Quantum Dots Capture Movies of 'Talking' Cells

HAYWARD, Calif., March 1 -- Researchers at the Max Planck Institute for Biophysical Chemistry in Goettingen, Germany, have used a new nano-sized imaging tool to capture the first-ever movies of cells transmitting the messages that control genes. The breakthrough is expected to help pharmaceutical companies speed and enhance the process of screening candidate cancer drugs.

In a study published in the February issue of the journal Nature Biotechnology, the researchers reported they used quantum dots developed and manufactured by Hayward-based Quantum Dot Corp. (QDC) to provide prolonged, real-time visualizations in living cells of the signaling mechanisms of the erbB family of receptors, the targets of many cancer drugs. Quantum dots are nano-scale crystals of semiconductor material -- up to ten-billionths of a meter in size -- that glow in several different colors, depending on their size, when excited by a light source such as a laser. The dramatic video clip images mark the first time researchers have been able to see moving images of a cell's basic means of communication with its environment.

Older imaging tools such as fluorescent dyes or polymer spheres fade too quickly -- within a matter of seconds -- to capture lengthy video images of living cells, the scientists wrote. QDC's Qdot conjugates, by contrast, let the researchers see multiple cell elements for minutes or hours at a time. Length of observation time is critical to studying cellular processes, which change rapidly over a span of several minutes. Previous observations using dyes have produced only quick snapshots of the process.

Researchers at Carnegie Mellon University and QDC announced in January they had developed Qdot particles that are compatible with prolonged, noninvasive imaging in living animals with unparalleled brightness, paving the way for direct detection and tracking of molecules within the animal models that are the basis of drug development in almost every major pharmaceutical company.

QDC's Qdot and Qbead products are used by life science researchers as tiny beacons or markers, allowing them to easily see individual genes, nucleic acids, proteins or small molecules. Qdot conjugates work by seeking out and bonding with target materials. Once bonded with a target, each individual Qdot particle emits light. Depending on their size, they can glow in a variety of colors and are up to 1,000 times brighter than fluorescent dyes.

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