利用不对称 PCR 的长 ssDNA 和非功能化的 AuNPs 提高沙门氏菌比色法的检测限。
Improving the detection limit of Salmonella colorimetry using long ssDNA of asymmetric-PCR and non-functionalized AuNPs.
机构信息
School of Food and Bioengineering, Xihua University, Chengdu, 610039, China.
School of Food and Bioengineering, Xihua University, Chengdu, 610039, China; Department of Nutrition and Food Science, University of Maryland, College Park, MD, 20742, United States.
出版信息
Anal Biochem. 2021 Aug 1;626:114229. doi: 10.1016/j.ab.2021.114229. Epub 2021 Apr 30.
A colorimetric sensor based on gold nanoparticles (AuNPs) and single-stranded DNA (ssDNA) is a simple and rapid method for detecting foodborne pathogens. However, the colorimetric method employed in previous studies involved short ssDNA (<100 nucleotides), including the aptamer and PCR products, resulting in the high detection limit of this technique. In this study, a colorimetric sensor was developed based on long ssDNA of asymmetric PCR (aPCR) and non-functionalized AuNPs for detecting Salmonella Typhimurium (S. Typhimurium). In the presence of S. Typhimurium, the long ssDNA (547 nt) amplified by aPCR-protected AuNPs from NaCl-induced aggregation, while the solution retained a red color. After optimizing parameters, the limit of detection (LOD) of the colorimetric sensor was 2.56 CFU/mL with high specificity. Recovery studies showed its feasibility for detecting S. Typhimurium (10 CFU/mL, 10 CFU/mL, and 10 CFU/mL) in spiked lettuce samples. This colorimetric sensor provides new opportunities for the highly sensitive detection of bacteria in real food samples.
基于金纳米粒子（AuNPs）和单链 DNA（ssDNA）的比色传感器是一种简单快速的检测食源性病原体的方法。然而，以前的研究中所采用的比色法涉及短 ssDNA（<100 个核苷酸），包括适体和 PCR 产物，导致该技术的检测限较高。本研究基于不对称 PCR（aPCR）的长 ssDNA 和非功能化的 AuNPs 开发了一种比色传感器，用于检测鼠伤寒沙门氏菌（S. Typhimurium）。在存在 S. Typhimurium 的情况下，aPCR 扩增的长 ssDNA（547 nt）保护 AuNPs 免受 NaCl 诱导的聚集，溶液保持红色。优化参数后，比色传感器的检测限（LOD）为 2.56 CFU/mL，具有高特异性。回收研究表明，该比色传感器在添加生菜样品中检测 S. Typhimurium（10 CFU/mL、10 CFU/mL 和 10 CFU/mL）具有可行性。这种比色传感器为在实际食品样品中高度敏感地检测细菌提供了新的机会。
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