Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity
Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity
复制标题
DOI：
10.1038/srep21379
复制
发表时间：
2016-02
影响因子：
4.6
通讯作者：
Qian Wang;Fuxing Kang;Yanzheng Gao;Xuewei Mao;Xiaojie Hu
中科院分区：
文献类型：
--
作者：
Qian Wang;Fuxing Kang;Yanzheng Gao;Xuewei Mao;Xiaojie Hu
大多数人工纳米材料都具有广谱杀菌活性，然而，细菌基于胞外聚合物(EPS)对纳米颗粒(NP)进行解毒的防御机制并不为人所知。我们排除了离子特异性杀菌活性的可能性，显示了缺乏等效的溶解锌和硅的毒性，并通过透析隔离实验测定了氧化锌和二氧化硅纳米颗粒(ZnONPs/SiO2NPs)的颗粒特异性毒性。令人惊讶的是，对你的操纵。大肠杆菌EPS(即没有EPS操纵或通过超声/离心法去除EPS)表明，它们的颗粒特异性杀菌活性可以被NP-EPS隔离所拮抗。PristineE.未经EPS处理的细胞存活率分别为65%(ZnONPs，500 mg L−1)和79%(SiO2 NPs，500 mg L−1)，而超声/离心法去除EPS后的存活率分别为11%和63%。透射电子显微镜结合荧光显微滴定分析和傅里叶变换红外光谱分析表明，类蛋白质物质(酰胺II中的N-H和C-N)和羧酸中的二次羰基(C=O)是参与NP固定的重要结合部位。因此，细菌产生的EPS的数量和组成对NPs的杀菌效果和潜在的环境影响具有重要的影响。
Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the particle-specific toxicity of ZnO and SiO2nanoparticles (ZnONPs/SiO2NPs) through dialysis isolation experiments. Surprisingly, the manipulation of theE. coliEPS (i.e., no EPS manipulation or EPS removal by sonication/centrifugation) showed that their particle-specific bactericidal activity could be antagonized by NP-EPS sequestration. The survival rates of pristineE. coli(no EPS manipulation) reached 65% (ZnONPs, 500 mg L−1) and 79% (SiO2NPs, 500 mg L−1), whereas survival rates following EPS removal by sonication/centrifugation were 11% and 63%, respectively. Transmission electron microscopy (TEM) combined with fluorescence micro-titration analysis and Fourier-transform infrared spectroscopy (FTIR) showed that protein-like substances (N-H and C-N in amide II) and secondary carbonyl groups (C=O) in the carboxylic acids of EPS acted as important binding sites that were involved in NP sequestration. Accordingly, the amount and composition of EPS produced by bacteria have important implications for the bactericidal efficacy and potential environmental effects of NPs.