An ultrarapid and regenerable microfluidic immunoassay coupled with integrated photosensors for point-of-use detection of ochratoxin A

The assurance of food and feed safety is one of the major challenges in modern society given the increasing pace at which food commodities are demanded, produced and traded across the globe. Ochratoxin A( OTA), a mycotoxin produced either in the field or during storage, has been increasingly associated with detrimental chronic and acute health implications such as carcinogenicity and hepatotoxicity. Currently, standard certified detection methods include complex and time consuming (> 1 h) methodologies based on packed-bed chromatography which must be performed by specialized personnel. However, to effectively monitor mycotoxin levels in crops prior to further processing, either after harvest, during transport or during storage, a rapid, simple, portable and sensitive means of screening is in high demand. In order to meet this demand, a novel ultra-rapid, sensitive (limit-of-detection (LoD) < 0.5 ng/mL) and simple physisorption-based microfluidic competitive immunoassay for OTA detection was developed with integrated photosensing and optimized to provide quantitative results in less than 5 min. Furthermore, a regeneration protocol was developed in order to effectively reuse the same PDMS microchannel and immobilized antigen molecules at least 8 times without a significant drop in sensitivity (LoD < 2 ng/mL). The optimized assay could also effectively detect OTA in red wine extracts at the regulatory limit (2 ng/mL). Thus, this biosensing device shows promise for further automation and reduction in assays times for a true point-of-use mycotoxin quantification tool. (C) 2016 Elsevier B.V. All rights reserved.