Imaging surface plasmon resonance detection for T-2 toxin in wheat

Authors: HOSSAIN, MD ZAKIR - Orise Fellow; Maragos, Chris

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/18/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: T-2 toxin is a trichothecene (Type A) mycotoxin harmful to humans and animals. It is produced by mainly Fusarium species, particularly F. sporotrichoides. Fusarium species often contaminate grains such as corn, wheat, barley, oats, rice and rye. T-2 toxin contamination in grains has been observed more frequently in Europe than Asia, Africa and the Americas. The critical toxic effects of T-2 toxin are general toxicity, hemotoxicity and immunotoxicity (EFSA, 2011). Based on this, the European Commission recommended a guideline in 2013 to monitor T-2 toxin in foods and feeds (EC, 2013). For such monitoring, a rapid, cost effective and sensitive method is required. Imaging surface plasmon resonance (iSPR) is a powerful and label-free technique that allows monitoring multiple interactions in real time. iSPR measures the changes in the refractive index as molecules bind at the metallic sensor surface. The signal detected by iSPR is proportionate to the mass of target molecules that bind. As mycotoxins are low molecular weight compounds, their binding with antibodies is not adequate to produce significant iSPR signal (Hu et al., 2014). To amplify the signal, gold nanoparticles (AuNPs) are an ideal alternative because of their easy and inexpensive synthesis, stability, unique optical properties and excellent biocompatibility (Gurunathan et al., 2014; Daniel and Astruc, 2004). To the best of our knowledge, no studies have been reported which use AuNP amplification to detect T-2 toxin using iSPR. In this research, a sensitive analytical method was developed and validated where secondary antibody conjugated with AuNPs was used as an amplification tag in iSPR. To determine the best combination of antigen and antibody, we investigated six different antigens and ten different antibodies. By using AuNPs the iSPR signal was increased nearly 20 fold compared to label-free primary antibody alone. Matrix matched calibration curves were constructed over the working range of 0.5 ng/mL to 50 ng/mL, equivalent to 20-2000 µg/kg in wheat. In spiked wheat, mean recoveries were observed from 84 to 105 % with RSDr of less than 10% at spiking levels of 50, 100 and 500 µg/kg. The developed method can detect as low as 0.1 ng/mL, equivalent to 4 µg/kg in wheat. Considering practical aspects of the method, a cut-off level was determined to separate blank samples from wheat samples spiked at the100 µg/kg concentration level recommended by European Commission. Therefore the iSPR method is sensitive enough to detect low levels of T-2 toxin in wheat. This study is the first step in the development of a multiplexed bio-sensing assay for Fusarium toxins in wheat. References: 1) Commission Recommendation 2013/165/EU on the presence of T-2 and HT-2 toxin in cereals and cereal products, (2013) Official Journal of the European Union 91, 12-15 2) Daniel, M.C., Astruc, D. Gold nanoparticle: assembly, supramolecular chemistry, quantum-size-related properties, and application toward biolody, catalysis, and nanotechnology. Chem Rev 104, 293-346 (2004) 3) EFSA Panel on Contaminants in the Food Chain (CONTAM) Scientific Opinion on the risks for animal and public health related to the presence of T-2 and HT-2 toxin in food and feed, EFSA Journal 9, 2481, 1-187 (2011) 4) Hu, W., Chen, H., Zhang, H., He, G., Li, X., Zhang, X., Liu, Y., Li, C.M. Sensitive detection of multiple mycotoxins by SPRi with gold nanoparticles as signal amplification tags. J Colloid Interface Sci 431, 71-76 (2014) 5) Gurunathan, S., Hun, J, Park, J.H., Kim, J.H. A green chemistry approach for synthesizing biocompatible gold nanoparticles. Nanoscale Res Lett 9, 248 (2014)