Application of electrochemical surface plasmon resonance spectroscopy for characterization of electrochemical DNA sensors

We report the use of electrochemical surface plasmon resonance spectroscopy (EC-SPR) in the characterization of electrochemical DNA sensors. Three DNA probes, including a stem-loop probe and two linear probes (LP), were used in this study. Among the three sensors, the 3xLP sensor, a new sensor design with three consecutive target recognition sites, showed the largest change in SPR signal upon hybridization to T-25, a 25-base target with overhang regions that do not bind to the 3xLP probe. A detection limit of 20 nM was determined for T-25 using this sensor. Overall, this work has demonstrated the main advantage of EC-SPR, which is the ability to monitor both optical and electrochemical signals simultaneously, from sensor fabrication to target interrogation and sensor regeneration. It also alludes to the potential use of this hybrid technique to differentiate between non-specific binding and non-specific adsorption of non-complement targets onto the sensor surface.