The present finding describes an efficient facile approach for the fabrication of nitrogen-doped carbon dots (N-CDs) as a “fluorescent nanoswitch”. Highly fluorescent blue-light-emitting N-CDs have been synthesized via a simpler hydrothermal method using 2,2′-(ethylenedioxy)-bis(ethylamine) and malic acid as the precursors. N-CDs showed excitation-dependent and pH-independent emission along with a quantum yield of ∼25%. The blue fluorescent emission of N-CDs has been selectively “turned off” (quenching of fluorescence (FL)) during the sensing of Cr(VI) with 0.02 μM limit of detection and further been selectively “turned on” (restoration of FL) on sensing ascorbic acid, compared with other metal cations and biomolecules tested. For testing the practical applicability of N-CDs, the switchable reversibility of the fluorescent nanoswitch has been tested for up to four cycles on the basis of FL “on–off–on”. Furthermore, the toxicological test showed the antibacterial effect of the N-CDs on the tested Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli cells. Additionally, these N-CDs can also be used as a fluorescent ink for imaging purposes.

This work describes availability of immobilization of monomers and dimers of erythrosine into collagenase molecules. By means of the spectral investigations it was obtained that emission of the dye dimers dissolved in collagenase solution is. Erythrosine dimers don't fluoresce in water and buffer solutions; however its fluorescence can be seen if complexes of monomer-ferment and dimers-ferment were formed.
Proc. of SPIE Vol. 8699 86990L-1

This paper describes regularity of the delayed fluorescence kinetics changes of xanthene dyes in the cancer cells received from tumors of different diameter. It shows that the rate constant of bimolecular reactions (singlet–triplet T
Laser physics, 2013, Vol.23, No2, p. 025604

The influence of selenium preparations on the selenium concentration in rabbit’s blood is considered. It is shown that the "Selenolin" preparation is more efficient than "E-Selen", because it is better assimilated in animals’ organisms. The selenium concentration in the blood of rabbit females was measured by a fluorometric technique. Data processing was based on decomposition of spectra into Gaussian-Lorentzian components. We found that selenium concentration in blood increases 3÷5 times compared with the control group after application of selenium preparations. It was also revealed that application of "Selenolin" leads to increased quantity of lactocytes. These results can be used to remove selenium deficiency of rabbits and for prevention of diseases.
Proceedings of III International Symposium "TOPICAL PROBLEMS OF BIOPHOTONICS", p. 77

Manufacturing of hydrogel-based microchips on metal-coated substrates significantly enhances fluorescent signals upon binding of labeled target molecules. This observation holds true for both oligonucleotide and protein microchips. When Cy5 is used as fluorophore, this enhancement is 8-10-fold in hemispherical gel elements and 4-5-fold in flattened gel pads, as compared with similar microchips manufactured on uncoated glass slides. The effect also depends on the hydrophobicity of metal-coated substrate and on the presence of a layer of liquid over the gel pads. The extent of enhancement is insensitive to the nature of formed complexes and immobilized probes and remains linear within a wide range of fluorescence intensities. Manufacturing of gel-based protein microarrays on metal-coated substrates improves their sensitivity using the same incubation time for immunoassay. Sandwich immunoassay using these microchips allows shortening the incubation time without loss of sensitivity. Unlike microchips with probes immobilized directly on a surface, for which the plasmon mechanism is considered responsible for metal-enhanced fluorescence, the enhancement effect observed using hydrogel-based microchips on metal-coated substrates might be explained within the framework of geometric optics.