Development of a Rainbow Lateral Flow Immunoassay for the Simultaneous Detection of Four Mycotoxins

Abstract

A multiplex lateral flow immunoassay (LFIA) for the determination of the mycotoxins deoxynivalenol, zearalenone, and T2/HT2-toxin in barley was developed with luminescent quantum dots (QDs) as label. The synthesized QDs were hydrophilized by two strategies, that is, coating with an amphiphilic polymer or silica. The water-soluble QDs were compared with regard to their bioconjugation with monoclonal antibody (mAb) and were tested on a LFIA. Silica-coated QDs that contained epoxy groups were most promising. Therefore, green, orange, and red epoxy-functionalized silica-coated QDs were conjugated with anti-ZEN, anti-DON, and anti-T2 mAb, respectively. The LFIA was developed in accordance with the European Commission legal limits with cutoff limits of 1000, 80, and 80 μg/kg for deoxynivalenol, zearalenone, and T2/HT2-toxin, respectively. The LFIA gave a fast result (15 min) with a low false-negative rate (<5%), and the results were easy to interpret without any sophisticated equipment.

Multicolor immunochromatographic strip test based on gold nanoparticles for the determination of aflatoxin B1 and fumonisins

“…This effort is testified also by the number of papers reporting new materials to be used as labels [10][11][12][39][40], sometimes in combination with innovative detection technologies [13,41], and of enhancement strategies aimed at increasing the sensitivity of the ICST compared to using traditional gold nanoparticles [42][43], as also summarized in two comprehensive reviews [44][45]. Within the number of novel materials for labeling antibodies in ICTS, the request for analytical devices with multiplexing capability is prompting towards using labels easily distinguishable from each other, such as nanoparticles with different colors [19][20]23]. Gold nanoparticles are widely employed as labels for ICST, thanks to well-recognized advantages, such as easy preparation, stability, easy conjugation to antibodies, brilliant and tunable color [6][7][8]45].…”

“…Mycotoxins detection is a relevant issue for food safety assessment and the need of multiplex analytical platform for their simultaneous detection has been widely highlighted [18,20,[30][31].…”

“…In this context, assigning different colors to different analytes would make easier and more intuitive the visual interpretation of the results provided by a multiplex dipstick ICST. Color-encoded ICSTs in the multiplex format have been described, which exploit the unique spectral characteristics of quantum dots (QDs) [19][20]. These inorganic nanocrystals are capable of emitting fluorescent light at different wavelengths depending on their size and composition, when excited by the same source.…”

“…Therefore, Taranova et al used QDs emitting at different wavelengths for labeling three antibodies and simultaneously determining three classes of antibiotics by a multiplex ICST [19]. Similarly, Foubert et al used three differently emitting QDs for labeling as many antibodies and to set an ICST for the multiple determinations of four mycotoxins [20]. Although QDs are particularly suited for multiplexing because of the tunable color of the emitted fluorescence, still they require a light source for excitation, thus limiting the portability and cost-effectiveness of QD-based ICSTs.…”

Ways to Reach Lower Detection Limits of Lateral Flow Immunoassays

“…Quantum dots are an effective tool for multi-analysis with different signals. The use of conjugated quantum dots with different spectral characteristics allows one to perform highly sensitive diagnostics with simultaneous detection of, for example, three antibiotics ("traffic light" in Taranova et al [146]) or four mycotoxins ("rainbow" in Foubert et al [147]).…”