Rapid Conductometric Detection of SARS-CoV-2 Proteins and Its Variants Using Molecularly Imprinted Polymer Nanoparticles.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) biosensors have captured more attention than the conventional methodologies for SARS-CoV-2 detection due to having cost-effective platforms and fast detection. However, these reported SARS-CoV-2 biosensors suffer from drawbacks including issues in detection sensitivity, degradation of biomaterials on the sensor's surface, and incapability to reuse the biosensors. To overcome these shortcomings, molecularly imprinted polymer nanoparticles (nanoMIPs) incorporated conductometric biosensor for highly accurate, rapid, and selective detection of two model SARS-CoV-2 proteins: (i) receptor binding domain (RBD) of the spike () glycoprotein and (ii) full length trimeric spike protein are introduced. In addition, these biosensors successfully responded to several other SARS-CoV-2 RBD spike protein variants including Alpha, Beta, Gamma, and Delta. Our conductometric biosensor selectively detects the two model proteins and SARS-CoV-2 RBD spike protein variant samples in real-time with sensitivity to a detection limit of 7 pg mL within 10 min of sample incubation. A battery-free, wireless near-field communication (NFC) interface is incorporated with the biosensor for fast and contactless detection of SARS-CoV-2 variants. The smartphone enabled real-time detection and on-screen rapid result for SARS-CoV-2 variants can curve the outbreak due to its ability to alert the user to infection in real time.