title: Low-cost and highly sensitive immunosensing platform for aflatoxins using one-step competitive displacement reaction mode and portable glucometer-based detection.
abstract: 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-antibody 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 μg/kg (ppb) with a detection limit (LOD) of 5 ng/kg (5 ppt) at the 3sblank 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.
authors.affiliation: Key Laboratory of Analysis and Detection for Food Safety (MOE & Fujian Province), Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University , Fuzhou 350108, People's Republic of China.
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
authors.forename: Youxiu
authors.initials: Y
authors.lastname: Lin
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.forename: Yuping
authors.initials: Y
authors.lastname: Lin
authors.forename: Peiwu
authors.initials: P
authors.lastname: Li
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
mesh_terms: D000348:Aflatoxins / Q000032:analysis*; D000937:Antigen-Antibody Reactions; D010367:Arachis / Q000737:chemistry; D001667:Binding, Competitive; D015190:Blood Glucose Self-Monitoring / Q000191:economics / Q000295:instrumentation*; D004797:Enzyme-Linked Immunosorbent Assay; D007118:Immunoassay / Q000191:economics*; D015203:Reproducibility of Results
chemical_list: D000348:Aflatoxins