This photo does not show an insect sting under the microscope or a strongly sharpened pencil, but a tiny pipette. Their tip is just two micrometers wide. For comparison: a human hair is 50 micrometers thick. With this pipette, researching ions can specifically promote individual nerve cells and thus activate them.
Nerve cells use the transport of ions to control electrical signals and thus pass on stimuli. They are supported by so -called glial cells – there is an extracellular space between them and the neurons. If the neuron rests, there are many potassium ions inside that load it negatively – outside the nerve cell, a higher concentration of sodium ions loads the exterior positively.
If a sufficiently strong stimulus arrives, sodium channels open in the membrane and sodium ions flow into the interior of the cell, so that the loads reverse. Shortly thereafter, potassium ions flock outwards through potassium channels. This ion transport creates the electrical action potential, fire by nerve cells. Then sodium-potassium pumps restore the original ion gradient. If the nerve cell cannot do this and remain the potassium ions outside the cell, this can lead to malfunctions and, for example, to an epileptic seizure.
It is correspondingly important to be able to carefully examine the ion transport of nerve cells. For this purpose, researchers have previously pumped ion -containing solutions into the extracellular space. However, the liquid disturbs the biochemical balance between the cells. This makes it difficult to recognize whether the activity is caused by the substances in the liquid, the changed pressure or the swirling extracellular liquid.
The pipette, which is shimmering with pink, is supposed to remedy the situation. A research team led by Theresia Arbring Sjöström from the University of Linköping has heated glass tubes and pulled on them until they broke – this is how the fine two micrometers wide.
The special thing about the microscopic laboratory device can also be seen in the photo: what looks like a pencil mine is a membrane made of polymers that the research team put into the top. If the researchers put on a tension to the pipette, migrate ions through the membrane and can thus be transported into the extracellular space between neurons and glial cells without a solution. Then the liquid cannot influence the results.