Remote eradication of biofilm on titanium implant via near-infrared light triggered photothermal/photodynamic therapy strategy

Biofilm formation is a main challenge in treatment of bone-implant-associated infections, resulting in tolerance to immune system and antibiotics. However, smart non-surgical or non-invasive treatment methods of combating established biofilm on an implant have been less reported. Herein, a therapeutic system consisting of mesoporous polydopamine nanoparticles (MPDA) to combat biofilm is reported for the first time. We develop a synergistic photothermal/photodynamic therapy (PTT/PDT) strategy aiming for biofilms eradication on titanium (Ti) implant, which is integrated with MPDA loading with photosensitizer Indocyanine Green (ICG) by pi-pi stacking. Specifically, MPDA is functionalized with RGD peptide to endow the modified Ti sample (Ti-M/I/RGD) with good cytocompatibility. More importantly, Ti-M/I/RGD implant remarkably kills Staphylococcus aureus (S. aureus) biofilm with an efficiency of 95.4% in vivo upon near infrared (NIR). After biofilm eradication, implant still displays great performance regarding osteogenesis and osseointegration. Overall, this study provides a PTT/PDT strtategy for the development of antibacterial Ti implants for potential orthpediac application.