Sensitive and Specific Virus and Protein Detection using Organic Electrochemical Transistors

There is a need for low-cost, fast, and sensitive sensors for the detection of viruses and proteins. Recent work has shown that organic electrochemical transistors (OECTs) can be used as highly sensitive and specific sensors for biological activity, electrochemical reactions, viruses, and biomolecules. Here, we demonstrate a general approach to the detection of SARS-CoV-2 spike protein and virus using OECTs functionalized with engineered proteins. The devices can be fabricated quickly without microfabrication techniques, and a specific response is achieved by immobilizing a protein engineered to bind to the SARS-CoV-2 spike protein on the OECT channel. Binding of SARS-CoV-2 spike protein or virus to the channel produces a significant shift in the transfer curve, and through analysis of the normalized current we determined a sensitivity as low as 10^-18 M for detection of SARS-CoV-2 spike protein and 40 pfu/mL for SARS-CoV-2 virus. The devices are non-responsive to other proteins or viruses, including influenza A, SARS-CoV-2, and OC43. This work demonstrates that OECTs are effective devices for rapid, sensitive, and specific detection of target viruses.