scholarly journals Investigation of Biocidal Effect of Microfiltration Membranes Impregnated with Silver Nanoparticles by Sputtering Technique

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1686 ◽  
Author(s):  
Aline M. F. Linhares ◽  
Cristiano P. Borges ◽  
Fabiana V. Fonseca
Keyword(s):  
Silver Nanoparticles ◽  
Phase Inversion ◽  
Diffusion Method ◽  
Inversion Method ◽  
X Ray Diffraction ◽  
Good Adhesion ◽  
X Ray ◽  
Log Reduction ◽  
Microfiltration Membranes ◽  
Phase Inversion Method

Silver nanoparticles were loaded in microfiltration membranes by sputtering technique for the development of biocidal properties and biofouling resistance. This technology allows good adhesion between silver nanoparticles and the membranes, and fast deposition rate. The microfiltration membranes (15 wt.% polyethersulfone and 7.5 wt.% polyvinylpyrrolidone in N,N-dimethylacetamide) were prepared by phase inversion method, and silver nanoparticles were deposited on their surface by the physical technique of vapor deposition in a sputtering chamber. The membranes were characterized by Field Emission Scanning Electron Microscopy, and the presence of silver was investigated by Energy-Dispersive Spectroscopy and X-ray Diffraction. Experiments of silver leaching were carried out through immersion and filtration tests. After 10 months of immersion in water, the membranes still presented ~90% of the initial silver, which confirms the efficiency of the sputtering technique. Moreover, convective experiments indicated that 98.8% of silver remained in the membrane after 24 h of operation. Biocidal analyses (disc diffusion method and biofouling resistance) were performed against Pseudomonas aeruginosa and confirmed the antibacterial activity of these membranes with 0.6 and 0.7 log reduction of viable planktonic and sessile cells, respectively. These results indicate the great potential of these new membranes to reduce biofouling effects.

Influence of the Addition of Polypropylene and Compatibilizer in PA6 Membranes Obtained by Phase Inversion

2014 ◽  
Vol 775-776 ◽  
pp. 173-177 ◽  
Author(s):  
Elieber Barros Bezerra ◽  
A.M.D. Leite ◽  
E.M. Araújo ◽  
T.J.A. Melo ◽  
C.T. Cunha ◽  
...  
Keyword(s):  
Phase Inversion ◽  
Chemical Species ◽  
Barrier Properties ◽  
Inversion Method ◽  
X Ray Diffraction ◽  
Binary Blends ◽  
Asymmetric Membranes ◽  
X Ray ◽  
Two Phases ◽  
Phase Inversion Method

Polymer blend is the name for the physical mixture of two or more polymers and/or copolymers, and this allows the obtention of new materials with superior properties to those of the pure components. The blends have been used in obtaining membranes in order to improve the barrier properties so that it can separate two phases totally or partially, restricting the transport of one or more chemical species. In this work, polymer membranes were obtained from blends of PA6/PPgAA and PA6/PP/PPgAA by phase inversion method and were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was observed through the diffractograms that there were no significant variations in the characteristic peaks of PA6, and through SEM, it was observed the formation of microporous asymmetric membranes, where they showed a surface with higher porosity to the binary and ternary blends and presented smallest pore diameter for binary blends.

scholarly journals Anticoagulant, thrombolytic and antibacterial activities of Euphorbia acruensis latex-mediated bioengineered silver nanoparticles

2019 ◽  
Vol 8 (1) ◽  
pp. 590-599 ◽  
Author(s):  
Kaushik Roy ◽  
Ambikesh K. Srivastwa ◽  
Chandan K. Ghosh
Keyword(s):  
Silver Nanoparticles ◽  
Analytical Techniques ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Antibacterial Study ◽  
X Ray ◽  
Transmission Electron ◽  
Human Blood Samples ◽  
Green Synthesized Silver Nanoparticles

Abstract In this report, we present a simple and unexplored procedure for green synthesis of silver nanoparticles featuring exudation of Euphorbia acruensis along with the study of its antibacterial and anticoagulant properties. Analytical techniques like ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) were used to analyse the production, crystallinity and morphology of bio-reduced silver nanoparticles. The antibacterial study was performed by following standard disc diffusion method. Most importantly, the anticoagulant and thrombolytic activities of biogenic silver nanoparticles were evaluated by addition of nanoparticles to human blood samples under practical conditions. These green synthesized silver nanoparticles were found to have potent antibacterial, anticoagulant and thrombolytic properties which make them an attractive choice for future medical applications.

