PCLGA/OV-FeTiO2 bone scaffold with enhancing Fenton reaction under NIR irradiation for fighting bacteria

Fenton reaction can kill bacteria by producing strong oxidizing •OH by the chain reaction between Fe 2+ and H 2 O 2 , exhibiting great potential in the treatment of bacterial infection caused by bone graft. However, the properties of bone implants endowed by the Fenton reaction are generally insufficient due to the limitation of the concentration of Fe ions and reaction conditions. Herein, photothermal therapy was applied to enhance the Fenton reaction of scaffold to obtain excellent antibacterial properties, and the scaffold composited of polycaprolactone/polyglycolic acid blends (PCLGA) and oxygen vacancy Fe 3 O 4 /TiO 2 (OV-FeTiO 2 ) nanoparticles was fabricated by selective laser sintering. The results showed that OV-FeTiO 2 nanoparticles possessed excellent photothermal conversion capability, and the temperature of scaffold rose from 20 to 45 °C after 5 min of irradiation by near-infrared (NIR) light at 0.3 W/cm 2 . Consequently, the Fe ions release rate increased due to the accelerated degradation of PCLGA, and the release of Fe ions reached about 5.1 ‰ at 54 °C, which was 1.41 times than that at 25 °C. Benefiting the increase of reaction temperature and release rate of Fe ions, the Fenton reaction activity was enhanced to generate more •OH. The antibacterial experiments showed that the PCLGA/OV-FeTiO 2 scaffold possessed the best antibacterial properties, and the bactericidal rates against E. coli and S. aureus were 97.2 % and 93.5 %, respectively. Besides, in vitro cell experiments demonstrated that the scaffold possessed good biocompatibility and the treatment of NIR irradiation was harmless for cell growth, proliferation and differentiation.