Double Elimination Voltammetry of Short Oligonucleotides

Abstract

In connection with adsorptive stripping (AdS) technique, elimination voltammetry with linear scan (EVLS) in double mode was successfully employed in the analysis of homo-ODNs: 5'-AAA AAA AAA-3' (dA 9 ) and 5'-CCC CCC CCC-3' (dC 9 ), and hetero-ODNs: 5'-CCC AAA CCC-3' (H3), 5'-CAC CAC CAC-3' (H4), and 5'-ACC CAC CCA-3' (H9) on hanging mercury drop electrode (HMDE). Analogously to single EVLS function E4 (conserving the diffusion current I d and eliminating kinetic and charging currents I k , I c ) for the electroactive substance adsorbed, the double EVLS function E4 yields well readable peak-counterpeaks of reducible nucleic acid bases (adenine A and cytosine C). In comparison with single EVLS these peak-counterpeaks are higher by more than one order of magnitude (twenty times for dA 9 , fourteen times for dC 9 , from eight to sixteen times for hetero-ODNs). The increase of reduction signals with higher resolution was also observed using other two EVLS functions in double mode, the functions E5 eliminating I c and I d , but conserving I k and E6 eliminating I d and I k , but conserving I c . The amplifications of double / single EVLS signals of A and C range from 3.4 to 8.4, and from 3.1 to 8.3 for E5 and E6, respectively. It was proved that AdS double EVLS offers a new, fast, simple and inexpensive electroanalytical tool, which can be considered as a device not only for very good resolution of A and C in ODNs, but also for sensitive detection of changes in the primary structure of nucleic acid bases in ODN chains, depending on experimental conditions, such as pH, temperature, and time and potential of accumulation.

Electrochemistry of Nucleic Acids

“…AdS in combination with elimination voltammetry with linear scan (EVLS) was shown to resolve overlapping reduction peaks of C and A by eliminating kinetic and charging currents, while conserving the diffusion current. EVLS was applied for studies involving not only short ODNs, − but also chromosomal DNAs . A heptamer d­(GCGAAGC), forming a stable hairpin-like structure, was also studied by EVLS and was detected down to 2 nM concentration .…”

G-quadruplex-based structural transitions in 15-mer DNA oligonucleotides varying in lengths of internal oligo(dG) stretches detected by voltammetric techniques

“…Several papers have been devoted to hairpinforming ODNs [12] and studies focused on DNA-mediated charge transfer [13]. Results of some quite recent studies showed that the behavior of ODNs at the mercury and amalgam electrodes is strongly dependent on their nucleobase composition (especially when a specific nucleobase or nucleobase type strongly prevails) [14] and nucleotide sequence (especially when it is non-random) [12,[15][16][17][18]. Grich ODNs have recently been studied by voltammetric methods at a glassy-carbon electrode in combination with atomic-force microscopy [19][20][21].…”

Voltammetric Study of Aminopurines on Pencil Graphite Electrode in the Presence of Copper Ions

“…The shape of this signal was calculated theoretically and the theoretical ratio of peak to peak-counterpeak height corresponds to 0.4097 [29]. This fact initiated the application of the adsorptive transfer stripping (AdS) technique together with EVLS for the analysis of oligonucleotides, including hairpins [27,30,31]. It was found that AdS EVLS was able to separate overlapped voltammetric peaks and to indicate quickly the adsorbed state of depolarizers.…”