利用Mariannaea sp.HJ菌株胞内提取物合成纳米银及其抗菌特性研究

Biosynthesis of silver nanoparticles by the cell-free extracts of Mariannaea sp. HJ and their antimicrobial characteristics research

摘要:

[目的] 近年来，纳米银由于其自身独特的抗菌活性而受到越来越多的关注，有研究表明纳米银是一种广谱的抗菌剂，其对数十种致病微生物都有强烈的抑制和杀灭作用。相较于传统的合成方法而言，具有反应条件温和、环境友好等优势的生物合成法是目前的研究热点。[方法] 本研究利用真菌Mariannaea sp.HJ的胞内提取物合成纳米银，并对其合成条件进行优化调控，还进一步考察了合成的纳米银颗粒的抗菌性能。[结果] 胞内提取物浓度350 mg/L、AgNO₃浓度5 mmol/L、pH 7.0为菌株HJ胞内提取物合成纳米银的最优条件；TEM图像表明合成的纳米银颗粒主要为球形和伪球形，分散性良好，无明显的团聚现象；XRD表明合成的纳米银晶体结构为面心立方体结构；通过FTIR分析结果推测提取物中的羟基、羧基等官能团可能参与了纳米银的还原和稳定过程。此外，在本实验条件下合成的纳米银颗粒对革兰氏阴性菌Escherichia coli BL21和革兰氏阳性菌Arthrobacter sp.W1都有较好的抗菌活性。[结论] 真菌Mariannaea sp.HJ胞内提取物能合成尺寸均一且分散性良好的球形纳米银颗粒，合成的纳米银颗粒在抗菌方面具有潜在的研究价值。

关键词:Mariannaea sp.HJ;生物合成;纳米银;抗菌活性

Abstract:

[Objective] Due to their unique antibacterial activity, silver nanoparticles (AgNPs) have attracted great attention recently. And it is said that AgNPs are extensively antibacterial agents which have strong inhibition and toxic effects on dozens of pathogenic microorganisms. Compared with traditional synthetic methods, biosynthesis way has the advantages of mild reaction conditions and environmental-friendliness and is becoming a hot research topic. [Methods] In this study, we have used the cell-free extracts of fungal Mariannaea sp. HJ to synthesize AgNPs. The conditions for synthesis and the antibacterial activity were also investigated. [Results] Study has shown that the cell-free extracts of 350 mg/L, AgNO₃ 5 mmol/L and pH 7.0 were the optimal synthesis conditions for this reaction. Transmission Electron Microscope (TEM) images showed that the as-synthesized AgNPs were mainly spherical and pseudo spherical with good dispersibility. Diffraction of x-rays (XRD) analysis indicated that the crystal structure of AgNPs were face-centered cubic. The Fourier Transform Infrared Spectrometer (FTIR) analysis results suggested that the hydroxyl, carboxyl and other functional groups in the extracts might have played a functional role in the reduction or stabilization process. Besides, it has been verified that the AgNPs synthesized under the optimal experimental conditions had good antibacterial activity against both Gram-negative bacteria Escherichia coli BL21 and Gram-positive bacteria Arthrobacter sp. W1. [Conclusion] In brief, the cell-free extracts of Mariannaea sp. HJ could greenly synthesize spherical AgNPs with uniform size and good dispersion. The synthesized AgNPs might have potential research value in antibacterial advances.

Key words:Mariannaea sp. HJ;biosynthesis;silver nanoparticles;antibacterial activity