Ion transport across bilayer lipid membranes using a track-etched membrane filter

Bilayer lipid membranes (BLM) are widely employed to study the electrochemical behavior across cell membranes, particularly the ion transport in the presence of hydrophobic ions or ionophores. However, owing to the physical fragility of BLMs, they are readily broken down by external shocks, such as the applications of a potential difference, current, and vibration. Thus, in this study, a facile method for enhancing the physical stability of BLMs was developed using a track-etched membrane (TM). Physically stable BLMs were rapidly fabricated within the apertures of TM by dropping an n-decane solution containing lecithin and cholesterol on TM. Therefore, BLM formation was confirmed by capacitance measurement, and the estimated membrane thickness and mean capacitance were 3.5 +/- 0.4 nm and 0.51 +/- 0.05 mu F cm-2, respectively. The applied membrane potential could be extended to >= 1.5 V, which is approximately 10 times higher than those of conventional BLMs, and the lifetime exceeded 40 min. The applicability of the fabricated BLM was verified by electrochemical measurements during ion transport.