Electrochemical Sensors for DNA Interactions and Damage

Fojta, Miroslav

doi:10.1002/1521-4109(200211)14:21<1449::aid-elan1449>3.0.co;2-z

Cited by 185 publications

(127 citation statements)

References 97 publications

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“…Electrocatalytic oxidation of the bases should be either nonexisting or very slow, since there is no guanine in the film and the oxidation potential of adenine and uracil is much higher than Ru-dppz. 22 As shown in Figure 3, only one oxidation peak at about 1.2 V was observed for Ru-dppz bound to the poly-(AU) film, the magnitude of which increased at higher Ru-dppz concentrations. This result suggests that the appearance of peak 1 in Figure 1 requires participation from guanine.…”

Section: Resultsmentioning

confidence: 90%

Multiple DNA Binding Modes of a Metallointercalator Revealed by DNA Film Voltammetry

2006

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Binding and the redox reaction of the metallointercalator Ru(bpy) 2 (dppz) 2+ (bpy ) 2,2′-bipyridine, dppz ) dipyrido[3,2-a:2′,3′-c]phenazine) with DNA was investigated by DNA film voltammetry. Calf-thymus DNA (CT-DNA) was assembled on a tin-doped indium oxide electrode by layer-by-layer electrostatic adsorption. Voltammetry of Ru(bpy) 2 (dppz) 2+ (Ru-dppz) bound to the DNA film was measured in a redox-free electrolyte and showed strong dependence on the concentration of the metallointercalator. At low Ru-dppz concentrations, a single oxidation peak was observed, the potential of which shifted from 1.25 to 1.1 V with increasing Ru-dppz concentration (peak 1). At high metal chelate concentrations, an additional oxidation peak emerged with a potential of 1.25 V which was unaffected by the Ru-dppz concentration (peak 2). Three experiments were performed to investigate the mechanism and structural basis of the multiple peaks. First, voltammetry of Os(bpy) 2 (dppz) 2+ bound to the CT-DNA film displayed only one peak at its oxidation potential of about 0.75 V. Second, the concentration dependence of Ru-dppz bound to a poly-(AU) film (which does not contain any guanine bases) exhibited only one oxidation peak at about 1.22 V that was independent of the Ru-dppz concentration. Third, when the guanine concentration in a mixed film of CT-DNA and poly-(AU) was changed and the bound Ru-dppz was kept constant, a pre-peak emerged and shifted to 1.1 V with increasing guanines. Based on these results, the appearance of two peaks in the voltammetric measurements of CT-DNA was rationalized by invoking two different DNA binding modes for the Ru-dppz complex: intercalation and electrostatic association. Peak 2 arises from slow oxidation of guanines catalyzed by Ru-dppz electrostatically associated with the DNA film, since the addition of Mg 2+ decreases the magnitude of peak 2. Peak 1 was not affected by Mg 2+ ions, leading us to conclude that it is due to intercalated Ru-dppz. The intercalation positions the metal complex in close contact with the guanines inside DNA resulting in fast electrocatalytic reaction, giving rise to a catalytic pre-peak.

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Section: Resultsmentioning

confidence: 90%

Multiple DNA Binding Modes of a Metallointercalator Revealed by DNA Film Voltammetry

2006

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“…The peptide nucleic acid, an artificial oligo-amide capable of binding very strongly to complementary oligonucleotide sequences has been attempted (Vo-Dinh and Cullum, 2000). The electrochemical platform is popular since it is ideal for studying DNA damage and interactions (Fojta, 2002). However, considerable research is still needed to develop methods for directly targeting natural DNA present in organisms and in human blood (Palecek, 2002) with high detection sensitivity.…”

Section: Biorecognition Elementsmentioning

confidence: 99%

Biosensor technology: Technology push versus market pull

Luong

Male

Glennon

2008

Biotechnology Advances

374

178

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“…Electrochemistry provides a simple, sensitive and inexpensive approach for investigating DNA/drug [8][9][10][11] and DNA/pollutant interactions [12,13] by monitoring the voltammetric signal of either the compound itself or the guanine bases in DNA. Recently, an electrochemical displacement method was developed by our group to investigate the binding interaction between organic molecules and DNA [14].…”

Section: Introductionmentioning

confidence: 99%

Highly sensitive electrochemiluminescence displacement method for the study of DNA/small molecule binding interactions

Huang¹,

Wang²,

Guo³

2010

Analytica Chimica Acta

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a b s t r a c tNon-covalent binding interactions of small molecules with DNA play important roles in regulating gene expression and gene function. In this work, a highly sensitive electrochemiluminescence (ECL) displacement method has been developed to investigate such interactions, particularly for weak DNA binders. This ECL method relies on a double-stranded DNA film deposited on an indium tin oxide electrode (ITO) surface by layer-by-layer self-assembly. A DNA intercalator, [Ru(bpy) 2 (dppz)] 2+ (bpy = 2,2 -bipyridine, dppz = dipyrido[3,2-a:2 3 -c]phenazine), is employed as the ECL signal indicator. If a test compound competes with the indicator for the same binding sites in DNA, it would displace the indicator from the film and reduce ECL signal. The new method was validated by measuring five well-known DNA-binding organic molecules including quinacrine, H33258, thiazole orange, ethidium bromide and 4,6-diamidine-2-phenylindole dihydrochloride. Due to high ECL sensitivity, only 0.4 mol L −1 [Ru(bpy) 2 (dppz)] 2+ was needed in the ECL displacement measurement, which is about 75-fold less than the concentration in the voltammetric measurement. The lowered concentration permitted direct measurement of IC 50 values of eight hydroxylated polycyclic aromatic hydrocarbons in their ECL displacement curves and subsequent calculation of their binding constants with DNA. The ECL displacement method is particularly useful for investigating weak DNA binders with limited aqueous solubility.

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Electrochemical Sensors for DNA Interactions and Damage

Cited by 185 publications

References 97 publications

Multiple DNA Binding Modes of a Metallointercalator Revealed by DNA Film Voltammetry

Multiple DNA Binding Modes of a Metallointercalator Revealed by DNA Film Voltammetry

Biosensor technology: Technology push versus market pull

Highly sensitive electrochemiluminescence displacement method for the study of DNA/small molecule binding interactions

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