This Is AuburnElectronic Theses and Dissertations

Improving Sensitivity and Validating Analyte Generalizability of an Electrochemical DNA Bowtie Sensor




Gurukandure, Asanka

Type of Degree

PhD Dissertation


Chemistry and Biochemistry

Restriction Status


Restriction Type


Date Available



Having a generalizable point-of-care (POC) detection method for diagnostic biomarkers would greatly enhance healthcare management and disease diagnosis, while also improving physiological understanding. POC methods are cost-effective and provide in-home measurements by excluding sophisticated labs and trained personnel. Biomolecules such as proteins, small molecules, and nucleic acids are present from minuscule concentrations to high concentrations in the human body, and there is thus far no single method available to detect all of these classes of molecules due to their diversity and specificity. As the gold standard approaches, enzyme-linked immunosorbent assay (ELISA) and mass spectrometry coupled with other techniques such as liquid chromatography (HPLC) and gas chromatography (GC) are being used in clinical laboratories to detect most analytes at low limits of detection (LOD) with high precision and accuracy. Although the advancement of technology allows for the automation of laborious steps and reduces the need for trained personnel, expensive instrumentation limits its widespread usage. As a complementary technique, electrochemical biosensors provide high sensitivity and cost-effectiveness, and some have been shown to work directly in human fluids by measuring analytes in real-time. The Easley research group recently developed a DNA-based bowtie sensor architecture for versatile detection of analytes, including small molecules and their larger protein binding partners (e.g. antibodies), in human serum. The bowtie sensor is built through on-electrode enzymatic ligation of three oligonucleotides for electrode attachment, target recognizing, and electrochemical signaling. This sensor is promising due to its easy synthesis, cost-effectiveness, and most importantly, its ability to be easily modified for detecting a wide range of clinically relevant analytes. Presumably, these sensors could be further developed for POC applications in the future.