UC San Diego

One of the biggest challenges in today’s world is the need to develop a rapid, simple, accurate and cost-effective mode of testing diseases in humans. One such device is the Graphene Field Effect Transistor (GFET) which is being rapidly looked at in the medical device industry. An important feature of this device is the ability of this device to act as a platform of diagnostic testing where any disease biomarker can be tested for on this device. To highlight this ability, in this thesis, a study of a few examples of detecting a variety of respiratory and neurodegenerative biomarkers in a highly sensitive and specific fashion is completed, where the GFET shows the ability to detect these biomarkers in the picomolar and femtomolar range. The GFET has shown to also detect live viruses in the order of 5 SARS-CoV-2 particles, showing better sensitivity than existing FDA tests while also correctly confirming positive and negative SARS-CoV-2 test results. The entire step by step process of functionalizing the GFET device towards testing for biomarkers is described. Confirmatory characterization tests using Raman Spectroscopy and Atomic Force Microscopy are performed. Since it shows promise towards being an effective Point of Care testing method, it is important to understand its inner workings and look towards improving quality control. This is attempted in this thesis using resistance tests and Electronic impedance spectroscopy.