Dual-Modal Immunochromatographic Test for Sensitive Detection of Zearalenone in Food Samples Based On Biosynthetic Staphylococcus aureus-Mediated Polymer Dot Nanocomposites

Abstract

The rapid detection of toxins is of great significance to food security and human health. In this work, a dual-modality immunochromatographic test (DICT) mediated by Staphylococcus aureus (SA)-biosynthesized polymer dots (SABPDs) was constructed for sensitive monitoring of zearalenone (ZEN) in agro products. The SABPDs as potent microorganism nanoscaffolds with excellent solubility, brightness, and stability were ingeniously fabricated employing hydroquinone and SA as precursors in the Schiff base reaction and a self-assembly technique. Thanks to the fact that they not only preserved an intact microsphere for loading Fc regions of monoclonal antibodies (mAbs) and the affinity of their labeled mAbs to antigen but also generated superb colorimetric−fluorescent dual signals, the versatile SABPDs manifested unique possibilities as the new carriers for dual-readout ICT with remarkable enhancement in sensitivity in ZEN screening (limit of detection = 0.036 ng/mL, which was 31-fold lower than that of traditional gold nanoparticlebased ICT). Ultimately, the proposed immunosensor performed well in millet and corn samples with satisfactory recoveries, demonstrating its potential for point-of-care testing. This work offers a bio-friendly strategy for biosynthesizing cell-based PD vehicles with bimodal signals for food safety analysis.

A Versatile PdRu Bimetallic Nanoenzyme-Integrated Enzyme-Linked Immunosorbent Assay for Highly Sensitive Escherichia coli O157:H7 Detection

“…Then, 100 μL of 10% BSA was added to the mixtures and incubated for 30 min to further block the vacancies. Last, the PdRu-mAb probe was isolated by centrifugation (9000 rpm, 4 min), resuspended in 100 μL of hyperpure water, and then kept at 4 °C for further use …”

“…Last, the PdRu-mAb probe was isolated by centrifugation (9000 rpm, 4 min), resuspended in 100 μL of hyperpure water, and then kept at 4 °C for further use. 27 Establishment of ELISA for the Detection of E. coli O157:H7 Based on the PdRu-mAb Probe. The experiments were executed on a NEST 96-well transparent microplate.…”

Double-Enzyme Active Vanadium Nanospheres-Mediated Ratiometric Multicolor Immunosensors for Sensitive Detection of the T-2 Toxin

“…Taking B / B 0 as the ordinate and the logarithm of the mass concentration of the T-2 standard as the abscissa, the T-2 competition inhibition curve was established. The limit of detection (LOD) of a single-mode nano-enzyme-linked immunosorbent assay using TMB (T-NLISA) and VNSs-RNLISA was defined as the T-2 concentration that resulted in 10% inhibition compared with the control of the B / B 0 signal intensity . The sensitivity of T-NLISA or VNSs-RNLISA was calculated according to the following four-parameter equation y = K 2 + false( K 1 − K 2 false) 1 + ( X X 0 ) d where K 1 is the asymptotic maximum, K 2 is the asymptotic minimum, d and X 0 are the slope of the curve and the analyte concentration at the inflection point, respectively, B is the OD value of the standard at different concentrations, and B 0 is the OD value of the standard at 0 ng/mL.…”

Recent Developments in the Field of Optical Immunosensors Focusing on a Label-Free, White Light Reflectance Spectroscopy-Based Immunosensing Platform

“…Starting with the former group, a simple yet highly useful screening assay for methicillin-resistant Staphylococcus aureus that may be considered as a type of colorimetric immunosensor was described; the assay was based on a pair of antibodies against penicillin binding protein 2a (anti-PBP 2a) and employed capture antibodies immobilized on activated cotton swabs along with detection antibodies immobilized on colored polymeric nanoparticles [ 54 ]. Moreover, a lately reported immunochromatographic strip (lateral flow immunoassay) for zearalenone can be considered as a type of dual colorimetric/fluorescent sensor; the key reagent of the strip consisted of Staphylococcus aureus biosynthesized polymer dots that could generate a colorimetric/fluorescent signal, onto which anti-zearalenone antibodies were coupled through their Fc region [ 55 ]. In addition, a fluorescence immunosensor was reported in [ 56 ] based on graphene quantum dots functionalized through covalent linking with an anti-neuron-specific enolase antibody (energy donor) along with a hybrid of Ti 3 C 2 -MXene nanosheets and silver nanoparticles (energy acceptor), which exhibited high quenching and energy-transfer efficiency.…”

“…Another group includes optical immunosensors that have been applied to and/or evaluated through the detection/quantification of basic and important biomolecules, such as human INF-γ or insulin [62], immunoglobulin G [69], CD5 [76], collagen I [72], cortisol [74], and estrone and estradiol [63]. On the other hand, other optical immunosensors have been applied to the detection/quantification of exogenous substances, especially natural or synthetic toxic compounds, such as methylamphetamine [64], ochratoxin A [85], aflatoxin B1 [58,67], microcystin-LR [61], zearalenone [55,79,82], hazelnut Cor a14 allergen [70], imidacloprid [77], carbendazim [86], and ricin and abrin [75]. a : non-competitive format (direct-type): In this, one primary anti-analyte antibody is used that is usually immobilized on the transducer surface and the binding of the analyte is directly recorded.…”