Electrostatic interactions of redox cations with surface-immobilized and solution DNA.
Association constants for ruthenium(III) hexaamine and cobalt(III) tris(2,2'-bipyridine) with solution and surface-immobilized DNA were determined. The interaction of the cationic redox molecules with calf thymus DNA was monitored via normal pulse voltammetry with analysis of the mass-transfer limited current assuming a discrete binding-site model. Single-stranded DNA was immobilized on gold via self-assembly of a 5' hexanethiol linker. Double-stranded surface-immobilized DNA was produced by hybridization of a complementary target to surface-immobilized single strands. The interaction between the metal complexes and surface-immobilized DNA was determined using chronocoulometry to construct adsorption isotherms. The measured binding constants for the cationic redox molecules with solution, surface-immobilized single-stranded, and double-stranded DNA are well-correlated, even as a function of ionic strength. The agreement between the determined association constants for the surface-immobilized and solution DNA indicates the potential utility of DNA-derivatized electrodes for examination of small molecule interactions with nucleic acids.
Steel
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Process Sensing Group, NIST, Gaithersburg, Maryland 20899, USA.
Herne
T M
TM
Tarlov
M J
MJ
D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry; D002412:Cations / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D017975:Ruthenium Compounds / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D055672:Static Electricity
D002412:Cations; D009942:Organometallic Compounds; D017975:Ruthenium Compounds; D012996:Solutions; C119791:tris(2,2'-bipyridyl)cobalt(III); C031584:hexammineruthenium; D015082:2,2'-Dipyridyl; D004247:DNA