纳米棒
抗坏血酸
赭曲霉毒素A
化学
检出限
适体
表面等离子共振
生物传感器
肉眼
色谱法
比色法
纳米技术
材料科学
生物化学
真菌毒素
纳米颗粒
分子生物学
生物
食品科学
作者
Fengyu Tian,Jing Zhou,Ruijie Fu,Yongliang Cui,Qiyang Zhao,Bining Jiao,Yue He
出处
期刊:Food Chemistry
[Elsevier]
日期:2020-08-01
卷期号:320: 126607-126607
被引量:73
标识
DOI:10.1016/j.foodchem.2020.126607
摘要
Colorimetric aptasensors have been intensively studied for the ochratoxin A (OTA) detection, but they mostly exhibit just one-color change, resulting in poor visual resolution and limited use for semi-quantitative analysis. Thus, we designed a high-resolution colorimetric assay on the basis of aptamer structural switching and enzyme-induced metallization of gold nanorods (AuNRs). DNA-alkaline phosphatase (ALP)-immobilized magnetic beads were prepared. The aptamer bounded to OTA to form G-quadruplexes, releasing ALP-labelled complementary DNA (cDNA-ALP). After magnetic separation, cDNA-ALP catalyzed the decomposition of ascorbic acid 2-phosphate to ascorbic acid that reduced Ag+, forming an Ag shell on the surface of AuNRs. This caused a blue-shift of the longitudinal local surface plasmon resonance peak of the AuNRs and a naked eye visible multicolor change. Under optimal conditions, the assay exhibited a 9.0 nM detection limit for OTA, with high specificity. This method is promising for the on-site visual semi-quantitative detection of mycotoxins in foods.
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