摘要

       银/金纳米颗粒和阳离子肽被认为是有效的抗菌剂，但它们的联合作用还没有被发现。本文报道了短阳离子二肽稳定的AuNPs/AgNPs纳米杂化材料的绿色合成。深入研究了短阳离子肽偶联对金属纳米粒子抗菌性能的影响。在对合成的纳米结合物进行抗菌评价的背景下，观察到肽端AgNPs与肽端AuNPs以及天然肽和非结合金属纳米粒子相比具有更高的抗菌活性。具体来说，l-His-l-Arg-OMe修饰的AgNPs对大肠杆菌、金黄色葡萄球菌和鼠伤寒沙门菌的MIC分别为0.50、0.37和0.25μM，对白色念珠菌和光滑念珠菌的MIC分别为0.80和10.00μM。这些结果表明，与天然的AgNPs和带正电的二肽相比，合成的二肽使AgNPs成为更好的抗菌剂。此外，阳离子肽（l-His-l-Arg-OMe）封端的AgNPs的时间杀伤曲线甚至比已知的抗生素更好。研究了所有合成的阳离子肽纳米偶联物的细胞毒性行为，发现其在可接受范围内。本研究为对抗多种细菌和真菌病原体开辟了一类全新的抗菌药物。另一个有趣而关键的发现是，二肽封端的AgNPs显示出最大的抗菌活性，观察到纳米制剂对受试微生物的剂量减少了约2-10倍。

       The nanoparticles of silver/gold and cationic peptides have been recognized as potent antimicrobials for long, but their combined effect has so far not been explored. The present study reports the green synthesis of short cationic dipeptide stabilized AuNPs/AgNPs based nanohybrid materials. It thoroughly investigates the effect of conjugation of short cationic peptides on the antimicrobial properties of metallic nanoparticles. In the context of the antimicrobial evaluation of synthesized nanoconjugates, it was observed that peptide capped AgNPs exhibited higher antimicrobial activity as compared to peptide capped AuNPs as well as native peptides and unconjugated metallic nanoparticles. Specifically, l-His-l-Arg-OMe capped AgNPs exhibited MIC of 0.50, 0.37 and 0.25μM against E.coli, S. aureus and S. typhimurium respectively and MIC of 0.80 and 10.00μM against C. albicans and C. glabrata respectively. These results indicate that synthetic dipeptides render AgNPs as better antimicrobial agents in comparison to the native AgNPs and positively charged dipeptides. In addition, the time kill profile of cationic peptide (l-His-l-Arg-OMe) capped AgNPs was found to be even better than the known antibiotics. The cytotoxic behavior of all synthesized nanoconjugates of cationic peptides was studied and was found to be within acceptable limits. The present study opens a completely new class of antimicrobials for combating a wide range of bacterial and fungal pathogens. Another interesting and crucial finding was that dipeptide capped AgNPs displayed maximum antimicrobial activity with observed approximate 2-10 fold reduction in nano formulation dosage against tested microbes.

        https://www.sciencedirect.com/science/article/abs/pii/S0927776517304216?via%3Dihub