Electrophysiological measurement of ion channels on plasma/organelle membranes using an on-chip lipid bilayer system

Abstract

Ion channels are located in plasma membranes as well as on mitochondrial, lysosomal, and endoplasmic reticulum membranes. They play a critical role in physiology and drug targeting. It is particularly challenging to measure the current mediated by ion channels in the lysosomal and the endoplasmic reticulum membranes using the conventional patch clamp method. In this study, we show that our proposed device is applicable for an electrophysiological measurement of various types of ion channel in plasma and organelle membranes. We designed an on-chip device that can form multiple electrical contacts with a measurement system when placed on a mount system. Using crude cell membranes containing ion channels extracted from cultured cells without detergents, we detected open/close signals of the hERG, TRPV1, and NMDA channels on plasma membranes, those of the TRPML1 channels on lysosomal membranes, and open/close signals of the RyR channels on SR membranes. This method will provide a highly versatile drug screening system for ion channels expressed by various cell membranes, including plasma, SR, mitochondrial, Golgi, and lysosomal membranes.

Parallel Recordings of Transmembrane hERG Channel Currents Based on Solvent-Free Lipid Bilayer Microarray

“…As shown in Figure 6 , channel activities with a single-channel conductance of ~10 pS were observed in the fourth cycle of the voltage protocol. This conductance level was similar to that reported for the hERG channels in a BLM reconstitution system (10–14 pS) [ 30 , 54 , 55 ] and the hERG channels expressed in Xenopus oocytes [ 44 ]. Figure 7 shows examples of the hERG channel currents recorded from multiple wells with numbers 1, 13, and 16.…”

Highly sensitive VOC detectors using insect olfactory receptors reconstituted into lipid bilayers

“…The device was wired to a mounting system connected to a patch clamp amplifier ( 31 ). To form a lipid bilayer, 4 μl of n -decane containing DOPC:DOPE (20 mg/ml) at a 3:1 (w/w) ratio was loaded into the wells with no microslits.…”

Formation and function of bacterial outer membrane proteins- incorporated liposomes using an in vitro translation system

“…To con rm the formation of nanopores of OmpG into the nano-sized liposomes, the current signals of the OmpG were measured by a BLM chip that was connected to a patch clamp ampli er 20 . The BLM was formed using the droplet contact method 21 .…”