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Prussian blue nanozymes possessing peroxidase-like activity gather significant attention as alternatives to natural enzymes in therapy, biosensing, and environmental remediation. Recently, Prussian blue nanoparticles with enhanced catalytic activity prepared by reduction of FeCl3/K3[Fe(CN)6] mixture have been reported. These nanoparticles were denoted as ‘artificial peroxidase’ nanozymes. Our study provides insights into the process of their synthesis. We studied how the size of nanozymes and synthesis yield can be controlled via adjustment of the synthesis conditions. Based on these results, we developed a reproducible and scalable method for the preparation of ‘artificial peroxidase’ with tunable sizes and enhanced catalytic activity. Nanozymes modified with gelatin shell and functionalized with affine molecules were applied as labels in colorimetric immunoassays of prostate-specific antigen and tetanus antibodies, enabling detection of these analytes in the range of clinically relevant concentrations. Protein coating provides excellent colloidal stability of nanozymes in physiological conditions and stability upon long-term storage.

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Research paper on sunthesis of protein nanoparticles<div><br><div><b>Abstract</b></div><div>The desolvation technique is one of the most popular methods for preparing protein nanoparticles for medicine, biotechnology, and food applications. We fabricated 11 batches of BSA nanoparticles and 2 batches of gelatin nanoparticles by desolvation method. BSA nanoparticles from 2 batches were cross-linked by heating at +70 °C for 2 h; other nanoparticles were stabilized by glutaraldehyde. We compared several analytical approaches to measuring their concentration: gravimetric analysis, bicinchoninic acid assay, Bradford assay, and alkaline hydrolysis combined with UV spectroscopy. We revealed that the cross-linking degree and method of cross-linking affect both Bradford and BCA assay. Direct measurement of protein concentration in the suspension of purified nanoparticles by dye-binding assays can lead to significant (up to 50-60%) underestimation of nanoparticle concentration. Quantification of non-desolvated protein (indirect method) is affected by the presence of small nanoparticles in supernatants and can be inaccurate when the yield of desolvation is low. The reaction of cross-linker with protein changes UV absorbance of the latter. Therefore pure protein solution is an inappropriate calibrator when applying UV spectroscopy for the determination of nanoparticle concentration. Our recommendation is to determine the concentration of protein nanoparticles by at least two different methods, including gravimetric analysis.<div><br></div></div></div>

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The effects of chorionic gonadotropin (hCG) on the expression of the hTERT gene in combination with the conversion of the phenotype of naive T-cells and T-cells of immune memory in vitro were studied. hCG inhibited expression of hTERT mRNA in naive T-cells (CD45RA+) and immune memory T cells (CD45RO+), causing a decrease in the replicative potential of the cells. The presence of hCG in the culture led to the conversion of the phenotype of T-lymphocytes. hCG reduced the number of proliferating T-cells of immune memory, estimated by phenotypic signs by differential gating. hCG (10 IU/ml and 100 IU/ml) inhibited expression of CD25 by the studied populations, but did not modulate expression of the CD71 proliferation marker. Thus, hCG inhibited the functional activity of naive T-cells and T-cells of immune memory, which, in the context of pregnancy, can contribute to the formation of immune tolerance to the semi-allogenic fetus.

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