Reliable, portable, fast graphene sensors for COVID-19

Graphene is an excellent platform for biosensing, that has even been applied in first trials of sensing COVID-19. Now researchers have shown high-sensitivity, fast, and stable COVID-19 detectors made of commercially available Graphenea CVD graphene, coupled with a portable electronic readout unit for field use. The research was published in RSC Sensors & Diagnostics under an Open Access license.

Graphene field-effect transistor (GFET) biosensors exhibit high sensitivity due to a large surface-to-volume ratio and high sensitivity of the Fermi level to the presence of charged biomolecules near the surface. When GFETs are functionalized with molecular binders, such as aptamers, biomarker specificity is added to the sensitivity, making for excellent sensing devices.

Image from Xu et al, Sens. Diagn., 2022, Advance Article.

The sensing device was built from GFETs that have on-chip liquid electrodes and are fabricated with a CMOS-compatible process that enables scalability and mass production. Coupled to miniature portable electronics, the devices yield a COVID test result within minutes. The limit of detection was 103 particles/ml, and the device-to-device signal variation was below 0.5%. The electronics module was powered by a 9V battery, with signal readout via USB and a custom made MATLAB code. Selectivity was tested against similar viruses such as MERS-CoV, human coronavirus, and BSA. For COVID-19 detection, the researchers used a commercially obtained solution that mimics swab samples.

Image from Xu et al, Sens. Diagn., 2022, Advance Article.

The wide availability of the graphene platform, as well as the high sensitivity, specificity and repeatability of the sensing performance, indicate high potential of this demonstrated portable device for mass rapid screening of COVID-19, and other pathogens.