DNA electronic switches based on analyte-responsive aptamers

Abstract

Aptamers have proven to be very useful as high-affinity and -specificity molecular recognition elements in analytical sensors of various forms. Herein, we describe a general process for creating an aptamer-based sensor that functions as an analyte-responsive, nano-sized, electronic switch. These sensors can provide an electrochemical readout, by switching through-DNA charge transfer across a DNA three-way junction from "off" to "on" in response to the binding of a target ligand to the sensor's aptamer domain. We detail the general design principles for such sensors, as well as the biochemical charge transfer assays used to identify functional sensors. In these gel electrophoresis-based assays, analyte-responsive conductivity switching is detected conveniently through biochemical experiments that characterize oxidative DNA damage patterns in sequencing PAGE gels. © Springer Science+Business Media New York 2014.