Kumar Vijay, Gundampati Ravi Kumar, Singh Devendra K, Bano Daraksha, Jagannadham Medicherla V, Hasan Syed Hadi
Nanomaterials Research Laboratory, Department of Chemistry, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India.
Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India; Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
J Photochem Photobiol B. 2016 Sep;162:374-385. doi: 10.1016/j.jphotobiol.2016.06.037. Epub 2016 Jun 23.
In this study, an eco-friendly and sustainable green route was employed for the synthesis of stable silver nanoparticles (AgNPs) using aqueous leaf extract of Euphorbia hirta (AEE) as both reducing as well as a stabilizing agent. The synthesis of AgNPs was confirmed by UV-visible spectroscopy which produced a prominent SPR band at λmax 425nm after 25min of sunlight exposure. The AgNPs thus synthesized were optimized using one factor at a time approach, and these optimized conditions were 25min of sunlight exposure time, 5.0% (v/v) of AEE inoculum dose and 3.0mM of AgNO3 concentration. The Field Emission Scanning Electron Microscopy (FE-SEM) and High Resolution Transmission Electron Microscopy (HRTEM) analysis confirmed the presence of spherical AgNPs with average size 15.5nm. The crystallinity was determined by X-ray Diffractometer (XRD) and Selected Area Electron Diffraction (SAED) pattern. Chemical and elemental compositions were determined by Fourier Transformed Infrared Spectroscopy (FTIR) and Energy Dispersive X-ray Spectroscopy (EDX) respectively. The Atomic Force Microscopy (AFM) images with average roughness 1.15nm represented the lateral and 3D topological characteristic of AgNPs. The AgNPs thus synthesized showed effective antibacterial activity against gram negative and gram positive bacteria as well as hydrogen peroxide sensing property with a minimum detection limit of 10(-7)M.
在本研究中，采用了一种环保且可持续的绿色路线，以大戟叶的水提物（AEE）作为还原剂和稳定剂来合成稳定的银纳米颗粒（AgNPs）。通过紫外可见光谱法确认了AgNPs的合成，在阳光照射25分钟后，在λmax 425nm处产生了一个明显的表面等离子体共振（SPR）带。采用一次只改变一个因素的方法对如此合成的AgNPs进行了优化，这些优化条件为阳光照射时间25分钟、AEE接种剂量5.0%（v/v）和AgNO3浓度3.0mM。场发射扫描电子显微镜（FE-SEM）和高分辨率透射电子显微镜（HRTEM）分析证实存在平均尺寸为15.5nm的球形AgNPs。通过X射线衍射仪（XRD）和选区电子衍射（SAED）图谱确定了结晶度。分别通过傅里叶变换红外光谱（FTIR）和能量色散X射线光谱（EDX）确定了化学和元素组成。平均粗糙度为1.15nm的原子力显微镜（AFM）图像代表了AgNPs的横向和三维拓扑特征。如此合成的AgNPs对革兰氏阴性菌和革兰氏阳性菌均表现出有效的抗菌活性以及过氧化氢传感特性，最低检测限为10^(-7)M。
