Voltammetric behavior of uric acid on carbon paste electrode modified with salmon sperm dsDNA and its application as label-free electrochemical sensor

A simple and sensitive label-free electrochemical DNA biosensor was proposed for the rapid determination of uric acid (UA) using a carbon nano tube paste electrode (CNTPE) modified with salmon sperm dsDNA. At first, the interaction between UA and the DNA was studied using differential pulse voltamme...

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Bibliographic Details
Published in:	Biosensors & bioelectronics 2014-04, Vol.54, p.211-216
Main Authors:	Mohamadi, Maryam, Mostafavi, Ali, Torkzadeh-Mahani, Masoud
Format:	Article
Language:	eng
Subjects:	Animals Biological and medical sciences Biosensing Techniques - methods Biosensors Biotechnology Carbon nano tube paste electrode DNA - chemistry DNA biosensor Electrochemical Techniques - methods Electrodes Fundamental and applied biological sciences. Psychology Humans Limit of Detection Male Methods. Procedures. Technologies Nanotubes, Carbon - chemistry Salmon Salmon sperm dsDNA Spermatozoa - chemistry Uric acid Uric Acid - analysis Uric Acid - blood Uric Acid - urine Various methods and equipments Voltammetry
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Summary:	A simple and sensitive label-free electrochemical DNA biosensor was proposed for the rapid determination of uric acid (UA) using a carbon nano tube paste electrode (CNTPE) modified with salmon sperm dsDNA. At first, the interaction between UA and the DNA was studied using differential pulse voltammetry (DPV). The addition of the DNA to UA solution resulted in a decrease in the peak current of UA and at the same time, a positive shift in the peak potential indicating an intercalative interaction. Then, the voltammetric response of a DNA-immobilized CNTPE was investigated for the determination of UA. The immobilization of the DNA was carried out using acid-functionalized carbon nanotubes and studied using Fe(CN)63−/Fe(CN)64− redox indicator. Compared with unmodified CNTPE, the oxidation signal of UA showed a significant increase at the DNA-coated electrode, and shifted to more positive potentials attributed to the pre-concentration of UA at the electrode surface due to interaction with the surface-confined DNA layer. This interaction was used for the fabrication of a simple and sensitive biosensor for determining UA. After the optimization of operational parameters, a linear dependence of the peak current on the UA concentration was observed in the range of 7.0×10−7 to 1.1×10−4molL−1, with the detection and quantification limits of 1.8×10−7 and 5.8×10−7molL−1, respectively. The proposed biosensor was successfully applied to validate its capability for the analysis of UA in human serum and urine samples. •Addition of dsDNA to uric acid solution shifted Epa positively and decreased Ipa.•It was concluded that the interaction mode was intercalation.•The voltammetric behavior of uric acid at a DNA-coated electrode was studied.•Accumulation of uric acid at DNA-coated electrode was much more than bare electrode.•The modified electrode was successfully applied for urine and serum analysis.
ISSN:	0956-5663 1873-4235