By Roland Piquepaille
German researchers at the Max Planck Institute are using nanotechnology to take movies of cellular processes. They used Quantum Dots (or QDs) as nano-sized markers to visualize DNA sequences. This new approach is crucial for the development of new cancer drugs.With the help of semiconductor nanocrystals, researchers at the Max Planck Institute for Biophysical Chemistry in Goettingen, Germany, and their collaborators at the Universidad de Buenos Aires are now able to capture movies of signal transmission processes involved in the control of gene expression.
This breakthrough is expected to speed up the development of new cancer-curing drugs. Quantum Dots (or QDs) can be used as nano-sized markers to visualize DNA sequences, proteins, or other molecules and track them in the cell. The complexes consisting of QDs and specific ligands, in this case a cellular growth factor, bind to target molecules such as receptors on the cell surface. The QDs glow in a variety of colors and are up to 1000 times brighter than conventional fluorescent dyes.
These Quantum Dots are nano-sized semiconductor crystals a mere ten millionth of a millimeter in diameter that fluoresce in several different colors upon excitation with a laser source. These crystals enabled the researchers to deliver real-time video-clips of signal transmission in the so-called erbB receptor family, important targets for many anti-tumor drugs such as antibodies directed against breast cancer. Among other processes, the movies capture the uptake and subsequent redistribution of the receptor-growth factor complexes into the interior of the cell.
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Here are cells expressing the epidermal growth factor receptor erbB1 - green fluorescent protein eGFP (green) fusion protein after a short incubation with complexes of epidermal growth factor EGF and Quantum Dots (QD, red) nanoparticles. (Credit for image and legend: Max Planck Institute for Biophysical Chemistry). |
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And here are some isolated shots from a movie showing live cells activation (Credit: Max Planck Institute for Biophysical Chemistry). |
The research work, "Quantum dot ligands provide new insights into erbB/HER receptor -- mediated signal transduction," has been published by Nature Biotechnology in its February 2004 issue. You can read the abstract and watch movies here.
You also can read the full report (PDF format, 6 pages, 1.8 MB).
Sources: Max Planck Institute for Biophysical Chemistry, March 12, 2004, via EurekAlert!; Nature Biotechnology, February 2004, Vol. 22, Issue 2, pp 198-203
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