Development of antimicrobial surfaces for sterilization is much needed to avoid the spreading of drug resistant bacteria. Light can activate antimicrobial surfaces by an interaction between nanoparticles and a photosensitizer dye to produce a steady and efficient killing of bacteria. The film studied in this work contains gold nanorods (AuNRs) of 32 nm length and 16 nm diameter and gold nanostars (AuNSs) of 50 nm of diameter, in combination with crystal violet (CV) dye. The surface plasmon resonance (SPR) of the nanoparticles used in the film was mathematically simulated and characterized to understand different SPR between the particles. Their effects on plasmonic coupling with the dye, and thus the production of reactive oxygen species (ROS) and consequently the activity of the film against bacteria, were studied. The films showed great antimicrobial activity against Gram-negative bacteria (E. coli) in 4 h of light exposure; when modified with AuNSs, it could kill E. coli with 5 orders of magnitude (5-log), and the one modified with AuNRs could kill with 4 order of magnitude (4-log), while maintaining partial activity against Gram-positive bacteria (S. aureus), i.e. being able to kill with 2.5 orders of magnitude by the film containing AuNSs and 3 orders of magnitude by those containing AuNRs. The differential response of Gram-negative and Gram-positive bacteria to the ROS generated by the films would allow a more targeted approach for specific bacterial species, for example, surfaces of bedpans or common contact surfaces (handles, handrails, etc.) that are contaminated principally by Gram-negative or Gram-positive bacteria, respectively.

中文翻译：

---

各向异性金纳米粒子对抗菌膜光敏剂等离子耦合影响的研究

非常需要开发用于灭菌的抗菌表面以避免耐药细菌的传播。光可以通过纳米颗粒和光敏染料之间的相互作用激活抗菌表面，从而稳定有效地杀死细菌。在这项工作中研究的薄膜包含长度为 32 nm、直径为 16 nm 的金纳米棒 (AuNR) 和直径为 50 nm 的金纳米星 (AuNS)，以及结晶紫 (CV) 染料。对薄膜中使用的纳米颗粒的表面等离子体共振 (SPR) 进行了数学模拟和表征，以了解颗粒之间的不同 SPR。研究了它们对与染料的等离子体耦合的影响，从而对活性氧 (ROS) 的产生以及薄膜对细菌的活性进行了研究。大肠杆菌）在 4 小时的光照下；当用 AuNS 修饰时，它可以杀死5 个数量级（5-log）的大肠杆菌，而用 AuNRs 修饰的可以杀死 4 个数量级（4-log），同时保持对革兰氏阳性细菌的部分活性（金黄色葡萄球菌），即含有AuNSs的薄膜能杀死2.5个数量级，含有AuNRs的薄膜能杀死3个数量级。革兰氏阴性菌和革兰氏阳性菌对薄膜产生的 ROS 的不同反应将允许对特定细菌种类采取更有针对性的方法，例如便盆表面或常见的接触表面（把手、扶手等）。主要分别被革兰氏阴性或革兰氏阳性细菌污染。