Mariannaea sp. HJ合成纳米金银合金的特性考察

Characterization of Au-Ag nanoparticles biosynthesized by fungus Mariannaea sp. HJ

摘要:

利用微生物合成纳米金银合金 (Au-AgNPs) 具有操作简便、生态友好等特点，但目前利用真菌合成的相关研究较少。本研究利用真菌Mariannaea sp. HJ胞内提取物合成纳米金银合金，考察了不同的金银离子浓度比例对生物合成纳米金银合金特性的影响。实验表明，金银离子浓度比例对生物纳米金银合金的组成影响较大，随着银离子浓度比例的增加，反应体系颜色会由浅紫色逐渐变为棕色，紫外-可见特征吸收峰发生了明显的蓝移，合成的纳米金银合金中银的比例也会逐渐增加。透射电子显微镜表明纳米金银合金的形貌主要为球形和伪球形，在0.5∶0.5、0.5∶1.5以及0.5∶3.0三种金银离子浓度比例下，纳米颗粒的平均粒径分别为19.24 nm、15.99 nm和19.33 nm。X射线衍射光谱结果显示纳米金银合金的晶胞为面心立方结构。利用傅里叶转换红外线光谱表征推测参与纳米金银合金还原稳定的官能团可能为-OH、-NH3、-COOH。此外，本研究以4-硝基苯酚为底物探究生物纳米金银合金的催化特性，结果表明纳米金银合金对4-硝基苯酚具有良好的催化活性，其催化反应速率常数为7.85×10–3 s–1。上述结果表明，真菌Mariannaea sp. HJ能够合成分散性较好的纳米金银合金，在催化还原硝基芳烃污染物方面具有潜在的应用价值。

Abstract:

Biosynthesis of gold-silver alloy nanoparticles (Au-AgNPs) is a simple operation and ecological friendly, but with limited reports on the availability of fungal resources. In this study, cell-free extracts of Mariannaea sp. HJ was used to synthesize Au-AgNPs, and the effects of the different ratios of Au and Ag ion concentrations on the synthesis of Au-AgNPs were also studied. The results clearly showed that the ratio of Au and Ag ion concentrations had an impact on the composition of Au-AgNPs. With the Ag ion increasing, the color of culture supernatant changed from light purple to brown and an obvious blue shift of characteristic absorption peak was observed in UV-vis spectra, indicating an increase of the percentage of Ag in the Au-AgNPs. Transmission electron microscope showed that the morphologies of the Au-AgNPs were mainly spherical and pseudo spherical, and the average particle sizes of the Au-AgNPs at three different ion concentrations, including 0.5:0.5, 0.5:1.5 and 0.5:3.0, were 19.24 nm, 15.99 nm and 19.33 nm, respectively. X-ray diffraction results showed that the Au-AgNPs had a surface-centered cubic structure. Fourier transform infrared spectroscopy was used to characterize and speculate the involvement of -OH, -NH3 and -COOH functional groups in the reduction and stability process of Au-AgNPs. Furthermore, 4-nitrophenol (4-NP) was used to explore catalytic activity of Au-AgNPs. Catalytic experiments demonstrated that the Au-AgNPs had a good catalytic activity on 4-NP reduction with a catalytic reaction rate constant of 7.85×10–3 s–1. In brief, the present study suggested that Mariannaea sp. HJ could synthesize Au-AgNPs with good dispersity, and had a potential application in the catalytic reduction of nitro aromatic hydrocarbons.