ИСТИНА

This work examines the fabrication regime and the properties of biosensor for choline based on polymer-enzyme nanolayers deposited via sequential adsorption of the conductive surfaces (graphite, gold). The films were formed via two-step adsorption of amphiphilic diblock copolymer (poly(n-butylmethacrylate)-block-poly(2-(dimethylamino)ethyl methacrylate) (PnBMA-b-PDMAEMA) micelles and enzyme choline oxidase (ChO) on to screen-printed graphite support. The resulting polymer-enzyme thin-films were found to be very active as biosensors for choline. The biosensors of this type exhibited good sensitivity, stability, and outstanding analytical characteristics, while cross-linking by glutaraldehyde imparted improved operational stability. The biosensors enabled rapid and precise assays of blood cholineesterases based on their hydrolysis of acetyl/butyryl cholines to the choline analyte. Quantitative determination of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities in samples of hemolised human and mouse blood showed good agreement between biosensor and spectrophotometric assays for these enzymes. Biosensor determination of changes in blood AChE/BChE ex vivo after dosing mice in vivo with an OP inhibitor of the enzyme yielded values higly correlated with those from a spectrophotometric method, thus validating the use of the biosensor for biomonitoring applications.