Resumen:
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The present manuscript describes studies of the electron transfer kinetics at gold electrodes modified by electrostatic self-assemblies of polyethylenimine (PEI), DNA and gold nanoparticles (NP) by Scanning Electrochemical Microscopy (SECM). Two redox mediators of similar structure, ferrocenemethanol (FcOH), and ferrocenecarboxylic acid (FcCOOH) were used to evaluate the effect of the electrode modification on the electron transfer process. For both redox probes, the observed electrochemical behavior was dependent of the charge of the external layer of the self-assembled structure. The corresponding apparent heterogeneous rate constant, k0, was determined. The effect of NP