Monitoring molecules may advance medicine.

Scientist at the U.S. Department of Energy's Ames (Iowa) Laboratory have developed a technique to zero in on and monitor the meanderings of single molecules in solution to gain insight on each step of a chemical reaction. This ultimately could lead to improved treatments for AIDS and cancer. "The ability to observe one molecule react with another molecule may have great implications in the fields of catalysis, medicine, and biotechnology," explains Ed Yeung, program director for physical and biological chemistry and distinguished professor of chemistry at Iowa State University. "Looking ahead, maybe we'll be able to detect a single HIV virus or one copy of a specific gene in DNA."

Working with Xiao-Hong Xu, a postdoctoral fellow at the lab, Yeung is able to track the motion of single molecules of rhodamine, a highly fluorescent compound, and rhodamine-labeled DNA in water solution. Other techniques can detect single molecules in solution, but Yeung says his and Xu's is the first to offer continuous monitoring. The ability to follow single molecules makes it possible to collect detailed information about their individual behaviors and physical and chemical properties. This represents a significant advancement over traditional methods, which determine the characteristics of molecules based on...