Date of Award
Doctor of Philosophy (PhD)
Biochemistry & Molecular Biophysics
A. T. Charlie Johnson
In an effort to diagnose and monitor disease progression, many healthcare specialists have moved towards using diagnostic tests capable of detecting biomolecules associated with particular diseased conditions. These molecules are referred to as biomarkers, and their concentrations in human samples can be used to gain information about a particular disease state. Many diagnostic tests capable of quantifying biomarker concentrations must be outsourced to diagnostic laboratories run by specialized technicians and health scientists. As a result, these tests are expensive to run and can have extensive delays in reporting results to patients. In an effort to create more sensitive and efficient diagnostic tests, scientists have begun exploring alternative methods of biomarker detection using all electronic nanomaterial based biosensors. These sensors are cost effective, easily fabricated, and capable of detecting low concentrations of biomarkers in small (<200 ul) sample volumes. Graphene based biosensors, created from graphene field effect transistors (GFETs), are once such sensor type. GFETs are all electronic devices that can be created by traditional photolithography. The graphene used in these devices is often synthesized by chemical vapor deposition (CVD) and functionalized with probe molecules specific for various biomarkers of interest. By quantifying the concentration of these biomarkers, GFETs have the potential to be used as point of care devices to both diagnose and monitor the progression of various diseases. This will allow for better treatment of diseased conditions by enabling specialists to detect small changes in their patient’s condition before obvious symptoms develop. This work discusses advancements towards creating point of care devices from GFETs by lowering the limit of detection of the nucleic acid biosensors to the few copy level, optimizing the detection system to perform measurements in complex solution, lowering the required sample volumes for sensing from 250 uL to 10 uL, using mis-matched lengths of probes and targets to create faster more sensitive biosensing devices, and performing sensing experiments to detect biomarkers for HIV-1 type B, SARS-COV-2, and Parkinson’s disease.
Dickens, Olivia O., "Graphene Biosensors For The Detection Of Disease Biomarkers" (2022). Publicly Accessible Penn Dissertations. 5050.