Abstract

Biosynthesis of silver nanoparticles (AgNPs) using plant extracts has become a promising alternative to the conventional chemical synthesis approach. In this study, cost-effective synthesis of AgNPs was attempted using leaves extract of Litchi chinensis. Bio-reduction reaction for the synthesis of NPs was checked by confirming the presence of AgNPs in solution by UV-vis spectrophotometry and with further characterization by fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Surface plasmon resonance (SPR) band showed absorption peak at 422 nm indicating the formation of AgNPs, and FTIR spectra confirmed the presence of biological molecules involved in AgNPs synthesis. TEM analysis revealed the spherical shape of AgNPs with particle size distribution in a range of 5–15 nm. Further, the biosynthesized AgNPs showed significant bactericidal and sporicidal activity against model spore former Bacillus subtilis. AgNPs at concentrations ranging from 25 to 100 µg/mL showed bactericidal activity with inhibition zone ranging from 4–19 mm and sporicidal activity at 100–200 µg/mL in a range of 4.46–61.6% with an exposure time of 2–8 h. These findings exhibit distinctive potential of biogenic AgNPs for their efficient use in developing novel bactericidal and sporicidal agent against spore forming bacilli.

摘要

使用植物提取物生物合成银纳米颗粒（AgNPs）已成为传统化学合成方法的有前途的替代方法。在这项研究中，尝试使用荔枝的叶子提取物来经济高效地合成AgNPs。通过UV-可见分光光度法确认溶液中存在AgNPs，并通过傅里叶变换红外光谱法（FTIR）和透射电子显微镜（TEM）进一步表征，检查了生物还原反应以合成NPs。表面等离振子共振（SPR）谱带显示在422 nm处有吸收峰，表明形成了AgNPs，FTIR光谱证实了参与AgNPs合成的生物分子的存在。TEM分析显示AgNPs的球形，其粒径分布在5-15 nm范围内。此外，生物合成的AgNPs显示出对模型孢子前枯草芽孢杆菌的显着杀菌和杀孢子活性。。浓度在25至100 µg / mL范围内的AgNPs表现出杀菌活性，抑制范围为4–19 mm，在100–200 µg / mL范围内的杀孢子活性为4.46–61.6％，暴露时间为2–8 h 。这些发现显示出生物型AgNP具有独特的潜力，可以有效地用于开发新型的杀菌剂和杀孢子剂以对抗形成芽孢的细菌。