This proposal outlines plans for the development of a new microdetection technique, which is to be coupled with the SBH method.
The specific aims to achieve the potential benefits of the proposed sequencing approach are categorized into microdetection technology development and transfer tasks consisting of the following components. Device development includes the design, fabrication, testing, and evaluation of microchips for directly detecting the hybridization of target DNA to probe DNA attached on interdigitated electrodes arrayed on a microfabricated substrate. Each electrode in the hybridization array is activated by an alternating electric field to detect variations in local dielectric properties to signify the presence of hybridized target DNA, thereby revealing the oligonucleotide content of the sample DNA under test. Device modeling entails the mathematical modeling of the biologic/electronic interface to enable calculation of the detection sensitivity of the devices. A Gouy-Chapman electrical double-layer model will be formulated with varying charge concentrations near the surface to represent the attached DNA probes. An equivalent electrical circuit model will then be derived to sufficiently describe the interface for sensitivity calculations. Surface chemistry involves developing a rapid, efficient method for attaching the oligonucleotide probes to the gold microelectrodes on the array. A three-step procedure outlined involves activation of the gold support with a dithiodecane linker, followed by activation of amine- modified oligonucleotides, and a final linker/probe coupling reaction. Surface chemistry also includes the specificity analysis of hybridization conducted directly in the micro-miniature test wells embedded within the micro-fabricated array. Technology transfer is addressed by the formation of a research consortium early in the research phase to effect efficient transfer of the proposed microdetection technology to industry. The Genosensor Consortium, to be composed of industry, academia, and government, will be formulated to develop and commercialize promising technology.
