Okamoto Ichie, Miyaji Hirofumi, Miyata Saori, Shitomi Kanako, Sugaya Tsutomu, Ushijima Natsumi, Akasaka Tsukasa, Enya Satoshi, Saita Satoshi, Kawasaki Hideya
Department of Periodontology and Endodontology, Faculty of Dental Medicine, Hokkaido University, N13 W7, Kita-ku, Sapporo, Hokkaido 060-8586, Japan.
Division of Periodontology and Endodontology, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsu-cho, Ishikari-gun, Hokkaido 061-0293, Japan.
ACS Omega. 2021 Mar 24;6(13):9279-9290. doi: 10.1021/acsomega.1c00838. eCollection 2021 Apr 6.
Antibacterial photodynamic therapy (aPDT) utilizes reactive oxygen species such as singlet oxygen (O) and free radicals via photosensitizers, which are light and light-sensitive agents, to reduce bacterial infections. It has been utilized as a treatment for dental diseases in place of antibiotic therapies. However, aPDT does not always cause the desired therapeutic effect due to the instability of organic photosensitizers and the formation of bacterial biofilms. To promote the antibacterial and antibiofilm effects of aPDT, we have proposed a lysozyme (Lys)-gold nanoclusters (Au NCs)/rose bengal (Lys-Au NCs/RB) conjugate as a novel photosensitizer. This conjugate was found to effectively impede the growth of both gram-positive and gram-negative bacteria when exposed to white light-emitting diode (LED) irradiation. The photoexcited Lys-Au NCs/RB showed significantly higher antibacterial activity than photoexcited Lys-Au NCs or RB alone. The synergistic effect is a result of the combination of Lys (an antibacterial protein) and enhanced O generation related to resonance energy transfer (RET) in the Au NCs/RB conjugate. Photoexcited Lys-Au NCs/RB increased the effects of aPDT in a dose- and time-dependent manner. Furthermore, the photoexcited Lys-Au NCs/RB successfully decreased biofilm formation. However, in contrast, it did not have a negative effect on the proliferation, adhesion, or spread of mammalian cells, indicating low cytotoxicity. Lys-Au NCs/RB is a novel photosensitizer with low cytotoxicity that is capable of bacterial inactivation and the suppression of biofilm formation, and could help to improve dental treatments in the future.
抗菌光动力疗法（aPDT）通过光敏剂利用单线态氧（O）和自由基等活性氧来减少细菌感染，其中光敏剂是对光敏感的物质。它已被用作替代抗生素疗法治疗牙科疾病。然而，由于有机光敏剂的不稳定性和细菌生物膜的形成，aPDT并不总是能产生预期的治疗效果。为了增强aPDT的抗菌和抗生物膜作用，我们提出了一种溶菌酶（Lys）-金纳米团簇（Au NCs）/孟加拉玫瑰红（Lys-Au NCs/RB）共轭物作为新型光敏剂。发现这种共轭物在暴露于白光发光二极管（LED）照射时能有效抑制革兰氏阳性菌和革兰氏阴性菌的生长。光激发的Lys-Au NCs/RB显示出比单独的光激发Lys-Au NCs或RB显著更高的抗菌活性。这种协同效应是Lys（一种抗菌蛋白）与Au NCs/RB共轭物中与共振能量转移（RET）相关的单线态氧生成增强相结合的结果。光激发的Lys-Au NCs/RB以剂量和时间依赖性方式增强了aPDT的效果。此外，光激发的Lys-Au NCs/RB成功减少了生物膜的形成。然而，与之形成对比的是，它对哺乳动物细胞的增殖、黏附或扩散没有负面影响，表明细胞毒性较低。Lys-Au NCs/RB是一种具有低细胞毒性的新型光敏剂，能够使细菌失活并抑制生物膜形成，未来可能有助于改善牙科治疗。
