scholarly journals Avaliação da Capacidade Antimicrobiana de Nanopartículas de Prata Sintetizadas com Mel de Abelha

2020 ◽  
Vol 24 (3) ◽  
pp. 305-309
Author(s):  
Gabriela Sousa Dourado ◽  
Julio César Amaral Cardoso ◽  
Igor Feijão Cardoso ◽  
Alan Kelbis Oliveira Lima ◽  
José Jeosafá V. Sousa Júnior ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Apis Mellifera ◽  
Candida Krusei ◽  
Information Storage ◽  
Hydrodynamic Diameter ◽  
Dry Period ◽  
Clinical Interest ◽  
Optical Information Storage ◽  
Average Hydrodynamic Diameter

Nos últimos anos, as nanopartículas de prata (AgNPs) têm atraído muita atenção devido às suas largas aplicações em diferentes campos como biotecnologia, microeletrônica, armazenamento de informação óptica, medicina e conversão de energia. O presente trabalho teve como objetivo sintetizar nanopartículas de prata a partir de amostras de mel de abelhas Apis mellifera produzidos na cidade de Santarém-Pará, Brasil. Além disso, avaliar a atividade antimicrobiana dessas amostras, obtidas em dois períodos distintos (seco e chuvoso), frente a patógenos de interesse clínico: Staphylococcus aureus, Staphylococus epidermidis e Cândida krusei. Todas as amostras apresentaram estabilidade, homogeinidade e diâmetro hidrodinâmico médio de 600 nm, tendo uma grande área superficial. Apresentaram índice de polidispersividade (PdI) médio de 0,36 e 0,28, utilizando méis do período seco e chuvoso, respectivamente. O potencial Zeta foi negativo para 5 amostras do período seco. As linhagens de S. aureus, S. epidermides e C. krusei foram sensíveis à todas as AgNPs sintetizadas, sendo que as CMI para S. aureus e S. epidermides variaram de 0,17 a 10,79 mg mL-1 e para C. krusei de 0,08 a 10,79 mg mL-1. De acordo com estudos as AgNPs sintetizadas se mostram mais ativas em bactérias Gram negativas do que Gram positivo. No entanto, os elevados valores de CMI obtidos neste trabalho estão associados aos maiores tamanhos das nanoparticulas sintetizadas.   Palavras-chave: Apis melífera. Staphylococcus aureus. Staphylococus epidermidis. Candida krusei. Abstract In recent years, silver nanoparticles (AgNPs) have attracted a lot of attention due to their wide applications in different fields such as biotechnology, microelectronics, optical information storage, medicine, and energy conversion. The present work aimed to synthesize silver nanoparticles from honey samples from Apis mellifera bees produced in the Santarém-Pará, Brazil. In addition, to evaluate the antimicrobial activity of these samples, obtained in two distinct periods (dry and rainy), against pathogens of clinical interest: Staphylococcus aureus, Staphylococus epidermidis and Candida krusei. All samples showed stability, homogeneity and an average hydrodynamic diameter of 600 nm, with a large surface area. They had an average polydispersity index (PdI) of 0.36 and 0.28, using honeys from the dry and rainy periods, respectively. The Zeta potential was negative for 5 samples from the dry period. The strains of S. aureus, S. epidermides and C. krusei were sensitive to all synthesized AgNPs, with the MIC for S. aureus and S. epidermides ranging from 0.17 to 10.79 mg mL-1 and for C krusei from 0.08 to 10.79 mg mL-1. According to studies, the synthesized AgNPs are more active in Gram negative bacteria than Gram positive. However, the high MIC values obtained in this work are associated with the larger sizes of the synthesized nanoparticles.   Keywords: Apis mellifera. Staphylococcus aureus. Staphylococus epidermidis. Candida krusei.

