scholarly journals In Situ Synthesis of a Silver-Containing Superabsorbent Polymer via a Greener Method Based on Carboxymethyl Celluloses

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2483 ◽  
Author(s):  
Jie Shen ◽  
Chang Cui ◽  
Jian Li ◽  
Lijuan Wang
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Acrylic Acid ◽  
Silver Nitrate ◽  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
Antibacterial Properties ◽  
Superabsorbent Polymer ◽  
Swelling Ratio ◽  
Silver Particles

An antibacterial superabsorbent polymer (SAP) was synthesized by grafting acrylic acid (AA) onto carboxymethyl cellulose (CMC) and mixing with silver particles, with N,N′-methylenebisacrylamide used as a crosslinker and potassium persulfate as an initiator. Silver nanoparticles were produced through the reaction between glucose and silver nitrate. The effects of the amount of silver nitrate added in the polymer on the swelling ratio were investigated and the maximum swelling ratio of the SAP loaded with silver particles in distilled water and in a 0.9 wt % NaCl solution reached 840 g/g and 71 g/g, respectively, when the silver nitrate added was 50 mg. The SAP was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy, and thermogravimetric analysis. Through these analysis methods, it could be seen that the acrylic acid was successfully grafted onto CMC, forming a three-dimensional network structure, with the successful production of silver nanoparticles with sizes ranging from 5 nm to 50 nm. Moreover, the antibacterial properties of the SAP loaded with silver nanoparticles against Staphylococcus aureus and Escherichia coli were investigated and the results show that they became more effective with increasing silver nitrate concentration. The obtained SAP can be useful in developing new antibacterial medical and public health supplies.

scholarly journals Preparation of Surface-Reinforced Superabsorbent Polymer Hydrogel Microspheres via Incorporation of In Situ Synthesized Silver Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 902
Author(s):  
Semin Kim ◽  
Minsu Kim ◽  
Won-Gun Koh
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Suspension Polymerization ◽  
Superabsorbent Polymer ◽  
Void Fractions ◽  
Inverse Suspension Polymerization ◽  
Fluid Permeability ◽  
Transmission Electron

Superabsorbent polymer (SAP) particles are primarily applied for absorbing and storing liquids. Here, poly (acrylic acid) (PAA)-based SAP microspheres incorporated with silver nanoparticles (AgNPs) are prepared as an effort to maintain microsphere shape during swelling and minimize gel blocking. PAA-based SAP spheres are synthesized via inverse suspension polymerization. AgNPs are formed within SAP spheres through in situ reduction of silver nitrate (AgNO3), using polyvinylpyrrolidone as the reducing agent. The formation of AgNPs within SAP was observed via techniques such as scanning electron microscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and transmission electron microscopy. Energy dispersive spectroscopy analyses reveal that thin and dense layers of AgNPs are formed on the outer regions of the SAP spheres at higher concentrations of AgNO3. The water absorbency capacity decreases on increasing the amount of incorporated silver nanoparticles; however, it is comparable with that of commercially available surface-crosslinked SAP particles. Finally, micro-computerized tomography (micro-CT) study revealed that AgNP-incorporated SAP spheres maintained their shapes during swelling and exhibit higher void fractions in the packed gel bed, minimizing gel blocking and improving fluid permeability.

scholarly journals Synthesis of Three-Dimensional Fe3O4/Graphene Aerogels for the Removal of Arsenic Ions from Water

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yan Ye ◽  
Da Yin ◽  
Bin Wang ◽  
Qingwen Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
3D Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Graphene Aerogels ◽  
Transmission Electron ◽  
Potential Applications ◽  
Removal Of Arsenic

We report the synthesis of three-dimensional Fe3O4/graphene aerogels (GAs) and their application for the removal of arsenic (As) ions from water. The morphology and properties of Fe3O4/GAs have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and superconducting quantum inference device. The 3D nanostructure shows that iron oxide nanoparticles are decorated on graphene with an interconnected network structure. It is found that Fe3O4/GAs own a capacity of As(V) ions adsorption up to 40.048 mg/g due to their remarkable 3D structure and existence of magnetic Fe3O4nanoparticles for separation. The adsorption isotherm matches well with the Langmuir model and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. In addition to the excellent adsorption capability, Fe3O4/GAs can be easily and effectively separated from water, indicating potential applications in water treatment.

