An In Situ Generated Prussian Blue Nanoparticle-Mediated Multimode Nanozyme-Linked Immunosorbent Assay for the Detection of Aflatoxin B1

Abstract

This work aims to develop a novel multimode (photothermal/colorimetric/fluorescent) nanozyme-linked immunosorbent assay (NLISA) based on the in situ generation of Prussian blue nanoparticles (PBNPs) on the surface of magnetic nanoparticles (MNPs). Being considered the most toxic among the mycotoxins, aflatoxin B1 (AFB1) was chosen as the proof-of-concept target. In this strategy, MNPs, on which an AFB1 aptamer was previously assembled via streptavidin-biotin linkage, are anchored to 96-well plates by AFB1 and antibody. In the presence of HCl and K4Fe­(CN)6, PBNPs formed in situ on the MNP surface, thereby achieving photothermal and colorimetric signal readout due to their photothermal effect and intrinsic peroxidase-like activity. Based on fluorescence quenching by MNPs, Cy5 fluorescence was recovered by the in situ generation of PBNPs to facilitate ultrasensitive fluorescence detection. Photothermal and colorimetric signals allow portable/visual point-of-care testing, and fluorescent signals enable accurate determination with a detection limit of 0.54 fg/mL, which is 6333 and 28 times lower than those of photothermal and colorimetric analyses, respectively. We expect that this proposed multimode NLISA can not only reduce the false-positive/negative rates through the multisignal crossdetection in AFB1 monitoring but also provide a universal way of sophisticated instrumentation-free, easy-to-use, cost-effective, and highly sensitive detection of other food hazards.

Lighting Up Agricultural Sustainability in the New Era through Nanozymology: An Overview of Classifications and Their Agricultural Applications

“…Particularly, a fluorescent sensor for AFB 1 was built with fluorescent "turn-off/turn-on" of Cy5 by the MNPs and PB NPs and was successfully employed in testing for AFB 1 in water, wine, vinegar, and peanut with a LOD as low as 0.54 fg mL −1 and a detection range of 10 −15 −10 −8 ng mL −1 (Figure 3E). 159 3.3.4. Other Sensors.…”

A controllable staining colorimetric method based on carboxylated cellulose membranes for early-warning and semi-quantitative detection of aflatoxins in water

“…Corn is an essential raw material for animal feed, and many countries have reported aflatoxin contamination in corn. 38,39 To evaluate the practicability of this sensing system, the sensing strategy, addition, and recovery experiments for determining the concentration of total AFs in corn samples were carried out. After adding different quality aflatoxins to 4 ground fresh corn samples, the spiked samples with mixed AFs were pretreated by liquidliquid extraction separation.…”

Achieving Ultrasensitive Point-of-Care Assay for Mercury Ions with a Triple-Mode Strategy Based on the Mercury-Triggered Dual-Enzyme Mimetic Activities of Au/WO3 Hierarchical Hollow Nanoflowers

“…By using different signal materials, multimode detection can be used for realizing recognition of a single target based on different principles. Multimode analysis can not only combine the advantages of various detection methods but also further provide accurate quantitative results due to its different mechanisms and independent signal conversion. − Furthermore, to meet the test requirements under different conditions, the appropriate detection method can be chosen according to the available instruments. Hence, the development of a multimode sensing platform with an accurate analytical method and convenient operation is significantly essential.…”