Nanobot pumps destroy nerve agents

Once in the territory of science fiction, "nanobots" are closer than ever to becoming a reality, with possible applications in medicine, manufacturing, robotics and fluidics. Today, scientists report progress in developing the tiny machines: They have made nanobot pumps that destroy nerve agents, while simultaneously administering an antidote. 

According to Ayusman Sen, Ph.D., the project's principal investigator, this study arose from more general research aimed at making nanobots from enzymes. "We have been looking at how to convert chemical energy into motion," he says. "We take the energy that's generated from catalytic reactions to cause the motion of enzymes."

To make his nanobots, Sen and his group at The Pennsylvania State University used enzymes found in nature. These are proteins that help specific chemical reactions occur, converting a reactant (raw material) into a product.

The realization that enzymes can move when catalyzing a reaction is a relatively new discovery. Sen and others have recently shown that when enzymes catalyze a reaction, they move. This feature make enzymes an attractive material for developing nanobots.

Sen and his coworkers made nanobots to neutralize organophosphates, a class of nerve agents. Exposure to these chemicals during military combat or terrorist attacks can cause permanent neurological damage, and in some cases, death.

An enzyme, called organophosphorus acid anhydrolase, can destroy these nerve agents. The researchers immobilized this enzyme on a gel that also contained an antidote. Exposure to organophosphates activates the enzyme. "The enzyme actively pumps in the organosphosphate compound and destroys it, and at the same time pumps out an antidote," Sen says. Importantly, the system requires no external power source because the enzyme is fueled by the organophosphate reactant.