Hydrogels That Actuate Selectively in Response to Organophosphates

Nerve agents and pesticides represent a category of extremely toxic organophosphate compounds (OPs) that irreversibly inhibit the enzyme acetylcholinesterase, disturbing transmission in the synaptic clefts of muscles and nerves. Protection from these compounds necessitates the development of breathable barriers that can selectively block the passage of OPs. Hydrogels prepared from acrylamide, N, N'-methylenebis(acrylamide), N,N'-bis(acryloyl) cystamine, and hydrophilic pendant oximes are herein prepared, showing the ability to decontaminate and respond to the presence of OPs through a change in swelling. The oxime-based hydrogels show selective response only to malaoxon when tested against chemicals that are found in sweat as well as other reactive chemicals that are found in the environment. Pore sealing is demonstrated in perforated equilibrated gels within 3-4 h after the addition of malaoxon, showing actuation of the gel in response to organophosphates. This strategy demonstrates the ability to couple oxime-based decontamination and disulfide chemistry to produce hydrogels that can decontaminate organophosphate compounds, sense the decontamination product, and transduce this sensing response into actuation of the gel, which can be used to close pores in gel sheets or between fibers in a protective fabric coating.