Voltammetric study of the ion-exchange binding of non-electroactive metal cations to DNA-modified surfaces.
We describe a simple electrochemical protocol for studying the ion-exchange binding of non-electroactive ions, specifically mono- and divalent metal cations of biological relevance (Mg(2+), Ca(2+), and K(+)), to DNA-modified surfaces. After incubation in a dilute solution of multiply charged transition metal complex (5.0 microM [Ru(NH(3))(6)]Cl(3)), gold electrodes modified with thiolate-DNA monolayers respond to the presence of these non-electroactive metal cations by producing significant changes in the cyclic voltammograms (i.e., decrease of the integrated charge and shift of formal potential) of the surface-bound redox complex ([Ru(NH(3))(6)](3+)). The divalent cations (particularly Mg(2+)) can be detected at very low concentrations (<10 microM), while the on-set value for K(+) is substantially higher (50 mM). The equilibrium binding constants for Mg(2+) and Ca(2+) to DNA-modified surfaces were calculated.
Su
Li
L
Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, CanadaV5A 1S6.
Sen
Dipankar
D
Yu
Hua-Zhong
HZ
D000818:Animals; D001667:Binding, Competitive; D002412:Cations / Q000032:analysis; D004247:DNA / Q000378:metabolism*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D008670:Metals / Q000378:metabolism*
D002412:Cations; D008670:Metals; D004247:DNA