Multiplex surface plasmon resonance biosensing and its transferability towards imaging nanoplasmonics for detection of mycotoxins in barley

Abstract

A 6-plex competitive inhibition immunoassay for mycotoxins in barley was developed on a prototype portable nanostructured imaging surface plasmon resonance (iSPR) instrument, also referred to as imaging nanoplasmonics. As a benchmark for the prototype nanoplasmonics instrument, first a double 3-plex assay was developed for the detection of deoxynivalenol (DON), zearalenone (ZEA), T-2 toxin (T-2), ochratoxin A (OTA), fumonisin B1 (FB1) and aflatoxin B1 (AFB1) using a well-established benchtop SPR instrument and two biosensor chips. To this end, ovalbumin (OVA) conjugates of mycotoxins were immobilized on the chip via amine coupling. The SPR response was then recorded upon injection of a mixture of antibodies at a fixed concentration and the sample (or matrix-matched standard) over a chip with immobilized mycotoxin-OVA conjugates. The chips were regenerated after each sample using 10 mM HCl and 20 mM NaOH and could be used for at least 60 cycles. The limits of detection in barley (in μg kg(-1)) were determined to be 26 for DON, 6 for ZEA, 0.6 for T-2, 3 for OTA, 2 for FB1 and 0.6 for AFB1. Preliminary in-house validation showed that DON, T-2, ZEA and FB1 can be detected at the European Union regulatory limits, while for OTA and AFB1 sensitivities should be improved. Furthermore, measurement of naturally contaminated barley showed that the assay can be used as a semi-quantitative screening method for mycotoxins prior to liquid chromatography tandem mass spectrometry (LC-MS/MS). Finally, using the same bio-reagents the assay was transferred to a 6-plex format in the nanoplasmonics instrument and subsequently the two assays were compared. Although less sensitive, the 6-plex portable iSPR assay still allowed detection of DON, T-2, ZEA and FB1 at relevant levels. Therefore, the prototype iSPR shows potential for future applications in rapid in-field and at-line screening of multiple mycotoxins.

Nanostructured Organic/Hybrid Materials and Components in Miniaturized Optical and Chemical Sensors

“…A film of the copolymer MCP-2F bearing active esters was successfully grafted by a combination of physical adsorption and covalent linking to the plasmonic nanostructure of Plasmore. It is worthwhile noticing that Plasmore plasmonic gratings have been used for example for the detection of long pentraxin 3 (PTX3), a biomarker for different human pathologies and infections [100] and for the detection of mycotoxins in barley and beers [103].…”

Developments in mycotoxin analysis: an update for 2017-2018

“…The obtained LOD of 1.4 ng/l, could not be calculated back to the OTA concentration in rice due to lack of information in the article. Finally, a competitive inhibition immunoassay for the detection of multiple mycotoxins was developed on a portable imaging surface plasmon resonance (SPR) instrument (Joshi et al, 2016). Actually two 3-plex assays were first developed for the detection of DON, ZEA, T-2, FB 1 , AFB 1 and OTA using a benchtop SPR instrument and two biosensor chips and later combined to a single 6-plex assay.…”

Advances in Biosensors, Chemosensors and Assays for the Determination of Fusarium Mycotoxins

“…Based on SPR, the rapid immunoassays for the DON [ 27 , 28 , 32 , 33 ], NIV [ 33 ] or T-2 toxin [ 47 ] detection were developed and improved subsequently, and applied in durum wheat, wheat products, maize-based baby foods, etc. SPR immunosensors for the simultaneous detection of two or more mycotoxins were also reported, such as “AFB1 (aflatoxin B1), ZEN, FB1 and DON” [ 79 ], “DON and ZEN” [ 84 ], and “DON, ZEN, T-2, OTA, FB1 and AFB1” [ 91 ] (see Table 4 ).…”