Human influenza virus detection using sialyllactose-functionalized organic electrochemical transistors

An organic electrochemical transistor (OECT) with a trisaccharide-grafted conductive polymer channel was developed for human influenza A virus detection under aqueous conditions. A target recognition element was introduced into the electrochemical amplifier of the OECT for highly sensitive, selective, and label-free virus sensing. 3,4-Ethylenedioxythiophene (EDOT) and its derivative bearing an oxylamine moiety (EDOTOA) were electrochemically copolymerized on the channel region composed of a PEDOT:PSS thin film. The trisaccharides composed of Sia-α2,6′-Gal-Glu (2,6-sialyllactose), a specific receptor for the hemagglutinin used as a spike protein on the surface of human influenza A virus, were covalently introduced into the EDOTOA unit. Changes in the drain current of the OECT were observed following virus adsorption onto the 2,6-sialyllactose-functionalized channel. A signal transduction mechanism involving a doping effect due to the adsorption of negatively-charged virus nanoparticles is proposed. The limit of detection was more than two orders of magnitude lower than commercial immunochromatographic influenza virus assays over the same detection time. Because of its processability with printing technologies and low power consumption, the OECT device developed here may be suitable for the wearable monitoring of influenza virus infection.