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.
Yang
Wensha
W
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
Butler
James E
JE
Russell
John N
JN
Hamers
Robert J
RJ
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