| AVS 66th International Symposium & Exhibition | |
| Applied Surface Science Division | Thursday Sessions |
| Session AS-ThP |
| Session: | Applied Surface Science Poster Session |
| Presenter: | Ramya Vishnubhotla, National Institute of Sandards and Technology (NIST) |
| Authors: | R. Vishnubhotla, National Institute of Sandards and Technology (NIST) S.M. Robinson, University of Maryland, College Park J.P. Giddens, University of Maryland, College Park S. Semancik, National Institute of Standards and Technology (NIST) |
| Correspondent: | Click to Email |
Electrochemical measurements have shown promise for detecting biomolecules such as DNA and proteins. In this presentation, we focus on surface-immobilized DNA aptamers that can be used to bind certain species and thereby produce electrochemical signals indicating detection of desired targets. Our sensing approach is based on monitoring binding events and conformation changes that occur on reusable, temperature-controlled electrochemical microdevices. We present our findings on two “model” aptamers that bind streptavidin and platelet-derived growth factor (PDGF), respectively. The commercially-purchased aptamers were bound to the Au working electrodes of the devices through a thiol group that was synthesized at the 5’ end of the DNA. Changes in temperature caused folding and unfolding of the aptamer, altering the average distance between a terminal redox-active methylene blue moiety (at the 3’ end) and the Au surface. The resulting change in current (due to electron transfer between each methylene blue molecule and the Au surface) was monitored over a temperature range of ~10 ⁰C – 60 ⁰C. Initial studies included surface characterization using XPS and AFM in order to better understand the behavior of the aptamers under environmental stressing, such as changes in the chemical environment and temperature. Surface plasmon resonance (SPR) studies were also performed to provide instrumental analyses of the aptamer-protein binding events, to compare to results obtained with the electrochemical microdevices.