How active a living cell is can be seen by its oxygen consumption. The method for determining this consumption has now been significantly improved by chemists in Bochum. The problem up to now was that the measuring electrode altered the oxygen consumption in the cell's environment much more than the cell itself. "We already found that out twelve years ago," says Prof. Dr. Wolfgang Schuhmann from the Department of Analytical Chemistry at the Ruhr-Universitt. "Now we have finally managed to make the measuring electrode an spectator." Together with his team, he reports in the "International Edition" of the journal "Angewandte Chemie".
Precise positioning of the measuring electrodes
Cells need oxygen for various metabolic processes, for example to break down glucose. To measure its consumption, researchers have to detect very small signals in a large background noise. For this they use scanning electrochemical microscopy, for which they need to position electrodes with a diameter of five micrometres or below at a distance of 200 nanometres from the cell. To this end, the RUB team has developed a special process over the last few years, with which the distance of the electrode to the cell can be precisely controlled.
Making competition to the cells with microelectrodes
Using the electrode, the researchers first generate oxygen in the aqueous environment of the cell, and then they measure how much of this oxygen the cell utilises. For this purpose, they give the electrode a certain potential at the beginning. This has the effect that electrons are extracted from water in the cell environment under formation of oxygen. The cell can use the oxygen for its metabolism; however, at the same time, the microelectrode applied by the researchers competes against it. They change the potential at the electrode so that the reaction reverses: oxygen is now converted to water. The scientists use the electrode to measure
|Contact: Dr. Wolfgang Schuhmann|