A Lab-on-a-Chip for the Concurrent Electrochemical Detection of SARS-CoV-2 Nucleic Acids and Anti-SARS-CoV-2 Antibodies in Saliva

Rapid, accurate and frequent detection of the RNA of SARS-CoV-2 and of serological host antibodies to the virus would facilitate the determination of the immune status of individuals who have COVID-19, were previously infected by the virus, or were vaccinated against the disease. This presentation describes the development and application of a 3D-printed lab-on-a-chip that concurrently detects, via multiplexed electrochemical outputs and within 2 h, SARS-CoV-2 RNA in saliva as well as anti-SARS-CoV-2 immunoglobulins in saliva spiked with blood plasma. The device automatedly extracts, concentrates and amplifies SARS-CoV-2 RNA from unprocessed saliva, and integrates the Cas12a-based enzymatic detection of SARS-CoV-2 RNA via isothermal nucleic acid amplification with a sandwich-based enzyme-linked immunosorbent assay on electrodes functionalized with the Spike S1, nucleocapsid and receptor-binding-domain antigens of SARS-CoV-2. This workflow introduces a new method for CRISPR-based detection of nucleic acids with an electrochemical readout and demonstrates how combining it with antibody detection can allow for a multiplexed electrochemical diagnostic at the point of care that can can facilitate widespread monitoring of infection and immunity in populations.

Learning Objectives:

1. Discuss how multiplexing an assay can improve infectious disease monitoring.

2. Discuss the differing methods used to detect the presence of antibodies and nucleic acids on the electrochemical chip.

3. Discuss how integrating microfluidics improves the CRISPR-based RNA assay workflow.