Bhardwaj Diksha, Singh Ruby
Department of Chemistry, School of Basic Sciences, Jaipur National University, 302017, Jaipur, Rajasthan, India.
Bioresour Bioprocess. 2021 Jan 2;8(1):1. doi: 10.1186/s40643-020-00357-z.
Studies of plant extract-mediated synthesis of nanoparticles is extensively explored and studied in recent time due to eco-friendly, cost-effectiveness and minimal use of toxic chemicals for synthesis. In this study, the synthesis of Ag-TiO nanocomposites (NCs) was carried out using Origanum majorana leaf extract under ultrasound irradiation. Origanum majorana leaf extract plays an important role as reducing and capping agent in synthesis of Ag-TiO nanocomposites (NCs). The antimicrobial activities of synthesised Ag-TiO NCs have been studied against Gram-positive and Gram-negative bacteria. In addition to this, the antioxidant activity of green Ag-TiO NCs was also evaluated on the basis of free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), and hydrogen peroxide free radicals.
Green-synthesised Ag-TiO NCs were successfully characterised on the basis of UV-Vis spectrophotometer, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The results revealed the spherical shape of nanocomposite with an average size 25-50 nm. The synthesised Ag-TiO NCs have showed significant antimicrobial activity against Escherichia coli, Bacillus subtilis and Aspergillus niger in comparison to TiO nanoparticles (NPs). The antioxidant evaluation of biomimetic synthesised Ag-TiO NCs also exhibited strong activity than TiO NPs and comparable to standard.
Green-synthesized Ag-TiO NCs provide a promising approach that can satisfy the requirement of large-scale industrial production bearing the advantage of low cost, eco-friendly and reproducible.
近年来，由于植物提取物介导的纳米颗粒合成具有环境友好、成本效益高以及合成过程中有毒化学物质使用量最少等特点，因此对其进行了广泛的探索和研究。在本研究中，在超声辐射下使用马郁兰叶提取物进行了Ag-TiO纳米复合材料（NCs）的合成。马郁兰叶提取物在Ag-TiO纳米复合材料（NCs）的合成中作为还原剂和封端剂发挥着重要作用。已对合成的Ag-TiO NCs对革兰氏阳性菌和革兰氏阴性菌的抗菌活性进行了研究。除此之外，还基于绿色Ag-TiO NCs对1,1-二苯基-2-苦基肼（DPPH）、2,2'-联氮-双-（3-乙基苯并噻唑啉-6-磺酸）（ABTS）和过氧化氢自由基的自由基清除活性评估了其抗氧化活性。
基于紫外可见分光光度计、傅里叶变换红外（FT-IR）光谱、X射线衍射分析（XRD）、扫描电子显微镜能量色散X射线光谱（SEM-EDS）和透射电子显微镜（TEM）对绿色合成的Ag-TiO NCs进行了成功表征。结果显示纳米复合材料呈球形，平均尺寸为25-50nm。与TiO纳米颗粒（NPs）相比，合成的Ag-TiO NCs对大肠杆菌、枯草芽孢杆菌和黑曲霉表现出显著的抗菌活性。仿生合成的Ag-TiO NCs的抗氧化评估也显示出比TiO NPs更强的活性，且与标准品相当。
绿色合成的Ag-TiO NCs提供了一种有前景的方法，该方法能够满足大规模工业生产的要求，具有低成本、环境友好和可重复的优点。
