Preconcentration of noble metals on a polymer support as complexes of organic reagents and their subsequent determination in the solid phase

2000 ◽  
Vol 55 (3) ◽  
pp. 249-254 ◽  
Author(s):  
R. F. Gur’eva ◽  
S. B. Savvin
Keyword(s):  
Noble Metals ◽  
Solid Phase ◽  
Polymer Support ◽  
Organic Reagents ◽  
Subsequent Determination

scholarly journals An Improved Procedure for the Preparation of Thrombin Low Molecular Weight Substrates - Peptide p-Nitroanilides

2018 ◽  
Vol 1 (4) ◽  
pp. e00057 ◽  
Author(s):  
A.A Chistov ◽  
A.V. Talanova ◽  
M.V. Melnikova ◽  
S.S. Kuznetsova ◽  
E.F. Kolesanova
Keyword(s):  
Molecular Weight ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Potassium Sulfate ◽  
Polymer Support ◽  
Low Molecular Weight ◽  
Chromogenic Substrate ◽  
Peptide Substrates ◽  
Terminal Amino ◽  
Hydrolysis Of

Low molecular weight chromogenic thrombin peptide substrates, p-nitroanilides of short peptides protected at their N-terminal amino group, were prepared by solid-phase peptide synthesis on polystyrene-divinylbenzene polymer with trityl groups with preliminary attached p-phenylene diamine moiety. After the cleavage from the resin peptide p-aminoanilides were mildly oxidized to p-nitroanilides with the mixture of potassium sulfate and persulfate. Adsorption onto polymer support Bio-Beads SM-2 with further elution by acetonitrile allowed easy separating peptide p-nitroanilides from the oxidizer and obtaining the thrombin chromogenic substrate preparations with the target substance contents of not less than 95% and yields of 30-40%. Thrombin effectively catalyzed hydrolysis of the prepared substrates with KM and Vmax values of 29-134 mM and 0.03-1/16 mM/s, respectively.

scholarly journals Antibacterial and Immunomodulatory Potentials of Biosynthesized Ag, Au, Ag-Au Bimetallic Alloy Nanoparticles Using the Asparagus racemosus Root Extract

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2453
Author(s):  
Musarat Amina ◽  
Nawal M. Al Musayeib ◽  
Nawal A. Alarfaj ◽  
Maha F. El-Tohamy ◽  
Gadah A. Al-Hamoud
Keyword(s):  
Noble Metals ◽  
Solid Phase ◽  
Sandwich Elisa ◽  
Root Extract ◽  
Asparagus Racemosus ◽  
Alloy Nanoparticles ◽  
Bacterial Strains ◽  
Microwave Assisted ◽  
Bimetallic Alloy ◽  
Cytokine Levels

Two noble metals, such as silver and gold alloy nanoparticles, were successfully synthesized by the microwave assisted method in the presence of the Asparagus racemosus root extract and were used as an antibacterial and immunomodulatory agent. The nanostuctures of the synthesized nanoparticles were confirmed by various spectroscopic and microscopic techniques. The UV-vis spectrum exhibits a distinct absorption peak at 483 nm for the bimetallic alloy nanoparticles. The microscopic analysis revealed the spherical shaped morphology of the biosynthesized nanoparticles with a particle size of 10–50 nm. The antibacterial potential of the green synthesized single metal (AgNPs and AuNPs) and bimetallic alloy nanoparticles was tested against five bacterial strains. The bimetallic alloy nanoparticles displayed the highest zone of inhibition against P. aeurgnosia and S.aureus strains when compared to single metal nanoparticles and plant extract. In addition, the inmmunomodulatory potential of the root extract of A. racemosus, AgNPs, AuNPs, and Ag-Au alloy NPs is achieved by measuring the cytokine levels in macrophages (IL-1β, IL-6, and TNF-α) and NK cells (IFN-γ) of NK92 and THP1 cells using the solid phase sandwich ELISA technique. The results showed that the root extract of A. racemosus, AgNPs, and AuNPs can reduce the pro-inflammatory cytokine levels in the macrophages cells, while Ag-Au alloy NPs can reduce cytokine responses in NK92 cells. Overall, this study shows that the microwave assisted biogenic synthesized bimetallic nanoalloy nanoparticles could be further explored for the development of antibacterial and anti-inflammatory therapies.

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