Despite its advantages, the MpD configuration has certain limitations compared to protein junctions with soft top electrodes. The requirement for dense protein coverage for achieving active junctions is more strict for MpD devices than for other common configurations. Even ~50% protein coverage yields a reasonably high percentage of the transport-active junctions of mechanical EGaIn top contact. The quality of the protein layer significantly impacts junction current distribution, which, in turn affects the accuracy of thickness-dependent electron transport characteristics for a given protein. In MpD devices, variations in protein layer thickness cannot be assessed by monitoring impedance-derived junction capacitance of individual isolated protein junctions. The reason is that the micropores are fabricated at the center of large square bottom electrodes, which are entirely coated with a 20 nm layer of insulating alumina, leaving less than 1% of the surface area exposed. This exposed region serves as the active area where the protein layer is added. In the final device configuration, the evaporated top electrode makes contact over a substantial area, effectively forming a junction composed of Au/20 nm Al2O3/Pd-Au. In comparison, the area of the central protein-coated region is negligible (< 1%). Consequently, impedance measurements primarily reflect the capacitive properties of the dielectric alumina, as the low-dielectric protein layer does not significantly influence the overall capacitance of the single micropore device junction.