Peptide-based hydrogels (PHGs) are biocompatible materials suitable for biological, biomedical, and biotechnological applications, such as drug delivery and diagnostic tools for imaging. Recently, a novel class of synthetic hydrogel-forming amphiphilic cationic peptides (referred to as series K), containing an aliphatic region and a Lys residue, was proposed as a scaffold for bioprinting applications. Here, we report the synthesis of six analogues of the series K, in which the acetyl group at the N-terminus is replaced by aromatic portions, such as the Fmoc protecting group or the Fmoc-FF hydrogelator. The tendency of all peptides to self-assemble and to gel in aqueous solution was investigated using a set of biophysical techniques. The structural characterization pointed out that only the Fmoc-derivatives of series K keep their capability to gel. Among them, Fmoc-K3 hydrogel, which is the more rigid one (G’ = 2526 Pa), acts as potential material for tissue engineering, fully supporting cell adhesion, survival, and duplication. These results describe a gelification process, allowed only by the correct balancing among aggregation forces within the peptide sequences (e.g., van der Waals, hydrogen bonding, and π–π stacking).

中文翻译：

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用于潜在生物医学应用的基于 Fmoc 衍生的阳离子六肽的自支撑水凝胶

肽基水凝胶 (PHG) 是一种生物相容性材料，适用于生物、生物医学和生物技术应用，例如药物输送和成像诊断工具。最近，一类新的合成水凝胶形成两亲性阳离子肽（称为 K 系列），包含一个脂肪族区域和一个赖氨酸残基，被提议作为生物打印应用的支架。在这里，我们报告了 K 系列的六个类似物的合成，其中 N 端的乙酰基被芳香族部分取代，例如 Fmoc 保护基团或 Fmoc-FF 水凝胶剂。使用一组生物物理技术研究了所有肽在水溶液中自组装和凝胶化的趋势。结构表征指出，只有 K 系列的 Fmoc 衍生物保持其凝胶能力。其中，Fmoc-K3 水凝胶是更坚硬的一种（G' = 2526 Pa），作为组织工程的潜在材料，完全支持细胞粘附、存活和复制。这些结果描述了凝胶化过程，只有在肽序列内的聚集力（例如，范德华、氢键和 π-π 堆积）之间正确平衡才允许。