Department of Chemistry, University of Reading, Reading RG6 6AD, United Kingdom.
Langmuir. 2013 Jul 23;29(29):9149-55. doi: 10.1021/la401771j. Epub 2013 Jul 12.
The self-assembly of three cosmetically active peptide amphiphiles C16-GHK, C16-KT, and C16-KTTKS (C16 denotes a hexadecyl, palmitoyl chain) used in commercial skin care products is examined. A range of spectroscopic, microscopic, and X-ray scattering methods is used to probe the secondary structure, aggregate morphology, and the nanostructure. Peptide amphiphile (PA) C16-KTTKS forms flat tapes and extended fibrillar structures with high β-sheet content. In contrast, C16-KT and C16-GHK exhibit crystal-like aggregates with, in the case of the latter PA, lower β-sheet content. All three PA samples show spacings from bilayer structures in small-angle X-ray scattering profiles, and all three have similar critical aggregation concentrations, this being governed by the lipid chain length. However, only C16-KTTKS is stained by Congo red, a diagnostic dye used to detect amyloid formation, and this PA also shows a highly aligned cross-β X-ray diffraction pattern consistent with the high β-sheet content in the self-assembled aggregates. These findings may provide important insights relevant to the role of self-assembled aggregates on the reported collagen-stimulating properties of these PAs.
本研究考察了三种在商业护肤品中应用的美容肽两亲性分子 C16-GHK、C16-KT 和 C16-KTTKS（C16 表示十六烷基，棕榈酰链）的自组装情况。采用一系列光谱学、显微镜和 X 射线散射方法来探测二级结构、聚集形态和纳米结构。肽两亲性分子（PA）C16-KTTKS 形成了具有高β-折叠含量的平坦带和延伸的纤维状结构。相比之下，C16-KT 和 C16-GHK 表现出类似晶体的聚集态，而后者的 PA 的β-折叠含量较低。所有三种 PA 样品在小角度 X 射线散射图谱中均显示出双层结构的间距，并且所有三种样品的临界聚集浓度都相似，这由脂质链长决定。然而，只有 C16-KTTKS 被刚果红染色，刚果红是一种用于检测淀粉样形成的诊断染料，这种 PA 还表现出高度排列的交叉-β X 射线衍射图案，与自组装聚集物中的高β-折叠含量一致。这些发现可能为这些 PA 的胶原蛋白刺激特性的报道提供有关自组装聚集物作用的重要见解。
