Application of Au@Pt Nanozyme as Enhancing Label for the Sensitive Lateral Flow Immunoassay of Okadaic Acid

Abstract

In this study, a lateral flow immunoassay (LFIA) was developed to detect okadaic acid (OA) belonging to the diarrheic shellfish poisoning group of aquatic toxins. Newly obtained anti-OA monoclonal antibodies and bimetallic core@shell Au@Pt nanoparticles were used in the indirect format of the LFIA. Peroxidase-mimicking nanozyme properties of Au@Pt enabled using them to enhance band coloration on the test strips and, consequently, for increasing the LFIA sensitivity. The instrumental limit of detection (LOD), the working range of detectable concentrations, and the visual cutoff of the assay were 0.5, 0.8–6.8, and 10 ng/mL, respectively. The assay duration was 20 min. The rapid and simple sample preparation procedure was applied for seawater, river water, and fish samples. The total duration of the sample pretreatment and LFIA was 25/40 min for water/fish samples, ensuring testing rapidity. The developed test system provides sensitive control of raw materials and food products and can be used to detect OA at all stages of the food industry «from sea to fork» chains.

A Sensitive Fluorescence Polarization Immunoassay for the Rapid Detection of Okadaic Acid in Environmental Waters

“…In general, LODs of OA are lower in ELISAs, approximately reaching picogram values [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. In ICAs [ 44 , 45 , 46 , 47 , 48 , 49 ], including multiparametric ones [ 18 , 20 , 50 ], the sensitivity of the determination is somewhat worse (up to the nanogram concentration range), and improvements in this method were achieved with amplification approaches aimed at increasing analytical signal [ 19 , 51 ]. The duration of the analysis in the case of ICA is 10–40 min.…”

“…Because there is no need for the separation of bound and unbound immunoreagents, the duration of the FPIA is only 5 min, which is even shorter than all the rapid ICA-based test systems considered. In addition, the FPIA does not require sample preparation of the liquid matrix, unlike the ICA of the same matrices [ 19 , 45 ]. The preparation for the analysis requires only the synthesis of a tracer and does not include any preliminary stages such as the sorption of coating antigens (similar to the microplate-based ELISA) or the application of the reagents on membrane carriers (similar to the ICA).…”

“…ELISA is a sensitive method that allows for testing dozens of samples simultaneously, but it cannot be considered fast because it is carried out in several stages (incubations) with microplate washing after each. A much faster immunoanalytical method is the immunochromatographic analysis (ICA), which allows for obtaining results in 10–15 min with ready-to-use test strips [ 17 , 18 , 19 , 20 ]. Among the shortcomings of the ICA, the time required for the assembly of a multi-membrane composite (test strips), including the application of specific immunoreagents on the membrane carriers, drying, cutting, etc., can be noted.…”

Research on the dentification of Panax ginseng and Panax quinquefolium using catalysed hairpin assembly technology

“…The effects of hairpin action time (15,30,45, and 60 min) on the hairpin reaction were detected. The results showed no difference among hairpin action times, suggesting that the hairpin reaction was rapid (Figure 5A,B).…”

Single-Atom Fe Nanozyme with Enhanced Oxidase-like Activity for the Colorimetric Detection of Ascorbic Acid and Glutathione

“…Over the past two decades, nanomaterials with enzyme-like characteristics, termed nanozyme, have attracted great attention because of their easy preparation, good stability in harsh conditions, and low cost. Up to now, a variety of nanomaterials have been discovered with enzyme-mimicking activity, such as transition metal oxide-based nanomaterials [ 14 , 15 , 16 , 17 ], noble metal- or metal-based nanostructures [ 18 , 19 , 20 ], carbon-based nanomaterials [ 21 , 22 , 23 ], and metal–organic framework-based nanostructures (MOFs) [ 24 , 25 , 26 ]. Although some progress has been made in this field, conventional nanozymes still face great challenges such as insufficient enzyme-like activity and low selectivity compared with natural enzymes.…”