Antibacterial and Cytotoxic Effects of Silver Nanoparticles on Staphylococcus aureus and Normal Vero Cells

2019 ◽  
Vol 22 (10) ◽  
pp. 184-190
Author(s):  
Rasha Hadi Saleh ◽  
Entisar J. Al-Mukhtar ◽  
Zaytoon A. Al-Khafaji ◽  
Mohammed H. Al Hasnawy ◽  
Huda H. Al-Hasnawy
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Vero Cells ◽  
Cytotoxic Effects

NaMgF 3 :Tb 3+ @NaMgF 3 Nanoparticles Containing Deep Traps for Optical Information Storage

2021 ◽  
pp. 2100624
Author(s):  
Yikuang Wang ◽  
Dunrong Chen ◽  
Yixi Zhuang ◽  
Wenjing Chen ◽  
Hangyu Long ◽  
...  
Keyword(s):  
Information Storage ◽  
Optical Information ◽  
Deep Traps ◽  
Optical Information Storage

scholarly journals The Antimicrobial and Anti-Inflammatory Effects of Silver Nanoparticles Synthesised from Cotyledon orbiculata Aqueous Extract

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1343
Author(s):  
Caroline Tyavambiza ◽  
Abdulrahman Mohammed Elbagory ◽  
Abram Madimabe Madiehe ◽  
Mervin Meyer ◽  
Samantha Meyer
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Metallic Nanoparticles ◽  
Methicillin Resistance ◽  
Antimicrobial Activities ◽  
Transmission Electron ◽  
Anti Inflammatory ◽  
Anti Inflammation ◽  
Important Medicinal Plant ◽  
Pro Inflammatory Cytokines

Cotyledon orbiculata, commonly known as pig’s ear, is an important medicinal plant of South Africa. It is used in traditional medicine to treat many ailments, including skin eruptions, abscesses, inflammation, boils and acne. Many plants have been used to synthesize metallic nanoparticles, particularly silver nanoparticles (AgNPs). However, the synthesis of AgNPs from C. orbiculata has never been reported before. The aim of this study was to synthesize AgNPs using C. orbiculata and evaluate their antimicrobial and immunomodulatory properties. AgNPs were synthesized and characterized using Ultraviolet-Visible Spectroscopy (UV-Vis), Dynamic Light Scattering (DLS) and High-Resolution Transmission Electron Microscopy (HR-TEM). The antimicrobial activities of the nanoparticles against skin pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Methicillin Resistance Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) as well as their effects on cytokine production in macrophages (differentiated from THP-1 cells) were evaluated. The AgNPs from C. orbiculata exhibited antimicrobial activity, with the highest activity observed against P. aeruginosa (5 µg/mL). The AgNPs also showed anti-inflammatory activity by inhibiting the secretion of pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-1 beta) in lipopolysaccharide-treated macrophages. This concludes that the AgNPs produced from C. orbiculata possess antimicrobial and anti-inflammation properties.

Ferrimagnetic Cobalt Ferrite Films Prepared by the Sol-Gel Process

1993 ◽  
Vol 313 ◽  
Author(s):  
Eva M. Wong ◽  
Haixing Zheng ◽  
John D. Mackenzie ◽  
T. Tsuchiya
Keyword(s):  
Remanent Magnetization ◽  
Cobalt Ferrite ◽  
Amorphous Film ◽  
Heat Treating ◽  
Fused Silica ◽  
Information Storage ◽  
Degree Of Crystallinity ◽  
Optical Information ◽  
Ferrite Films ◽  
Optical Information Storage

ABSTRACTFerrimagnetic oxide films have been shown to have potential for use as Magneto-optical information storage Materials. Cobalt ferrite films are particularly interesting for magneto optical information storage due to their high magneto optical rotation [1]. In this work, synthesized soluble cobalt (II) and iron (III) Methoxyethoxides were mixed in stoichiometric ratios for use as Co and Fe precursors in the preparation of CoFe2O4ferrimagnetic films. The decomposition of the precursors was characterized by thermogravimetric analysis.CoFe2O4 films were prepared by the dip coating technique using fused silica substrates. These films were then heat treated at temperatures ranging from 200°C to 600°C to study the transformation from an amorphous film to a crystalline film as determined by x-ray diffraction. The Magnetic hysteresis behavior of the films as a function of heat treating temperature and hence crystallinity was also studied. As a general trend, films having a greater degree of crystallinity exhibited larger values of saturation magnetization and remanent Magnetization. The amorphous film was found to exhibit the highest coercive field, but low values of saturation and remanent Magnetization. The effect of heat treating under the influence of a magnetic field of 1.88 kÖe was found to enhance crystallization only slightly and had very little effect on the magnetic properties of the film.

