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We report a straightforward and reproducible electrochemical approach to develop polydopamine-ethanolamine (ePDA-ETA) films to be used as immunosensing interfaces. ETA is strongly attached to polydopamine films during the potentiodynamic electropolymerization of dopamine. The great advantage of the electrochemical methods is to generate the oxidized species (quinones), which can readily react with ETA amine groups present in solution, with the subsequent incorporation of this molecule in the polymer. The presence of ETA and its effect on the electrosynthesis of polydopamine was accessed by cyclic voltammetry, ellipsometry, atomic force microscopy, FTIR and X-ray photoelectron spectroscopy. The adhesive and biocompatible films enable a facile protein linkage, are resilient to flow assays, and display intrinsic anti-fouling properties to block non-specific protein interactions, as monitored by real-time surface plasmon resonance, and confirmed by ellipsometry. Immunoglobulin G (IgG) and Anti-IgG were used in this work as model proteins for the affinity sensor. By using the one-step methodology (ePDA-ETA), the lower amount of immobilized biorecognition element, IgG, compared to that deposited on ePDA or on ETA post-modified film (ePDA/ETA), allied to the presence of ETA, improved the antibody-antigen affinity interaction. The great potential of the developed platform is its versatility to be used with any target biorecognition molecules, allowing both optical and electrochemical detection.

ZnO nanorod arrays have been grown by potentiostatic pulse electrodeposition between a reduction potential and a "rest" potential. The effect of the duty cycle and pulse frequency as well as the heat-treatment in air on the properties of the electrodeposits has been studied. Surface morphology, structural, optical and electrical properties were evaluated. Absorption spectra reveal a high energy bandgap Burstein-Moss shift for the as-grown nanorods, in line with the donor density (1.1 × 10 19 and 9.5 × 10 19 cm −3 ) determined from electrochemical impedance spectroscopy. After annealing, the carrier concentration decreases to 10 17 -10 18 cm −3 , which is accompanied by an increase of the optical quality of the samples, assessed by the narrowing of the full width at half maximum of the near band edge recombination and steeper absorption at ∼3.3 eV. The donor density and the flatband potential are dependent of the applied duty cycle and pulse frequency. All the analyzed samples evidence deep broad emission bands in the visible region, whose intensity is enhanced after annealing. The defect luminescence is due to an overlap of emitting centers in the red, yellow and green spectral regions, as evidenced and discussed by comparing the steady-state and transient spectroscopies.