Donald Tomalia (1938–)

When Donald A. Tomalia first proposed building macromolecules with an ordered, predictable structure, his colleagues at the Dow Chemical Company greeted him with skepticism. Unfazed, Tomalia continued his research and, in 1979, he and a colleague made a breakthrough. By adding methanol as a solvent to normal random-coil polymer production procedures, they were able to produce polymers with a central core and tendrils that branch outward in a precise, predictable manner. Tomalia called them dendrimers, after dendra, the Greek word for “tree.”

Dendrimers are the fourth major class of macromolecular architecture, and they are special because of the precision of their structure. Traditionally polymers were long and chaotic, and their manufacturing process yielded molecules in a range of sizes. Dendrimers, however, are grown in a precise manner, with each successive generation stemming from one of the old branches.

Dendrimers’ cavity size can be tailored to hold different molecules or therapeutic agents, and their chemical properties can be designed to release their contents in a proper setting. Since their inception dendrimers of all manner have been built: graphite-like dendrimers, light-harvesting dendrimers, dendrimers with cross-linked surfaces, and dendrimers that self-destruct. Dendrimers are currently used for heart-attack detection and as an MRI contrasting agent. Cheaper manufacturing techniques and faster delivery times are making dendrimers much more affordable to use. Presently researchers are exploring the use of dendrimers in an AIDS-prevention gel, as a means for anti-scarring—especially during eye surgery, and as a drug delivery agent. Researchers are also moving toward attaching catalysts and bio-sensory agents to the surface of dendrimers. The first dendrimer-based pharmaceutical is poised to enter the market as early as 2008.

Since inventing dendrimers, Tomalia has been deeply involved in dendrimer-related research and has developed a working partnership with Dow Chemical, his former employer. Recently Dow assigned its entire intellectual property portfolio and associated royalties in the field of dendrimers to Dendritic NanoTechnologies, where Tomalia serves as president and chief technology officer. Tomalia is also scientific director of the National Dendrimer and Nanotechnology Center at Central Michigan University. Tomalia obtained a B.A. from the University of Michigan, an M.S. from Bucknell University, and a Ph.D. in physical organic chemistry from Michigan State University. He holds more than 100 dendrimer-related U.S. patents and has published over 180 articles.