Highly sensitive electrochemiluminescence displacement method for the study of DNA/small molecule binding interactions

Abstract

a b s t r a c tNon-covalent binding interactions of small molecules with DNA play important roles in regulating gene expression and gene function. In this work, a highly sensitive electrochemiluminescence (ECL) displacement method has been developed to investigate such interactions, particularly for weak DNA binders. This ECL method relies on a double-stranded DNA film deposited on an indium tin oxide electrode (ITO) surface by layer-by-layer self-assembly. A DNA intercalator, [Ru(bpy) 2 (dppz)] 2+ (bpy = 2,2 -bipyridine, dppz = dipyrido[3,2-a:2 3 -c]phenazine), is employed as the ECL signal indicator. If a test compound competes with the indicator for the same binding sites in DNA, it would displace the indicator from the film and reduce ECL signal. The new method was validated by measuring five well-known DNA-binding organic molecules including quinacrine, H33258, thiazole orange, ethidium bromide and 4,6-diamidine-2-phenylindole dihydrochloride. Due to high ECL sensitivity, only 0.4 mol L −1 [Ru(bpy) 2 (dppz)] 2+ was needed in the ECL displacement measurement, which is about 75-fold less than the concentration in the voltammetric measurement. The lowered concentration permitted direct measurement of IC 50 values of eight hydroxylated polycyclic aromatic hydrocarbons in their ECL displacement curves and subsequent calculation of their binding constants with DNA. The ECL displacement method is particularly useful for investigating weak DNA binders with limited aqueous solubility.

Ruthenium Polypyridine Complexes Combined with Oligonucleotides for Bioanalysis: A Review

“…Due to its high sensitivity and selectivity, detection of DNA using ECL method has drawn much attention from all over the world [72,75,76,100,156,172,173,174,175,176,177,178,179,180]. Table 1 summarizes the performances of selected ECL detection approaches listed in this review.…”

Electrochemical Study of Novel 3-(6-bromo-2-oxo-2H-chromen-3yl-amino)-2-(3-chloro-phenyl)-thiazolidine-4-one by Cyclic Voltammetry and its DNA Interaction Study by UV-Visible Spectroscopy

“…There has been considerable interest in the binding studies of small molecules with DNA owing to their diverse applications 10 . DNA is the pharmacological target of many drugs that are currently in clinical use or are in advanced clinical trials [11][12] . DNA has been the recognition and characterization site for the interaction of small molecules as they yield effective information for the development of therapeutic agents for controlling gene expressions [13][14] .…”