Porous Silicon Optical Biosensor for Highly Sensitive Detection Of Mycotoxins in Field Crops

I. Freidman, G. Shtenberg
Bar Ilan University,

Keywords: fumonisin, porous silicon, biosensor, mycotoxins


Food and agricultural commodities contamination by various toxigenic molds (fungi) is a serious neglected problem, affecting ~25% of the world’s crops with staggering economical loses. Regardless of decades of extensive research, mycotoxins continue to penetrate food chain and pose health risks to both humans and livestock. Mycotoxins are secondary metabolites produced by specific filamentous fungi species usually belong to Aspergillus, Penicillium or Fusarium that infect crops at the field level and endure on foods during storage. Due to the increased toxicological effects, many countries have set stringent limits for mycotoxins residues in food and feedstuffs particularly with respect to international trade, including developed and developing countries. Current detection methods are mostly based on off-line monitoring of a single compound/analyte or bulk parameters with low frequency data sampling and delay upon results availability. Thus, it is rather essential to have an accurate, rapid and sensitive method for multiplex detection of mycotoxins in unprocessed food and feed. An oxidized porous silicon (PSi) nanostructures, a Fabry-Pérot thin film, is synthesized and used as an optical transducer element for the detection and quantification of Fumonisin B1 (FB1, target molecule). The nanostructure is modified with specific robust bioprobes for the validation of fungal contamination and its secreted toxins by indirect immunoassay amplified by FB1-horseradish peroxidase conjugates. The catalytic activity is monitored in real-time by reflective interferometric Fourier transform spectroscopy. Optical studies reveal high specificity and selectivity towards FB1, presenting LOD of 0.38 ppm. The main advantage of the presented biosensing concept is the ability to detect fumonisin contamination, at environmentally relevant concentrations, using a simple and portable experimental setup.