S. E. Kondakov

A new dried milk sampling technique and its application for progesterone detection in cows.

A new method for milk sample collection and storage, based on a dried milk sampling technique, is proposed. The method includes application of a whole milk sample to a porous membrane followed by drying. One hundred whole milk samples (dried and liquid) taken on day 21 post insemination were analysed for progesterone by ELISA and results for both dried and liquid samples were well correlated (r=0.911). Milk progesterone ELISA accuracy for pregnancy diagnosis in cows was 87%.

Comparison of PCR and ELISA methods for the detection of bovine leucosis in dried blood spots

PCR and ELISA methods for the detection of bovine leucosis in dried blood spots on porous membranes were compared. Dry samples were analyzed through real-time PCR, using several diagnostic test systems. Nineteen and 20 samples were identified as positive by PCR and ELISA, respectively. Fourteen of these samples were identified as positive by both methods. When using PCR and ELISA, 26 samples were identified as positive for leucosis, which amounted to 47% of the total number of tested samples. The results of the analysis of dried and native samples were in good agreement. The obtained results showed that whole blood sampling in the form of dried spots applied on membrane can be used as a convenient and reliable way to obtain dry samples of biological fluids with the purpose of screening herds for infectious diseases, in particular for bovine leucosis.

Assay of caffeine and its metabolites in the rat blood plasma using HPLC as a method for determination of metabolic ratios

A technique has been developed for the assay of caffeine and its metabolites in biological liquids (the rat blood plasma). The analysis was carried out using high-performance liquid chromatography with an ultraviolet detector. The limits of quantification (LOQ) for caffeine, paraxanthine, theobromine, and theophylline were calculated to be 10 ng/mL, and the LOQ of 1,3,7-trimethyluric acid was 25 ng/mL.

Preparation and evaluation of bioavailability of gatifloxacine-loaded nanoparticles

Pharmacokinetics of nanoparticles loaded with the antituberculosis drug gatifloxacine, as a new delivery system, was studied. In vivo experiments performed in laboratory animals showed that the dosage form of gatifloxacine incorporated into nanoparticles of poly(DL-lactic-co-glycolic acid) has a different pharmacological pattern as compared with the dosage form manufactured in industry. An increase in half-life (T1/2) and in mean residence time (MRT) was observed for gatifloxacine nanoparticles in blood plasma. The area under the “concentration versus time” pharmacological curve (AUC(0→36) was shown to increase mostly owing to the terminal part of the curve.

Porous membrane strip microsampling: a dried biofluid collection format and application for quantitative enzyme immunoassay

Applicability of a new and simple membrane-strip microsampling format for the analysis of human blood serum in a strip-dried form for the presence of a range of model low and high molecular weight analytes by ELISA was demonstrated. Biofluid was applied onto a narrow strip of porous membrane, dried and analysed using a square piece of membrane (0.5 × 0.5 cm). An antigen distribution along a sampling strip and storage stability in strip-dried human serum samples were investigated in a quantitative assay. It was demonstrated that thyroxine, progesterone, thyroglobulin, prostate specific antigen and antibodies (IgG) against H. pylori were stable on the strip-dried sample for at least a week at ambient temperature and 37 °C. For all antigens, the concordance of the data obtained for liquid and strip-dried serum samples was observed (Bland–Altman data analysis). The proposed new strip microsampling format provides volumetric sample collection and can find application in quantitative immunoassays, for instance, in ELISA.

Application of nonspecific biosensors in controlling the pharmaceutical activity of drugs

Here we explore the principal opportunity of using a erythrocyte sedimentation rate as a nonspecific biosensor to study variations in activity in different batches of the same pharmaceutical substance.

Modification of membrane materials used in dried blood spot technology by zinc oxide nanoparticles

The modification of hydrophilic fiberglass and cellulose membrane materials with zinc oxide has been investigated. The surfaces of zinc oxide nanoparticles was hydrophilized by modification with 3-amino-propyltriethoxysilane. It was shown using methods of Fourier transform IR-spectroscopy and scanning electron microscopy that coating with hydrophilized zinc oxide nanoparticles did not change the structure of glass fibers and membrane material, while the treatment of cellulose-based membrane materials caused irreversible changes in the structure of fibers and the material as a whole.

Metal nanoparticles as a new type of labels in rapid immunoassay methods

The study offers a brief overview of the main directions of development of rapid immunoassays. Emphasis is placed on the principles and functioning of lateral-flow immunoassay systems. The basic physical and chemical properties, the features of registration, and the advantages of the labels of biospecific reagents of metal nanoparticles, including gold nanoparticles, quantum dots, and magnetic particles, in rapid methods of immunochemical analysis are considered.

Blood as active colloid system: Study of blood sedimentation upon dilution of saline

Dependence of dynamics of blood sedimentation upon successive dilution of blood with saline solution in vitro was studied basing on the application of the principles of the system of technical vision. Oscillatory nature of the process of sedimentation of boundary between blood cells and plasma dependent on the degree of blood dilution with saline was found rate changes. The correlation between ESR (erythrocyte sedimentation rate) and the concentration of saline was determined.

Metrological approaches to drug development. Fast screening using universal biosensors at the stage of drug development

We expect that in the near future drug development will become the most interesting and demanded application of the suggested approach. Taking a known drug as the reference point and performing its chemical modification, one can sharply reduce the time and financial expenses for bioactivity testing of new substances and experimentally predict its general toxicity on a biological model the most adequate to human body.