利用 sp. ARY1 的培养上清液合成银纳米粒子及其抗菌活性。

PURPOSE: In this study, silver nanoparticles (AgNPs) were biosynthesized using culture supernatant of strain sp. ARY1, characterized and their antibacterial activity was investigated against Gram-negative bacteria and METHODS: The strain sp. ARY1 was isolated from river Yamuna, Delhi and used for biosynthesis of AgNPs via extracellular approach. Biosynthesized AgNPs were characterized by UV-Visible (UV-Vis) spectrophotometer, fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Antibacterial activity of AgNPs was determined by well diffusion, broth microdilution and streaking plate assay to determine the zone of inhibition (ZOI), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), respectively. The effect of AgNPs on treated bacteria was investigated by electron microscopy analysis. Further, the biocompatibility of AgNPs was tested against mice erythrocytes (RBC) by hemolytic assay. RESULTS: The UV-Vis spectral analysis revealed absorption maxima at 450 nm which confirmed the formation of AgNPs. The FTIR analysis suggested the involvement of various supernatant biomolecules, as reducing and capping agents in the synthesis of AgNPs. The XRD and EDX analysis confirmed the crystalline and metallic nature of AgNPs, respectively. The TEM and SEM analysis showed nanoparticles were spherical with an average size of 38 nm. The biosynthesized AgNPs inhibited the growth and formed a clear zone of inhibition (ZOI) against tested Gram-negative strains. The MIC and MBC were determined as 8-16 µg/mL and 32 µg/mL, respectively. Further, electron microscopy analysis of treated cells showed that AgNPs can damage the outer membrane, release of cytoplasmic contents, and alter the normal morphology of Gram-negative bacteria, leading to cell death. The hemolytic assay indicated that the biosynthesized AgNPs were biocompatible at low dose concentrations. CONCLUSION: This study demonstrates an eco-friendly process for extracellular synthesis of AgNPs using sp. ARY1 and these AgNPs exhibited excellent antibacterial activity, which may be used to combat Gram-negative pathogens.

目的：在本研究中，使用 sp. ARY1 的培养上清液生物合成了银纳米粒子（AgNPs），并对其进行了表征，研究了其对革兰氏阴性细菌和的抗菌活性。

方法：从德里亚穆纳河分离出 sp. ARY1 菌株，并通过胞外途径用其生物合成 AgNPs。用紫外-可见分光光度计（UV-Vis）、傅里叶变换红外光谱（FTIR）、X 射线衍射（XRD）、能谱（EDX）、透射电子显微镜（TEM）和扫描电子显微镜（SEM）对生物合成的 AgNPs 进行了表征。采用孔扩散法、肉汤微量稀释法和划线平板法分别测定抑菌圈直径（ZOI）、最小抑菌浓度（MIC）和最小杀菌浓度（MBC），以确定 AgNPs 的抗菌活性。通过电子显微镜分析研究了 AgNPs 对处理过的细菌的影响。此外，通过溶血试验测试了 AgNPs 对小鼠红细胞（RBC）的生物相容性。

结果：紫外-可见光谱分析显示，在 450nm 处有最大吸收峰，证实了 AgNPs 的形成。FTIR 分析表明，在 AgNPs 的合成中，上清液中的各种生物分子作为还原剂和封端剂参与了反应。XRD 和 EDX 分析分别证实了 AgNPs 的结晶性和金属性质。TEM 和 SEM 分析表明，纳米粒子为球形，平均粒径为 38nm。生物合成的 AgNPs 抑制了革兰氏阴性菌的生长，并形成了清晰的抑菌圈（ZOI）。MIC 和 MBC 分别确定为 8-16μg/ml 和 32μg/ml。此外，对处理过的细胞的电子显微镜分析表明，AgNPs 可以破坏革兰氏阴性菌的外膜，释放细胞质内容物，并改变其正常形态，导致细胞死亡。溶血试验表明，生物合成的 AgNPs 在低剂量浓度时具有生物相容性。

结论：本研究采用 sp. ARY1 进行了一种环保的胞外合成 AgNPs 的方法，该方法合成的 AgNPs 表现出优异的抗菌活性，可用于对抗革兰氏阴性病原体。