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Laser beam to track shape shifting bugs?

A new optical trap can grab and scan tiny, agile, shape shifting bugs with the help of a laser beam, opening the way to a better understanding of infectious diseases.

Their miniscule size and rapid movements could not be observed through a conventional microscope. But the light-scanning optical trap helps biophysicists track the bugs’ movement in high-speed 3D images, with excellent contrast and resolution, by measuring imperceptible deflections of the light particles.

Alexander Rohrbach, professor and Matthias Koch from Freiburg University, investigated so-called spiroplasmas or spiral-shaped bugs with a diameter of only 200 nanometers, thick as 1,000 atoms. Since they do not have a cell wall, they can rapidly shape shift and move, the journal Nature Photonics reported.

“This is fascinating in a physical sense, because the movements of the bacteria are connected with extremely small changes in energy that are usually almost impossible to measure,” said Rohrbach, member of the Cluster of Excellence BIOSS, the Centre for Biological Signalling Studies at Freiburg, according to a Freiburg statement.

One important attribute of laser light is that overlapping light particles can increase or decrease the beam’s brightness.

In this way, the researchers were able to take up to 1,000 3D images per second and record the rapid movements of the bug’s in detail.

M. Koch, A. Rohrbach. Object-adapted optical trapping and shape-tracking of energy-switching helical bacteria. Nature Photonics, 2012.

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