (NIR) light irradiation, the mild photothermal effect of the accumulated GNRs can effectively promote healing of fracture in mice. The molecular mechanism of osteogenic capability is revealed by transcriptome sequencing and subsequent confirmatory experiments, indicating enhanced two key osteogenic signal transduction (MAPK, PI3K-Akt) and multiple key osteogenesis related factors expression following the treatment. Our strategy offers an alternative way to promote bone regeneration following a fracture.