A closed-loop system for millisecond readout and control of membrane tension

Area of Science:

• Biophysics
• Molecular Biology
• Cell Physiology

Background:

• Force-gated ion channels are crucial for cellular functions and disease understanding.
• Current methods like pressure-clamp electrophysiology do not directly measure membrane tension, the primary stimulus for many such channels.
• Accurate characterization requires precise control and measurement of membrane tension.

Purpose of the Study:

• To develop and validate a novel system for real-time, closed-loop control of membrane tension.
• To enable precise and efficient generation of tension-response relationships for force-gated ion channels.
• To improve the throughput and reduce bias in characterizing channel mechanics.

Main Methods:

• Combined patch-clamp electrophysiology with differential interference contrast microscopy.
• Implemented machine learning object detection for millisecond-scale membrane curvature analysis.
• Developed a dynamic control program for closed-loop membrane tension clamping with automated error propagation.

Main Results:

• The system achieved >93% accuracy and 0.3 mN/m precision in clamping membrane tension.
• Automated analysis reduced bias and increased experimental throughput.
• Demonstrated the system's capability by characterizing TMEM63A, showing half-maximal activation at 5.5 ± 0.1 mN/m.

Conclusions:

• The developed membrane tension clamp system provides precise and efficient control over membrane tension.
• This technology facilitates accurate characterization of force-gated ion channel mechanosensitivity.
• Enables long-duration recordings for low-expression or low-conductance ion channels.