Modification of BDD Electrodes By Organic Films Towards Detection of Selected Nucleobases Nucleosides and Nucleotides
Authors: Niedzialkowski Pawel , Bogdanowicz Robert , Zieba Patrycja , Ryl Jacek , Sobaszek Michal , Smietana Mateusz , Ossowski Tadeusz 
Published: February 2020

The detection of DNA sequences has been attracting in many fields such as molecular diagnostics, medical diagnosis, forensic analysis and treatment[i],[ii]. Nucleobases, are known as a structural parts present in DNA and RNA. Nucleotides are the basic building block of nucleic acid and are consists of nucleobases, pentose sugar and phosphate group[iii], while nucleosides are without a phosphate group. These compounds are considered as electrochemically active in the sense of electron exchange. Due to this phenomenon the electrochemical methods have been applied for the study of electrochemical behaviour of nucleobases, nucleosides and nucleotides using different electrode materials.
Boron-doped diamond (BDD) electrodes found to be very attractive for electrolysis and electroanalytical applications due to their advantages: very low capacitance, relatively low signal to background current ratio, high stability, and wide working potential window[iv]. Nowadays BDD electrodes is one of the most widely used materials in electro analytical applications: in analysis of DNA, recognition of biomolecules and detection of organic species in environmental samples[v].
An amorphous carbon with a high fraction of diamond-like (sp3) bonds is known as diamond-like carbon (DLC). DLC are very similar to diamond: are hardness, chemical inertness, optical transparency. It is much cheaper to produce than diamond[vi]. DLC and nitrogen-doped amorphous diamond-like carbon (N-DLC) have found also many applications as electrodes in creation of new sensitive electrodes[vii].
The main aim of this study was a modification of the carbon derivatives electrodes in order to obtain a very sensitive electrodes in detection of selected nucleobases nucleosides and nucleotides. The modification mainly of BDD or N-DLC surface by electro-polymerization for the detection of selected nucleobases, nucleosides and nucleotides is presented. Mainly melamine films were used for the modification of BDD surface to create sensitive sensors for electrochemical detection of selected analytes. Cyclic voltammetry (CV), were used to characterize obtained monolayer formed on the BDD electrode surface, whereas pulse voltammetry (DPV) were used to determination of limit detection and quantification of different nucleobases, nucleosides and nucleotides.

Nucleobases, nucleosides and nucleotides were detected on the BDD modified electrodes by immobilizing of organic molecules deposited directly on the electrode surface. This work describe the modification of BDD surface electrode by melamine and others organic molecules. This modification gives the possibility of determining of different nucleobases nucleosides and nucleotides at low concentration. The use of modified electrodes gives a significantly higher detection capabilities compared to bare BDD electrodes and convectional electrodes. The authors gratefully acknowledge financial support from the Polish National Science Centre (NCN) under grant no. 2014/14/M/ST5/00715 and 2014/14/E/ST7/00104.

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