高效广谱复合光催化抗菌剂Ag-AgVO3/BiVO4的设计合成及抗菌机制

合成了一种具有树叶状形貌的Ag-AgVO₃/BiVO₄复合光催化抗菌剂, 并对其晶体结构、 形貌、 组成及光学性质等进行了表征. 研究结果表明, 以3,3',5,5'-四甲基联苯胺(TMB)的氧化反应为模型, Ag-AgVO₃/BiVO₄表现出优异的光响应类氧化酶活性. 光催化抗菌实验结果表明, Ag-AgVO₃/BiVO₄对金黄色葡萄球菌和大肠杆菌均具有良好的抗菌效果, 4 min内的抗菌效率可以达到99%以上. 采用多种实验方法系统研究了其抗菌机制: 活性物种捕获剂实验和细胞内活性氧荧光标记实验表明, 在可见光照射下, Ag-AgVO₃/BiVO₄所产生的电子与O₂反应生成的·O₂^?起主要作用; Live/Dead细胞的荧光实验、 扫描电子显微镜形貌观察实验以及处理前后细胞内外核酸和蛋白质含量的测定实验结果均证实了·O₂^?可以破坏细胞膜的完整性, 导致细胞内容物的破坏和流出, 从而造成细菌死亡. 另外, Ag-AgVO₃/BiVO₄对包括革兰氏阳性菌、 革兰氏阴性菌和真菌在内的9种致病菌均具有良好的抗菌效果, 说明其具有广谱抗菌性能.

Design， Synthesis and Photocatalytic Antibacterial Mechanism of Ag-AgVO3/BiVO4 Composite as a High-efficient and Broad-spectral Antibacterial Agent

A leaf-like Ag-AgVO₃/BiVO₄ photocatalyst with broad-spectrum disinfection activity under visible light irradiation was prepared. Detailed characterizations confirmed the formation of the composites and good optical properties. Using 3,3',5,5'-tetramethylbenzidine(TMB） oxidation as a model， the Ag-AgVO₃/BiVO₄ nanocomposites exhibited good oxidase-like activity which can convert O₂ into reactive oxygen species and oxidize TMB to ox-TMB in blue color. Furthermore， the nanocomposites demonstrated excellent antibacterial activity against Staphylococcus aureus and Escherichia coli， over 99% of both bacteria were killed in 4 min under visible light irradiation. More importantly， the antibacterial mechanism was systematically studied by a variety of experimental methods. Scavenger experiments of different reactive species proved that the photoinduced electrons generated at the oxidation site of Ag-AgVO₃/BiVO₄ play a key role as oxidative species. Results of fluorescent-based cell live/dead tests， SEM technology， and intracellular macromolecular substances and proteins assays confirmed that generated reactive oxygen species（ROS） could kill the bacteria by destroying the integrity of cell membrane and disrupting the cell metabolism. In addition， Ag-AgVO₃/BiVO₄ has a good antibacterial effect on nine pathogenic bacteria including Gram-positive bacteria， Gram-negative bacteria and fungi， indicating its broad-spectrum antibacterial property.