Interfacial electrical properties of DNA-modified diamond thin films: intrinsic response and hybridization-induced field effects.
We have investigated the frequency-dependent interfacial electrical properties of nanocrystalline diamond films that were covalently linked to DNA oligonucleotides and how these properties are changed upon exposure to complementary and noncomplementary DNA oligonucleotides. Frequency-dependent electrical measurements at the open-circuit potential show significant changes in impedance at frequencies of >10(4) Hz when DNA-modified diamond films are exposed to complementary DNA, with only minimal changes when exposed to noncomplementary DNA molecules. Measurements as a function of potential show that at 10(5) Hz, the impedance is dominated by the space-charge region of the diamond film. DNA molecules hybridizing at the interface induce a field effect in the diamond space-charge layer, altering the impedance of the diamond film. By identifying a range of impedances where the impedance is dominated by the diamond space-charge layer, we show that it possible to directly observe DNA hybridization, in real time and without additional labels, via simple measurement of the interfacial impedance.
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
Wensha
W
Yang
James E
JE
Butler
John N
JN
Russell
Robert J
RJ
Hamers
D003460:Crystallization; D004247:DNA / Q000737:chemistry*; D018130:Diamond / Q000737:chemistry*; D017097:Electric Impedance; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning / Q000379:methods; D049329:Nanostructures / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000737:chemistry*; D010316:Particle Size; D012680:Sensitivity and Specificity; D013499:Surface Properties
D008567:Membranes, Artificial; D009841:Oligonucleotides; D018130:Diamond; D004247:DNA