Low-Cost and Highly Sensitive Immunosensing Platform for Aflatoxins Using One-Step Competitive Displacement Reaction Mode and Portable Glucometer-Based Detection

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• 作者：Dianping Tang ; Youxiu Lin ; Qian Zhou ; Yuping Lin ; Peiwu Li ; Reinhard Niessner ; Dietmar Knopp
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：November 18, 2014
• 年：2014
• 卷：86
• 期：22
• 页码：11451-11458
• 全文大小：416K
• ISSN：1520-6882

文摘

Aflatoxins are highly toxic secondary metabolites produced by a number of different fungi and present in a wide range of food and feed commodities. Herein, we designed a simple and low-cost immunosensing platform for highly sensitive detection of mycotoxins (aflatoxin B₁, AFB₁, used as a model) on polyethylenimine (PEI)-coated mesoporous silica nanocontainers (PEI-MSN). The assay was carried out by using a portable personal glucometer (PGM) as the readout based on a competitive displacement reaction mode between target AFB₁ and its pseudo-hapten (PEI-MSN) for monoclonal anti-AFB₁ antibody (mAb). To construct such an assay protocol, two nanostructures including mAb-labeled gold nanoparticle (mAb-AuNP) and PEI-MSN were initially synthesized, and then numerous glucose molecules were gated into the pores based on the interaction between negatively charged mAb-AuNP and positively charged PEI-MSN. In the presence of target AFB₁, a competitive-type displacement reaction was implemented between mAb-AuNP and PEI-MSN by target AFB₁ through the specific antigen鈥揳ntibody reaction. Accompanying the reaction, target AFB₁ could displace the mAb-AuNP from the surface of PEI-MSN, resulting in the release of the loading glucose from the pores due to the gate opened. The released glucose molecules could be quantitatively determined by using a portable PGM. Under optimal conditions, the PGM signal increased with the increment of AFB₁ concentration in the range from 0.01 to 15 渭g/kg (ppb) with a detection limit (LOD) of 5 ng/kg (5 ppt) at the 3s_blank criterion. The selectivity and precision were acceptable. Importantly, the methodology was further validated for assaying naturally contaminated or spiked blank peanut samples, and consistent results between the PGM-based immunoassay and the referenced enzyme-linked immunosorbent assay (ELISA) were obtained. Therefore, the developed immunoassay provides a promising approach for rapid screening of organic pollutants because it is simple, low-cost, sensitive, specific, and without the need of multiple separation and washing steps.