Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
Colloids Surf B Biointerfaces. 2010 Nov 1;81(1):329-35. doi: 10.1016/j.colsurfb.2010.07.027. Epub 2010 Jul 16.
Amphiphilic peptide and their derivatives, with distinguished advantages over conventional materials, have received extensively research interesting recently. In this work, four peptide amphiphiles (PAs1-4) with different length of hydrophobic alkyl tails (C9 for PA1, C11 for PA2, C13 for PA3, and C15 for PA4) were fabricated and their self-assembly behaviors in aqueous medium at different pHs were investigated systematically. It was found that all the peptide amphiphiles can self-assemble in water at a neutral pH of 7 to form tightly packed nanofibers with a beta-sheet conformation. When altering the solution environment to basic medium (pH 11), due to the strong hydrophobic interaction of long alkyl tails in PA3 and PA4, the fibrous nanostructure self-assembled from PA3 and PA4 was not destroyed. However, the nanofibers self-assembled from PA1 in which the length of alkyl tail was relatively short converted into loose spherical micelles with a beta-sheet conformation. Due to the moderate length of alkyl tail in PA2, both nanofibers and micelles can be formed via the self-assembly of PA2 when increasing the pH of the self-assembling system.
两亲肽及其衍生物具有优于传统材料的独特优势，最近受到了广泛的研究关注。在这项工作中，我们制备了四种具有不同疏水烷基链长度（C9 用于 PA1、C11 用于 PA2、C13 用于 PA3 和 C15 用于 PA4）的肽两亲物（PAs1-4），并系统地研究了它们在不同 pH 值下在水相中的自组装行为。结果发现，所有肽两亲物在中性 pH 值 7 下都可以在水中自组装形成具有β-折叠构象的紧密堆积纳米纤维。当改变溶液环境为碱性介质（pH 11）时，由于 PA3 和 PA4 中长烷基链的强疏水相互作用，自组装的纤维纳米结构没有被破坏。然而，在 PA1 中，由于烷基链的长度相对较短，自组装形成的纳米纤维转变成具有β-折叠构象的疏松的球形胶束。由于 PA2 中烷基链的长度适中，当增加自组装体系的 pH 值时，PA2 可以通过自组装形成纳米纤维和胶束。
