Highly sensitive and practical detection of plant viruses via electrical impedance of droplets on textured silicon-based devices

Early diagnosis of plant virus infections before the disease symptoms appearance may represent a significant benefit in limiting disease spread by a prompt application of appropriate containment steps. We propose a label-free procedure applied on a device structure where the electrical signal transduction is evaluated via impedance spectroscopy techniques. The device consists of a droplet suspension embedding two representative purified plant viruses i.e.,Tomato mosaic virus and Turnip yellow mosaic virus,put in contact with a highly hydrophobic plasma textured silicon surface. Results show a high sensitivity of the system towards the virus particles with an interestingly low detection limit,from tens to hundreds of attomolar corresponding to pg/mL of sap,which refers,in the infection time-scale,to a concentration of virus particles in still-symptomless plants. Such a threshold limit,together with an envisaged engineering of an easily manageable device,compared to more sophisticated apparatuses,may contribute in simplifying the in-field plant virus diagnostics.