Host-[2]-Rotaxanes as drug transport agents

CHED 405

Erin N. Fleck, Department of Chemistry, Illinois Wesleyan University, P.O. Box 2900, Bloomington, IL 61702 and David B. Smithrud, David.Smithrud@uc.edu, Department of Chemistry, University of Cincinnati, P.O. Box 210172, Cincinnati, OH 45221-0172.
There continues to be a great demand for synthetic agents that recognize targeted compounds as well as proteins. These artificial receptors could be key components in affinity chromatography and sensors, act as catalysts, or agents that transport drugs across cell membranes. We have created a new class of binding agents that highlight a convergent arrangement of recognition elements that adjust to provide maximum binding free energy with a guest. Experiments have shown that a convergent arrangement of functional groups provides for a greater binding free energy for guest recognition than a divergent arrangement. Furthermore, the dynamic component of the binding agents does not detract significantly from the binding free energy. These binding agents also efficiently transport fluorescein and some fluorescein derivatives into eukaryotic cells. Most likely, the ability of the functional groups to adjust to their environment, e.g., cell membrane and aqueous milieu is responsible for the observed transportation.