Self-assembled peptide gels have generated interest as antibacterial materials to prevent biomaterial-related infections but these peptides are often associated with poor proteolytic stability. Efforts have been made to stabilize peptides by incorporating non-natural amino acids and/or linkages but complexation with polymers have not been explored. Therefore, we developed self-assembled peptide/chitosan gels, Boc-D-Phe-γ⁴-L-Phe-PEA (NH007)/chitosan and Boc-L-Phe-γ⁴-L-Phe-PEA (NH009)/chitosan, by complexing dipeptide NH007 or NH009 with chitosan in DMSO:acetic acid. The gels were characterized using SEM, FTIR, contact angle, and rheology data and found to exhibit excellent viscoelastic and self-healing characteristics. Complexation with chitosan led to an increase in stability against proteolytic degradation. Peptide/chitosan gels showed broad spectrum antibacterial activities against Gram-negative and Gram-positive bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis at a high inoculum of 10⁷–10⁸ cfu/mL. NH007/chitosan gels showed 70–75% inhibition, whereas NH009/chitosan showed 78–81% inhibition and NH009/chitosan gels, in particular, showed strong antibacterial activity against pathogenic strain of P. aeruginosa. A unique feature of these gels is that the antibacterial activities did not decrease gradually but were sustained for up to 48 h. The mechanistic studies using SEM and HR-TEM indicated interaction of gels with bacterial membrane components, leading to cell lysis. The MTT and LDH assays indicated >90% cell viability and only 8–10% toxicity towards NIH 3T3 fibroblast cells. Thus, peptide/chitosan gels developed in the present work showed improved proteolytic stability and sustained antibacterial activities and, therefore, may be used for preventing biomaterial-related infections.

自组装的肽凝胶作为抗菌材料已引起人们的兴趣，以防止生物材料相关的感染，但这些肽通常与不良的蛋白水解稳定性有关。已经通过结合非天然氨基酸和/或键合来努力稳定肽，但是尚未探索与聚合物的络合。因此，我们开发自组装肽/脱乙酰壳多糖凝胶，将Boc-d-PHE-γ ⁴ -L-PHE-PEA（NH007）/脱乙酰壳多糖和Boc-L-PHE-γ ⁴-L-Phe-PEA（NH009）/壳聚糖，方法是将二肽NH007或NH009与壳聚糖在DMSO：乙酸中络合。使用SEM，FTIR，接触角和流变学数据对凝胶进行表征，发现其具有出色的粘弹性和自修复特性。与壳聚糖的络合导致抗蛋白水解降解的稳定性增加。肽/壳聚糖凝胶在高接种量10 ⁷ –10 ^8下显示出对革兰氏阴性和革兰氏阳性细菌（如大肠杆菌，铜绿假单胞菌，金黄色葡萄球菌和枯草芽孢杆菌）的广谱抗菌活性。 cfu / mL。NH007 /壳聚糖凝胶显示出70-75％的抑制作用，而NH009 /壳聚糖凝胶显示出78-81％的抑制作用，尤其是NH009 /壳聚糖凝胶显示出对P致病菌株的强抗菌活性。铜绿。这些凝胶的独特之处在于其抗菌活性并未逐渐降低，而是持续长达48小时。使用SEM和HR-TEM进行的机理研究表明，凝胶与细菌膜成分相互作用，导致细胞裂解。MTT和LDH分析表明，对NIH 3T3成纤维细胞的细胞活力> 90％，毒性仅为8-10％。因此，在本工作中开发的肽/壳聚糖凝胶显示出改善的蛋白水解稳定性和持续的抗菌活性，因此可以用于预防生物材料相关的感染。