Rapid Detection of COVID-19 Causative Virus (SARS-CoV-2) in Human Nasopharyngeal Swab Specimens Using Field-Effect Transistor-Based Biosensor

TLDR

COVID‑19, caused by SARS‑CoV‑2, has become a global pandemic with no specific treatments, making rapid diagnosis essential for outbreak control. The authors present a field‑effect transistor biosensor to detect SARS‑CoV‑2 in clinical samples. The sensor uses graphene‑coated FETs functionalized with anti‑spike antibodies and is tested with antigen, cultured virus, and patient swabs. The device detects spike protein at 1 fg/mL in buffer and 100 fg/mL in transport medium, with limits of detection of 1.6 × 10¹ pfu/mL in culture and 2.42 × 10² copies/mL in clinical samples, demonstrating high sensitivity without pretreatment.

Abstract

Coronavirus disease 2019 (COVID-19) is a newly emerging human infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously called 2019-nCoV). Based on the rapid increase in the rate of human infection, the World Health Organization (WHO) has classified the COVID-19 outbreak as a pandemic. Because no specific drugs or vaccines for COVID-19 are yet available, early diagnosis and management are crucial for containing the outbreak. Here, we report a field-effect transistor (FET)-based biosensing device for detecting SARS-CoV-2 in clinical samples. The sensor was produced by coating graphene sheets of the FET with a specific antibody against SARS-CoV-2 spike protein. The performance of the sensor was determined using antigen protein, cultured virus, and nasopharyngeal swab specimens from COVID-19 patients. Our FET device could detect the SARS-CoV-2 spike protein at concentrations of 1 fg/mL in phosphate-buffered saline and 100 fg/mL clinical transport medium. In addition, the FET sensor successfully detected SARS-CoV-2 in culture medium (limit of detection [LOD]: 1.6 × 101 pfu/mL) and clinical samples (LOD: 2.42 × 102 copies/mL). Thus, we have successfully fabricated a promising FET biosensor for SARS-CoV-2; our device is a highly sensitive immunological diagnostic method for COVID-19 that requires no sample pretreatment or labeling.