Hydrogels That Actuate Selectively in Response to Organophosphates

Abstract

1 of 10) 1602784 compounds, the V-type nerve agents are the most toxic, rendering the development of novel decontamination and protection technologies highly important. Decontamination or sequestration of high toxicity OP compounds can be accomplished through hydrolysis of the phosphate ester bond [9][10][11][12] with the enzyme organophosphorus hydrolase, [9][10][11][12][13][14][15] entrapment in nanoporous materials, [16,17] enzyme/ polymer conjugates [18][19][20][21][22][23][24] and highly bioactive enzyme/amphiphilic polymer formulations, [25] chemically modified fluorescent probes, [26][27][28] and oxime reactivators. [29][30][31][32] V-type organophosphates contain a P-S bond and a choline-like moiety and are hydrolyzed very slowly by natural enzymes. Therefore, new and efficient approaches that target VX are necessary for mitigation of the agent.A major challenge in the mitigation of threats from OP compounds is developing protective garments that can eliminate exposure of the wearer to the toxic chemical. Some rubbers can serve as effective barrier materials, [33] but in sufficient thickness they are not breathable and extremely uncomfortable to wear for an extended period of time. Therefore, there is a strong interest in a garment or barrier membrane that could remain in a porous state when it is not in the presence of an organophosphate, but close its pores autonomously in the presence of the toxic agent to prevent its passage. Such a smart barrier needs to be able to efficiently sense the OP compound and also transduce the sensing response into an actuated change of state without an external input of energy.The reactivity of oximes with OP compounds, yielding phosphorylated adducts, [34][35][36][37][38][39][40][41][42][43][44] provides a potential basis for detection and response in an autonomous material. As part of antidotal therapy against OP poisoning, oximes help reactivate phosphorylated AChE. Quaternary pyridine aldoximes substituted in the para position have been shown to be highly reactive in reversing poisoning from different OP compounds, screened over AChE of different origins. [36] Polymeric materials with enhanced nucleophilic activity provided by N-alkyl 4-pyridinium aldoximes also recently showed significant detoxification of diisopropyl fluorophosphate. [31] Coupling oxime decontamination with responsive crosslinkers could potentially enable the triggering of responsive Nerve agents and pesticides represent a category of extremely toxic organo phosphate compounds (OPs) that irreversibly inhibit the enzyme acetyl cholinesterase, 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 oximebased h...

Amyloid Peptide Scaffolds Coordinate with Alzheimer’s Disease Drugs

“…The physical complexation at higher peptide concentration, yielding hydrogels, − was examined post formation of both of the amyloid gels at 10 mg/mL. The complexation of the AD compounds by the designed amyloid gels was quantified by both UV–vis and MRM-MS after overnight incubation to allow for complexation to occur (the peptide concentration was reduced to 5 mg/mL), followed by centrifugation and pellet formation (containing amyloid peptides/AD drugs), while the AD drug retention was also examined after subsequent pellet washings (Table ).…”

Active and Strippable PVA/Borax/NaBO3 Hydrogel for Effective Containment and Decontamination of Chemical Warfare Agents

“…Various gel formulations have been proposed by us and others over the years for mild decontamination purposes. These formulations include gels based on oxone and fumed silica ( l -Gel), polyalkylamines, hypochlorite, organogels containing oximate or peroxides, ionic liquids and polysaccharide hydrogels containing active fluoride species. , Notably, the decontamination gels reported to date were either corrosive, nonuniversal, and/or not strippable or required complicated removal methods. Aiming to achieve a hydrogel that would avoid such disadvantages, we have developed a new oxidizing decontamination gel based on polyvinyl alcohol (PVA)/Borax and sodium perborate as the active ingredient.…”

Double‐crosslinked reversible redox‐responsive hydrogels based on disulfide–thiol interchange

“…Lee et al investigated swelling behavior and mechanical properties of PNiPAAm–BAC–BIS bulk hydrogels . More recently, a PAAm–BAC–BIS hydrogel with hydrophilic pendant oximes has been prepared by Gkikas et al, demonstrating the ability to decontaminate and respond to toxic organophosphate compounds . Nevertheless, none of these systems shows a durable redox‐triggered reversibility both on swelling behavior and mechanical strength.…”

“…48 More recently, a PAAm-BAC-BIS hydrogel with hydrophilic pendant oximes has been prepared by Gkikas et al, demonstrating the ability to decontaminate and respond to toxic organophosphate compounds. 49 Nevertheless, none of these systems shows a durable redox-triggered reversibility both on swelling behavior and mechanical strength. More importantly, the correlation between mechanical properties, swelling behaviors, and swelling kinetics of the disulfidereversible hydrogels is still undiscovered.…”