Department of Oral Medicine and Stomatology, Tsurumi University School of Dental Medicine, 2-1-3, Tsurumi, Tsurumi-ku, Yokohama, Kanagawa, 230-8501, Japan.
Department of Removable Partial Prosthodontics, Graduate School, Tokyo Medical and Dental University (TMDU), 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
Lasers Med Sci. 2022 Mar;37(2):857-866. doi: 10.1007/s10103-021-03323-z. Epub 2021 Apr 30.
This study investigated: (1) the microbicidal effect of 405-nm blue LED light irradiation on biofilm formed by Candida albicans hyphae and Streptococcus mutans under dual-species condition on denture base resin, (2) the generation of intracellular reactive oxygen species (ROS) induced by irradiation, and (3) the existence of intracellular porphyrins, which act as a photosensitizer. Denture base resin specimens were prepared and C. albicans and S. mutans dual-species biofilms were allowed to form on the specimens. The biofilms were irradiated with 405-nm blue LED light and analyzed using the colony-forming unit assay, fluorescence microscopy, and scanning electron microscopy (SEM). Single-species biofilms of C. albicans and S. mutans formed on the specimens were irradiated with 405-nm blue LED light. After the irradiation, the intracellular ROS levels in C. albicans and S. mutans cells were measured. In addition, the level of intracellular porphyrins in C. albicans and S. mutans were measured. Irradiation for more than 30 min significantly inhibited the colony formation ability of C. albicans and S. mutans. Fluorescence microscopy revealed that almost all C. albicans and S. mutans cells were killed by irradiation. SEM images showed various cell damage patterns. Irradiation led to the generation of intracellular ROS and porphyrins were present in both C. albicans and S. mutans cells. In conclusion, irradiation with 405-nm blue light-emitting diode light for 40 min effectively disinfect C. albicans hyphae and S. mutans dual-species biofilms and possibly react with intracellular porphyrins resulting in generation of ROS in each microorganism.
(1) 405nm 蓝光照射对义齿基托树脂上白色念珠菌菌丝和变形链球菌形成的双物种生物膜的杀菌效果，(2) 照射诱导的细胞内活性氧 (ROS) 的产生，以及 (3) 细胞内卟啉的存在，它作为一种光敏剂。制备义齿基托树脂标本，在标本上允许白色念珠菌和变形链球菌双物种生物膜形成。用 405nm 蓝光照射生物膜，并通过集落形成单位测定、荧光显微镜和扫描电子显微镜 (SEM) 进行分析。在标本上形成白色念珠菌和变形链球菌的单物种生物膜，用 405nm 蓝光照射。照射后，测量白色念珠菌和变形链球菌细胞内的 ROS 水平。此外，还测量了白色念珠菌和变形链球菌细胞内卟啉的水平。照射 30 分钟以上显著抑制了白色念珠菌和变形链球菌的集落形成能力。荧光显微镜显示，几乎所有的白色念珠菌和变形链球菌细胞都被照射杀死。SEM 图像显示了各种细胞损伤模式。照射导致细胞内 ROS 的产生，并且在白色念珠菌和变形链球菌细胞中都存在卟啉。总之，用 405nm 蓝光发光二极管照射 40 分钟可有效消毒白色念珠菌菌丝和变形链球菌双物种生物膜，并且可能与细胞内卟啉反应，导致每个微生物中 ROS 的产生。
