The 3DP electrode kinetics was studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using 0.01 M PBS with 1 mM [Fe(CN)6] 3-/4-. The scan rates used in CV studies ranged from 10 to 100 mV/s. The EIS analysis was performed under open circuit potential (OCP) in the frequency range from 100,000 to 0.1 Hz, with 10 points per frequency decade and an amplitude of 10 mV. ESA estimation was based on the modified Randles-Sevcik equation for an irreversible, onestep, one-electron reaction , as shown in eq. ( ):