nanoparticles of silver
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Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 527
Author(s):  
Denis N. Chausov ◽  
Veronika V. Smirnova ◽  
Dmitriy E. Burmistrov ◽  
Ruslan M. Sarimov ◽  
Alexander D. Kurilov ◽  
...  

Microbial antibiotic resistance is an important global world health problem. Recently, an interest in nanoparticles (NPs) of silver oxides as compounds with antibacterial potential has significantly increased. From a practical point of view, composites of silver oxide NPs and biocompatible material are of interest. A borosiloxane (BS) can be used as one such material. A composite material combining BS and silver oxide NPs has been synthesized. Composites containing BS have adjustable viscoelastic properties. The silver oxide NPs synthesized by laser ablation have a size of ~65 nm (half-width 60 nm) and an elemental composition of Ag2O. The synthesized material exhibits strong bacteriostatic properties against E. coli at a concentration of nanoparticles of silver oxide more than 0.01%. The bacteriostatic effect depends on the silver oxide NPs concentration in the matrix. The BS/silver oxide NPs have no cytotoxic effect on a eukaryotic cell culture when the concentration of nanoparticles of silver oxide is less than 0.1%. The use of the resulting composite based on BS and silver oxide NPs as a reusable dry disinfectant is due to its low toxicity and bacteriostatic activity and its characteristics are not inferior to the medical alloy nitinol.


Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Kashif Sadiq ◽  
Fahd Jarad ◽  
Imran Siddique ◽  
Bagh Ali

In this article, ethylene glycol (EG) + waterbased Maxwell nanofluid with radiation and Soret effects within two parallel plates has been investigated. The problem is formulated in the form of partial differential equations. The dimensionless governing equations for concentration, energy, and momentum are generalized by the fractional molecular diffusion, thermal flux, and shear stress defined by the Caputo–Fabrizio time fractional derivatives. The solutions of the problems are obtained via Laplace inversion numerical algorithm, namely, Stehfest’s. Nanoparticles of silver (Ag) are suspended in a mixture of EG + water to have a nanofluid. It is observed that the thermal conductivity of fluid is enhanced by increasing the values of time and volume fraction. The temperature and velocity of water-silver nanofluid are higher than those of ethylene glycol (EG) + water (H2O)-silver (Ag) nanofluid. The results are discussed at 2% of volume fraction. The results justified the thermo-physical characteristics of base fluids and nanoparticles shown in the tables. The effects of major physical parameters are illustrated graphically and discussed in detail.


Author(s):  
Aditya Singh ◽  
Vaseem A. Ansari ◽  
Farogh Ahsan ◽  
Juber Akhtar ◽  
Poonam Khushwaha ◽  
...  

Cancer predicament is a global concern because of the ability of swift growth to cause infection to the cell. Breast cancer is the fifth contemplative reason for cancer death many scientific approaches have been thriving to deal with it and to make anticancer agent, therapeutic, safe and effective. In this burgeon silver was found as antitumor agent with noteworthy properties of conductivity, stability, and activity. Soy isoflavones mainly derived from soybean have accure much attention as dietary components having inhibitory effects on breast cancer and prostate cancer in Asians, who consume 20-50 times more than Americans, soy diet act as a natural chemopreventive agent. Previous data show that nanoparticles of silver are effective against a wide spectrum of bacteria, fungi, viruses, some infectious diseases and burn wounds. Now genistein has been found to inhibit the growth of various cancer cell lines including prostate and breast cancer cells. Nanoparticles needed to be biosynthesized because of the expensive, physical and. chemical processes. Chemical synthesis also contributes to the appearance on the surface of some toxic chemical that can adversely affect medical applications. Green synthesis offers advances over chemical and physical method because it is price effective, environmentally friendly, easily scaled up for large scale synthesis and does not requires use high pressure, energy, temperature and toxic chemicals.


