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 crosslinking of amine-functionalized oligonucleotides to this surface displaying primary amine groups. To increase the sensitivity of our system, we are coupling a novel exponential isothermal DNA amplification reaction (EXPAR) with impedimetric DNA detection. We are further investigating the effect of co-immobilizing DNA functionalized Au nanospheres to the surface, using a sandwich assay format. Experimental results are compared to numerical simulations of different equivalent circuit models to assess the influence of main experimental parameters.
Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: May 20, 2007
Pages: 489 - 492
Industry sector: Sensors, MEMS, Electronics
Topics: Biomaterials, Chemical, Physical & Bio-Sensors