A Nanophotosensitizer Based on Oxyhemoglobin for Specific and Synergistic Photothermal and Photodynamic Therapies Against Porphyromonas Gingivalis Oral Infection

Photothermal therapy (PTT) and photodynamic therapy (PDT) are emerging alternative antibacterial approaches. However, due to the lack of selectivity of photosensitizers for pathogenic bacteria, these methods often show a certain degree of in vivo toxicity. Moreover, it is difficult for PDT to exert effective antibacterial effects against anaerobic infections owing to oxygen deficiency. As one of the major anaerobic pathogens in oral infections, Porphyromonas gingivalis ( P. gingivalis ) acquires iron and porphyrin mainly from hemoglobin in the host. Herein, we developed a novel nanophotosensitizer named as oxyHb@IR820 via the complexation of oxyhemoglobin with IR820, a photosensitizer that has both PTT and PDT performances, for fighting P. gingivalis oral infection more specifically and efficiently. Owing to hydrophobic interaction, oxyHb@IR820 had much stronger photoabsorption at 808 nm than free IR820, and thus exhibited significantly enhanced photothermal conversion efficiency. As an oxygen supplier, oxyHb played an important role for promoting the photodynamic efficiency of oxyHb@IR820. More importantly, oxyHb@IR820 showed an efficient and specific uptake in P. gingivalis , and exerted synergistic PTT and PDT against P. gingivalis and oral infection in golden hamsters. This study provides an efficient strategy for the specific delivery of photosensitizers targeting P. gingivalis and the augment of antibacterial PDT against anaerobic infections