2021 ◽  
pp. 34-37
Author(s):  
Sruti S Nair ◽  
Anchana Devi. C ◽  
Pushpa. N

Nanoparticles are particles of any shape with size ranging from 10 to 100 nm. Synthesis of metal nanoparticle is a single step process, which is inexpensive and eco-friendly method. Metals such as silver, zinc and copper can be used for the production of nanoparticles. Tabernaemontana divericata have been reported to exhibit antimicrobial, antioxidant, antitumor and analgesic effect. It's used for wound healing and treatment of various diseases like skin diseases, aches, ascaris, scabies eye diseases and pain. Nanoparticles of silver, zinc and copper were biosynthesised from the stem extract of Tabarnaemontana divaricata. Characterization studies were carried out using UV spectrophotometer, FTIR & SEM analysis. The nanoparticle were tested for it potential antibacterial activities. Among the three, AgNPs nanoparticle exhibited more antimicrobial activity than the CuNPs, and ZnNPs. The biomolecules in T. divericata stem extract with the potential to reduce and cap the bio reduced AgNPs were assessed with FTIR spectral measurements.


2021 ◽  
Vol 30 ◽  
pp. 02004
Author(s):  
Aleksandr Dudoladov ◽  
Marina Alekhina ◽  
Aleksandra Revina ◽  
Olga Souvorova

On the basis of granular synthetic zeolites NaY, HY, and ZSM-5, adsorbents containing nanoparticles of silver, cobalt, molybdenum, and tungsten were obtained. The samples have a lower surface polarity in comparison with the initial zeolites, which is reflected in the selectivity of a number of samples with respect to argon. This is due to the fact that the argon molecule interacts with zeolites only through nonspecific forces. Modification was performed by interacting with reverse-micellar solutions of nanoparticles. The actual sizes of metal particles and their distribution over the surface of the modified samples of zeolites have been determined by the method of transmission electron microscopy. The samples’ equilibrium adsorption capacities for oxygen and argon (25°С and atmospheric pressure) and the separation coefficient of the argon–oxygen mixture as the ratio of Henry’s coefficients have been determined. It has been demonstrated that samples of the NaY zeolite modified with silver nanoparticles have the separation coefficient value of the argon–oxygen gas mixture equal to 1.6.


2021 ◽  
Vol 10 (1) ◽  
pp. 811-823
Author(s):  
Mousa A. Alghuthaymi ◽  
Zainab R. El-Sersy ◽  
Ahmed A. Tayel ◽  
Mohammed A. Alsieni ◽  
Ahmed I. Abd El Maksoud

Abstract Candida genus includes many hazardous and risky species that can develop resistance toward various antifungal types. Metals nanoparticles (NPs) possess powerful antimicrobial actions, but their potential human toxicity could limit their practices. The algal polysaccharide fucoidan (Fu) was extracted from the macro-brown algae, Cystoseira barbata, analyzed, and used for biosynthesizing nanoparticles of silver (Ag-NPs) and selenium (Se-NPs). The extracted Fu had elevated fucose levels (58.73% of total monosaccharides) and exhibited the main biochemical characteristic of customary Fu. The Fu biosynthesis of Ag-NPs and Se-NPs was achieved via facile direct protocol; Fu-synthesized NPs had 12.86 and 16.18 nm average diameters, respectively. The ultrastructure of Fu-synthesized NPs emphasized well-distributed and spherical particles that were embedded/capped in Fu as combined clusters. The Fu/Ag-NPs and Fu/Se-NPs anticandidal assessments, against Candida albicans, Candida glabrata, and Candida parapsilosis, revealed that both NPs had powerful fungicidal actions against the examined pathogens. The ultrastructure imaging of subjected C. albicans and C. parapsilosis to NPs revealed that Fu/Ag-NPs and Fu/Se-NPs triggered remarkable distortions, pore formation, and destructive lysis in cell surfaces within 10 h of exposure. The innovative usage of C. barbata Fu for Ag-NP and Se-NP synthesis and the application of their composites as powerful anticandidal agents, with minimized human toxicity, are concluded.


