UC Davis

In the onset of a rapidly spreading disease, it is critical to have reliable diagnostic tools that detect pathogens at low concentrations to enable early preventative measures that can protect against an uncontrolled outbreak. Electrochemical biosensors that detect nucleic acids are favorable bioanalytical tools that have been a crucial research area for applications in the medical, defense, and agricultural industry. This class of sensor transduces naturally occurring biological phenomena, such as DNA hybridization into quantifiable electrical readouts. These biomolecular events occur at the working electrode site and thus it is regarded as the most important component of the electrochemical sensor. Nanostructuring the working electrode has been shown to enhance sensor performance by significantly improving the limit of detection in both buffer and complex media. However, as the target DNA concentration in a sample decrease to trace amounts, biochemical sensing schemes become transport-limited regardless of electrode properties. The primary goal of this work is to address this challenge by implementing a droplet evaporation technique that alleviates diffusion limited transport. This method aims to increase sensor performance by introducing a convective transport mechanism that directs target DNA to the sensor surface, thus increasing the probability of a surface interaction compared to solely relying on diffusion.