Nanoscale materials in the composition of biosensors for the determination of amitriptyline

Biosensor devices including hybrid nanostructures as modifiers of transducer surfaces meet current requirements for the methods of research and determination of drugs, including antidepressants. The fea­tures of amperometric monoamine oxidase biosensors based on printed carbon electrodes modified with nanocomposite compositions C 60  / cobalt nanoparticles/amino derivative of polyether polyol of the second generation/chitosan nanocomposite structures used for the detection of tricyclic antidepressant amitriptyline are considered. The choice of the best modifier was made proceeding from the data of transmission electron microscopy, scanning electron microscopy, electrochemical impedance spectroscopy, and differential pulse voltammetry. When developing the biosensor, conditions for depositing the composite composition of cobalt nanoparticles/amino derivative of polyether polyol on the electrode surface were varied: electrochemical deposition, sequential layer-by-layer deposition, and deposition of the mixture. The peak of electrochemical oxidation of hydrogen peroxide, which is formed during the enzymatic reaction of serotonin oxidation under the action of monoamine oxidase was used as an analytical signal of the biosensor. The principle of the biosensor action is based on the inhibitory effect of amitriptyline on the catalytic activity of immobilized monoamine oxidase. The proper choice of a modifier and optimal working conditions provided the range of detectable concentrations of amitriptyline: 1 x 10 -4  - 1 x 10 -8  M, the lower limit of the determined content at a level of 5 x 10 -9 M for monoamine oxidase biosensor. Comparison of the results on the amitriptyline content determination in the pharmaceutical preparation and urine obtained using the monoamine oxidase biosensor and polarization fluorescence immunoassay (dilution of the tracer 1:32, dilution of antibodies 1:128, the range of working concentrations 5 x 10  -8  — 5 x 10 -9  M), well-proven in the quantitative determination of medicinal substance, confirmed the correctness of the results obtained.