CPOS Seminar: Interrogation of Electrochemical Aptamer-Based Biosensors via Electrochemical Impedance Spectroscopy

Speaker: BRIAN ROEHRICH , Graduate Research Student, Department of Chemistry and Biochemistry, University of California Santa Barbara 

Abstract: Electrochemical aptamer-based (EAB) biosensors are an emerging technology which aim to monitor drug, metabolite, and biomarker concentrations in real time, in the living body. To realize this, EAB sensors use short, target-specific single-stranded DNA sequences (aptamers) which reversibly bind to the target molecule. For electrochemical detection, the aptamer is functionalized with a redox-active probe and bound to the surface of an electrode. Binding of the target molecule induces a conformational change in the aptamer, which brings the redox probe closer to the electrode surface and increases the electron transfer rate compared to the unbound state.

Various electrochemical techniques have been used to measure the state of EAB sensors, each with their own advantages and drawbacks. In this presentation, I will discuss our development of time-resolved electrochemical impedance spectroscopy (EIS) as a new interrogation method for EAB sensors. Despite the depth of information obtained from EIS and its broad applicability towards characterizing materials and devices, its application to EAB sensors remains underexplored. We show that time resolved EIS supports rapid, real time measurement of drug concentrations, even in the living body. I will discuss the various benefits EIS offers compared to conventional EAB interrogation methods, as well as the limitations of the measurement technique.