Fluid-pumping proteins that are embedded into jelly-like membranes could be used to intercept toxic nerve agents and deliver an antidote at the same time.
Exposure to organophosphate nerve agents 鈥� which include Novichok nerve agents 鈥撀燾an disrupt muscle function and lead to convulsions or difficulty breathing. Researchers have now shown that an enzyme can catalyse the breakdown of such compounds, creating a nanometre-sized pump that can both devour the nerve agent and spew out an antidote.
鈥淭he nerve agents are their food, or fuel,鈥� says Ayusman Sen at Pennsylvania State University, who presented this work at the annual meeting of the American Chemical Society on 21 August.
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Sen and his colleagues anchored the enzymes 鈥� called organophosphorus acid anhydrolase 鈥� onto a jelly-like membrane called a hydrogel and then submerged them in water that contained a small amount of nerve agent. As the enzyme eats through the nerve agent it turns the chemical energy into mechanical movement through a process that the researchers still don鈥檛 fully understand.
Pumping out antidote
鈥淲hen you anchor the enzymes to a surface so they can鈥檛 move, the force is transmitted to the surrounding fluid, so they pump it,鈥� Sen says. These enzymes are also naturally drawn towards a higher concentration of their food 鈥� the nerve agent in this case. But because they are stuck in place, that force results in a higher speed of flow in the nerve agent-containing fluid around them. The more nerve agent present, the faster the enzymes will pump and digest it.
Sen and his team made the technology even more useful by filling the hydrogel with a nerve agent antidote, creating a reservoir the enzyme can pull from. As the liquid around the enzyme flows through the gel, some of the antidote enters the enzyme and gets pumped out at the same time as the nerve agent is being pumped in. Sen says the nanobot can pump liquid at several micrometres per second.
These enzymes could work to combat a nerve agent, so long as it鈥檚 delivered in a liquid form. 鈥淚f it鈥檚 delivered as a spray or some kind of droplet, it would work,鈥� Sen says. The enzymes could be attached to gel particles which would be impregnated into clothing or used as an ointment on the skin, he says.
Read more: What was the nerve agent used to poison Sergei Skripal?
