Oral and Dental Disease Research Center, Oral and Maxillofacial Medicine Department, School of Dentistry, Shiraz University of Medical Sciences, Zand Street, Shiraz, Iran.
HIV/AIDS Research Center, Institute of health, Shiraz University of Medical Sciences, Shiraz, Iran.
Lasers Med Sci. 2022 Apr;37(3):1717-1725. doi: 10.1007/s10103-021-03422-x. Epub 2021 Oct 25.
In this experimental study, we aimed to evaluate the antibacterial and anti-biofilm effects of photodynamic therapy with a photosensitizer in conjunction with Gold nanoparticles against Streptococcus mutans as an important cariogenic bacterial agent. This experimental in vitro study evaluated the antibacterial and anti-biofilm effect of five groups as followed against S. mutans: methylene blue (MB), Gold nanoparticles (AuNPs), methylene blue conjugated with Gold nanoparticles (MB-AuNPs), MB mediated photodynamic therapy (MB mediated PDT) and methylene blue conjugated with Gold nanoparticles mediated photodynamic therapy (MB-AuNPs mediated PDT). InGaAlP laser (Azor-2 K) with 25 mW total output, 660 nm wavelength and laser probe cross-section of 0.78 cm was used for methylene blue activation. Total dose of 19.23 J/cm for 10 min was irradiated to each group. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and colony forming unit (CFU) were determined. Bacterial biofilm formation inhibition was assessed by crystal violet staining (The microtiter plate biofilm assay). The viability of S. mutans cells was assessed by MTT assay. MB mediated PDT and MB-AuNP mediated PDT were the most effective method for S. mutans biofilm inhibition (P < 0.05). MB alone, MB-AuNP alone and MB mediated PDT and MB-AuNP mediated PDT had the same effect against the planktonic phase of S. mutans (P > 0.05). Also they had similar pattern for bacterial growth inhibition and bactericidal effect (P > 0.05). Gold nano particle mediated photodynamic therapy represented antibacterial and antibiofilm activity against S. mutans; but this modality was not more effective than routine PDT.
在这项实验研究中，我们旨在评估光动力疗法与金纳米粒子结合光敏剂对变形链球菌（一种重要的致龋细菌）的抗菌和抗生物膜作用。这项体外实验研究评估了以下五个组对变形链球菌的抗菌和抗生物膜作用：亚甲蓝（MB）、金纳米粒子（AuNPs）、亚甲蓝与金纳米粒子结合（MB-AuNPs）、MB 介导的光动力疗法（MB 介导的 PDT）和亚甲蓝与金纳米粒子结合介导的光动力疗法（MB-AuNPs 介导的 PDT）。使用波长为 660nm、总输出功率为 25mW、激光探头横截面为 0.78cm 的 InGaAlP 激光（Azor-2K）激活亚甲蓝。每个组照射 10 分钟，总剂量为 19.23J/cm。测定最小抑菌浓度（MIC）、最小杀菌浓度（MBC）和菌落形成单位（CFU）。通过结晶紫染色（微量平板生物膜测定法）评估细菌生物膜形成抑制。通过 MTT 测定评估 S. mutans 细胞的活力。MB 介导的 PDT 和 MB-AuNP 介导的 PDT 是抑制 S. mutans 生物膜最有效的方法（P<0.05）。单独的 MB、单独的 MB-AuNP 以及 MB 介导的 PDT 和 MB-AuNP 介导的 PDT 对变形链球菌浮游期的作用相同（P>0.05）。它们对细菌生长抑制和杀菌作用也有相似的模式（P>0.05）。金纳米粒子介导的光动力疗法对 S. mutans 具有抗菌和抗生物膜活性；但这种方式并不比常规 PDT 更有效。
