Electrochemical Detection of Single-Stranded DNA Using Polymer-Modified Electrodes

Abstract

Glassy carbon electrodes modified by reductive electropolymerization of a thin film of poly[Ru(vbpy)(3)(2+)] or poly[Ru(vbpy)(3)(2+)/vba] (vbpy = 4-vinyl-4'-methyl-2,2'-bipyridine and vba = p-vinylbenzoic acid) were prepared. The Ru(III/II) couples for the polymer films were reversible in nonaqueous solution but were irreversible in aqueous media. The films modified with poly[Ru(vbpy)(3)(2+)] catalyzed the oxidation of aqueous guanosine 5'-monophosphate (GMP) and poly[G], producing a current enhancement in the Ru(III/II) couple for the polymer film. The catalysis was due both to electrostatic condensation of GMP and poly[G] to the Ru-modified surface and to more facile electron transfer to the Ru(III) centers in the polymer compared to the bare electrode. The presence of GMP in solution decreased the extent of decomposition of Ru(III). When single-stranded DNA containing multiple guanines was attached to the electrode modified with the poly[Ru(vbpy)(3)(2+)/vba] copolymer, enhancement of 8-13 &mgr;A for the Ru(III/II) couple was observed with 8 pmol of attached DNA. This degree of enhancement corresponds to a current efficiency of 65% based on a one-electron oxidation of guanine.

Attachment of Amine‐ and Maleimide‐Containing Ferrocene Derivatives onto Self‐Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross‐Linking Efficiencies and Surface Coverage of Electroactive Groups

“…/vba] film-modified electrode [39]. The coupling efficiency between NHS esters and FcNH 2 is expected to be better than that between COOH groups and FcNH 2 with the aid of carbodiimide and Nhydrosuccinimide.…”

“…The impetus behind this work partially stems from the fact that an accurate determination of the cross-linking efficiency should provide a guide for the construction of well-defined and effective chemosensors and biosensors. For example, Thorp and co-workers used aminoferrocene (FcNH 2 ) to assess the possibility of attaching DNA molecules onto a thin film of poly[Ru(vbpy) 3 2þ ] (vbpy ¼ 4-vinyl-4'-methyl-2,2'-bipyridine) [39]. Another noteworthy work is the successful utilization of N-(2-ethyl-ferrocene)maleimide (Fc À Mi) to label electroinactive proteins in solution for subsequent voltammetric characterization [33,34].…”

A structure-based investigation on the binding interaction of hydroxylated polycyclic aromatic hydrocarbons with DNA

“…Electrochemistry offers great advantages because it provides rapid, simple and low-cost detection. Recently, the recognition of various electrostatic and intercalative binders with DNA was investigated (Kelley et al, 1999;Ontko et al, 1999;Pang and Abruna, 2000;Steel et al, 1999). Extensive work has also been done on the electrochemical investigation of DNA/drug (Erdem and Ozsoz, 2002;Fojta, 2002) and DNA/pollutant interactions by monitoring the electrochemical signal of either the compound itself, or the guanine base in DNA.…”

Electrochemical Studies of the Interaction of 2‐Nitroacridone with DNA and Determination of DNA

“…It is well known that electrochemical analysis of nucleic acids based on their direct oxidation of guanine base in aqueous solution have been reported previously at different electrodes such as gold [18], glassy carbon [19], pyrolytic graphite [20], indium tin oxide [21], pencil electrode [22], mercury [23], polymer modified electrodes [24], and carbon paste electrodes [25,26]. However, the electrochemical detection of DNA using electrochemical probes has been received much attention due to its much more simplicity and higher sensitivity compared with that based on direct oxidation of guanine base.…”