Nanoparticles-Modified Glassy Carbon Electrode in Microflow Arrangement for Analysis of Nucleic Acids Containing Repeated Adenine Sequences

Abstract

In this study we have used the microfluidic tool with a glassy carbon electrode modified with CuS nanoparticles for adenine determination using differential pulse voltammetry.  The optimal parameters for adenine detection were the initial potential 0 V, and potential 1.8 V, step potential 0.015 V, amplitude 0.1 V, scan rate 0.07 V/s, pulse period 200 s and equilibration time 20 s. Prior the analysis the glassy carbon electrode (GCE) was modified by CuS nanoparticles. The optimal conditions for GCE modification were estimated as deposition potential –0.4 V for 200 s in the presence of 0.1M  KCl solution containing 200 mM CuS nanoparticles. Subsequently the cyclic voltammetry was carried out in 0.1M NaOH solution repetitively for 20 cycles under potentials ranging from –0.5 to 0.3 V at 100 mV/s. The limit of detection (3 S/N) was estimated as 70 pg/cell volume. The method was applied for the analysis of oligonucleotides containing repetitions of adenine. We have found the dependence between number of adenine molecules in oligonucleotide and the electrochemical signal. This method might be useful for analysis of DNA sequences.