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1.
Int J Mol Sci ; 22(19)2021 Oct 01.
Article in English | MEDLINE | ID: covidwho-1463707

ABSTRACT

The electron density of a nanoparticle is a very important characteristic of the properties of a material. This paper describes the formation of silver nanoparticles (NPs) and the variation in the electronic state of an NP's surface upon the reduction in Ag+ ions with oxalate ions, induced by UV irradiation. The calculations were based on optical spectrophotometry data. The NPs were characterized using Transmission electron microscopy and Dynamic light scattering. As ~10 nm nanoparticles are formed, the localized surface plasmon resonance (LSPR) band increases in intensity, decreases in width, and shifts to the UV region from 402 to 383 nm. The interband transitions (IBT) band (≤250 nm) increases in intensity, with the band shape and position remaining unchanged. The change in the shape and position of the LSPR band of silver nanoparticles in the course of their formation is attributable to an increasing concentration of free electrons in the particles as a result of a reduction in Ag+ ions on the surface and electron injection by CO2- radicals. The ζ-potential of colloids increases with an increase in electron density in silver nuclei. A quantitative relationship between this shift and electron density on the surface was derived on the basis of the Mie-Drude theory. The observed blue shift (19 nm) corresponds to an approximately 10% increase in the concentration of electrons in silver nanoparticles.


Subject(s)
Electricity , Electrons , Metal Nanoparticles/chemistry , Silver/chemistry , Solutions/chemistry , Chemical Phenomena , Electrochemistry , Metal Nanoparticles/ultrastructure , Microscopy, Electron, Transmission , Models, Theoretical , Particle Size , Surface Plasmon Resonance
2.
Int J Mol Sci ; 22(12)2021 Jun 17.
Article in English | MEDLINE | ID: covidwho-1282513

ABSTRACT

Novel antiviral nanotherapeutics, which may inactivate the virus and block it from entering host cells, represent an important challenge to face viral global health emergencies around the world. Using a combination of bioorthogonal copper-catalyzed 1,3-dipolar alkyne/azide cycloaddition (CuAAC) and photoinitiated thiol-ene coupling, monofunctional and bifunctional peptidodendrimer conjugates were obtained. The conjugates are biocompatible and demonstrate no toxicity to cells at biologically relevant concentrations. Furthermore, the orthogonal addition of multiple copies of two different antiviral peptides on the surface of a single dendrimer allowed the resulting bioconjugates to inhibit Herpes simplex virus type 1 at both the early and the late stages of the infection process. The presented work builds on further improving this attractive design to obtain a new class of therapeutics.


Subject(s)
Antiviral Agents/pharmacology , Dendrimers/pharmacology , Glycoproteins , Herpesvirus 1, Human , Peptides/pharmacology , Viral Proteins , Amino Acid Sequence , Animals , Antiviral Agents/chemistry , CHO Cells , Cell Line , Cell Survival/drug effects , Chemical Phenomena , Chemistry Techniques, Synthetic , Chromatography, High Pressure Liquid , Cricetulus , Dendrimers/chemistry , Glycoproteins/chemistry , Herpesvirus 1, Human/metabolism , Microbial Sensitivity Tests , Molecular Structure , Peptides/chemistry , Spectrum Analysis , Viral Proteins/chemistry
3.
J Mol Model ; 26(8): 200, 2020 Jul 07.
Article in English | MEDLINE | ID: covidwho-650087

ABSTRACT

Beta-lactamase (ampC) in general causes the onset of antibiotic resistance in pathogenic bacteria against the ß-lactam antibiotics. Morganella morganii which belongs to the Proteae tribe of the Enterobacteriaceae family is a Gram-negative bacillus. Gram-negative bacteria are the key problematic agents among the human population in overexpressing resistance against ß-lactam antibiotics. These ß-lactam antibiotics being experimentally well studied still lack the key information and mechanism for their resistance. The structural information of the ampC protein is unknown and poorly studied; hence, it is the need of the hour to find effective inhibitors against it. In our study, the prediction of the three-dimensional structure of ampC protein from Morganella morganii was performed using a comparative modelling approach. The predicted structure was energetically stabilized and functional conformations were mapped through 100-ns molecular dynamics simulation runs. Also, Ramachandran plot shows the model to be stereo-chemically stable with most residues found under core allowed regions. Drug screening with several experimentally tested inhibitors was then confirmed to check the activity against ampC protein using an AutoDock tool. The results suggested OncoglabrinolC molecule as the best inhibitor (out of 21 drug molecules) with a binding affinity of - 11.44 kcal/mol. Anti-bacterial/anti-parasitic inhibitors have not only been used against bacterial infections, but later reports have also shown them to work against deadly viruses such as SARS-CoV2. This key structural and inhibitory information is certain to help in the discovery of specific and potent substitute therapeutic drugs and the development of experimental procedures against human infection.


Subject(s)
Anti-Bacterial Agents/chemistry , Molecular Docking Simulation , Molecular Dynamics Simulation , beta-Lactamase Inhibitors/chemistry , beta-Lactamases/chemistry , Anti-Bacterial Agents/pharmacology , Base Sequence , Binding Sites , Chemical Phenomena , Drug Discovery , Drug Evaluation, Preclinical , Humans , Ligands , Mutation , Protein Binding , Protein Conformation , beta-Lactamase Inhibitors/pharmacology , beta-Lactamases/genetics
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