Nanoparticle-induced enhancement of cholinesterase activity in the presence of malathion: A potential nerve agent therapeutic

Organophosphate nerve agents are associated with assassination, terrorism and chemical warfare, but there has been slow progress in developing a broad-spectrum response to poisoning. For some nerve agents the oxime component of the therapy may not be effective, limiting the effectiveness of emergency treatment that is desperately needed. An alternative therapy may be possible based on accelerating enzyme (acetylcholinesterase) catalysis in unaffected adjacent enzymes. Herein we demonstrate a restoration of acetylcholinesterase activity in malathion-inhibited cell membrane preparations by the administration of functional nanoparticles. The molecularly imprinted polymer nanoparticles were designed to bind selectively to designated enzyme epitopes. Enzyme activity of membrane-bound acetylcholinesterase was measured in the presence of the organophosphate malathion and the selected nanoparticles. Enzymatic acceleration of the cholinesterase was observed at 162 ± 17 % the rate of erythrocyte ghosts without bound nanoparticles. This may restore sufficient acetylcholine hydrolysis to mitigate the effects of poisoning, offsetting the acetylcholine accumulation resulting from enzyme inhibition

New protocol for optimisation of polymer composition for imprinting of peptides and proteins

We present here a novel screening tool for optimisation of polymerisation mixtures used in imprinting of peptides and proteins. To facilitate rapid synthesis and screening of a combinatorial library of polymers the solid-phase synthesis method developed by Piletsky and co-workers was scaled down to 50 mg of template-immobilised solid phase, allowing a single well of a 96-well microplate to function as an individual reaction vessel. In this way, 32 different polymer compositions containing N-isopropylacrylamide, acrylic acid, N-(3-aminopropyl)methacrylamide hydrochloride, and N-tert-butylacrylamide, were tested in imprinting of three peptides and three proteins. Utilising filtration microplates has allowed the elution and washing steps to be performed in a similar manner to the large-scale synthesis, whilst incorporation of a fluorescent monomer (N-fluoresceinylacrylamide) made it possible to analyse the binding of synthesised polymer nanoparticles to the solid phase with immobilised templates under different washing conditions. The experiment has proven that the variations in monomer compositions had an effect on the yield and affinity of synthesised molecularly imprinted polymers for the peptides, but not for the proteins. Imprinting in this way presents an ideal method for performing small-scale syntheses for testing polymerisation mixtures, as information regarding the molecularly imprinted polymers affinity can be assessed as part of the elution process, without a need for time-consuming analysis such as quartz crystal microbalance or surface plasmon resonance