Electrical Detection of Biomarkers Using Electrolyte-Gated Organic Field-Effect Transistors

The ability to detect single molecules of biomarkers in patient samples is of great importance for early diagnosis of diseases such as cancer. This thesis presents biosensors based on organic electronics, which can detect very low concentrations of biomarkers. The technology is based on a field-effect transistor with an organic material as the semiconductor and water is as the insulator. A layer of biomolecules, designed to capture the specific biomarker of interest, is functionalized to the gate terminal of the transistor. When the biomarker binds to the surface, there is a measurable change in the current through the semiconductor, even at very low biomarker concentrations. The layer of biomolecules attached in the transistor is customizable, making it possible to configure the biosensor to detect different biomarkers provided that a receptor molecule can be identified for each marker. Scaling up the technology to 96 interconnected biosensors enables high-throughput screening, for example for early detection of pancreatic cancer. The thesis also compares the performance of this technology with the state-of-the-art optical analysis methods used in the field today.