Patch clamp

The patch-clamp technique is an electrophysiological tool to study the ion channel behavior of excitable cells like neurons and muscle fibers.

The patch-clamp setup includes a glass micropipette placed against a small area of cell membrane containing one or more ion channels. It consists of an electrolyte solution and a chlorinated silver electrode to measure voltages and currents.

When a small suction is applied, the ‘membrane patch' gets tightly sealed against the pipette tip.

This omega-shaped area of the membrane, called the gigaohm seal, is electrically isolated, ensuring the ions flowing through the channel pass only into the pipette.

The recording electrode within the micropipette is connected to a highly sensitive amplifier that amplifies current or voltage fluctuations resulting from the movement of ions through the ion channels, allowing for the measurement of generated electrical signals.

In the ‘voltage clamp', the voltage is set at a particular value, and the resulting changes in current flow are measured. Alternatively, the current can be clamped to a set value, and the voltage variation across the membrane can be measured.