ИСТИНА

The creation of highly sensitive and selective optical sensor systems for the determination of different biologically active compounds (such us phenolic compounds, catecholamines, dibenzothiophenes and the products of its oxidation, organic peroxides) without preliminary pretreatment of samples with complex matrices is one of the promising directions of modern biochemical analysis. The determination of such compounds is necessary to control of the quality of pharmaceutical and food products, plant materials, diesel oil, and etc. In the present work the constructions of solid-phase biosensors with photometric, fluorescent and SERS detections of analytical signal were developed. The action of the proposed biosensors is based on the molecular recognition of the above mentioned analytes by the enzyme (horseradish peroxidase or hemoglobin from bovine blood) or indicator reagents (aromatic amines or quinones), which are included into a self-assembled optical transparent film or gel of a biopolymer - chitosan. A novel future of the proposed optical biosensors is the measurement of the analytical signal as absorbance, emission or scattering of a glass slide with bio- or chemorecognizing films or gels {polyelectrolyte-enzyme-indicator reagents} rather than absorbance, emission or scattering of a same indicator reaction solution. The solid-phase photometric, fluorescent and SERS indicator systems for each group of the above mentioned analytes were elaborated. A unique approach expanding the range of important analytes (such as dibenzothiophenes and the products of its oxidation) becoming available for SERS due to trapping them into charge – transfer complexes immobilized onto SERS – active nanostructures was developed. As a result, it is possible to analyze emulsions and non-transparent solutions by optical methods, the solutions with high content of polar organic solvents (including non polar media) without preliminary separation of a matrix. The developed optical biosensors were applied for the analysis of a wide range of real samples, including those with water insoluble matrices.