Electrochemical and plasmonic detection methods yield comparable analytical performance for DNA hybridization

DNA-based biosensors have been engineered for the measurement of different molecular targets. Depending on the means through which binding is transduced, this may introduce differences in analytical performance, especially when looking at the target's molecular weight and length. To address this question, we developed a combined approach of two commonly used transduction methods in DNA-based biosensors - electrochemistry and surface plasmon resonance - for concomitant surface interrogation. Specifically, we looked at the limits of detection and maximal responses of redox-reporter-modified DNA interfaces of increasing lengths binding to their complementary sequences. In doing so, along with comparable limits of detection, we observed that both methods produced similar sigmoidal target-responses that monotonically varied as a function of sequence length. We envision that our combined electrochemical-surface plasmon resonance (eSPR) approach showcases that SPR could be used as a first method to help engineer recognition elements before purchasing costly redox modifications, and in turn accelerate their translation into sensing platforms.