Author(s):  
C. Martínez Vieyra ◽  
M.T Olguin ◽  
E. Gutiérrez Segura ◽  
G. López Tellez

The characteristics of the nanoparticles of silver, copper and zinc obtained from two synthetic routes were investigated. A possible future application of these nanoparticles is as bactericidal agents. The reduction methods were Aloe vera extract and gamma ray irradiation with a dose rate of 0.756 kGy/h and a total dose of 40 kGy from a 60Co-source. The chemical species of the nanoparticles (NPs) obtained by Aloe vera extract were Ag, CuO, and ZnO; while the NPs obtained using gamma irradiation were Ag and Cu2O. The precursor to obtaining the nanoparticles and the route of synthesis define the purity, morphology, crystallinity, and chemical speciation of the metal.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Huanlei Yang ◽  
Shuxin Zhang ◽  
Jinhua Yan

MFC/NFC aerogel has water sensitivity, and it should be improved in strength in water before application. Chitosan was investigated as a MFC/NFC aerogel reinforcing agent in this paper. The reinforced aerogel showed slightly tighter structure and very good water stability and mechanical strength. FTIR disclosed the chemical bonds formed between chitosan and cellulose. Nanoparticles of silver (Ag-NPs) were loaded using the reinforced aerogel. The excellent Ag-NP monodistribution on the aerogel was expressed by TEM. Both chitosan-reinforced Ag-NPs loaded MFC aerogel and NFC aerogel and expressed great antibacterial activity, though reinforced MFC aerogel exhibited better properties, like higher BET, lighter density, more Ag-NP loading, and better distribution, than NFC aerogel in this research. Chitosan-reinforced MFC aerogel is a good potential substrate for nanoparticle loading and biocomposite making.


Author(s):  
Lakmini Inoka Wijesooriya ◽  
Dilshan Waidyathilake

Wounds present serious health problems in humans and animals. Importantly, if left untreated, wounds invariably lead to long-term morbidity. The inappropriate use and costs of antibiotics place significant challenges globally and affect the health budgets of many countries. Though some antibiotics are administered systemically, treatment of localized infections, in particular, chronic wound infections, does not need such therapy—this would minimize development of antibiotic resistance. Of these measures, nanoparticles of silver, ZnO, and gold seem to give promising results against common wound pathogens while having few limitations. Chemical components of essential oils, which are extracted from different plants, have been shown to act against common wound pathogens. Plant extracts have shown different mechanisms in biofilm elimination. Chlorhexidine and chlorine derivatives act as wound antiseptics. Attempts with biological agents such as maggots have also been shown to provide anti-infective as well as mechanical removal of wound debris. Honey, including those obtained from bees, has a wide coverage against wound pathogens. Glycerin and hypertonic saline are anti-infective through the concentration-dependent killing of pathogens. Hyperbaric oxygen acts against many wound pathogens, in particular anaerobes. This review is focused on nonantibiotic attempts for the cure of localized infections, in particular, chronic wounds with common wound pathogens.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 702
Author(s):  
F. Javier Gil ◽  
Eduardo Espinar-Escalona ◽  
Nuria Clusellas ◽  
Javier Fernandez-Bozal ◽  
Montserrat Artes-Ribas ◽  
...  

A potential new bactericide treatment for NiTi orthodontic archwires based in the electrodeposition of silver nanoparticles on the surface was studied. Twenty-five archwires were treated by electrodeposition, obtaining nanoparticles of silver embedded on the archwire surface. These were evaluated in order to investigate the possible changes on the superelastic characteristics (critical temperatures and stresses), the nickel ion release, and the bacteria culture behavior. The chemical composition was analyzed by Energy Dispersive X-Ray Spectroscopy-microanalysis; the singular temperatures of the martensitic transformation were obtained by a flow calorimeter. Induced martensitic transformation stresses were obtained by mechanical testing apparatus. Nickel ion release was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) equipment using artificial saliva solution at 37 °C. Bacterial tests were studied with the most used oral bacterial strains: Streptococcus sanguinis and Lactobacillus salivarius. NiTi samples were immersed in bacterial suspensions for 2 h at 37 °C. Adhered bacteria were separated and seeded on agar plates: Tood-Hewitt (TH) and Man-Rogosa-Sharpe (MRS) for S. sanguinis and for L.salivarius, respectively. These were then incubated at 37 °C for 1 day and the colonies were analyzed. The results showed that the transformation temperatures and the critical stresses have not statistically significant differences. Likewise, nickel ion release at different immersion times in saliva at 37 °C does not present changes between the original and treated with silver nanoparticles archwires. Bacteria culture results showed that the reduction of the bacteria due to the presence to the nanoparticles of silver is higher than 90%. Consequently, the new treatment with nanoparticles of silver could be a good candidate as bactericidic orthodontic archwire.


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