Fig. 4: Impact of flow channel thickness, redox species, and electrode materials on device performance.

a Effect of channel thickness on current response under 1 V; b Optimizing the flow rate and concentration of the redox solution on the current response under 1 V (the maximum flow rate and pressure limit for the redox channel of microfluidics are 5 mL/min and 372 mBar, respectively); c Current response of redox iontophoresis with different electrode materials under 1 V