Electrochemistry of phenothiazine and methylviologen biosensor electron-transfer mediators at nanoelectrode ensembles

Voltammetry of redox analytes at trace concentrations with nanoelectrode ensembles

“…Other characteristics of the CVs were comparable with previous reports [3,8]; in particular, the capacitive currents were significantly lower than those observed at macro-electrodes of the same geometric area.…”

“…2b) in solutions containing (sub)micromolar concentrations of FA + . At variance with the CV case [3,8], DPV peak currents (faradaic currents) at the NEE are slightly lower than those at the Au-macro. This is related to the smaller time scale of the DPV experiments, this parameter being equal to the pulse time for such a technique (namely, 50 ms for DPV in the experimental conditions of Fig.…”

“…Experiments showed that for f values between 10 −3 and 10 −2 detection limits at NEEs were 2-3 orders of magnitude lower than with conventional electrodes [3,8,10]. However, NEEs of rather large geometric area (typically 0.07 cm 2 ) were used in these experiments.…”

“…The nanoelectrode ensembles were prepared using the electroless plating procedure described previously [3] and following modifications [8].…”

“…The theory developed by Amatore et al [7] for electrodes with partially blocked surface has been applied successfully for measuring heterogeneous electron transfer rate constants at NEEs [3,8]. Cyclic voltammetric responses at regular microdisc electrode arrays were also simulated recently [9], showing that there is a minimum number of elements in the array above which the normalized current response become independent on the size of the array.…”