DNA-binding studies of complex of Pt(bpy)(pip)]2+ and [Pt(bpy)(hpip)]2+ by electrochemical methods: development of an electrochemical DNA biosensor

Abstract

The electrochemical properties and deoxyribonucleic acid (DNA)-binding affinities of [Pt(bpy)(pip)] 2+ (1) and [Pt(bpy)(hpip)] 2+ (2) in homogeneous solution were studied. These platinum(II) complexes have shown to interact with DNA via intercalation mode. For the cyclic voltammetry (CV) experiments, since 2 leads to a larger decrease in the peak current and more positive shift in the peak potential in comparison to the analogous compound of 1, it could be noted that 2 exhibits higher intercalative binding affinity against DNA. The effect of ionic strength and competitive binding studies in the presence of ethidium bromide (EB) were also investigated by CV. Electrochemical DNA biosensor based on the immobilization of double-stranded DNA (dsDNA) and singlestranded DNA (ssDNA) probe and 1 and 2 onto electrochemically activated glassy carbon (GC) electrode was also achieved. The immobilization of dsDNA and ssDNA probe and hybridization were monitored by differential pulse voltammetry using 1 and 2 as hybridization indicators. It was found that both platinum complexes show larger and more evident electrochemical signals for the hybridized probe dsDNA with respect to ssDNA immobilized on GC electrode. The developed electrochemical DNA biosensor showed good selectivity and analytical performance for the complementary target nucleotide with limit of detection of 1.23×10 −8 and 8.05×10 −9 mol L −1 and limit of quantification of 4.06×10 −7 and 2.66×10 −8 for 1 and 2, respectively.

Effect of the extended π-surface and N-butyl substituents of imidazoles on their reactivity, electrochemical behaviours and biological interactions of corresponding Pt(ii)-CNC carbene complexes: exploring DFT and docking interactions

“…It is known that the electron-donating groups on the ligand increase the electron density in the imidazole rings of the coordinated ligands, making reduction more difficult. 57 In other words, the complexes with the poor p-accepting property and more electron-rich ligands have more negative reduction potentials appliers E pc values at higher negative values i.e., Pt(II), leading to lower reactivity. Consequently, PtL 2 's reduction potential appears at a more negative value (À1.21 V) since it bears a bis-NHC chelating ligand with extended p-conjugation when compared with PtL 1 (À1.07 V), which lowers the reactivity.…”

“…It is known that the electron-donating groups on the ligand increase the electron density in the imidazole rings of the coordinated ligands, making reduction more difficult. 57 In other words, the complexes with the poor π-accepting property and more electron-rich ligands have more negative reduction potentials appliers E pc values at higher negative values i.e. , Pt( ii ), leading to lower reactivity.…”