(172f) Toward Label-Free Electrochemical Sensing of Nucleic Acids

?Oligonucleotide-modified surfaces are at the core of the microarray and biosensor technologies, in which the ability of surface-tethered DNA ?probes? to bind complementary ?target? molecules in solution is the key element. The efficiency of this binding event is lessened to a large extent by electrostatic repulsions between DNA chains. As comparative systems that might reveal the nature of such interactions, monolayers of uncharged end-tethered DNA-analogues have been prepared and subsequently characterized by the use of FTIR and XPS. An electrochemical method that allows for the non-destructive quantification of coverage of these uncharged DNA-analogues was also developed. In addition, the hybridization behaviors of uncharged DNA analogues and charged DNA films to target analytes are being compared and interpreted in terms of the interfacial charge organization."