Electrochemical aptamer-based sensors (E-ABs) are sensors fabricated using nucleic acid aptamers – single-stranded DNA (ssDNA) or RNA (ssRNA) sequences that bind to a specific target. E-ABs are commonly fabricated on Au electrodes via a process known as self-assembled monolayer (SAM) chemistry using a thiolated nucleic acid. The E-AB fabrication via SAM is straightforward and easily reproducible, but the stability of the gold-thiol bond is not ideal for point-of-care applications. To improve this stability, we investigated the use of covalent chemistry for the surface modification of gold electrode surfaces for the fabrication of E-AB sensors. The modification protocol involved the reductive grafting of diazonium salts to create chemical handles for further surface modification. We used cyclic voltammetry of the redox couple hexaammineruthenium (RuHex) at various pH’s to probe the various steps of surface modification. Our results, while inconclusive, demonstrate that surface modification of the gold electrodes was successful; however, the results suggest that either a combination of diazonium and thiol coupled aptamers or only diazonium coupled aptamers remain on the surface. Nonetheless, we believe these results are promising for the future development of stable, electrochemical aptamer-based sensors for use in point-of-care analysis.

Development of novel surface chemistry for the fabrication of electrochemical aptamer-based sensors

2019 Spring National Meeting

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