Now, a team of chemists at the University of Illinois at Urbana-Champaign, led by professors Steven C. Zimmerman and Kenneth S. Suslick, has developed a way of creating artificial antibodies. The process -- which they describe in the July 25 issue of the journal Nature -- is a general approach wherein one molecule imprints its structure within a larger host molecule, in much the same way an object can cast its own shape in plaster of paris.
"This is the first example of molecular imprinting in which a single molecular template is imprinted into a single macromolecule -- a highly branched polymer called a dendrimer," said Zimmerman, a William H. and Janet Lycan Professor of Chemistry at Illinois. "Upon removal of the template, we have a synthetic molecular shell that can bind specifically shaped molecules and reject all others, just like a natural antibody."
The process Zimmerman and Suslick describe is analogous to Linus Pauling's 1940 proposal for how antibodies are formed in response to the presence of an antigen. Although Pauling's mechanism proved to be incorrect, it inspired considerable experimental work, which ultimately led to the modern field of polymer imprinting.
One disadvantage of conventional polymer imprinting is that each "antigen" or template molecule produces an artificial antibody containing all kinds of different binding sites, most of which have poor recognition abilities and are therefore ineffective.