Molecular 'wrench' gives delivery machinery an edge

A blue wrench (of molecules) to adjust a green bolt (a pillarene ring) that binds a yellow chemical "guest"--Courtesy of Severin Schneebeli

The shape of molecules used to deliver drugs determines how and when the drugs are able to interact with their target. And having the right tools to operate that intricate machinery is an important part of that process.

Researchers at the University of Vermont have developed a "wrench" using the chirality of molecules at the nanoscale to create customized compounds that can perform specific functions. Chirality is the three-dimensional shape of a molecule insofar as it affects how it operates--like the way a right hand and a left hand are structured similarly, but only one can fit inside a right-handed glove.

Lead researcher Severin Schneebeli has likened the new tool to Lego, in that it is designed to fit each other in one direction "in a manner similar to how a 5-sided bolt head fits into a pentagonal wrench."

The molecule strip is C-shaped with an opening of only 1.7 nanometers. And it keeps its shape in all circumstances, giving it the ability to bind to other molecules in a specific way, allowing the researchers to maneuver the compound the way one would twist a bolt with a wrench. The specific molecules in the study are called pillarene macrocycles.

"By embracing pillarenes," Schneebeli and his team wrote in a statement, "the C-shaped strips are able to regulate the interactions of pillarene hosts with conventional guests."

Using this tool, they can give shape to drug delivery molecules specific to a certain task, like releasing a drug at a certain location.

Leading chemist Sir Fraser Stoddart said of the tool: "Brilliant and elegant! Creative and simple. … It's all based on geometry that controls the symmetry of the molecules. This is the only shape it can take--which makes it very useful."

- here's the UVM report