Once a tool of science fiction writers, tiny machines dubbed nanobots are getting closer to becoming a reality. With possible applications in medicine, manufacturing, robotics, and fluidics, this week scientists provided an update on nanobot pumps that destroy nerve agents, while simultaneously administering an antidote. The presentation took place at the 256th National Meeting & Exposition of the ACS (American Chemical Society).
According to Dr. Ayusman Sen, the project leader, this study stemmed from research aimed at making nanobots from enzymes and converting chemical energy into motion. In this instance, that approach involved taking the energy generated from catalytic reactions in making enzymes move.
To make his nanobots, Dr. Sen and company used naturally occurring enzymes. These proteins help specific chemical reactions occur, converting a reactant (raw material) into a product.
When enzymes catalyze a reaction, they move. Researchers still aren’t sure why, but it likely involves a change in the enzyme's shape. Dr. Sen’s group has demonstrated the ability of these proteins to even move along a path toward higher levels of reactant. This dynamic makes enzymes an attractive material for developing nanobots.
“If we take enzymes and anchor them to a surface so they cannot move, and we give them their reactant, they end up pumping the fluid surrounding them,” Sen says. He notes that the nanobots pump liquid at the rate of several microliters – or millionths of a liter – per second.
Dr. Sen and his coworkers made nanobots to neutralize organophosphates, a class of nerve agents. Exposure to these chemicals during combat or terrorist attacks can cause permanent neurological damage or death. An enzyme, called organophosphorus acid anhydrolase, can destroy these nerve agents.
Exposure to these organophosphates stimulates the enzyme, which actively pumps in the organophosphate compound and kills it. Most promising is that the system requires no external power source because the enzyme is fueled by the organophosphate reactant.
In the near future, the nanobot pumps could be incorporated into protective clothing for soldiers or first responders. The team is also exploring applications for nanobots based on other enzymes, such as an insulin-pumping device to treat diabetes and an enzyme-powered drug-delivery system.
The researchers acknowledge funding and additional support from the NSF (National Science Foundation) and the Defense Threat Reduction Agency.
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