Multiphysics simulations of screen-printed electrodes for electrochemical biosensing.

In this work, we propose a new multiphysics model to simulate the cyclic voltammetry (CV) response of electrochemical biosensors through COMSOL Multiphysics®. The experimental CV response of a commercial screen-printed device is compared with the simulated one when tested with $[Fe(CN)_{6}]^{3-/4-}$. The multiphysics model is based on the device 3D geometrical structure and includes the dominant electrochemical mechanisms occurring in the solution, the metal/solution interface, and the contacts. The CV technique is simulated by including the equivalent circuit of the potentiostat, which is connected to the terminals of the 3D device structure. The proposed model is calibrated through specific experimental measurements and by setting proper material and interface properties, e.g., red/ox diffusivity, electrolyte conductivity, and equilibrium potentials. Then, the model is validated by comparing the CV responses of the real sensors with the simulated ones at different scan rates and redox molecules concentrations. The comparison shows CV responses with differences <10%, confirming the relatively great agreement between simulated and experimental values.