On the adsorption and electrochemical oxidation of DNA at glassy carbon electrodes

Brett, Christopher M. A.; Oliveira-Brett, Ana Maria; Serrano, Sı́lvia Helena Pires

doi:10.1016/0022-0728(93)02994-s

Cited by 149 publications

(93 citation statements)

References 18 publications

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“…As can be seen, no faradaic signal was detected over the entire potential window for free ODN-III or for the ODN-III lipoplex. This was expected for free ODN since the oxidation of the thymidine and cytidine nucleotides in ODN can be detected only at high positive potential, for the pH used, and their peaks are usually masked by the electrolyte oxidation [14][15][16][17]. The absence of signals for the ODN-III lipoplex shows, as predicted [16], that the presence of thymidine and cytidine [10], in the ODN sequence gave no detectable electrochemical signals.…”

Section: Effect Of Thymidine and Cytidine Nucleotides On Odn Lipoplexmentioning

confidence: 54%

“…Indeed, it was found that guanosine nucleotides in ODN lipoplexes undergo oxidation at the same potential at which they are oxidised in free ODN. This is crucial, as it is known that guanosine is the most easily oxidised base in DNA [14,15,17] and that its principal oxidation product, 8-oxoguanosine [23], is mutagenic. This implies that even if the lipoplex formulation succeeds, in gene delivery there is a possibility that some of the bases composing the DNA could be oxidised during its travel to reach the nucleus of the target cell.…”

Section: Discussionmentioning

confidence: 99%

“…2, present oxidation peaks corresponding to guanosine at +0.90 V, peak (G), to adenosine at +1.15 V, peak (A) in the single strand [14][15][16][17] and to adenosine in the lipoplexes at +0.60 V, peak L.…”

Section: Effect Of Guanosine and Adenosine Nucleotides On Odn Lipoplementioning

confidence: 99%

“…By voltammetry, it is possible to distinguish between single strand and double helix DNA [14,15] since the peaks due to guanosine and adenosine nucleotide oxidation in DNA are comparably much higher and well defined for the single strand. In the double strand the bases are hindered inside the helix core, charge transfer to the electrode is more difficult, and normally no signal is observed in a first scan voltammogram [14,15]. This feature of DNA voltammetry was used to verify whether it is possible to sense voltammetrically a denaturation effect undergone by a double helix ODN hybrid inside the lipoplex.…”

Section: Voltammetric Detection Of Denaturation Of Hybrid Odns In Lipmentioning

confidence: 99%

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Voltammetric behaviour of oligonucleotide lipoplexes adsorbed onto glassy carbon electrodes

Piedade

Mano

Lima

et al. 2004

Journal of Electroanalytical Chemistry

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The voltammetric behaviour of oligonucleotide lipoplexes (ODN-lipoplexes) prepared from short oligodeoxynucleotides (ODN), with different base compositions, and liposomes of the cationic lipid DOTAP, was studied by differential pulse voltammetry with a glassy carbon mini-electrode. It was found that the ODN base composition influences the ODN-lipoplex voltammetric response. Differential pulse voltammograms for ODN-lipoplexes of the ODN adenosine nucleotides present two different features when compared with the differential pulse voltammograms obtained for free ODN: a new peak appeared and the peak attributed to oxidation of adenosine diminished or was absent, depending on whether the ODN sequence had guanosine nucleotides or not. The presence of guanosine nucleotides in the ODN-lipoplex led to a peak due to guanosine oxidation with similar potential and current to the peak obtained for guanosine oxidation in free ODN. No detectable peaks were recorded in the voltammograms obtained with lipoplexes composed of ODN containing only pyrimidine bases. It was possible to show by voltammetry the occurrence of partial denaturation of short double helices of ODN when mixed with DOTAP liposomes to generate lipoplexes. The extent of denaturation was observed to increase with lipoplex (+/)) charge ratio as shown by the increase in the differential pulse voltammetry peak currents. The electrochemical characterisation of lipoplex properties at a charged interface can be important for understanding and development of these gene therapy vectors.

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Section: Effect Of Thymidine and Cytidine Nucleotides On Odn Lipoplexmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Section: Effect Of Guanosine and Adenosine Nucleotides On Odn Lipoplementioning

confidence: 99%

Section: Voltammetric Detection Of Denaturation Of Hybrid Odns In Lipmentioning

confidence: 99%

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Voltammetric behaviour of oligonucleotide lipoplexes adsorbed onto glassy carbon electrodes

Piedade

Mano

Lima

et al. 2004

Journal of Electroanalytical Chemistry

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“…The oxidation mechanism of hypoxanthine, which involves the loss of two electrons and two protons, probably follows the same route as that described for guanine [27]. The fact that hypoxanthine does not have the amino group in position 2 of the purinic ring, as in the case of guanine, should not influence the mechanism of electron transfer.…”

Section: Introductionmentioning

confidence: 76%

Voltammetric and impedance studies of inosine-5′-monophosphate and hypoxanthine

Oliveira-Brett

Silva

Farace

et al. 2003

Bioelectrochemistry

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The oxidation mechanism and adsorption of inosine 5V -monophosphate and hypoxanthine were investigated in solutions of different pH using voltammetric and impedance methods at glassy carbon electrodes. For both compounds, the pH dependence from differential pulse voltammetry showed that the same number of electrons and protons are involved in the rate-determining step of the electrochemical reaction. In the case of hypoxanthine, it was also possible to study the effect of different concentrations. At high concentrations of hypoxanthine, two oxidation peaks were observed, the first due to hypoxanthine oxidation with formation of oligomers and the second due to hypoxanthine oligomer oxidation, both compounds adsorbing strongly. Impedance measurements corroborated the voltammetric results and enabled the study of the adsorption of hypoxanthine on glassy carbon. D

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Differential transport of DNA by a rectified Brownian motion device

et al. 2000

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An interdigitated electrode array (IDEA) device has been designed and used to transport DNA based on a Brownian ratchet mechanism. This migration is produced by the periodic formation of an asymmetric sawtooth electric field in the device. Oligonucleo tides of 25, 50, and 100 bases in length were tested using two different array geometries. DNA transport as a function of DNA size, electric field frequency, and array geometry is shown to be in qualitative agreement with theory. Such a device could provide for DNA separations over a broad size range, and can be readily scaled as a component in a microfabricated DNA analysis system.

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On the adsorption and electrochemical oxidation of DNA at glassy carbon electrodes

Cited by 149 publications

References 18 publications

Voltammetric behaviour of oligonucleotide lipoplexes adsorbed onto glassy carbon electrodes

Voltammetric behaviour of oligonucleotide lipoplexes adsorbed onto glassy carbon electrodes

Voltammetric and impedance studies of inosine-5′-monophosphate and hypoxanthine

Differential transport of DNA by a rectified Brownian motion device

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