Experimental and simulation study of the effect of pipette roughness on giga-seal formation in patch clamping

The effect of pipette tip roughness on giga-seal formation of patch clamp recording has been studied through FEA simulation and patch clamp experiments. FEA simulation results show that the membrane cannot fill up all of the peaks and valleys of a rough pipette tip. As a result in three dimensions the seal between inside and outside is compromised by channels in the order of several nanometres. These channels increase the leakage current between two electrodes, increase the noise and decrease the seal resistance. In contrast focused-ion-beam polished pipettes have very flat tips. Single ion channel currents recorded by FIB polished pipettes show significantly smaller leakage current and noise than the currents recorded by conventional pipettes. Results of FEA simulation are consistent with the results of patch clamp experiments.