Transformation of Nano-Size Titanium Dioxide Particles in the Gastrointestinal Tract and Its Role in the Transfer of Nanoparticles through the Intestinal Barrier.

In this work, the size transformation of the TiO nanofraction from pharmaceutical grade E171 powder was studied during its transit through the gastrointestinal tract (GIT). It was shown that pharmaceutical-grade TiO powder contained about 0.68% (/) of particles smaller than 240 nm in diameter.

Fluorescent DNA Probes: Study of Properties and Methods of Application.

The results of long-term author's studies of the optical and complex-forming properties of more than 30 synthetic low-molecular-weight fluorophores specific for DNA are described. These studies made it possible to significantly expand the already existing database of properties of such compounds, clarify the ideas about the patterns linking the mentioned properties of fluorophores with their structure, and formulate recommendations on designing new effective DNA-specific fluorophores. The results of these studies can be used, in particular, in the development of new rapid methods for diagnosing various diseases, biotesting of probiotic and antibiotic properties of various products and wastes, etc.

New Method of Integrated Photofluorescence Microbiotesting.

A biotesting procedure that makes it possible to record the changes in the intensities of elastic light scattering, light absorption, and intrinsic photofluorescence of the protein component, as well as the determination of the concentration and structuring coefficients of the genomic component, of the samples with viable unicellular test organisms incubated in a liquid nutrient medium in the presence and absence of various external chemical factors, is described. The results of the analysis of the antibiotic activity of various metal cations with the use of this technique are presented. This technique is much more rapid, objective, and comprehensive for the assessment of the effect on the reproduction rate, metabolic activity, and genome structure of the test organisms from the samples of various products, wastes, etc.

An Integrated Method of Instrumental Microbiotesting of Environmental Safety of Various Products, Wastes, and Territories.

The described microbiotesting technique provides the recording of pH changes, redox potential, electrical conductivity, optical density, light scattering and luminescence intensities, and other parameters of samples with viable test microorganisms incubated in a liquid nutrient medium in the presence and absence of the tested factors. The results of using this system for the analysis of pro- and antibiotic activity of various oil products, as well as weak electromagnetic fields of the megahertz range, are presented. It has been shown that the proposed technique, compared to the standard methods, yields more detailed and objective information and is less time- and labor-consuming.

Spectral study of the interaction of DNA with benzothiazolyl-benz-alpha-chromene.

Absorption and luminescence excitation and emission spectra of newly synthesized 2-(4-methylphenylimino)-3-(2 -benzothiazolyl)benz-alpha-chromene (BCBT) have been studied in the presence of various DNA concentrations. BCBT is characterized by the existence of two different fluorescent systems, exhibiting radiationless fluorescence resonance energy transfer between them. In the range of molar ratios of polynucleotide/dye concentrations from 0 to 50, BCBT preferentially intercalates into DNA due to its benz-alpha-chromene fragment, whereas the 2-benzothiazolyl fragment is responsible for fluorescence.