Adsorptive stripping potentiometry of DNA at electrochemically pretreated carbon paste electrodes

Abstract

Potentiometric stripping analysis is employed for highly sensitive measurements of single-stranded DNA at carbon paste electrodes. Electrochemical (oxidative) pretreatment is used to condition the carbon paste surface prior to the accumulation process. The low background response of the potentiometric stripping mode offers convenient quantitation of low nanogram quantities of DNA. Experimental variables of the pretreatment and measurement procedures are explored and optimized. Results are also reported for the quantitation of nanogram levels of the long terminal repeat (LTR) from the human leukemia virus and for the stripping operation of microfabricated screen-printed electrodes.

DNA Electrochemical Behaviors, Recognition and Sensing by Combining with PCR Technique

“…ssDNA produced a cathodic peak due to the reduction of adenine and an anodic peak due to the oxidation of the guanine reduction product. Wang et al [128] reported a method to quantitate nanogram quantities of ssDNA using adsorptive stripping potentiometry at electrochemically pretreated carbon paste electrode (CPE). The cyclic voltammogram of 2 mg l -1 ssDNA at the pretreated CPE gave one anodic peak at about +1.05 V corresponding to the oxidation of the guanine residue.…”

Adsorption and Detection of DNA Dendrimers at Carbon Electrodes

“…Similar to DNA molecules [10], nucleic acid dendrimers can be adsorbed and accumulated onto pretreated carbon paste surfaces to yield a well-defined anodic peak (associated with the oxidation of the guanine residue). The detection of this oxidation signal is greatly facilitated by the use of the chronopotentiometric measurement scheme [3,10]. Figure 2 compares differential-pulse voltammograms (A) and chronopotentiograms (B) for 600 pM of the 4-layer dendrimer obtained with (b) and without (a) adsorptive accumulation.…”

Advances Towards Integrated Biodetection Systems for Environmental Molecular Microbiology

“…PSA and cyclic voltammetry can quantify DNA or RNA at 1.0 -2.5 pg/µl utilizing carbon paste or graphite electrodes (66)(67)(68)(69), detection sensitivities almost on par with fluorescent methods (in an environmental context). Highly sensitive electrochemical measurements are possible because DNA is accumulated at the electrode prior to the electrochemical measurement, a mass action principle not possible with passive adsorption methods.…”

“…Both PSA and cyclic voltammetry are amenable to indicator-free operation, whereby an intrinsic property of the nucleic acid target is utilized to generate an electrical signal. For example, multiple and distinct electrochemical signatures can be generated from guanine (G) oxidation (66,70) or combined cytosine/adenine (C/A) reduction (70,71). Redox manipulation of intercalator labels is also commonplace (67).…”