APPLICATION OF AMINOPHENYLBORONIC ACID CONJUGATED WITH PROTEIN CARRIER FOR APTACHROMATOGRAPHIC DETECTION OF LEAD IONS

This work was financially supported by Russian Science Foundation (project # 19-44-02020)

LATERAL FLOW TEST STRIPS FOR HG2+ IONS DETECTION BASED ON COMBINATION OF OLIGONUCLEOTIDE-MODIFIED GOLD NANOPARTICLES AND CHELATION BY GLUTATHIONE

The environment requires special attention due to the development of the industry, the transition to industrial automation, battery use and human waste disposal. At the same time, the development of analytical test systems makes it possible to determine the content of various contaminants and regulate their entry into the surrounding world. However, a number of toxic contaminants can accumulate in the environment (water, soil) and cause long-term toxic effects on living organisms, including humans. Therefore, the analytical techniques being developed (colorimetric, electrochemical, chromatographic etc.) and the laboratory methods (ICP-MS, ICP-AES) of their analysis existing in practice are in demand.This work was financially supported by Russian Science Foundation (project # 19-44-02020)

COMPARISON OF Au, Au-Pt, AND Au-Ag NANOPARTICLES AS MARKERS FOR THE IMMUNOCHROMATOGRAPHIC DETERMINATION OF NONYLPHENOL

This work was supported by the Russian Science Foundation (grant no. 22-13-00293)

Comparison of Au, Au–Pt, and Au–Ag nanoparticles as markers for immunochromatographic determination of nonylphenol

Received: 25.11.22. Revised: 07.12.22. Accepted: 07.12.22. Available online: 19.12.22.The authors are grateful to S.M. Pridvorova from A.N. Bach Institute of Biochemistry (Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia) for the support with TEM images.Gold spherical nanoparticles, gold-platinum nanoflowers, and gold-silver nanostars were obtained and compared as labels for immunochromatographic analysis. The nanoparticles were synthesized by chemical reduction from various precursors and then conjugated with staphylococcal protein A to be used in indirect immunochromatographic determination of nonylphenol. The results obtained were evaluated in terms of analytical characteristics and R2 value, as well as the color intensity of the test band. According to the comparison results, it was revealed that the R2 value varied from 0.82 for the gold-silver nanostars to 0.96 for the spherical gold nanoparticles. The working range of determined concentrations was from 2 to 100 μg/mL for unspherical and from 2 to 50 μg/mL – for spherical markers used; the analysis time was 20 min.This work was supported by the Russian Science Foundation (grant no. 22-13-00293)

Engineering of Thermal Stability in a Cold-Active Oligo-1,6-Glucosidase from Exiguobacterium sibiricum with Unusual Amino Acid Content

A gene coding for a novel putative amylase, oligo-1,6-glucosidase from a psychrotrophic bacterium Exiguobacterium sibiricum from Siberian permafrost soil was cloned and expressed in Escherichia coli. The amino acid sequence of the predicted protein EsOgl and its 3D model displayed several features characteristic for the cold-active enzymes while possessing an unusually high number of proline residues in the loops—a typical feature of thermophilic enzymes. The activity of the purified recombinant protein was tested with p-nitrophenyl α-D-glucopyranoside as a substrate. The enzyme displayed a plateau-shaped temperature-activity profile with the optimum at 25 °C and a pronounced activity at low temperatures (50% of maximum activity at 5 °C). To improve the thermal stability at temperatures above 40 °C, we have introduced proline residues into four positions of EsOgl by site-directed mutagenesis according to “the proline rule”. Two of the mutants, S130P and A109P demonstrated a three- and two-fold increased half-life at 45 °C. Moreover, S130P mutation led to a 60% increase in the catalytic rate constant. Combining the mutations resulted in a further increase in stability transforming the temperature-activity profile to a typical mesophilic pattern. In the most thermostable variant A109P/S130P/E176P, the half-life at 45 °C was increased from 11 min (wild-type) to 129 min

Estimation of total IgE by immunochromatographic assay and ELISA: mean (n = 8) and standard deviation.

<p>Estimation of total IgE by immunochromatographic assay and ELISA: mean (n = 8) and standard deviation.</p

Estimation of total IgE by immunochromatographic assay: mean (n = 10) and standard deviation.

<p>Estimation of total IgE by immunochromatographic assay: mean (n = 10) and standard deviation.</p

Correlation between ELISA and immunochromatographic assay results for samples from 95 human subjects.

<p>The immunochromatographic assay is able to estimate total IgE in the serum of human subjects, with good correlation kit (R² = 0.9884) to the results of a commercial ELISA.</p

Fluorescence intensity in the test zone of an immunochromatographic test strip at different combinations of antibodies against human IgE.

<p>Fluorescence intensity in the test zone of an immunochromatographic test strip at different combinations of antibodies against human IgE.</p

Change in fluorescence intensity with analysis time.

<p>The figure shows the relationship between the analysis time and the fluorescence intensity in the test zone of the immunochromatographic test system. A standard solution of IgE with a concentration of 200/L was used as a sample.</p