Study on the electrochemical and spectroscopic characteristics of holmium ion and its interaction with DNA.

Metal ion-DNA interactions play a crucial role in modulating the structure and function of genetic material in the natural environment. In this study, we report on the favorable electrochemical activity of holmium(III) (Ho) on a glassy carbon electrode (GCE) and its interaction with double-stranded DNA. The interaction between DNA and Ho was investigated for the first time using cyclic voltammetry and differential pulse voltammetry. The electrochemical behavior of Ho ions on a GCE exhibited a reversible electron transfer process, indicative of its redox activity. A linear correlation between the peak current and the square root of the scan rate was observed, suggesting a diffusion-controlled kinetic regime for the electrochemical process. Additionally, fluorescence and absorption spectroscopy were employed to confirm the binding of Ho to DNA. Our findings demonstrate that, at pH 7.2, specific DNA bases and phosphate groups can interact with Ho ions. Moreover, electrochemical measurements suggest that Ho ions bind to DNA via a groove binding mode, with a calculated binding ratio of 1:1 between Ho and DNA. Notably, under optimal conditions, an increase in the amount of DNA leads to a significant reduction in the current intensity of Ho ions.