Rheology Assessment of PSf/ NMP Solution and its Influence on Membrane Structure

2012 ◽  
Vol 326-328 ◽  
pp. 422-427 ◽  
Author(s):  
Priscila Anadão ◽  
Rafael Rezende Montes ◽  
Henrique Souza de Santis ◽  
Hélio Wiebeck
Keyword(s):  
Membrane Structure ◽  
Phase Inversion ◽  
Molar Mass ◽  
Polymer Concentration ◽  
Inversion Method ◽  
Asymmetric Membranes ◽  
Wet Phase Inversion ◽  
Microfiltration Membranes ◽  
Skin Formation ◽  
Phase Inversion Method

Asymmetric polysulfone membranes were prepared by wet-phase inversion method from casting solutions consisting of PSf/NMP and water as non-solvent. The effects of polymer concentration and molar mass were investigated by rheological studies. Moreover, membranes were characterized by scanning electron microscope (SEM). It was found that polymer solutions containing between 22 and 25 wt% PSf/NMP originated microfiltration membranes. The use of a higher mass molar polysulfone has been shown to reduce diameter pore and to maintain morphology. All the results were interrelated into a discussion of the skin formation of asymmetric membranes.

The Research of Hydrophilic Modification of PVC/PES Blended Membrane by the Additive of CA

2014 ◽  
Vol 1052 ◽  
pp. 8-13
Author(s):  
Shu Hong Jiang ◽  
Jun Wu ◽  
Hong Zhong Zhou ◽  
Chuan Wei Jiang ◽  
Jun Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Phase Inversion ◽  
Water Flux ◽  
Inversion Method ◽  
Equilibrium Water Content ◽  
X Ray ◽  
Hydrophilic Modification ◽  
Poly Vinyl Chloride ◽  
Phase Inversion Method ◽  
Blended Membrane

In order to improve the performance of Poly(vinyl chloride)(PVC)/ polyethersulfone (PES) blended membranes, cellulose acetate (CA) was used as a hydrophilic enhancer to blend with PVC and PES for membrane preparation by phase inversion method. In this study, the results of equilibrium water content (EWC), contact angle and X-ray photoelectron spectroscopy (XPS) confirmed the addition of CA could effectively improve the hydrophilicity of PVC/PES blended membrane. It was also found that water flux of PVC/PES/CA blended membranes increased with the increase of CA concentration.

scholarly journals Bactericidal activity of Ag nanoparticle-impregnated fibreglass for water disinfection

2009 ◽  
Vol 7 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Gordon Nangmenyi ◽  
Wei Xao ◽  
Sharifeh Mehrabi ◽  
Eric Mintz ◽  
James Economy
Keyword(s):  
Silver Nanoparticles ◽  
Silver Content ◽  
Immersion Test ◽  
Water Disinfection ◽  
X Ray Diffraction ◽  
Thermal Regeneration ◽  
X Ray ◽  
E Coli ◽  
Log Reduction ◽  
Activated Carbon Fibres

A new bactericidal system composed of fibreglass impregnated with silver (Ag) nanoparticles was developed and tested. Silver content, particle size and distribution were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The antibacterial effectiveness was evaluated against Escherichia coli (E. coli, ATCC 29055). The minimum inhibitory loading was determined to be less than 1.8 wt% of silver nanoparticles per gram of fibreglass. In a 1 h immersion test, using a 0.1 mg fibreglass mat ml−1, with 2.9 wt% loading of silver nanoparticles completely disinfected 100 ml of 106 CFU ml−1 of E. coli, dramatically outperforming activated carbon fibres impregnated with silver. Inactivation rate studies of 0.05 mg fibreglass mat ml−1 (Ag 1.8 wt%) with 1012 CFU E. coli displayed a 7 log reduction in 5 minutes. The activation and reuse of fibreglass (Ag 4.3 wt%) maintained its full effectiveness after two cycles of use and thermal regeneration at 350°C.

