Enzyme micropumps deliver insulin in response to glucose levels

Micropumps deliver compounds using enzymes (click to enlarge)--Courtesy of Nature Chemistry

A small molecular pump devised by researchers from the U.S., Russia and Puerto Rico could offer a new insulin delivery method for people with diabetes, using enzymes to convert chemical energy into a propulsion system for drugs.

The engineers hail from Pennsylvania State University, the Russian Academy of Sciences and the University of Puerto Rico and published their findings in the journal Nature Chemistry, demonstrating a nonmechanical pump with control over the flow rate in response to signals from the body. For instance, the pump could respond to a rise in glucose levels and release insulin accordingly. And the chemical pumps can do this at the nano- and microscale.

Many biological pumps work with the energy molecule adenosine triphosphate, or ATP. But by using other reactions to initiate movement, these enzyme-powered pumps can operate under conditions that might not be optimal for ATP.

The team started with a patterned gold surface that holds enzymes, which react to the presence of a substrate to convert the chemical energy into motion, according to a report in ChemistryWorld. The pump worked with the enzymes catalase, glucose oxidase, lipase and urease, and the velocity of the pump increased with a higher concentration of each one.

In addition to their use as a self-regulating insulin pump, which the engineers used as a proof-of-concept the system has attracted funding from the U.S. Defense Threat Reduction Agency, which sees the pump as a possible way to break down nerve agents by delivering an antidote when necessary.

- here's the ChemistryWorld report
- and here's the Nature Chemistry abstract