Development of an automated system to measure ion channel currents using a surface-modified gold probe

Minako Hirano,Masahisa Tomita,Toru Ide,Chikako Takahashi,Nobuyuki Kawashima

doi:10.1038/s41598-021-97237-z

Minako Hirano, Masahisa Tomita + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-97237-z

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Abstract

Artificial lipid bilayer single-channel recording technique has been employed to determine the biophysical and pharmacological properties of various ion channels. However, its measurement efficiency is very low, as it requires two time-consuming processes: preparation of lipid bilayer membranes and incorporation of ion channels into the membranes. In order to address these problems, we previously developed a technique based on hydrophilically modified gold probes on which are immobilized ion channels that can be promptly incorporated into the bilayer membrane at the same time as the membrane is formed on the probes’ hydrophilic area. Here, we improved further this technique by optimizing the gold probe and developed an automated channel current measurement system. We found that use of probes with rounded tips enhanced the efficiency of channel current measurements, and introducing a hydrophobic area on the probe surface, beside the hydrophilic one, further increased measurement efficiency by boosting membrane stability. Moreover, we developed an automated measurement system using the optimized probes; it enabled us to automatically measure channel currents and analyze the effects of a blocker on channel activity. Our study will contribute to the development of high-throughput devices to identify drug candidates affecting ion channel activity.

Highlights

Artificial lipid bilayer single-channel recording technique has been employed to determine the biophysical and pharmacological properties of various ion channels
Disfunction of the voltage-gated N a+ channels causes epilepsy or arrhythmia[5,6,7]; malfunction of the CFTR channel leads to cystic fibrosis, a known fatal disease[8,9]; and the activity of the P2X4 channel is associated to neuropathic p ain[10,11]
By using gel beads or a gold probe covered with polyethylene glycol (PEG), on which ion channels are immobilized, ion channels are promptly incorporated into the bilayer membranes that are made on the beads or the probe by contacting two lipid monolayers; one such monolayer is formed on the gel bead or the probe whereas the other is formed at the interface between a lipid solution and an aqueous solution (Fig. 1)

Summary

Introduction

Artificial lipid bilayer single-channel recording technique has been employed to determine the biophysical and pharmacological properties of various ion channels. Artificial lipid bilayer recording is a technique that can be employed to measure ion channel activities electrophysiologically[13].

Results

Conclusion