A Disposable Biosensor for Organophosphorus Nerve Agents Based on Carbon Nanotubes Modified Thick Film Strip Electrode

Abstract

A disposable biosensor based on acetylcholinesterase-functionalized acid purified multi-wall carbon nanotubes (CNTs) modified thick film strip electrode for organophosphorus (OP) insecticides was developed. The degree of inhibition of the enzyme acteylcholinesterase (AChE) by OP compounds was determined by measuring the electrooxidation current of the thiocholine generated by the AChE catalyzed hydrolysis of acteylthiocholine (ATCh). The large surface area and electro-catalytic activity of carbon nanotubes lowered the overpotential for thiocholine oxidation to 200 mV (vs. Ag/AgCl) without the use of mediating redox species and enzyme immobilization by physical adsorption. The biosensor detected as low as 0.5 nM (0.145 ppb) of the model organophosphate nerve agent paraoxon with good precision, electrode to electrode reproducibility and stability. Analysis of real water sample using the sensor demonstrated the feasibility of the application of the sensor for on site monitoring of OP compounds.

Mercaptobenzothiazole-on-Gold Organic Phase Biosensor Systems: 3. Thick-Film Biosensors for Organophosphate and Carbamate Pesticide Determination

“…The sample width, pulse width and pulse period were 17 ms, 50 ms and 200 ms, respectively. The DPV was first obtained in the absence of the substrate ATCh, followed by analysis in the presence of ATCh as substrate Joshi et al 2005;Sotiropoulou et al 2005;Somerset et al, 2007;Somerset et al, 2009). …”

Developments in Analytical Methods for Detection of Pesticides in Environmental Samples

“…With the help of biosensors, on site analysis can be performed to understand the extent of pollution almost immediately [43][44][45][46]. The advantages of using biosensors are: 1) disposable, selective, reliable and economical 2) they can be produced in large quantities and can be miniaturized for efficient use for onsite detection, 3) require less sample size and 4) easy to operate even by non skilled personnel [47][48][49][50]. In spite of their clear advantages, they have certain limitations.…”

Microfluidic Device for Coulometric Detection of Organophosphate Pesticides

“…1 They form covalent bonds to serine residues that are located in the active site of AChE, impairing the enzyme's function. Subsequent build-up of acetylcholine blocks cholinergic nerve impulses, leading to paralysis, suffocation, and ultimately to death.…”