Nanoscale Materials in the Composition of Biosensors for the Determination of Amitriptyline

Biosensor devices that include hybrid nanostructures as transducer surface modifiers meet current requirements for methods of research and determination of drugs, including antidepressants. Here, we consider the features of amperometric monoamine oxidase biosensors based on screen-printed graphite electrodes modified with nanocomposite consisting of C60/cobalt nanoparticles/amino derivative of a second-generation polyether polyol/chitosan in the determination of the tricyclic antidepressant amitriptyline. The best modifier was selected using transmission electron microscopy, scanning electron microscopy, electrochemical impedance spectroscopy, and differential pulse voltammetry. In the biosensor development, the conditions for applying the composite based on cobalt nanoparticles/amino derivative of polyether polyol to the electrode surface were varied: electrochemical deposition, sequential deposition by the layer-on-layer method, and deposition of a mixture. As an analytical signal of the biosensor, we used the peak of the electrochemical oxidation of hydrogen peroxide, which is formed during the enzymatic oxidation of serotonin under the action of monoamine oxidase. The operating principle of the biosensor is based on the inhibitory effect of amitriptyline on the catalytic activity of immobilized monoamine oxidase. For the selected modifier, the determined concentration range of amitriptyline is 1 × 10–4–1 × 10–8 mol/L and the lower limit of the determined contents is 5 × 10–9 mol/L under optimal operating conditions. Comparison of the results of the amitriptyline determination in a pharmaceutical preparation and urine that were obtained using a monoamine oxidase biosensor and the method of fluorescence polarization immunoassay (dilution of the tracer of 1 : 32, dilution of antibodies of 1 : 128, range of working concentrations from 5 × 10–8 to 5 × 10–9 mol/L), which has proven itself in the determination of medicinal substances, confirmed the correctness of the developed method.