Food Science Program, Division of Food Systems & Bioengineering, University of Missouri, Columbia, MO 65211, USA.
J Appl Microbiol. 2009 Oct;107(4):1193-201. doi: 10.1111/j.1365-2672.2009.04303.x. Epub 2009 Apr 17.
To investigate antibacterial activities of zinc oxide nanoparticles (ZnO NP) and their mode of action against an important foodborne pathogen, Escherichia coli O157:H7.
ZnO NP with sizes of 70 nm and concentrations of 0, 3, 6 and 12 mmol l(-1) and NP-free solutions were used in antimicrobial tests against E. coli O157:H7. ZnO NP showed increasing inhibitory effects on the growth of E. coli O157:H7 as the concentrations of ZnO NP increased. A complete inhibition of microbial growth was achieved at the concentration level of 12 mmol l(-1) or higher. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy were used to characterize the changes of morphology and cellular compositions of bacterial cells treated with ZnO NP and study the mode of action of ZnO NP against E. coli O157:H7. The intensity of lipid and protein bands in the Raman spectra of bacterial cells increased after exposure to ZnO NP, while no significant changes in nucleic acid bands were observed.
ZnO NP were found to have antibacterial activity against E. coli O157:H7. The inhibitory effects increase as the concentration of ZnO NP increased. Results indicate that ZnO NP may distort and damage bacterial cell membrane, resulting in a leakage of intracellular contents and eventually the death of bacterial cells.
These results suggest that ZnO NP could potentially be used as an effective antibacterial agent to protect agricultural and food safety.
研究氧化锌纳米粒子（ZnO NP）的抗菌活性及其对一种重要食源性病原体大肠杆菌 O157:H7 的作用模式。
使用粒径为 70nm、浓度分别为 0、3、6 和 12mmol l(-1)的 ZnO NP 及不含 NP 的溶液进行抗菌试验，以检测其对大肠杆菌 O157:H7 的抑制作用。结果表明，随着 ZnO NP 浓度的增加，对大肠杆菌 O157:H7 的抑制作用逐渐增强。当 ZnO NP 的浓度达到 12mmol l(-1)或更高时，可完全抑制微生物的生长。扫描电子显微镜（SEM）、透射电子显微镜（TEM）和拉曼光谱用于研究 ZnO NP 对大肠杆菌 O157:H7 的作用模式，对经 ZnO NP 处理后的细菌细胞形态和细胞成分的变化进行了特征化分析。结果表明，细菌细胞的脂质和蛋白质带在拉曼光谱中的强度在暴露于 ZnO NP 后增加，而核酸带没有明显变化。
研究结果表明，ZnO NP 对大肠杆菌 O157:H7 具有抗菌活性。随着 ZnO NP 浓度的增加，抑制效果增强。结果表明，ZnO NP 可能会使细菌细胞膜变形和损坏，导致细胞内物质泄漏，最终导致细菌细胞死亡。
这些结果表明，ZnO NP 可能具有作为一种有效的抗菌剂来保护农业和食品安全的潜力。
