Photosensitization of Oral Bacteria

描述（由申请人提供）：本研究的总体目标是发展一种临床有用的方法来提高光敏剂（PS）在人类牙菌斑中的渗透和有效性，以预防和治疗牙周炎。需要测试的假设有：(a)激光光力学波（PW）可以诱导不同密度的口腔细菌生物膜对带正电荷的PS，如聚l -赖氨酸（p1）与PS氯离子e6 （ce6）和阳离子亚甲基蓝（MB）之间的聚阳离子偶联物的渗透，这种方法可以显著增加细菌对ce6和MB的吸收；(b)用pl-ce6偶联物和MB致敏后，再暴露于PW和红光下，这些细菌生物膜在体外可能被光破坏。

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.