Detection of Protein-Ligand Interactions by IGZO Thin Film Transistors

Protein-ligand interaction and bio-chemical reaction are detected by a-IGZO thin-film transistor-based (TFT-based) biosensor with an extended sensing pad in this thesis. These two issues are discussed separately in two parts. The first part is about the interaction between protein and ligand, i.e. MDH and NADH. The TFT-based biosensor is integrated with a microfluidic channel. Due to concentration gradient in the solution, the bio-molecules diffuse to the sensing pad and then cause a drain current change. The diffusion and electrical signals of NADH and MDH are measured separately. Then the interaction between NADH and MDH is detected by our TFT biosensor. In the second part, a bio-chemical reaction in metabolic pathway is detected. This reaction is one step in malate-aspartate shuttle, which is an important bio-chemical system for electron translocation. Solutions with different concentration are tested. By sensing the induced charge on extended pad, the relation between current change and complete/incomplete reactions, or reaction rate constant, k, is revealed.