Construction of an acetylcholinesterase sensor based on synthesized paramagnetic nanoparticles, a simple tool for neurotoxic compounds assay

Abstract

Magnetic particles (MPs) are widely used in biological applications in recent years as a carrier for various molecules. Their big advantage is in repeated use of immobilized molecules including enzymes. Acetylcholinesterase (AChE) is an enzyme playing crucial role in neurotransmission and the enzyme is targeted by various molecules like Alzheimer drugs, pesticides and warfare agents. In this work, an electrochemical biosensor having AChE immobilized onto MPs and stabilized through glutaraldehyde molecule was proposed for assay of the neurotoxic compounds. The prepared nanoparticles were modified by pure AChE and they were used for the measurement anti-Alzheimer drug galantamine and carbamate pesticide carbofuran. All measurements were carried out using screen-printed sensor with carbon working, silver reference and carbon auxiliary electrode. Standard Ellman´s assay was used for validation measurement of both inhibitors. Part of this work was elimination of reversible inhibitors represented by the galantamine from active site of AChE. For this purpose, we used lower pH to get original activity of AChE after inhibition by galantamine. We also observed decarbamylation of AChE-carbofuran adduct. Influence of organic solvents to AChE as well as repeatability of measurement with MPs with AChE was also established.