School of Chemistry, Pharmacy and Food Biosciences , University of Reading , Reading RG6 6AD , U.K.
Nanomicroscopy Center , Aalto University , Puumiehenkuja 2 , Espoo FIN-02150 , Finland.
ACS Appl Mater Interfaces. 2019 Sep 18;11(37):33573-33580. doi: 10.1021/acsami.9b09065. Epub 2019 Sep 3.
A novel lipopeptide CKTTβAH was designed that incorporates the KTT tripeptide sequence from "Matrixyl" lipopeptides along with the bioactive βAH (β-alanine-histidine) carnosine dipeptide motif, attached to a C hexadecyl lipid chain. We show that this peptide amphiphile self-assembles above a critical aggregation concentration into β-sheet nanotape structures in water, phosphate-buffered saline (PBS), and cell culture media. Nanotape bundle structures were imaged in PBS, the bundling resulting from nanotape associations because of charge screening in the buffer. In addition, hydrogelation was observed and the gel modulus was measured in different aqueous media conditions, revealing tunable hydrogel modulus depending on the concentration and nature of the aqueous phase. Stiff hydrogels were observed by direct dissolution in PBS, and it was also possible to prepare hydrogels with unprecedented high modulus from low-concentration solutions by injection of dilute aqueous solutions into PBS. These hydrogels have exceptional stiffness compared to previously reported β-sheet peptide-based materials. In addition, macroscopic soft threads which contain aligned nematic structures can be drawn from concentrated aqueous solutions of the lipopeptides. The anti-cancer activity of the lipopeptide was assessed using two model breast cancer cell lines compared to two fibroblast cell line controls. These studies revealed selective concentration-dependent cytotoxicity against MCF-7 cancer cells in the mM concentration range. It was shown that this occurs below the onset of lipopeptide aggregation (i.e., below the critical aggregation concentration), indicating that the cytotoxicity is not related to self-assembly but is an intrinsic property of CKTTβAH. Finally, hydrogels of this lipopeptide demonstrated slow uptake and release of the Congo red dye, a model diagnostic compound.
一种新型的脂肽 CKTTβAH 被设计出来，它结合了“Matrixyl”脂肽中的 KTT 三肽序列和具有生物活性的βAH（β-丙氨酸-组氨酸）瓜氨酸二肽基序，连接到 C16 脂酰链上。我们表明，这种肽两亲物在超过临界聚集浓度时自组装成β-折叠纳米带结构，在水中、磷酸盐缓冲盐水（PBS）和细胞培养基中。在 PBS 中，纳米带束结构被成像，由于缓冲液中的电荷屏蔽，束的形成是由于纳米带的缔合。此外，还观察到水凝胶化，并在不同的水介质条件下测量了凝胶模量，结果表明，根据水相的浓度和性质，水凝胶模量可调。通过直接在 PBS 中溶解观察到硬水凝胶，并且还可以通过将稀水溶液注入 PBS 来制备具有前所未有的高模量的水凝胶。与以前报道的基于β-折叠肽的材料相比，这些水凝胶具有非常高的硬度。此外，还可以从脂肽的浓缩水溶液中拉出含有排列的向列结构的宏观软线。与两种成纤维细胞系对照相比，用两种乳腺癌细胞系评估了脂肽的抗癌活性。这些研究表明，在 mM 浓度范围内，对 MCF-7 癌细胞具有选择性的浓度依赖性细胞毒性。结果表明，这种情况发生在脂肽聚集的起始（即低于临界聚集浓度）之下，这表明细胞毒性与自组装无关，而是 CKTTβAH 的固有特性。最后，这种脂肽的水凝胶表现出对刚果红染料的缓慢吸收和释放，刚果红染料是一种模型诊断化合物。
