Electrochemical fluorescence microscopy in print-and-plate electrodes. As an initial demonstration we evaluated architected electrodes composed of a woodpile structure (Fig. ) via electrochemical fluorescence microscopy in which AQDS was used as a catholyte fluorophore. For this experiment, the AQDS half-cell was prepared with the print-and-plate electrode positioned against a flow field prepared by patterning an array of channels and ribs in PDMS to manipulate the velocity field, and placed on a 3D printed base embedded with a glass cover slide to enable direct visualization via a Output current increased with overpotential. However, each stepwise transition afforded a transient (~ 0.5-1.0 s) current spike before decaying to an equilibrium value. Moreover, this occurred for both increases and decreases in applied voltage, but with opposite polarity in each case. We estimate an RC timescale of ~2 ms for our electrode in aqueous acid, eliminating capacitance as a contributor to this effect. To explain this, we note that the 10 s intervals at OCV offer sufficient time for transport of reduced species away from the electrode surface and the replenishment of unreacted AQDS. Upon repolarization, local regions close to the electrode match the bulk AQDS concentration, leading to transient low resistance until AQDS is again locally depleted and the system returns to steady-state. Upon depolarization, the current spike is negative, suggesting reversed current due to an initially high, transient local concentration of reduced species.