Self-assembled Nanoparticles of Polycationic b Rush and p Hotosensitizer for Synergistic Photothermal and Photodynamic Therapies Against Periodontitis

Abstract Background: Periodontitis is a chronic inflammatory disease in oral cavity owing to bacterial infection. Photothermal therapy (PTT) and photodynamic therapy (PDT) have many advantages for antibacterial treatment. As an excellent photosensitizer, indocyanine green (ICG) shows prominent photothermal and photodynamic performances. However, it is difficult to pass through the negatively charged bacterial cell membrane, thus limits its antibacterial efficacy for periodontitis treatment.Results: In this work, we developed a nanosystem from self-assembly of ICG and polycationic brush for synergistic PTT and PDT against periodontitis. A star-shaped polycationic brush, poly(2-(dimethylamino)ethyl methacrylate) (sPDMA), was synthesized via atom transfer radical polymerization (ATRP) of DMA monomer from bromo-substituted β-cyclodextrin initiator (CD-Br). ICG was then self-assembled with sPDMA to form ICG-loaded sPDMA (sPDMA@ICG) nanoparticles (NPs), and the physicochemical properties of these NPs were characterized in detail. In vitro antibacterial effects of sPDMA@ICG NPs were evaluated in porphyromonas gingivalis (Pg), one of the recognized periodontitis pathogens, and in vivo anti-periodontitis effects of NPs were investigated in a rat periodontitis model. Benefiting from the unique brush-shaped architecture of sPDMA polycation, sPDMA@ICG NPs efficiently delivered ICG into the bacterial cells through promoting their adsorption and penetration abilities, and also exhibited effective antibacterial and anti-periodontitis actions via synergistic PTT and PDT both in vitro and in vivo.Conclusions: This work developed a promising nano-photosensitizer for synergistic PTT and PDT for antibacterial and periodontitis treatments in clinic.