scholarly journals GREEN SYNTHESIS, CHARACTERIZATION OF SILVER NANOPARTICLES OF A MARINE RED ALGA SPYRIDIA FUSIFORMIS AND THEIR ANTIBACTERIAL ACTIVITY

2017 ◽  
Vol 9 (5) ◽  
pp. 192 ◽  
Author(s):  
Subbiah Murugesan ◽  
Sundaresan Bhuvaneswari ◽  
Vajiravelu Sivamurugan
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Green Synthesis ◽  
Red Alga ◽  
Diffusion Method ◽  
Present System ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Uv Visible

Objective: In the present system, the green synthesis of silver nanoparticles using marine the red alga Spyridia fusiformis and antibacterial activity was carried out.Methods: The seaweed extract was used for the synthesis of AgNPs at room temperature. The silver nanoparticles were characterized by using UV–Visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscope and X-ray diffraction (XRD) techniques. The antibacterial activity of biosynthesized silver nanoparticles was carried out by disc diffusion method against pathogenic bacteria.Results: The UV-visible spectroscopy revealed surface plasmon resonance at 450 nm. The FT-IR measurements showed the possible functional groups responsible for the formation of nanoparticles. The X-ray diffraction analysis showed that the particles were crystalline in nature. TEM micrograph has shown the formation of silver nanoparticles with the size in the range of 5–50 nm. The silver nanoparticles synthesized from the S. fusiformis showed higher activity and proved their efficacy in controlling the pathogenic bacterial strains. The nanoparticles showed highest inhibition activity on K. pneumaniae and S. aureus up to 26 and 24±0.01 mm at 100 μg/ml of nanoparticles.Conclusion: The synthesised AgNPs have shown the best antibacterial activity against human pathogens E. coli, K. pneumoniae, S. aureus and P. aeruginosa. The above eco-friendly AgNPs synthesis procedure could be a viable solution for industrial applications in the future and therapeutic needs.

scholarly journals Biogenic Synthesis of Silver Nanoparticles (AgNPs) using Celosia cristata L. Leaves Extract and Their Antimicrobial Activity against Otorhinolaryngological Isolated Pathogen

2019 ◽  
Vol 11 (06) ◽  
Author(s):  
Ramveer Singh ◽  
Navneet Kumar
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Silver Nitrate ◽  
Positive Control ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Disc Diffusion Method ◽  
Biogenic Synthesis ◽  
X Ray ◽  
Celosia Cristata

This work focused on the biogenic synthesis of silver nanoparticles (AgNPs) by silver nitrate using Celosia cristata leaves extract in four different solvents namely petroleum ether, acetone, methanol, and water. Silver nitrate and leaves extract were used as a precursor and capping reducing agent respectively. Biogenic AgNPs were characterized and identified by UV-Vis spectrophotometer, X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), and energy dispersive spectroscopy (EDX). Disc diffusion method was used for antibacterial activity of AgNPs and effective antibacterial activity was shown against IS-3, IS-4, IS-6, and IS-7 as compared to a positive control (ciprofloxacin).

Technology of high quality protein crystals’ obtaining aboard the ISS at execution of joint Japanese–Russian experiments

2020 ◽  
pp. 5-25
Author(s):  
Koji INAKA ◽  
Saori ICHIMIZU ◽  
Izumi YOSHIZAKI ◽  
Kiyohito KIHIRA ◽  
Elena G. LAVRENKO ◽  
...  
Keyword(s):  
Drug Design ◽  
International Space Station ◽  
Space Station ◽  
Protein Crystals ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
High Quality ◽  
International Space ◽  
X Ray ◽  
High Quality Protein

