National Medal of Science winner to speak Oct. 21-22 in Delaware
To speed the search for new medicines, pharmaceutical researchers developed techniques to simultaneously synthesize thousands of potentially useful substances, thereby developing vast libraries of chemical compounds.
This mass-manufacturing approach, known as "combinatorial chemistry," is now being applied to the search for new materials, specialty chemicals and catalysts. But, it continues to pose challenges for researchers, who must find new ways to analyze thousands of compounds at the same time.
Tiny, chip-based "laboratories" for characterizing combinatorial results could be the key to faster, more cost-effective discovery.
The latest developments in microscale analysis will be described Oct. 21-22 at the University of Delaware, as part of a conference on "Microscale Characterization for Materials Discovery." Top industrial and academic researchers--including National Medal of Science Winner George M. Whitesides of Harvard University and John F. Rabolt of UD--are expected to outline their current research.
Rabolt, the only scientist ever to win all four Coblentz Society awards for molecular and vibrational spectroscopy, says he will discuss the possibility of a rapid, optical imaging tool that may someday allow the characterization of hundreds of samples simultaneously.
"When you run many simultaneous chemical reactions," says Rabolt, chairperson of UD's Department of Materials Science and Engineering, "it's hard to keep track of what you're producing. Combinatorial chemical reactions happen so much faster than we can interrogate the system to learn about the resulting product. A parallel optical or spectroscopic technique might make analysis faster, and simultaneous."
Also during the conference, Rabolt says he will discuss efforts to pattern materials using DNA sequences that can be immobilized. "We want to use DNA molecules as the patterned substrate for biospecific reactions and perhaps even devices," he explains. "We can affix certain DNA sequences to a surface. If a complementary sequence exists in a solution of many different DNA sequences, then when we dip the immobilized sequence into the mixture, intermolecular association with this complementary sequence will occur through a process call hybridization."
The resulting double helix will have "significantly different structure and exhibit different surface properties than the initial, immobilized single-stranded DNA," he says. "Being able to detect the difference between immobilized, single-stranded DNA and immobilized, hybridized DNA by a fast spectroscopic, optical or electronic method is our goal, and would be a substantial accomplishment."
Downsizing chemistry
Increasingly, efforts to "downsize chemistry" are setting the stage for chip-based analysis, Rabolt notes. Emerging lab-on-a-chip technologies may prove useful for analyzing bar-code DNA sequences; screening drug candidates; rapidly detecting biological and chemical warfare agents; or for developing simpler, less expensive clinical tests, according to Rabolt.
In the future, he says: "A device the size of a postage stamp might simultaneously analyze many different substances in hospitals, on the factory floor, in the corn field or at home."
George Whitesides, Harvard's Mallinckrodt Professor of Chemistry, is one of the world's leading authorities on the fabrication of microsystems. During his Delaware presentation, Whitesides says he will discuss soft lithography, a set of replication techniques that show promise for rapid prototyping, especially of microanalytical and microfluidic systems.
Other speakers at the event will include: Thomas J. Baiga, Charybdis Technologies; Richard J. Colton, Naval Research Laboratory; M. Bonner Denton, University of Arizona; Nathan S. Lewis, California Institute of Technology; William F. Maier, Germany's Max-Planck Institute; Bruce D. Quimby, Hewlett-Packard; Nadrian C. Seeman, New York University; Selim Senkan, University of California, Los Angeles; W. Henry Weinberg, Symyx Technologies; Richard C. Willson, University of Houston; and Daniel W. van der Weide, University of Wisconsin-Madison.
Planning the meeting, in collaboration with the UD Office of Engineering Outreach, are representatives of 3-Dimensional Pharmaceuticals; Merck & Co.; DuPont Pharmaceuticals; Astra-Zeneca; DuPont; and Hercules.
Call for a copy of the program, or browse the event web site: http://www.udel.edu/engg/outreach/conferences/microchar/index.html.