Modulated Growth of Nanoparticles. Application for Sensing Nerve Gases

Abstract

Hydrolysis of acetylthiocholine mediated by acetylcholine esterase yields the thiol-bearing compound thiocholine. At trace concentrations, thiocholine modulates the growth of Au-Ag nanoparticles on seeding gold nanoparticles in the presence of ascorbic acid. Inhibition of the enzyme by 1,5-bis(4-allyldimethylammoniumphenyl)pentan-3-one dibromide (BW284c51) or by diethyl p-nitrophenyl phosphate (paraoxon) produces lower yields of thiocholine, promoting the catalytic growth of Au-Ag nanoparticles. Here, we describe the development of a simple and sensitive colorimetric assay for the detection of AChE inhibitors.

Nanomaterials - Acetylcholinesterase Enzyme Matrices for Organophosphorus Pesticides Electrochemical Sensors: A Review

“…This detection limit has been found to be much lower than that measured using chromatographic techniques MEKC, GC, MSPD combined GC and OPEEs discussed in Table 1. Though AuNP-modified matrices displayed significant improvement in OP pesticide determination, there is always possibility for thiocholine, the AChE mediated hydrolysis product, to bind with the AuNP-modified surface (due to the greater affinity of thiol (-SH) groups towards metallic gold), which might reduce the performance of the sensor [45]. Finally, the AChE/QCdS-PVP/GCE has also been used to monitor the OP pesticide, trichlorfon in nM range.…”

A Molecular Probe for the Highly Selective Chromogenic Detection of DFP, a Mimic of Sarin and Soman Nerve Agents

“…Nevertheless, examples of selective and sensitive chromofluorogenic probes for detection of these derivatives are still rare. The chemosensors described in the literature make use of easily observable and measurable fluorescence and color changes, and involve photon-induced electron transfer (PET)-based processes, [10] oximate-containing derivatives, [11] molecularly imprinted polymers, [12] nanoparticles, [13] carbon nanotubes, [14] cyclization reactions in push-pull chromophores, [15] displacement assays, [16] and organic-inorganic hybrid materials. [17] In most of these studies nerve-gas simulants, such as diethylcyanophosphate (DCNP) and diisopropylfluorophosphate (DFP), are used.…”

Colorimetric assay for acetylcholinesterase and inhibitor screening based on the Ag [I] ion–3,3′,5,5′-tetramethylbenzidine (TMB)

“…The utilization of two kinds of enzymes increases cost that limits their applications. Recently, nanomaterials such as fluorescent conjugated polymers, Fe 3 O 4 nanoparticles [17], gold nanoparticles [18][19][20][21][22][23], graphene quantum dots [24], upconversion nanoparticles [25], DNA-templated copper/silver nanoclusters [26], CdTe quantum dots [27] have also been successfully employed for the detection of AChE activity and its inhibitors. However, most of these nanomaterials-based methods show certain drawbacks, such as labor-intensive and time-consuming sample pretreatment, the use of other enzymes for signal amplification and readout, low sensitivity, and sophisticated instrument manipulation.…”