A series of space experiments aboard the International Space Station (ISS) associated with high-quality Protein Crystal Growth (PCG) in microgravity conditions can be considered as a unique and one of the best examples of fruitful collaboration between Japanese and Russian scientists and engineers in space, which includes also other ISS International Partners. X-ray diffraction is still the most powerful tool to determine the protein three dimensional structure necessary for Structure based drug design (SBDD). The major purpose of the experiment is to grow high quality protein crystals in microgravity for X-ray diffraction on Earth. Within one and a half decade, Japan and Russia have established an efficient process over PCG in space to support latest developments over drug design and structural biology. One of the keys for success of the experiment lies in how precisely pre-launch preparations are made. Japanese party provides flight equipment for crystallization and ensures the required environment to support the experiment aboard of the ISS’s Kibo module, and also mainly takes part of the experiment ground support such as protein sample characterization, purification, crystallization screening, and solution optimization for microgravity experiment. Russian party is responsible for integration of the flight items equipped with proteins and precipitants on board Russian transportation space vehicles (Soyuz or Progress), for delivery them at the ISS, transfer to Kibo module, and returning the experiments’ results back on Earth aboard Soyuz manned capsule. Due to close cooperation of the parties and solid organizational structure, samples can be launched at the ISS every half a year if the ground preparation goes smoothly. The samples are crystallized using counter diffusion method at 20 degree C for 1–2.5 months. After samples return, the crystals are carefully taken out from the capillary, and frozen for X-ray diffraction at SPring8 facility in Japan. Extensive support of researchers from both countries is also a part of this process. The paper analyses details of the PCG experiment scheme, unique and reliable technology of its execution, and contains examples of the application. Key words: International Space Station, Protein crystals, Microgravity, International collaboration.

scholarly journals Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Valentina Krylova ◽  
Mindaugas Andrulevičius
Keyword(s):  
Photoelectron Spectroscopy ◽  
Copper Sulfide ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
Xrd Studies ◽  
Polyamide Film ◽  
Indirect Band Gap ◽  
Xrd Method

Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol⋅  solutions and acidified with HCl (0.1 mol⋅) at . After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied by UV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with ions. It has been established by the XRD method that, beside , the layer contains as well. For PA 6 initially sulfured 4 h, grain size forchalcocite, , was  nm and fordjurleite, , it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 .

scholarly journals Crystallization and preliminary X-ray diffraction analysis of the Csu pili CsuC–CsuA/B chaperone–major subunit pre-assembly complex fromAcinetobacter baumannii

2015 ◽  
Vol 71 (6) ◽  
pp. 770-774 ◽  
Author(s):  
Natalia Pakharukova ◽  
Minna Tuittila ◽  
Sari Paavilainen ◽  
Anton Zavialov
Keyword(s):  
Diffusion Method ◽  
X Ray Diffraction ◽  
Hanging Drop ◽  
Unit Cell Parameters ◽  
Gram Negative ◽  
X Ray ◽  
Cell Parameters ◽  
Abiotic Surfaces ◽  
Vapour Diffusion ◽  
Fimbrial Adhesins

The attachment of many Gram-negative pathogens to biotic and abiotic surfaces is mediated by fimbrial adhesins, which are assembledviathe classical, alternative and archaic chaperone–usher (CU) pathways. The archaic CU fimbrial adhesins have the widest phylogenetic distribution, yet very little is known about their structure and mechanism of assembly. To elucidate the biogenesis of archaic CU systems, structural analysis of the Csu fimbriae, which are used byAcinetobacter baumanniito form stable biofilms and cause nosocomial infection, was focused on. The major fimbriae subunit CsuA/B complexed with the CsuC chaperone was purified from the periplasm ofEscherichia colicells co-expressing CsuA/B and CsuC, and the complex was crystallized in PEG 3350 solution using the hanging-drop vapour-diffusion method. Selenomethionine-labelled CsuC–CsuA/B complex was purified and crystallized under the same conditions. The crystals diffracted to 2.40 Å resolution and belonged to the hexagonal space groupP6422, with unit-cell parametersa=b= 94.71,c = 187.05 Å, α = β = 90, γ = 120°. Initial phases were derived from a single anomalous diffraction (SAD) experiment using the selenomethionine derivative.

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