Biophotonics laboratory, Institute of Biomedical Engineering, Boğaziçi University, Kandilli Campus, Çengelköy, Istanbul 34684, Turkey.
J Microbiol Methods. 2023 Aug;211:106773. doi: 10.1016/j.mimet.2023.106773. Epub 2023 Jun 22.
The rapid spread of antimicrobial resistance is one of the biggest threats to global health. In the search for new treatment approaches that can eradicate pathogens without inducing drug-resistant strains, photodynamic therapy stands as a promising one. The aim of this study was to investigate the antimicrobial photodynamic potential of mesoporous silica nanoparticles (MSN) loaded with IR780 iodide on one of the most common multidrug-resistant bacteria both in hospitals and in the community, which is methicillin-resistant Staphylococcus aureus (MRSA). Mesoporous silica nanoparticles loaded with IR780 iodide were synthesized, their photodynamic and photothermal properties were examined, and their antimicrobial photodynamic potential against one methicillin-susceptible Staphylococcus aureus (MSSA), and one MRSA strain was investigated. Irradiation was achieved via a 785 nm diode laser (500 mW/cm, 5 min). Viable bacterial cells were counted by serial dilution method. The post-treatment biofilm recurring ability of MRSA was assessed 24 h post-PDT treatment using Crystal Violet assay. Scanning Electron Microscopy (SEM) of post-treatment biofilms was acquired. Data were analyzed by ANOVA followed by Tukey's test (p ≤ 0.05). Results revealed that mesoporous silica nanoparticles loaded with IR780 iodide-mediated photodynamic therapy were effective in killing both tested strains. The antimicrobial effect was stronger on MRSA, in which 99.97% of photokilling (3.54 log reduction) was observed. The killing was mainly due to the photodynamic action of the nanoparticles. Post-treatment biofilm recurring ability of MRSA was much less in the treated group than that of the control group (50% inhibition), as confirmed by both optical density at 570 nm (OD) measurement, and Scanning Electron Microscope (SEM) imaging.
抗菌药物耐药性的迅速传播是对全球健康的最大威胁之一。在寻找可以消灭病原体而不诱导耐药菌株的新治疗方法时，光动力疗法是一种很有前途的方法。本研究旨在研究载有 IR780 碘化物的介孔硅纳米粒子（MSN）对医院和社区中最常见的一种多药耐药菌即耐甲氧西林金黄色葡萄球菌（MRSA）的抗菌光动力潜力。合成了载有 IR780 碘化物的介孔硅纳米粒子，研究了它们的光动力和光热特性，并研究了它们对一种耐甲氧西林金黄色葡萄球菌（MSSA）和一种 MRSA 菌株的抗菌光动力潜力。通过 785nm 二极管激光器（500mW/cm，5 分钟）进行照射。通过连续稀释法计数活菌细胞。在 PDT 治疗后 24 小时，通过结晶紫测定法评估 MRSA 的后处理生物膜再生长能力。获得了后处理生物膜的扫描电子显微镜（SEM）图像。通过方差分析（ANOVA） followed by Tukey's test（p≤0.05）进行数据分析。结果表明，载有 IR780 碘化物的介孔硅纳米粒子介导的光动力疗法能有效杀灭两种测试菌株。对 MRSA 的抗菌效果更强，观察到 99.97%的光杀伤（3.54 对数减少）。这种杀伤主要是由于纳米粒子的光动力作用。与对照组相比，MRSA 的后处理生物膜再生长能力在治疗组中明显降低（50%抑制），这一点通过 570nm 处的光密度（OD）测量和扫描电子显微镜（SEM）成像都得到了证实。
