Size-Dependent Interactions between Au Nanoparticles and DNA in Electrochemical Oxidation by Metal Complexes

作者：Wu Qiong; Kang Hee Kyung; Oh Byul Nim; Kim Jinheung^*

来源：Journal of Physical Chemistry C, 2012, 116(14): 8020-8026.

DOI：10.1021/jp209470g

Single-stranded oligonucleotides (ssDNA) contaming guanine bases in their sequences were adsorbed onto gold nanoparticles (AuNPs) by electrostatic interaction. Cyclic voltammetry of Ru(bpy)(3)(2+) in the presence of the ssDNA-AuNP complex resulted in an enhanced anodic current due to the oxidation of the guanine bases of DNA. The current obtained with ssDNA-AuNP appeared Much smaller than the corresponding ssDNA alone. This current reduction was due to the decrease in solvent accessibility of the guanines in ssDNA immobilized to AuNPs. A progressive decrease in the current was observed in the titration of AuNPs to ssDNA, and a minimum current was eventually obtained, indicating complete binding of ssDNA. The size dependences of AuNPs on the interaction between ssDNA and AuNP were also studied, and the ssDNA adsorbed to 5 nm AuNPs was more solvent-accessible for the Ru mediator than 13 and 30 nm AuNPs.

• 出版日期2012-4-12