绿色合成纳米银材料的制备及其对水产病原菌的抗菌效果测定

近年来随着水产养殖规模不断扩大，渔药安全问题备受重视。为积极寻找抗生素替代品，本研究采用银杏叶提取物和硝酸银反应合成纳米银材料，并通过紫外-可见光全波段扫描、透射电镜以及X射线衍射对其结构表征进行鉴定。在此基础上，以金黄色葡萄球菌、大肠杆菌，以及水产病原菌迟缓爱德华氏菌和嗜水气单胞菌为测试对象，采用杯碟法、常量肉汤稀释法以及抑菌动力学实验测定合成的纳米银抗菌效果。结果显示，在波长450 nm处有纳米银等离子共振体形成的吸收峰；透射电镜观察到纳米银颗粒平均直径小于10 nm；X射线衍射图谱验证了金属银的生成；本研究所合成的纳米银材料对4种病原菌均有良好的抗菌效果。研究表明，采用银杏叶绿色合成纳米银，不仅方便、快捷，而且成本低廉、环境友好，在水产病害防控中具有良好的前景。

Green synthesis of silver nanoparticles and its bactericidal effects against aquaculture pathogens

With the development of aquaculture, far more attention has been paid to safety in fish drugs usage. In order to find alternatives to antibiotics, silver nanoparticles (AgNPs) were synthesized using extracts of Ginkgo leaves with AgNO₃ in this study. The synthesized silver nanoparticles were characterized by UV-Visible spectrophotometer, transmission electron microscope and X ray diffraction spectrum. The antibacterial efficacy was assessed against Staphylococcus aurous, Escherichia coli and common bacterial pathogens in aquacuture including Edwardsiella tarda and Aeromonas hydrophila, by using cylinder plate method, broth macrodilution method and bacteriostasis kinetic experiments. The results showed that the absorbance maximum was observed at 460 nm corresponding to the plasmon absorbance of the AgNPs. Transmission electron microscope revealed that the AgNPs had an average size below 10 nm.The X-Ray Diffraction (XRD) spectrum of the nanoparticles confirmed the formation of metallic silver.The AgNPs synthesised in this research exhibited good antibacterial efficacy against the test pathogens. This investigation demonstrated that the green synthesis of AgNps with leaves of Ginkgo biloba was not only fast and convenient but also cost effective and ecofriendly, which has good prospects in control of aquaculture diseases.