Efficient single-channel current measurements of the human BK channel using a liposome-immobilized gold probe.

The human BK channel (hBK) is an essential membrane protein that regulates various biological functions, and its dysfunction leads to serious diseases. Understanding the biophysical properties of hBK channels is crucial for drug development. Artificial lipid bilayer recording is used to measure biophysical properties at the single-channel level. However, this technique is time-consuming and complicated; thus, its measurement efficiency is very low. Previously, we developed a novel technique to improve the measurement efficiency by rapidly forming lipid bilayer membranes and incorporating ion channels into the membrane using a hydrophilically modified gold probe. To further improve our technique for application to the hBK channel, we combined it using the gold probe with a liposome fusion method. Using a probe on which liposomes containing hBK channels were immobilized, the channels were efficiently incorporated into the lipid bilayer membrane, and the measured channel currents showed the current characteristics of the hBK channel. This technique will be useful for the efficient measurements of the channel properties of hBK and other biologically important channels.