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Fluorescent Label-Free Aptasensor Integrated in a Lab-on-Chip System for the Detection of Ochratoxin A in Beer and Wheat
journal contribution
posted on 2019-11-19, 23:43 authored by Francesca Costantini, Nicola Lovecchio, Albert Ruggi, Cesare Manetti, Augusto Nascetti, Massimo Reverberi, Giampiero de Cesare, Domenico CaputoThis paper reports on the development of a fluorescent
label-free aptamer assay integrated in a lab-on-chip (LoC) system
for the detection of Ochratoxin A (OTA). The detection system relies
on the integration, on a single glass substrate, of an array of amorphous
silicon photosensors and a long pass interferential filter. The aptamer
assay, integrated into the microfluidic network, is an aptasensor
having affinity versus OTA, selected as a case study. The fluorescent
molecule is a “light switch” complex [Ru(phen)2(dppz)]2+. The aptamer is directly anchored into a layer
of poly(2-hydroxyethyl methacrylate) polymer brushes grown inside
the channels. The fluorophore is intercalated between the base pairs
of the aptamer. Upon the interaction of OTA with the aptasensor, a
change of the aptamer conformation causes the release of the fluorophore,
yielding a decrease of the fluorescent signal detected by the array
of the amorphous silicon photosensors positioned underneath the microfluidic
network. The developed LoC is a portable system capable of performing
the analysis with a small volume of sample (about 10 μL) in
a short time (5 min) with a limit of detection for OTA equal to 1.3
ng/mL. The LoC has been applied for the detection of OTA (5–200
ng/mL) in beer and wheat samples.