Trypsinolysis of Polyurethane Particles Based on Сyclodextrin with Encapsulated Moxifloxacin

2021 ◽  
Vol 37 (5) ◽  
pp. 72-79
Author(s):  
L.R. Yakupova ◽  
А.А. Skuredina ◽  
Е.V. Kudryashova
Keyword(s):  
Enzymatic Degradation ◽  
Dosage Forms ◽  
Oral Dosage ◽  
Hydrodynamic Diameter ◽  
Prolonged Action ◽  
Cyclodextrin Complexes ◽  
Acidic Media ◽  
Drug Molecules ◽  
Oral Dosage Forms ◽  
Average Hydrodynamic Diameter

Abstract-Moxifloxacin encapsulation in polymer cyclodextrin-based particles with an average hydrodynamic diameter of 150--200 nm has led to the formation of potential delivery systems with a degree of moxifloxacin inclusion of more than 80%. Cross-linking of the moxifloxacin-cyclodextrin complexes caused a pronounced slowdown in the release of the drug molecules in acidic media to less than 10% per day. In the presence of trypsin, the drug release was accelerated by 15--20% within 90 min. It was shown by Fourier-transform infrared spectroscopy that this acceleration was due to the partial enzymatic degradation of the urethane bonds of the polymer matrix near the surface of the particles. The results obtained are important for the development of highly effective oral dosage forms of prolonged action. Key words: fluoroquinolones, cyclodextrins, FTIR spectroscopy, trypsin

scholarly journals A simple and sensitive sensor for silver ions based on unmodified gold nanoparticles by using dynamic light scattering techniques

2017 ◽  
Vol 95 (12) ◽  
pp. 1267-1272 ◽  
Author(s):  
Zhiyou Xiao ◽  
Anjiang Tang ◽  
Hongsheng Huang ◽  
Ze Wang
Keyword(s):  
Gold Nanoparticles ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
High Sensitivity ◽  
Silver Ions ◽  
Hydrodynamic Diameter ◽  
Optimum Conditions ◽  
Sensitivity And Selectivity ◽  
Sensitive Sensor ◽  
Average Hydrodynamic Diameter

A simple and sensitive assay for Ag+ was developed with unmodified gold nanoparticles (AuNPs) by using dynamic light scattering techniques. Ag+ could induce the oligonucleotide (5′-ATC ACT ATA TCA TAT ACT CAT-3′) to change from a single-stranded structure to a double-stranded structure and desorb from the surface of AuNPs, which triggered the aggregation of AuNPs in the salt solution. The average hydrodynamic diameter of aggregated AuNPs could be detected by using dynamic light scattering techniques. Under the optimum conditions, the average hydrodynamic diameter of AuNPs is proportional to the concentration of Ag+ within the range of 13.3–100.0 nmol/L, with a detection limit of 3.2 nmol/L. The method is easy to operate and has low sample consumption, high sensitivity and selectivity.

scholarly journals Antimicrobial activity of honeys from two stingless honeybee species and Apis mellifera (Hymenoptera: Apidae) against pathogenic microorganisms

2014 ◽  
Vol 44 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Carolinie Batista Nobre da Cruz ◽  
Fabio Alessandro Pieri ◽  
Gislene Almeida Carvalho-Zilse ◽  
Patrícia Puccinelli Orlandi ◽  
Carlos Gustavo Nunes-Silva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Apis Mellifera ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Therapeutic Approaches ◽  
E Coli ◽  
Agar Dilution ◽  
Amazonas State

Honeys are described possessing different properties including antimicrobial. Many studies have presented this activity of honeys produced by Apis mellifera bees, however studies including activities of stingless bees honeys are scarce. The aim of this study was to compare the antimicrobial activity of honeys collected in the Amazonas State from Melipona compressipes, Melipona seminigra and Apis mellifera against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Chromobacterium violaceum, and Candida albicans. Minimum inhibitory concentrations were determined using the agar dilution method with Müller-Hinton agar (for bacteria) or Saboraud agar (for yeast). Staphylococcus aureus and E. faecalis were inhibited by all honeys at concentrations below 12%, while E. coli and C. violaceum were inhibited by stingless bee honeys at concentrations between 10 and 20%. A. mellifera honey inhibited E. coli at a concentration of 7% and Candida violaceum at 0.7%. C. albicans were inhibited only with honey concentrations between 30 and 40%. All examined honey had antimicrobial activity against the tested pathogens, thus serving as potential antimicrobial agents for several therapeutic approaches.

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