Colour-encoded paramagnetic microbead-based direct inhibition triplex flow cytometric immunoassay for ochratoxin A, fumonisins and zearalenone in cereals and cereal-based feed

Abstract

A combined (triplex) immunoassay for the simultaneous detection of three mycotoxins in grains was developed with superparamagnetic colour-encoded microbeads, in combination with two bead-dedicated flow cytometers. Monoclonal antibodies were coupled to the beads, and the amounts of bound mycotoxins were inversely related to the amounts of bound fluorescent labelled mycotoxins (inhibition immunoassay format). The selected monoclonal antibodies were tested for their target mycotoxins and for cross-reactivity with relevant metabolites and masked mycotoxins. In the triplex format, low levels of cross-interactions between the assays occurred at irrelevant high levels only. All three assays were influenced by the sample matrix of cereal extracts to some extent, and matrix-matched calibrations are recommended for quantitative screening purposes. In a preliminary in-house validation, the triplex assay was found to be reproducible, sensitive and sufficiently accurate for the quantitative screening at ML level. The triplex assay was critically compared to liquid chromatography–tandem mass spectrometry using reference materials and fortified blank material. Results for the quantification of ochratoxin A and zearalenone were in good agreement. However, the fumonisin assay was, due to overestimation, only suitable for qualitative judgements. Both flow cytometer platforms (Luminex 100 and FLEXMAP 3D) performed similar with respect to sensitivity with the advantages of a higher sample throughput and response range of the FLEXMAP 3D and lower cost of the Luminex 100.The priciple of the direct inhibition microbead immunoassay using fluorescent mycotoxin-reporter conjugatesElectronic supplementary materialThe online version of this article (doi:10.1007/s00216-013-7095-7) contains supplementary material, which is available to authorized users.

Occurrence of Fusarium Mycotoxins in Cereal Crops and Processed Products (Ogi) from Nigeria

“…Except for sorghum, most of the maize and millet samples in this study exceeded the maximum regulatory limit set for the sum of FB 1 and FB 2 (1000 μg/kg) by the European Union (EU) [27] suggesting the high exposure of the population to this toxin. A similar high FB incidence rate has been reported in several studies from sub-Saharan Africa [28,29,30,31,32,33,34] at concentrations ranging up to 53,863 μg/kg [30]. High incidence of FB, especially in maize may be explained by the susceptibility of the maize crop to FB producing fungi ( F. verticillioides and F. proliferatum ) [35].…”

Romantic surfaces : Zwitterionic polymer brushes for biomedical applications

“…58 As a result, materials derived from SB or CB are considered as biomimetic. 1 Their biomimetic nature along with their excellent antifouling characteristics make them interesting for a wide range of applications, 13,59 such as biosensing, [60][61] drug delivery, 12,62 filtration, 51,[63][64] as well as for antibacterial 65 and marine coatings. 15,66 A fundamental difference between SB and CB is that CB-based materials can be directly functionalized (mostly via EDC/NHS chemistry to attach antibodies, see below), and are therefore often used for biosensing applications.…”

“…15,66 A fundamental difference between SB and CB is that CB-based materials can be directly functionalized (mostly via EDC/NHS chemistry to attach antibodies, see below), and are therefore often used for biosensing applications. 26,61,67 However, this functionalization comes at the expense of charge neutrality. 68 Another difference is that the CB-based materials are pH sensitive: the carboxyl groups will be protonated at low pH.…”

“…However, the immobilization of recognition units is still challenging and often occurs at the expense of the antifouling properties. 61,68,100 Scheme 1.2 ATRP mechanism.…”

“…The most commonly used method to introduce functionality to antifouling zwitterionic polymer brushes is the direct modification of the carboxylic acid groups of CB monomers using EDC/NHS chemistry. 26,52,61,97 This method allows for the immobilization of aminebearing (bio)molecules including peptides and proteins. It has, for example, successfully been used to incorporate anti-ALCAM antibodies to capture ALCAM, a glycoprotein present on (among others) epithelial cells.…”