Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, MA 02114, USA.
Harvard Medical School, Department of Dermatology, Boston, MA 02114, USA.
Sci Rep. 2016 Sep 19;6:33270. doi: 10.1038/srep33270.
This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue - MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts.
本研究旨在评估木瓜凝乳蛋白酶凝胶与红光吸收颜料（亚甲蓝 - MB）联合介导光动力疗法（PDT）对变形链球菌生物膜的影响。将 PapaMBlue 与游离 MB 进行比较，使用荧光探针（SOSG 和 HPF）产生活性氧。针对在塑料盘或胶原蛋白膜上生长的 S. mutans 生物膜进行 PDT（660nm 光），并通过 CFU、使用共聚焦显微镜进行死活染色、透射电子显微镜和胶原蛋白膜的 H&E 染色进行检测。在人成纤维细胞中研究细胞毒性和亚细胞定位。将可生物吸收的 I 型胶原蛋白膜的海绵暴露于基于木瓜蛋白酶的凝胶中，用激光照射，并通过 ATR-FTIR 分析其完整性。PapaMBlue 比游离 MB 产生更多的单线态氧和羟基自由基，可能是由于染料在溶液中的更好的解聚。PapaMBlue 对生物膜的抗菌作用能够减少 S. mutans。MTT 和 PrestoBlue 测定均显示，用 PapaMBlue 和 MB 处理的成纤维细胞的细胞活力和代谢评分更高，可能是由于线粒体活性的刺激以及胶原蛋白三螺旋不受影响。PapaMBlue 与 MB 一样有效，可在不影响成纤维细胞的情况下破坏在塑料或胶原蛋白上生长的 S. mutans 生物膜。