scholarly journals Antibacterial, Flexible, and Conductive Membrane Based on MWCNTs/Ag Coated Electro-Spun PLA Nanofibrous Scaffolds as Wearable Fabric for Body Motion Sensing

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 120 ◽  
Author(s):  
Lu Gan ◽  
Aobo Geng ◽  
Ying Wu ◽  
Linjie Wang ◽  
Xingyu Fang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Silver Nanoparticles ◽  
Three Dimensional ◽  
Antibacterial Properties ◽  
Human Motion ◽  
Body Motion ◽  
Body Parts ◽  
Motion Sensing ◽  
Nanofibrous Scaffolds ◽  
Conductive Membrane

In the present study, flexible and conductive nanofiber membranes were prepared by coating PLA nanofibrous scaffolds with carbon nanotubes and silver nanoparticles. The morphology and structure of the prepared membrane was characterized, as well as its mechanical properties, electrical sensing behavior during consecutive stretching-releasing cycles and human motion detecting performance. Furthermore, the antibacterial properties of the membrane was also investigated. Due to the synergistic and interconnected three-dimensional (3D) conductive networks, formed by carbon nanotubes and silver nanoparticles, the membrane exhibited repeatable and durable strain-dependent sensitivity. Further, the prepared membrane could accurately detect the motions of different body parts. Accompanied with promising antibacterial properties and washing fastness, the prepared flexible and conductive membrane provides great application potential as a wearable fabric for real-time body motion sensing.

Properties of Silver Nanoparticles Prepared by the Electric Spark Dispersion Method

2013 ◽  
Vol 872 ◽  
pp. 74-78 ◽  
Author(s):  
S.P. Zhuravkov ◽  
Evgeny Plotnikov ◽  
Dmitry Martemiyanov ◽  
Nikolay A. Yavorovsky ◽  
Ulrich Hasse ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Structural Characteristics ◽  
Silver Particles ◽  
Dispersion Method ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Light Scattering Spectroscopy

The morphological and structural characteristics of nanoscale silver particles obtained by the method of electric spark dispersion of metal granules in the liquid aprotic medium were obtained using atomic force microscopy, transmission electron microscopy, and dynamic light scattering spectroscopy. The specific surface, morphology, structure and the distribution by size of the particles are presented.

scholarly journals Fabrication, Characterization, and Antibacterial Properties of Electrospun Membrane Composed of Gum Karaya, Polyvinyl Alcohol, and Silver Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Vinod Vellora Thekkae Padil ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Miroslav Černík
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Polyvinyl Alcohol ◽  
Food Packaging ◽  
Chemical Reduction ◽  
Antibacterial Properties ◽  
Hydroxyl Groups ◽  
Ag Nps ◽  
Gum Karaya ◽  
Nanofiber Membranes

Gum karaya (GK), a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA) at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs) were synthesised through chemical reduction of AgNO3(at different concentrations) in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs). Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negativeEscherichia coliandPseudomonas aeruginosaand Gram-positiveStaphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.

scholarly journals Green Silver Nanoparticles Embedded in Cellulosic Network for Fresh Food Packaging

2021 ◽  
Author(s):  
S. Chaitanya Kumari ◽  
P. Naga Padma ◽  
K. Anuradha
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Shelf Life ◽  
Food Packaging ◽  
Nitrate Solution ◽  
Packaging Material ◽  
Packaging Materials ◽  
Coated Paper ◽  
Fresh Food

