Takahashi Chisato, Moriguchi Keiichi
Department of Materials and Chemistry, National Institute of Advanced Industrial Science and Technology (AIST) 4-205, Sakura-zaka, Moriyama-ku Nagoya Aichi 463-8560 Japan
Department of Rehabilitation, Faculty of Health and Sciences, Wakayama Professional University of Rehabilitation Minato-machi, Wakayama-shi Wakayama 640-8222 Japan.
Nanoscale Adv. 2024 Aug 31;6(20):5020-30. doi: 10.1039/d4na00249k.
Silver nanoparticles exert high antibacterial activity and thus have been used in polymeric formulations for drug delivery. In recent years, polymeric formulations containing silver nanoparticles have been found to be highly effective against biofilm infections, which are difficult to treat with drugs only. However, the antibacterial effects of silver nanoparticles in polymer composites depending on administration time are still unknown. In this study, we used transmission electron microscopy to investigate the antibacterial activity of silver decorated poly(dl-lactide--glycolide) (PLGA) (Ag PLGA) nanoparticles against biofilms at different treatment times. LIVE/DEAD assay result showed that approximately 85% of the bacteria in the biofilms was killed after 6 h of administering the Ag PLGA nanoparticles. The formulation comprising Ag PLGA nanoparticles was found to be highly effective and to exhibit low cytotoxicity. However, silver nanoparticles were ejected from the bacterial cells up to 4 h after treatment administration due to the self-protection properties of the bacteria. On the basis of the results, we propose a potential mechanism for the antibacterial activity of silver nanoparticles per treatment time, taking into account the detoxification activity of bacterial cells. This information can contribute not only to an understanding of foreign-body elimination but also to the design of effective formulations against biofilm infections.
银纳米颗粒具有很高的抗菌活性，因此已被用于药物递送的聚合物制剂中。近年来，已发现含有银纳米颗粒的聚合物制剂对生物膜感染具有高度有效性，而仅用药物治疗生物膜感染是很困难的。然而，银纳米颗粒在聚合物复合材料中的抗菌效果取决于给药时间，这一点仍然未知。在本研究中，我们使用透射电子显微镜来研究银修饰的聚（dl-丙交酯-乙交酯）（PLGA）（Ag PLGA）纳米颗粒在不同处理时间对生物膜的抗菌活性。活/死检测结果表明，在施用Ag PLGA纳米颗粒6小时后，生物膜中约85%的细菌被杀死。发现包含Ag PLGA纳米颗粒的制剂具有高度有效性且细胞毒性低。然而，由于细菌的自我保护特性，在给药后长达4小时内，银纳米颗粒从细菌细胞中被排出。基于这些结果，考虑到细菌细胞的解毒活性，我们提出了每个处理时间银纳米颗粒抗菌活性的潜在机制。这些信息不仅有助于理解异物清除，也有助于设计针对生物膜感染的有效制剂。
