ИСТИНА

Biogenic amines (BA), such as serotonin, dopamine (DA), noradrenaline (NA) and adrenaline (AD), are important foundation for regulation activities of the central and peripheral nervous systems. Pathological violations of their metabolism lead to neuroendocrinal (neuroblastoma, pheochromocytoma, paraganglioma, etc.) and neurodegenerative (Alzheimer’s, Parkinson’s, etc.) diseases. Due to the fact that the level of BA in the body of a healthy person and a patient with the pathology is different, biogenic amines are markers for the diagnosis (including early) diseases. The difficulty in determining BA in blood plasma, cells and other biological samples is extremely low normal concentrations (from 10 pM), and for some neurodegenerative disorders they become an order of magnitude lower. In this work, we propose new fluorescent system for ultra-sensitive determination of these compounds (at the level of single molecules) in biological samples (blood plasma, urine, cells, etc) based on forming of intensely fluorescing ternary complexes of BA with europium and oxytetracycline (OTC) (fig.1) in hydrogels. The hybrid polymeric hydrogels (chitosan, alginate and collagen) serve as the matrix for the formation of artificial models of neural and vascular networks, as well as the basis for optical sensor elements adapted for commercially available equipment. The fluorescence spectra was measured in the 96-well microplates. Analytical signals were detected at excitation wavelength of 416 nm and emission wavelength of 617 nm. All conditions for ternary complex formation for BA determination were carefully optimized. Using the example of the PC 12 cell line, a possibility to use such polymer matrices as a culture medium for growing artificial 3D cell structures has been demonstrated. Based on the toxicity data, recommendations have been made for the practical use of the obtained optical sensor systems for imaging of neurotransmitters in biological liquids and living cell structures without sample pretreatment. We are grateful to RFBR for the financial support of this research (grant no. 19-0300901).