Ultrasensitive and Label-Free Detection of the Measles Virus Using an N-Heterocyclic Carbene-Based Electrochemical Biosensor

With the current intense need for rapid and accurate detection of viruses due to COVID-19, we report on a platform technology that is well suited for this purpose, using intact measles virus fora demonstration. Cases of infection due to the measles virus are rapidly increasing, yet current diagnostic tools used to monitor for the virus rely on slow (>1 h) technologies. Here, we demonstrate the first biosensor capable of detecting the measles virus in minutes with no preprocessing steps. The key sensing element is an electrode coated with a self-assembled monolayer containing the measles antibody, immobilized through an N-heterocyclic carbene (NHC). The intact virus is detected by changes in resistance, giving a linear response to 10-100 mu g/mL of the intact measles virus without the need to label or process the sample. The limit of detection is 6 mu g/mL, which is at the lower limit of concentrations that can cause infections in primates. The NHC-based biosensors are shown to be superior to thiol-based systems, producing an approximately 10x larger response and significantly greater stability toward repeated measurements and long-term storage. This NHC-based biosensor thus represents an important development for both the rapid detection of the measles virus and as a platform technology for the detection of other biological targets of interest.