Temporal change of AC impedance measured across a free-standing bilayer lipid membrane

摘要

We traced AC impedance across a free-standing bilayer lipid membrane (BLM) through buffer solutions. A BLM was formed over a 24-μm-diameter aperture in a Si/Si_3N_4 chip, whereas AC impedance at 40 Hz was monitored using an LCR meter with a voltage signal of 50 mV_(rms). We conducted six experiments in which BLMs exhibited various lifespans from 1.8 to 18.4 h. We confirmed that AC impedance always decreases continuously, and that BLM lifespan correlates with AC impedance change rates. These results suggest that AC impedance change rate should provide a useful index of BLM stability.