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) (Ho³⁺) on a glassy carbon electrode (GCE) and its interaction with double-stranded DNA. The interaction between DNA and Ho³⁺ was investigated for the first time using cyclic voltammetry and differential pulse voltammetry. The electrochemical behavior of Ho³⁺ 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 Ho³⁺ to DNA. Our findings demonstrate that, at pH 7.2, specific DNA bases and phosphate groups can interact with Ho³⁺ ions. Moreover, electrochemical measurements suggest that Ho³⁺ ions bind to DNA via a groove binding mode, with a calculated binding ratio of 1:1 between Ho³⁺ and DNA. Notably, under optimal conditions, an increase in the amount of DNA leads to a significant reduction in the current intensity of Ho³⁺ ions.