The small and the beautiful
Max Planck researchers use nanotechnology to visualize cellular processes crucial for the development of new cancer drugs
With the help of semiconductor nanocystals, 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 (Nature Biotechnology, February 2004 issue). 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.
In a study published in the February issue of the acclaimed science journal Nature Biotechnology, Diane Lidke and her colleagues present results of their experiments with Quantum Dots. These 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.
"The in vivo measurements reported in our study revealed new insights into cellular processes and interactions that could previously only be studied on fixed (dead) cells," wrote the researchers, led by Dr. Thomas Jovin, chairman of the Max Planck Institute for Biophysical Chemistry’s Department of Molecular Biology. "An understanding of receptor-mediated transduction is essential for rational receptor-targeted cancer therapeutics. Quantitative approaches based on multiple combinations of quantum dots and ligands will be invaluable for such investigations."