Photosensitization of Oral Bacteria

描述（由申请人提供）：本研究的总体目标是开发一种临床上有用的方法来增强光敏剂（PS）在人类牙菌斑中的渗透和有效性，以预防和治疗牙周炎。待检验的假设为：（a）激光产生的光机械波（PW）可以诱导不同密度的口腔细菌生物膜对带正电荷的PS的体外增强的透化，所述带正电荷的PS例如聚-L-赖氨酸（p1）与PS二氢卟酚e6（ce 6）和阳离子亚甲蓝（MB）之间的聚阳离子缀合物，这是一种可以显著增加细菌对ce 6和MB的摄取的方法，和（B）这些细菌生物膜在体外的光破坏在它们用p1-ce 6缀合物和MB敏化之后接着暴露于PW和红光之后是可能的。 将使用两种体外模型研究PS与牙周病原体生物膜的相互作用：a）附着于天然釉质表面生长的单特异性生物膜，和B）在恒化器系统中生长于天然釉质表面的多特异性生物膜。通过测量荧光定量PS的摄取，并通过共聚焦扫描激光显微镜评价其与细菌和生物膜基质的局部相互作用。在存在PS的情况下应用激光诱导PW以扰乱生物膜结构并增加其渗透。细菌生物膜的其他破坏剂将用于比较。在所有情况下，将通过共聚焦扫描激光显微镜评价PS的渗透。在相同的生物膜模型中，将建立PS的光动力学效应，并评价PS对牙周病原体的PW增强光敏作用。

DESCRIPTION (provided by applicant): The overall goal of this research is to develop a clinically useful way to enhance the penetration and effectiveness of photosensitizers (PS) in human Dental plaque for prevention and treatment of periodontitis. The hypotheses to be tested are: (a) Laser-generated photomechanical waves (PW) can induce in vitro enhanced permeabilization of oral bacterial biofilms of different density to positively charged PS, such as a polycationic conjugate between poly-L-lysine (p1) and the PS chlorin e6 (ce6) and the cationic methylene blue (MB), an approach which can significantly increase uptake of ce6 and MB by bacteria, and (b) Photodestruction of these bacterial biofilms in vitro may be possible after their sensitization with the pl-ce6 conjugate and MB followed by exposure to PW and red light. The interaction of the PS with biofilms of periodontopathogens will be studied using two in vitro models: a) monospecific biofilms growing attached to natural enamel surfaces, and b) multispecific biofilms growing on natural enamel surfaces in a chemostat system. The uptake of PS will be quantitated by measuring fluorescence and their local interaction with bacteria and the biofilm matrix will be evaluated by confocal scanning laser microscopy. Laser-induced PW will be applied in the presence of the PS to disorganize the biofilm structure and increase their penetration. Other disorganizing agents of the bacterial biofilm will be used for comparisons. In all cases, the penetration of the PS will be evaluated by confocal scanning laser microscopy. In the same biofilm models the photodynamic effects of the PS will be established and PW-enhanced photosensitization of periodontopathogens by the PS will be evaluated.