An In vitro Study on the Antibacterial Effect of a Combined Photodynamic and Sonodynamic Therapy Using IR780 Iodide-loaded Mesoporous Silica Nanoparticles Against P. aeruginosa and Multi-Drug Resistant P. aeruginosa

The aim of this study was to investigate the antimicrobial photodynamic, sonodynamic, and combined photodynamic and sonodynamic potentials of IR780 iodideloaded mesoporous silica nanoparticles against gram-negative Pseudomonas aeruginosa (P. aeruginosa) and multi drug resistant Pseudomonas aeruginosa (MDR P. aeruginosa). The results revealed that for P. aeruginosa, the combined photodynamic therapy (PDT) and sonodynamic therapy (SDT) showed a 44% reduction in bacterial cell viability as compared to 18% and 31% when exposed to SDT alone and PDT alone, respectively. For MDR. P. aeruginosa, the combined treatment resulted in a 45% reduction in bacterial cell viability, as compared to 14% and 30% when exposed to SDT alone and PDT alone, respectively. The results of this study demonstrated that IR780 iodide-loaded mesoporous silica nanoparticles have the potential to be utilized as photo/sono therapeutic agents for the inactivation of drug-resistant bacteria. The killing effect was mainly due to the photodynamic and sonodynamic effects of the nanoparticles, mainly caused by singlet oxygen. No photothermal effect was involved in the killing.