title: Label-free femtomolar detection of target DNA by impedimetric DNA sensor based on poly(pyrrole-nitrilotriacetic acid) film.
abstract: An ultrahigh performance impedimetric DNA sensor is presented showing detection limits in the femtomolar range. This electrochemical setup was constructed initially by electrogeneration of poly(11-pyrrol-1-yl-undecanoic acid N(alpha'),N(alpha)-bis(carboxymethyl)-L-lysine amide) (poly(pyrrole-NTA)) film. The latter was then modified by the coordination of Cu(2+) ions onto the chelating NTA centers followed by the immobilization of the ssHIV-DNA previously modified by a polyhistidine tag by affinity binding. The immobilization of the DNA probe and hybridization with the complementary target ssHIV-DNA were investigated using fluorescence microscopy and quantified with quartz crystal microbalance experiments leading to DNA probe and duplex coverage of 1.7 x 10(-11) and 7.7 x 10(-12) mol cm(-2), respectively. The duplex formation was corroborated by amperometric measurements through the duplex labeling by a glucose oxidase. In the presence of hydroquinone as redox indicator, the DNA sensor was applied to the impedimetric detection of target DNA without a labeling step. A linear quantification of the HIV DNA target was carried out in the range 10(-15) to 10(-8) mol L(-1).
authors.affiliation: Département de Chimie Moléculaire, UMR 5250, ICMG FR 2607, CNRS, Université Joseph Fourier Grenoble I, BP 53, 38041 Grenoble cedex 9, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Baur
authors.forename: Chantal
authors.initials: C
authors.lastname: Gondran
authors.forename: Michael
authors.initials: M
authors.lastname: Holzinger
authors.forename: Eric
authors.initials: E
authors.lastname: Defrancq
authors.forename: Hubert
authors.initials: H
authors.lastname: Perrot
authors.forename: Serge
authors.initials: S
authors.lastname: Cosnier
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002614:Chelating Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry*; D004279:DNA, Viral / Q000032:analysis*; D017097:Electric Impedance; D055664:Electrochemical Techniques / Q000379:methods*; D005949:Glucose Oxidase / Q000378:metabolism; D006678:HIV / Q000235:genetics; D008239:Lysine / Q000737:chemistry*; D008839:Microelectrodes; D009571:Nitrilotriacetic Acid / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D011758:Pyrroles / Q000737:chemistry*; D011791:Quartz
chemical_list: D002614:Chelating Agents; D015342:DNA Probes; D004279:DNA, Viral; D011758:Pyrroles; D011791:Quartz; D003300:Copper; D005949:Glucose Oxidase; D008239:Lysine; D009571:Nitrilotriacetic Acid