E. coli O157:H7 is one of the most important pathogens in food-borne diseases and is the main cause of the pseudo pandemic development of hemorrhagic colitis and hemolytic uremic syndrome. Also E. coli O157:H7 is the most common serotype of Shiga-toxin-producing E. coli. Traditional methods for detecting E. coli O157:H7 are expensive, time-consuming, and less sensitive. A method with high sensitivity and high-resolution optical detection is utilizes the LSPR property of spherical gold nanoparticles (GNP). In this work, we constructed a novel nano-bio probe to detect E. coli O157:H7 by synthesizing citrate gold nanoparticle conjugated (non-covalent bond) with specific chicken anti-E. coli O157:H7 antibody (IgY) by changing the pH of the nanoparticles’ environment. UV-visible and DLS methods were used to confirm the bonding between the antibody and nanoparticles and the LSPR sensitivity of the nano-bio probe was evaluated by ELISA method. We could optically detect this bacterium in less than 2 h by measuring the LSPR band λ max shifts of GNPs. The sensitivity of this novel biosensor was determined by about 10 CFU/ml, using the LSPR property of spherical gold nanoparticles. So that, the LSPR λ max red shifted from 530 to 543 nm in presence of 10 CFU bacterium. In conclusion, this nano biosensor can be used to detect this important pathogen among the clinical specimens.

中文翻译：

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利用与鸡抗体结合的金纳米颗粒对大肠杆菌O157：H7进行免疫诊断的局部表面等离子体共振（LSPR）生物传感器的设计

大肠杆菌O157：H7是食源性疾病中最重要的病原体之一，是出血性结肠炎和溶血性尿毒症综合征假性大流行发展的主要原因。同样，大肠杆菌O157：H7是产生志贺毒素的大肠杆菌最常见的血清型。检测大肠杆菌O157：H7的传统方法昂贵，费时且灵敏度较低。具有高灵敏度和高分辨率光学检测的方法是利用球形金纳米颗粒（GNP）的LSPR特性。在这项工作中，我们构建了一种新型纳米生物探针，该探针通过合成与特异性鸡抗大肠杆菌的柠檬酸金纳米粒子（非共价键）合成来检测大肠杆菌O157：H7 。O157：H7抗体（IgY）通过改变纳米颗粒环境的pH值来实现。用紫外可见光和DLS方法确认抗体与纳米颗粒之间的结合，并通过ELISA方法评估纳米生物探针的LSPR敏感性。我们可以通过测量GNPs的LSPR波段λ最大位移，在不到2小时的时间内光学检测到这种细菌。利用球形金纳米粒子的LSPR特性，该新型生物传感器的灵敏度约为10 CFU / ml。因此，在10个CFU细菌的存在下，LSPRλmax红色从530 nm变为543 nm。总之，这种纳米生物传感器可用于检测临床标本中的这种重要病原体。