Theses and Dissertations Collection

Electrochemical deoxyribonucleic acid (DNA) sensors have emerged as a promising clinical diagnostic technology for infectious disease and cancer. DNA biosensors can exploit DNA recognition events and convert them into an electrochemical signal. Rapid response, selectivity, good sensitivity, and ease of miniaturization are a few advantages of electrochemical biosensors. Chapter 1 describes the various classifications of electrochemical biosensor techniques (e.g., impedimetric, amperometric, and others). We also discuss recent strategies for DNA immobilization on the surface of electrodes including covalent and non-covalent bonding. Sensors are described for DNA, RNA, protein and small molecule targets. Chapter 2 discusses DNA immobilization by DVS conjugation for the electrochemical detection of complementary DNA. Conjugation of DNA on the surface of the electrode through DVS is a new method for detection of complementary DNA. Graphene oxide was used is an immobilization platform to improve the charge transfer. This DNA biosensor avoids the need for modified oligonucleotides with synthetic attachment chemistry. We also analyzed the mechanism of DNA conjugation through mass spectrometry. In chapter 3, we describe a low-cost method for detecting nucleic acids with more conventional attachment chemistry. Carbodiimide chemistry was used for conjugation of DNA on the surface of electrode. Cyclic voltammetry and electrochemical impedance were used to detect DNA.