Here is another working GrapheneFET COVID-19 bio sensor
Why aren't they mass producing this?
https://arxiv.org/abs/2003.12529Abstract
Here, in an effort towards facile and fast screening/diagnosis of novel coronavirus
disease 2019 (COVID-19), we combined the unprecedently sensitive graphene field-
effect transistor (Gr-FET) with highly selective antibody-antigen interaction to develop
a coronavirus immunosensor. The Gr-FET immunosensors can rapidly identify (about
2 mins) and accurately capture the COVID-19 spike protein S1 (which contains a
receptor binding domain, RBD) at a limit of detection down to 0.2 pM, in a real-time
and label-free manner. Further results ensure that the Gr-FET immunosensors can be
promisingly applied to screen for high-affinity antibodies (with binding constant up to
2×10 11 M -1 against the RBD) at concentrations down to 0.1 pM. Thus, our developed
electrical Gr-FET immunosensors provide an appealing alternative to address the early
screening/diagnosis as well as the analysis and rational design of neutralizing-antibody
locking methods of this ongoing public health crisis."