Richard D. Powell has worked for Nanoprobes, Incorporated since March 1991. He has a Ph.D. (1988) and B.Sc. (1985) in Chemistry from Imperial College, London, UK, where he was a graduate student with Prof. William P. Griffith. He conducted postdoctoral research on transition metal complexes with novel macrocyclic tetraamide ligands with Prof. Terrence J. Collins (chemistry) at Carnegie Mellon University, Pittsburgh, PA. Before moving to Nanoprobes, he worked with the STEM Group in the Biology Departmentat Brookhaven National Laboratory.