In western countries, one patient on twenty will develop a nosocomial infection during his hospitalization at health care facilities. Classical antibiotics being less and less effective, this phenomenon is expanding year after year. Prevention of bacteria colonization of implantable medical devices constitutes a major medical and financial issue. In this study, we developed an antibacterial coating based on self-assembled Fmoc-tripeptide. Fmoc-FFpY peptides (F: phenylalanine; Y: tyrosine; p: PO42–) are dephosphorylated enzymatically into Fmoc-FFY by action of alkaline phosphatase functionalized silica nanoparticles (NPs@AP), previously deposited on a surface. Fmoc-FFY peptides then self-assemble through π–π stacking interactions, hydrogen bonds and hydrophobic interactions adopting β-sheets secondary structures. The obtained hydrogel coatings show fibrillary structures observed by cryo-scanning electron microscopy with a thickness of few micrometers. At low concentration (≤0.5 mg.mL–1), self-assembled Fmoc-FFY has a superior antibacterial activity than Fmoc-FFpY peptide in solution. After 24 h of incubation, Fmoc-FFY hydrogel coatings fully inhibit the development of Gram-positive Staphylococcus aureus (S. aureus). The antibacterial effect is maintained on an in vitro model of repetitive infection in the case of S. aureus. This coating could serve in infections were Gram positive bacteria are prevalent, e.g., intravascular catheter infections. This work gives new insights toward the design of an alternative antimicrobial coating.

中文翻译：

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Fmoc-三肽表面触发自组装作为抗菌涂层


在西方国家，一名二十岁的患者在医疗机构住院期间会发生院内感染。传统抗生素的效果越来越差，这种现象正在逐年扩大。防止植入式医疗器械的细菌定植构成了重大的医疗和财务问题。在这项研究中，我们开发了一种基于自组装Fmoc-三肽的抗菌涂层。 Fmoc-FFpY 肽（F：苯丙氨酸；Y：酪氨酸；p：PO42–）通过先前沉积在表面上的碱性磷酸酶功能化二氧化硅纳米颗粒 (NPs@AP) 的作用，酶促脱磷酸为 Fmoc-FFY。然后，Fmoc-FFY 肽通过 π-π 堆积相互作用、氢键和采用 β-折叠二级结构的疏水相互作用进行自组装。通过冷冻扫描电子显微镜观察到，所获得的水凝胶涂层显示出厚度为几微米的纤维结构。在低浓度（≤0.5 mg.mL–1）下，自组装Fmoc-FFY比溶液中的Fmoc-FFpY肽具有更优异的抗菌活性。孵育 24 小时后，Fmoc-FFY 水凝胶涂层完全抑制革兰氏阳性金黄色葡萄球菌（S. aureus）的生长。在金黄色葡萄球菌重复感染的体外模型中仍保持抗菌作用。该涂层可用于革兰氏阳性菌普遍存在的感染，例如血管内导管感染。这项工作为替代抗菌涂层的设计提供了新的见解。