金属离子诱导Aspergillus sp. WL-Au合成纳米金的特性

Characteristics of Gold Nanoparticles Synthesized by Aspergillus sp. WL-Au Induced by Metal Ions

纳米金凭借其独特的光电特性、良好的稳定性及生物相容性被广泛应用于工业催化、污染控制及医学诊断等领域。近年来,微生物法合成纳米金具有绿色低毒、条件温和、成本低廉等优势而倍受关注。然而,如何对纳米金的形貌尺寸进行定向调控仍有待进一步探究。该研究选取Fe^(3+)、Zn^(2+)、Al^(3+)、Co^(2+)、Ni^(2+)、Pb^(2+)及Sn^(2+)等多种金属离子,诱导曲霉菌(Aspergillus sp.) WL-Au合成纳米金,对其形貌进行定向调控。紫外-可见光谱分析结果表明,经Fe^(3+)、Sn^(2+)诱导的菌株合成的纳米金分散性较好,其余金属离子诱导菌株合成的纳米金单分散性较差、易沉聚。透射电子显微镜分析结果表明,大多数金属离子诱导菌株合成的纳米金为球形和伪球形,有少量的三角形;其中,经Fe^(3+)诱导后,菌株WL-Au胞外合成形貌均一、粒径较小的球形纳米金,而经Pb^(2+)诱导后,合成形貌均一的纳米棒。此外,Fe^(3+)诱导菌株合成的球形纳米金对4-硝基苯酚具有良好的催化还原性能,其催化速率常数k为13.3×10^(-3)s^(-1)。研究表明曲霉菌(Aspergillus sp.)WL-Au经Fe^(3+)诱导后可显著提高胞外合成纳米金的能力,且合成的纳米金具有形貌均一、分散性好、催化速率高的特点,在催化还原污染物方面具有较好的应用潜力。

Gold nanoparticles(AuNPs) with their unique photoelectric properties and good stability have been widely used in industrial catalysis, pollution control and medical diagnosis. In recent years, biosynthesis of AuNPs has attracted great attention due to their cost-effective, mild reaction conditions and environmentally friendly nature. However, how to control the size and shape of synthesized nanoparticles needs to be further explored. In this study, the effects of different metal ions such as Fe^3+, Zn^2+, Al^3+, Co^2+, Ni^2+, Pb^2+ and Sn^2+ on AuNPs synthesized by strain WL-Au were investigated. The UV-vis spectra showed that strain WL-Au induced by Fe^3+ and Sn^2+ could synthesize AuNPs with good dispersion, but in the system induced by other metal ions were easily aggregated. TEM revealed that the morphology of AuNPs was mainly focused on pseudo spherical and spherical, with only a few triangles. After being induced by Pb2+ and Fe3+, strain WL-Au could directionally synthesize spherical and rod like AuNPs. And the spherical AuNPs could serve as a highly efficient catalyst for 4-nitrophenol reduction with the reaction rate constant k of 13.3×10^-3s^-1. In a word, this study indicates that Aspergillus sp. WL-Au induced by Fe3+ could significantly improve the ability of AuNPs synthesis, and these spherical AuNPs with good dispersion, uniformed size and efficient catalytic ability have better potential applications in catalytic reduction of environmental pollutants.