▎ 摘　　要

NOVELTY - Electrochemical sensor device comprises a substrate, a working electrode and a counter electrode disposed on the substrate, a sample placement area on the substrate, the sample placement area configured for deposition of a fluid sample into the sample placement area, where the deposited fluid sample covers the working and counter electrodes, one or more functionalization layers deposited on a surface of the working electrode, the surface configured for exposure to the fluid sample deposited in the sample placement area, where each functionalization layer comprises one or more sensor elements, metallic nanoparticles, a crosslinker, a redox reagent, and a virus receptor. USE - Electrochemical sensor device for detection of virus in fluid sample, where the virus is selected from human immunodeficiency virus (HIV) 1, HIV-2, Zika virus, severe acute respiratory syndrome coronavirus (SARS-CoV), SARS-CoV-2, influenza virus, hepatitis virus, and Ebola, where the fluid sample is selected from saliva, urine, tears, sweat, blood, and interstitial fluid (all claimed). ADVANTAGE - The electrochemical sensor device provides saliva-based POC biosensor capable of performing rapid, non-invasive, highly sensitive, reliable, and accurate COVID-19 test DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a system, which comprises an electrochemical sensor device, a power source capable of supplying a desired voltage signal to the electrodes of the device, and a detection circuit capable of detecting current between electrodes of the device.