Voltammetric H/D Isotope Effects on Redox‐Active Small Molecules Conjugated with DNA Self‐Assembled Monolayers

Abstract

This paper describes the largest H/D kinetic isotope effect (KIE) at room temperature (25 °C) reported to date (kH/kD=2400). In voltammetric measurements with DNA monolayers on gold electrodes, a maximum shift of −400 mV was recorded for the reduction peak potential of 50 μM hexammine cobalt(III) (CoHex) in 10 mM Tris buffer upon replacing water with deuterium oxide in the electrolyte. In subsequent comparative investigations, a much smaller shift (ca. −80 mV) was recorded with daunomycin, whereas no potential shift was recorded with hexammine ruthenium(III) (RuHex). The interactions of RuHex, CoHex, and daunomycin with a mixed self‐assembled monolayer of single‐stranded DNA and 6‐mercapto‐1‐hexanol (ssDNA/MCH SAM) immobilized on gold electrodes were studied by using cyclic and differential‐pulse voltammetry (CV and DPV, respectively). The hydrogen‐bond network within the ssDNA layer seems to amplify the voltammetric H/D isotope effect with CoHex. Voltammetric studies of H/D isotope effects can provide a platform to investigate amplified isotope effects probably not only on DNA layers, but also on proteins and small organic molecules and may be useful for studies of cell proliferation as well as drug testing.

The Direct Electrochemical Detection of Hepatitis B Virus

“…Electrodes containing carbon material, such as glass carbon electrode (GCE), [14] have been used to analyze the electrochemical behavior of the reduction and oxidation of G and A on DNA strand. [27][28][29] Chen [30] and Gu [31] et al have demonstrated that the PGCE has obvious current response, good reproducibility and high stability, which can be used for studying thermal denaturation and acid denaturation dsDNA into ssDNA by cyclic voltammetry (CV) at PGCE. According to our previous study, we have not only achieved the simultaneous acquisition of the electrochemical signals of G and A at PGCE, but also realized the direct electron transfer of G in complex samples.…”

“…Electrochemical methods for the detection and analysis of DNA, purines and their derivatives have been developed rapidly. Electrodes containing carbon material, such as glass carbon electrode (GCE), [14] have been used to analyze the electrochemical behavior of the reduction and oxidation of G and A on DNA strand [27–29] . Chen [30] and Gu [31] et al.…”