Soman Soumya, Ray J G
Laboratory of Ecology and Ecotechnology, School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, India -686560.
School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, India -686560.
J Photochem Photobiol B. 2016 Oct;163:391-402. doi: 10.1016/j.jphotobiol.2016.08.033. Epub 2016 Aug 31.
Biological approach to synthesis of metal nanoparticles using aqueous leaf extract is a highly relevant and recent theme in nanotechnological research. Phytosynthesized AgNPs have better inhibitory and antimicrobial effects compared to aqueous leaf extract and silver nitrate. In the present investigation crystalline silver nanoparticles (AgNPs) with size of 10nm have been successfully synthesized using aqueous leaf extract (AQLE) of Ziziphus oenoplia (L.) Mill., which act as both reducing as well as capping agent. The particles were characterized using UV Visible spectroscopy, HRTEM-EDAX, XRD, FT-IR and DLS. An evaluation of the anti bacterial activity was carried out using Agar well diffusion method and MIC determination against four bacterial strains, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi; the AgNPs exhibited quite high antibacterial activity. Furthermore, bactericidal studies with TEM at different time intervals after AgNPs treatment showed the presence of AgNPs near cell membrane of bacteria at about 30min exposure and the bacterial-lysis was found completed at 24h. This gave an insight on the mechanism of bacterial-lysis by direct damage to the cell membrane.
利用植物叶片水提取物合成金属纳米粒子的生物学方法是纳米技术研究中一个高度相关的最新主题。与植物叶片水提取物和硝酸银相比，植物合成的银纳米粒子具有更好的抑制和抗菌效果。在本研究中，已成功使用枣（Ziziphus oenoplia (L.) Mill.）的叶片水提取物（AQLE）合成了尺寸为10nm的结晶银纳米粒子（AgNPs），该提取物同时充当还原剂和封端剂。使用紫外可见光谱、高分辨率透射电子显微镜-能谱分析（HRTEM-EDAX）、X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）和动态光散射（DLS）对这些粒子进行了表征。采用琼脂扩散法和最小抑菌浓度（MIC）测定法对肺炎克雷伯菌、铜绿假单胞菌、大肠杆菌和伤寒沙门氏菌这四种细菌菌株进行了抗菌活性评估；AgNPs表现出相当高的抗菌活性。此外，在AgNPs处理后的不同时间间隔用透射电子显微镜进行的杀菌研究表明，在暴露约30分钟时细菌细胞膜附近存在AgNPs，并且在24小时时发现细菌裂解完成。这为通过直接损伤细胞膜导致细菌裂解的机制提供了见解。
