May 18, 2009 --
Researchers at the University of Gothenburg, Sweden, have developed a
new method to study single cells while exposing them to controlled
environmental changes. The unique method, where a set of laser tweezers
move the cell around in a microscopic channel system, allows the
researchers to study how single cells react to stress induced by a
constantly changing environment.
on how cells react to changes in their environment, such as reduced
availability of nutrients, have traditionally used cultures consisting
of millions of cells. While such studies show how cells on average
react to a new environment, they say nothing about individual
variation, for example how quickly a single cell responds.
Catches and moves cells
Researcher Emma Eriksson and her
colleagues at the Department of Physics, University of Gothenburg,
Sweden, developed a method where laser tweezers are used to catch a
cell the size of about one micrometer, or 0.001 of a mm, and then move
the cell between different environments. Placing the cell in a system
of channels made of silicone, in which each channel is finer than a
human hair, enables the researchers to add and remove substances so
that the environment surrounding a single cell changes in a split
second - while at the same time watching the reactions through a
The channels in the so-called
microfluidic system can be likened to tiny water pipes. In a channel, a
single cell can be exposed to tests and various substances for very
exact time periods, which enables the researchers to repeatedly add and
remove a substance to see how it affects the behaviour of the cell.
This new method gives researchers information that would not be
possible to obtain with traditional methods.
How cells survive
its first stage, the new method has been tested on yeast cells. One of
the cells' proteins was tagged with a green fluorescent protein (GFP),
enabling researchers to trace the movements of the protein within the
cell while it adjusts to a new environment.
'The method can be
used to reveal how a cell reacts to stress induced by a change in its
environment. The information gained from this may eventually lead to a
better understanding of how cells work and what they do to stay alive
and healthy in a constantly changing environment', says Eriksson.
University of Gothenburg, Sweden