Researchers from University of Texas at Austin have developed an antibody (Ab)-modified graphene field effect transistor (GFET)-based biosensor for precise and rapid influenza A virus (IAV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) protein detection and differentiation.
The sensor chip that was developed comprised of four GFETs in a quadruple arrangement, separated by polydimethylsiloxane (PDMS) enclosures. Every quarter was biochemically functionalized with SARS-CoV-2 and IAV antigen-targeted Abs, one chemically passivated control, and one bare control. The third (chemically passivated) GFET was deployed to ensure that the results observed were due to Ab-antigen interaction rather than electronic fluctuations or drifts.
A test analysis was performed using BSA (bovine serum albumin) as a control analyte to evaluate device specificity. To evaluate the device sensing ability, time trace measurements were performed wherein all GFET transistors were subjected to varying concentrations of SARS-CoV-2 S and IAV HA proteins at different time intervals. The voltage range between 120mV and 200mV showed the greatest transconductance and, thus, was chosen for the sensor to ensure maximal sensitivity.
The biosensor design enabled isolated and targeted biochemical graphene channel functionalization with a common medium for analyte introduction and subsequent translation into a change in Ab-modified GFET conductance. Overall, the study findings highlighted using an Ab-modified GEFT-based biosensor for swift, ultraprecise, sensitive, specific, and cost-effective detection of diverse SARS-CoV-2 variants and IAV subtypes. The versatile biosensor LoD surpassed the minimal LoD needs of 163 fM and 16 aM for nasal and saliva samples, respectively, potentially decreasing the time required for test administration post-viral exposure.