September 1, 1999

 
 
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A new type of biological probe developed by Berkeley Lab scientists has been commercially licensed by a start-up firm in Palo Alto. Last fall, Lab researchers announced they had found a way to use nanometer-sized crystals of semiconductors, such as cadmium selenide and cadmium sulfide, as highly effective fluorescent probes for labeling and measuring biological molecules. Now, through the Lab's Technology Transfer Department, the technology has been exclusively licensed to the Quantum Dot Corporation for use in biological assays.
IN THIS CROSS-SECTION OF MOUSE CELLS LABELED WITH TWO DIFFERENT SIZES OF SEMICONDUCTOR NANOCRYSTALS, NUCLEI SHOW UP AS GREEN AND ACTIN FIBERS SHOW UP AS RED UNDER THE SAME ILLUMINATION

The firm, which started up expressly to develop and commercialize this technology, also has a nonexclusive license to manufacture semiconducting nanocrystals as molecular-scale LEDs (light-emitting diodes) and transistors.

As part of the licensing transaction, the University of California, through Berkeley Lab, has been issued shares in the Quantum Dot Corporation as part of the licensing fees.

"Taking equity is a win-win situation for the company and the Lab," says Tech Transfer's Viviana Wolinsky, who negotiated the deal. "It allows Quantum Dot to devote more of its initial capital to moving the technology forward, and gives Berkeley Lab the prospect of significant financial returns."

In addition to the licensing agreement with Berkeley Lab, the Quantum Dot Corporation also sought and licensed complimentary nanocrystal technology from MIT and the University of Melbourne.

Semiconductor nanocrystal fluorescent probes (dubbed "QdotsŪ" by the Quantum Dot Corporation) offer a distinct advantage over conventional dye-molecules in that they emit multiple colors of light, which means they can be used to label and measure several biological molecules simultaneously. The unique optical properties of these semiconductor nanocrystals also hint at the possibility of observing changes that take place in labeled biological systems, such as living cells, over a period of time.

Development of the original semiconductor nanocrystal fluorescent probe technology was led by Paul Alivisatos and Shimon Weiss. Alivisatos is an expert in the production by chemical means of semiconductor nanocrystals, simple inorganic solids consisting of a hundred to a hundred thousand atoms. He holds a joint appointment as a senior staff scientist with Berkeley Lab's Materials Sciences Division (MSD) and as a professor of chemistry at UC Berkeley. Weiss, a staff scientist with MSD, is an authority on single molecule fluorescence and spectroscopy.

"The development of semiconductor nanocrystals for biological labeling gives biologists an entire new class of fluorescent probes for which no small organic molecule equivalent exists," said Weiss at the time the research was first announced."These nanocrystal probes can be complementary, and in some cases may be superior to existing fluorophores."

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