Electrochemical and microscopic studies of surface-confined DNA

We have studied the micropatterning and characterization of the organic monolayers using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM), atom force microscopy, and AC impedance, and have determined the electrochemical parameters, i.e., the apparent reaction rate constant (K _f) and the coverage of the electrode surface (θ). CV and SECM experiments demonstrated that the surface of the modified electrode represents an insulating substrate for ferricyanide. Using the high sensitivity of the electron transfer of ferricyanide to the modification of the gold surface with DNA, we selected this reaction as a probe to study the different modification stages at this modified electrode. SECM images obtained from bare, partially modified, and totally modified electrodes showed very good resolution with different topographies or null according to the extent of modification. Based on a comparison with the results of the experiments, a reasonable agreement can be obtained, which means a conjunction of these techniques.