Elemike Elias E, Onwudiwe Damian C, Ekennia Anthony C, Ehiri Richard C, Nnaji Nnaemeka J
Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho, South Africa; Department of Chemistry, School of Mathematical and Physical Sciences, North-West University (Mafikeng Campus), Mmabatho 2735, South Africa; Department of Chemistry, College of Sciences, Federal University of Petroleum Resources Effurun, Delta State, Nigeria.
Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho, South Africa; Department of Chemistry, School of Mathematical and Physical Sciences, North-West University (Mafikeng Campus), Mmabatho 2735, South Africa.
Mater Sci Eng C Mater Biol Appl. 2017 Jun 1;75:980-989. doi: 10.1016/j.msec.2017.02.161. Epub 2017 Mar 1.
Nanoscience and nanotechnology represent new and enabling platforms that promise to provide broad range of novel and improved technologies for environmental, biological and other scientific applications. This study reports the synthesis of silver nanoparticles mediated by aqueous leaf extract of Lippia citriodora at two different temperatures of 50°C and 90°C. The synthesis of colloidal silver nanoparticles (AgNPs) was monitored by the use of UV-visible spectroscopy at different temperatures and time intervals. The surface plasmon bands (SPBs) showed peaks between 417 and 421nm at 90°C and around 430nm at 50°C, indicating a red shift at lower temperature. Fourier transform infrared (FTIR) analysis of the nanoparticles showed the presence of similar peaks found in the spectra of the plant extract. The size of the AgNPs was confirmed by transmission electron microscopy (TEM) which indicated an average size of 23.8nm (90°C) and 25nm (50°C). The nanoparticles showed better antimicrobial activities when compared to the crude plant extract against several screened pathogens: Gram negative (Escherichia coli, and Salmonella typhi) and Gram positive (Bacillus subtilis and Staphylococcus aureus) strains and a fungi organism; Candida albicans. In addition, the AgNPs showed good larvicidal efficacy against early 4th instar of Culex quinquefasciatus (a vector of lymphatic filariasis). Finally, the nanoparticles exhibited photocatalytic properties on an industrial waste pollutant, methylene blue.
纳米科学和纳米技术代表了新的且具有赋能作用的平台，有望为环境、生物及其他科学应用提供一系列广泛的新颖且经过改进的技术。本研究报告了在50°C和90°C这两种不同温度下，由柠檬马鞭草水叶提取物介导合成银纳米颗粒的情况。通过在不同温度和时间间隔下使用紫外可见光谱法监测胶体银纳米颗粒（AgNPs）的合成。表面等离子体带（SPBs）在90°C时显示出417至421nm之间的峰值，在50°C时约为430nm，表明在较低温度下出现红移。对纳米颗粒的傅里叶变换红外（FTIR）分析显示，在植物提取物光谱中发现了类似的峰值。通过透射电子显微镜（TEM）确认了AgNPs的尺寸，其平均尺寸为23.8nm（90°C）和25nm（50°C）。与粗植物提取物相比，纳米颗粒对几种筛选出的病原体表现出更好的抗菌活性：革兰氏阴性菌（大肠杆菌和伤寒沙门氏菌）、革兰氏阳性菌（枯草芽孢杆菌和金黄色葡萄球菌）菌株以及一种真菌生物白色念珠菌。此外，AgNPs对致倦库蚊（淋巴丝虫病的传播媒介）的4龄初期幼虫显示出良好的杀幼虫效果。最后，纳米颗粒对工业废污染物亚甲基蓝表现出光催化性能。
