Division of Molecular Physics, Department of Physics, Chemistry and Biology , Linköping University , SE-581 83 Linköping , Sweden.
Division of Microbiology and Molecular Medicine, Department of Clinical and Experimental Medicine , Linköping University , SE-581 83 Linköping , Sweden.
Langmuir. 2019 Feb 5;35(5):1818-1827. doi: 10.1021/acs.langmuir.8b01625. Epub 2018 Aug 28.
Self-assembled monolayers (SAMs) are widely used in science and engineering, and recent progress has demonstrated the utility of zwitterionic peptides with alternating lysine (K) and glutamic acid (E) residues for antifouling purposes. Aiming at developing a peptide-based fouling-resistant SAM suitable for presentation of surface-attached pheromones for barnacle larvae, we have investigated five different peptide SAMs, where four are based on the EK motif, and the fifth was designed based on general principles for fouling resistance. The SAMs were formed by self-assembly onto gold substrates via cysteine residues on the peptides, and formation of SAMs was verified via ellipsometry, wettability, infrared reflection-absorption spectroscopy and cyclic voltammetry. Settlement of cypris larvae of the barnacle Balanus (=Amphibalanus) amphitrite, the target of pheromone studies, was tested. SAMs were also subjected to fouling assays using protein solutions, blood serum, and the bacterium Mycobacterium marinum. The results confirm the favorable antifouling properties of EK-containing peptides in most of the assays, although this did not apply to the barnacle larvae settlement test, where settlement was low on only one of the peptide SAMs. The one peptide that had antifouling properties for barnacles did not contain a pheromone motif, and would not be susceptible to degredation by common serine proteases. We conclude that the otherwise broadly effective antifouling properties of EK-containing peptide SAMs is not directly applicable to barnacles, and that great care must be exercised in the design of peptide-based SAMs for presentation of barnacle-specific ligands.
自组装单分子层（SAMs）在科学和工程中得到了广泛应用，最近的进展表明，带有交替赖氨酸（K）和谷氨酸（E）残基的两性离子肽在抗污方面具有实用性。为了开发一种基于肽的抗污 SAM，用于展示藤壶幼虫附着的信息素，我们研究了五种不同的肽 SAM，其中四种基于 EK 基序，第五种基于抗污的一般原则设计。这些 SAM 通过肽上的半胱氨酸残基自组装到金基底上，通过椭圆光度法、润湿性、红外反射吸收光谱和循环伏安法验证了 SAM 的形成。藤壶（= Amphibalanus）藤壶的幼体（藤壶幼虫）附着测试了这些 SAM。还使用蛋白质溶液、血清和细菌分枝杆菌对 SAM 进行了抗污试验。结果证实，在大多数试验中，含 EK 的肽具有良好的抗污特性，尽管这不适用于藤壶幼虫附着试验，在该试验中，只有一种肽 SAM 的附着率较低。具有抗污性的肽中有一种不含有信息素基序，并且不易被常见的丝氨酸蛋白酶降解。我们得出结论，含 EK 的肽 SAM 具有广泛有效的抗污特性，但不能直接应用于藤壶，在设计基于肽的 SAM 以展示藤壶特异性配体时，必须格外小心。
