Self-assembled nanoparticles containing photosensitizer and polycationic brush for synergistic photothermal and photodynamic therapy 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 limiting its antibacterial application for periodontitis treatment. Results In this work, self-assembled nanoparticles containing ICG and polycationic brush were prepared for synergistic PTT and PDT against periodontitis. First, 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). Next, ICG was assembled with sPDMA to prepare ICG-loaded sPDMA (sPDMA@ICG) nanoparticles (NPs) and the physicochemical properties of these NPs were characterized systematically. In vitro antibacterial effects of sPDMA@ICG NPs were investigated in porphyromonas gingivalis (Pg), one of the recognized periodontitis pathogens. A ligature-induced periodontitis model was established in Sprague–Dawley rats for in vivo evaluation of anti-periodontitis effects of sPDMA@ICG NPs. Benefiting from the unique brush-shaped architecture of sPDMA polycation, sPDMA@ICG NPs significantly promoted the adsorption and penetration of ICG into the bacterial cells and showed excellent PTT and PDT performances. Both in vitro and in vivo, sPDMA@ICG NPs exerted antibacterial and anti-periodontitis actions via synergistic PTT and PDT. Conclusions A self-assembled nanosystem containing ICG and polycationic brush has shown promising clinical application for synergistic PTT and PDT against periodontitis. Graphical Abstract

Advanced materials and technologies for oral diseases

“…By modified with targeting ligand, such photosensitizers will decrease internalization of normal cells but increase in bacteria, so as to enhance the antibacterial PDT and reduce side-effect. For example, sPDMA (star-shaped polycationic brush poly (2-(dimethylamino) ethyl methacrylate) can increase the bacterial targeting of indocyanine green (ICG) [ 173 ].…”

Weak polyelectrolyte brushes

“…6). 166 Although charge is a useful means of interacting with organisms, pH can be used with weak polyelectrolytes to turn on and off adhesion. This phenomenon has been used with Staphylococcus epidermis deposited on uncharged PAA brushes.…”

“…However, the effectiveness of this is at its greatest when the ICG is loaded in the nanoparticles, which attach to the bacteria. The figure is taken from the original article, 166 and is reproduced under a CC BY 4.0 licence.…”

Biomedical applications and prospects of temperature‐orchestrated photothermal therapy

“…In the experiment of Shi et al, a self‐assembled nano‐system of ICG and polycationic brushes (sPDMA@ICG NPs) was developed to PTT‐PDT for treating periodontitis. The high temperature of 51.2°C in vitro proved to kill bacteria effectively and prevent the resorption of alveolar bone 200 …”

“…The high temperature of 51.2°C in vitro proved to kill bacteria effectively and prevent the resorption of alveolar bone. 200 When chemotherapy was combined with PTT, the previously discovered inefficient antibiotics can be reused. PTT was combined with traditional antibiotics to act on drug-resistant bacteria, hoping to find a way to reuse and prolong the working life of the old antibiotics.…”