Electronic DNA detection on semiconductor surfaces

Electronic biosensors offer a viable alternative to optical biosensors for the rapid, specific, and sensitive detection of DNA. We are utilizing an electrolyte-oxide-semiconductor (EOS) biosensor system on a SiO2/Si surface for impedimetric detection of DNA. Detection in this system is based on the intrinsic negative charge of DNA. Hybridization of target DNA to the probe-functionalized semiconductor electrode causes a change in the surface charge density, which results in a measurable shift of the impedance response. To covalently bind probe DNA sequences to the biosensor surface, we have activated and functionalized the SiO2/Si surface with aminosilanes, followed by coupling with activated probe DNA. Efficient and specific hybridization was verified via fluorescence and atomic force microscopy (AFM). To increase the sensitivity of our system, we are coupling a novel exponential isothermal DNA amplification reaction (EXPAR) with impedimetric DNA detection.