## 3 Results and Discussion
### Galvanodynamic Deposition  
As the previous experiments show, EPD should be efficiently promoted by applying high current (or potential) values at the deposition electrode while minimizing the concurrent and undesired solvent discharge causing gas bubbling on top of it. Operating under the hypothesis that the kinetics of the two concurrent processes were almost different, a galvanodynamic electrophoretic deposition technique was investigated. In this approach, a pulsed current sequence (see Scheme 1) was applied at the deposition electrode while varying the maximal current \(I\) and the pulse duty cycle by varying \(t_{1}\) and \(t_{2}\). Figure 2: Potential attained at the deposition electrode for each constant current application in galvanostatic experiments, as shown in Figure S1; for each experiment, the potential was sampled at 120 s. Inset: typical chronopotentiometric curve observed for galvanostatic deposition experiments; current density: 1 mA/cm\({}^{2}\). Figure 3 shows typical chronopotentiometric curves at the deposition electrode due to the application of current pulse sequences in a fixed duty cycle while varying \(I\), as described in the figure. As can be seen, whatever the value of \(I\), the expected potential increase was observed with the application of current pulse. Notably, a hysteresis effect was also evident, wherein the maximal potential reached by the deposition electrode increased with the increase in the time of the current pulse sequence application: due to the formation of platinum oxides on the electrode surface, this last effect was particularly revealing since it is well known that water discharge (and hence gas evolution at the electrode) is indeed mediated by the formation of metal oxides on the electrode surface. As evident from Figure 3, increasing \(I\) in the current pulse perturbation at the electrode promotes higher oxide formation on the surface of the electrode and hence dioxygen evolution. In particular, lower \(I\) values ensured lower, if any, water discharge, but electrodeposition was practically absent: these experimental conditions evidently do not promote any significant electrophoretic movements of proteins and hence any in situ co-crosslinking, even when extending the experiment for a very long time. Oppositely, higher \(I\) values promoted an evident and significant degree of protein deposition, but the water discharge was so intense that it destroyed any deposits. A \(I\) value of 2 mA/cm\({}^{2}\) was an optimal current density value and a good compromise between efficient protein deposition and lower gas evolution at the electrode surface. Regarding the duty cycle optimization of the current pulse sequence and its frequency, Figure 4 shows typical chronopotentiometric curves at the deposition electrode due to the application of a current pulse sequence at a fixed maximal current \(I\) (2 mA/cm\({}^{2}\)) while varying \(t_{1}\) and \(t_{2}\), as described in the figure. As can be seen, an increase in the duty cycle of the pulse sequence, i.e., increasing \(t_{2}\) while keeping \(t_{1}+t_{2}\) constant, was equivalent to an increase in \(I\), as observed in the previous experiments; in fact, the deposition electrode reached higher potential values (suggesting intense kinetics of platinum oxide formation on its surface), and dioxygen evolution was more evident, destroying any formation of the protein deposit. On the contrary, lower duty cycle values permitted the formation of a compact protein layer even if at a lower rate. Further, increasing the frequency of the current pulse sequence by lowering both \(t_{1}\) and \(t_{2}\) was not effective for protein deposition: in fact, due to the inherent inertia of the electrophoresis of big molecules like proteins, electrophoresis could be considered negligible at the higher frequency values.