Label-free electrochemical DNA and protein detection using ruthenium complexes and functional polyethylenedioxythiophenes

Abstract

This thesis presents our study on the development of label-free electrochemical biosensors for DNA and protein detection. In part I, we studied label-free electrochemical DNA detection using ruthenium-complexed intercalators. The electroactive intercalators have dual function, selective binding of double-stranded DNA (ds-DNA) and generation of catalytic electrochemical signals, allowing simple yet sensitive detection. In part II, we explored the use of a conducting polymer, functionalized polyethylenedioxythiophene (PEDOT), as an intrinsic transducer for label-free protein sensing. Various approaches for the synthesis of 1-D PEDOT nanostructures were studied. Label-free detection of a blood-clogging factor, thrombin, was demonstrated using aptamer-modified nanowires. In comparison with 2-D thin films, 1-D nanostructures are crucial for field effect transistor (FET) based sensing. Finally, we evaluated functional PEDOT thin films as tunable nanobiointerfaces for cell based studies, for future in-vivo applications. Specific protein adsorption and controlled cell attachment were achieved on these biologically-relevant functionalized PEDOT surfaces.