Krishna Thapa , a doctoral candidate in chemistry, will defend their dissertation titled “Exploring the Applications of DNA Nanostructures in Electrochemical Biosensors and Microbial Fuel Cells.” Their advisor, Dr. Risheng Wang, is an associate professor in the chemistry department. The dissertation abstract is provided below.

DNA nanostructures, with extraordinary biocompatibility and programmability, offer precise nanoscale material organization, making them valuable in biosensing, imaging, drug delivery, and stimuli-responsive devices. Over the past few decades, DNA-based electrochemical biosensors have attracted significant scientific and clinical interests due to their unique hybridization specificity, rapid response, and potential for miniaturization.

This research encompasses four journal topics. The first topic describes a novel ultrasensitive electrochemical biosensor based on 3D DNA origami for the detection of let-7i miRNA, a biomarker for Traumatic Brain Injury (TBI). This represents the first use of 3D DNA origami in electrochemical DNA biosensing. The second topic explores DNA origami-based biosensing for protein MUC1, a biomarker of breast cancer. Additionally, due to its ability to self-assemble into diverse multidimensional structures, DNA origami nanostructures have shown great promise as carriers for small organic molecules, such as chemotherapy drugs and fluorescent dyes. In the third topic, for the first time, 3D DNA origami nanostructures serving as electron mediator-methylene blue carriers were employed to enhance electron production and transfer in E. coli system-based Microbial Fuel Cells (MFCs). The last topic presents a dual approach to electrode modification, integrating polyaniline and gold nanoparticles on carbon felt anodes, coupled with a unique cathode composed of DNA origami and chitosan. These findings demonstrate the promising applications of DNA nanostructures in biosensing and green energy production fields.