For the first time, scientists have succeeded in recording the current in membrane channels of contracting cardiac cells.
Led by Tomaso Zambelli, a lecturer at the Institute of Biomedical Engineering at ETH Zurich, and Hugues Abriel, a professor at the Department of Clinical Research at the University of Bern, the researchers have combined the conventional patch-clamp technique with an atomic force microscope (AFM).
A sensor tip is seated on a cantilever to scan the surface of the microscopic object. Several years ago, the researchers succeeded in producing sensor tips with an internal channel, which allows the computer-controlled injection of molecules into a cell. However, they continued to develop the technique by fitting the micro-injection needle with an electrode to carry out patch-clamp measurements.
Longer measurements and automation possible
With the new method, the micro-needle is controlled by a computer using force measurements from the AFM to hold it at a constant short distance from the cell surface. “This makes the contact between the needle and cell much more stable, which allows us to take measurements over a longer period of time and even test moving cells,” explained Zambelli. For the first time, researchers have thus succeeded in measuring electric potential changes in the ion channels of beating cardiac cells. Zambelli said he could imagine using this as a foundation for the development of an automated method for testing any cell, regardless of its shape or size.