Supramolecular Chemistry of Pyrogallolarene Channels, Nanotubes, and Receptors

University Of Missouri-Saint Louis, Saint Louis MO

Investigators

Abstract

This research program builds on fundamental discoveries that macrocyclic pyrogallol[4]arenes insert into bilayer membranes and form functional channels, the properties of which can be varied by altering membrane properties. These will be exploited as ion and molecule receptors and delivery systems and as reporters of changes in membrane composition and properties. When the sidechains are branched, rather than linear, hexameric nanotubes are formed that are physically interlocked. Work will be undertaken to determine their chemical stability, their ability to transport ions and molecules, their potential to function as "nano-containers," and even to form physical tunnels within other structures. These nanopore and nanotube formers will be useful in developing new materials and in biological applications. These studies will provide students with experience in synthetic chemistry, and a range of analytical methods such as planar bilayer conductance, X-ray crystallography, electron microscopy, Langmuir trough, and Brewster angle microscopy. Taken together, the program will produce novel structures with novel properties and practical applications and educate students to understand supramolecular interactions and offer valuable practical applications in nanoscience. With the support of this award from the Macromolecular, Supramolecular, and Nanochemistry Program, Professor George Gokel, of the Department of Chemistry and Biochemistry and the Center for Nanoscience at the University of Missouri - St. Louis, is preparing novel chemical compounds that have remarkable chemical -- and potentially biological -- properties. These compounds, called pyrogallolarenes, are doughnut shaped and have "arms" radiating from them. Depending on the length and shape of the arms, the compounds form molecular capsules or "nanotubes" and exhibit a range of remarkable properties. Some of these compounds insert into bilayer membranes of the type that surround cells and form pores or channels within the membranes. The nanotubes are of a previously unknown type and will be used as "pipes" to transport ions and chemicals much as metal wires transport electrons. The combination of these properties opens the possibility of developing extremely small sensing devices and exploiting the individual compounds as antibiotics or in other pharmaceutical applications. The project will be valuable to recruit students to cross-disciplinary studies because it involves both chemistry and biophysics and a broad range of analytical techniques. Students will be prepared for the range of programs currently underway in American industry. Individual components of the program can be undertaken by undergraduate students or even high school students with appropriate supervision. This project will have an important impact to society because variations on these structures can lead to drug delivery systems or to drugs themselves.