In the course of a busy day, sometimes it seems like not a lot can be accomplished in 40 minutes. But French researchers found that in 40 minutes you might be able to gather the beginnings of what could result in life-saving drugs.

The scientists used Hayward, Calif.-based Quantum Dot Corp.'s technology, which is an imaging tool the size of individual molecules. The company said it was the first time researchers have been able to track single-molecule properties in living cells for extended periods within a single experiment.

"This significant study again validates the importance of quantum dots for biomolecular imaging and drug development," said Carol Lou, president of Quantum Dot (QDC).

In a study published in the Oct. 17, 2003, issue of Science, the French researchers reported that they used quantum dots, or Qdots, to track the movements of individual glycine receptor molecules in the membranes of living cells for as long as 40 minutes, compared to about five seconds with other technologies. Receptors, such as the glycine receptor molecule, are a "critical target" for scientists who develop new drugs for diseases, including neurological disorders such as epilepsy and depression, the company said.

But what exactly are Qdots? They are nanoscale crystals of semiconductor material that glow, or fluoresce, when excited by a light source such as a laser, QDC said. They are used by life science researchers as tiny beacons, or markers, allowing scientists to see individual genes, nucleic acids, proteins or small molecules. Qdot conjugates seek out and bond with target materials, the company said, noting that depending on their size, they can glow in various colors and are up to 1,000 times brighter than fluorescent dyes.

The older technologies, such as those fluorescent dyes or polymer spheres, the scientists reported, are either too unstable or too big to effectively perform single-molecule tracking.

"Length of observation time is critical to studying cellular processes, which change rapidly over a span of several minutes," the company said.

By contrast, the scientists noted, Qdot conjugates produced photo resolutions up to eight times more detailed than the older imaging tools.

QDC Vice President of Business Development, Andy Watson, said the reason the Qdot technology is an improvement is that with older technologies you have "photo bleaching."

"[Most people are] familiar with photo bleaching, because the paint on your old Datsun would fade, but the new Nissans are great because they don't fade at all in the sun," he said. "There's a similar effect going on here, except it's much more pronounced. Then, imagine that you can only see something when it's actually bright and shining. When it becomes dull and dim, you can't see it anymore."

Watson said that the company's customers are biotechnology and pharmaceutical companies, academicians and other researchers. And while the French researchers looked at neurological diseases, Watson said that "a range of [QDC's] other customers also benefit from that property, from the simplicity and ease that it gives them and also from the perspective of increased sensitivity it can give them in a range of other applications."

The technology itself was licensed from the Massachusetts Institute of Technology in Cambridge and the University of California at Berkeley. While QDC was formed in 1998, the company did not actually have products to offer until November 2002.

"We licensed the technology from MIT and Berkeley in a format that we thought was a lot more advanced than it really was, and so it's taken us a long time, really, to take what we [received] and make it into something that does give real significant benefit to our users," Watson said.

Prior to offering something commercially, the company was in a range of alpha and beta tests with customers and collaborators.

And there are other uses coming, he said.

"You'll see some studies coming up," Watson said. "People are using them in pathology, tissue detection to allow a diagnosis of different diseases. That's one of the applications you'll see coming up via a corporate partner."

Researchers at Cornell University in Ithaca, N.Y. and QDC reported in May that they had used Qdot particles to see into the tissues of living mice, a study that was also published in Science.