The demand for increasing the shelf life of fresh food as well as the need for protecting the food against foodborne infections warrant the demand for increasing the shelf life of fresh food. The incorporation of nanoparticles into the packaging material can enhance the preservation of perishable foods. Silver nanoparticles (AgNPs), in particular, have antibacterial, anti-mold, anti-yeast, and anti-viral activities can be embedded into the biodegradable packaging materials for this purpose. This study focuses on antimicrobial packaging materials for food by mixing the extracts of different plants with silver nitrate and depositing this mixture as a layer on the blotting papers, which are thick sheets of paper made of cellulose. Because the blotting papers are highly absorbent and porous, silver nitrate solution along with the plant extracts can be easily applied and allowed for in situ synthesis of AgNPs. Subsequently, these papers were analyzed and characterized using scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, and energy dispersive X-ray analysis. The coated paper exhibited good antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, the coated paper when used as a packaging material for tomatoes and coriander leaf, the shelf life was extended to about 30 days and 15 days respectively. The prepared cost-effective silver packing material can be used in food packaging for various perishable foods.

scholarly journals Carbene modification and reversible crosslinking of silver nanoparticles for controlled antibacterial activity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Liling Jing ◽  
Mark G. Moloney ◽  
Hao Xu ◽  
Lian Liu ◽  
Wenqiang Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Photoelectron Spectroscopy ◽  
Inhibition Zone ◽  
Insertion Reaction ◽  
Ag Nps ◽  
Zone Method ◽  
Transmission Electron

Abstract Silver nanoparticles (Ag NPs) system capable of exhibiting different particle size at different temperature was developed, which depended on the extent of Diels–Alder (DA) reaction of bismaleimide with furan. Thus, Ag NPs were functionalized on the surface by a furyl-substituted carbene through an insertion reaction. Subsequent reversible DA crosslinking achieved a controlled aggregation with different particle size, which gives a series of different antibacterial activity. These Ag NPs were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Nanoparticle Size Analyzer. The aggregation of the Ag NPs could be reliably adjusted by varying the temperature of DA/reverse-DA reaction. The antibacterial activity was assessed using the inhibition zone method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which decreased first and then increased in agreement with the size evolution of Ag NPs. This approach opens a new horizon for the carbene chemistry to modify silver nanoparticles with variable size and give controlled antibacterial activity.

scholarly journals Characterization of Silver Nanoparticles Obtained by a Green Route and Their Evaluation in the Bacterium of Pseudomonas aeruginosa

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 395 ◽  
Author(s):  
Juan Carlos Martínez Espinosa ◽  
Raúl Carrera Cerritos ◽  
Maria Antonieta Ramírez Morales ◽  
Karla Paola Sánchez Guerrero ◽  
Rocio Alejandra Silva Contreras ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Bacterial Resistance ◽  
Antimicrobial Effect ◽  
X Ray ◽  
Transmission Electron ◽  
Green Route

Metal nanoparticles are widely used in different areas such as biotechnology and biomedicine, for example in drug delivery, imaging and control of bacterial growth. The antimicrobial effect of silver has been identified as an alternative approach to the increasing bacterial resistance to antibiotics. Silver nanoparticles were synthesized by the green route using the Geranium extract as a reducing agent. The characterization was carried out by the techniques of UV-Vis spectrophotometry, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray emitted photoelectron spectroscopy (XPS) and X-ray diffraction. Nanoparticle diameters between 15 and 50 nm were obtained and the interplanar spaces calculated from the electron diffraction pattern corresponding to a mixture of silver with 4H and FCC structures. To determine the minimum inhibitory concentration of silver nanoparticles (AgNPs) on the Pseudomonas aeruginosa bacteria (ATCC-27853), different concentrations of colloidal solution 0.36, 0.18, 0.09 and 0.05 μg/mL were evaluated as a function of the incubation time, measuring the inhibition halo and colony forming unit (CFU) during 0, 2 and 4 h of incubation. The minimum inhibitory AgNPs concentration (MIC) is 0.36 μg/mL at 0 h while the concentration of 0.18 μg/mL presents a total inhibition of the bacterium after 2 h. For the rest of the dilutions, gradual inhibitions as a function of time were observed. We evaluate the antibacterial effect of silver nanoparticles obtained by a green methodology in Pseudomonas aeruginosa bacteria. Finally, the colloidal nanoparticle solution can be an antibacterial alternative for different biomedical approaches.

scholarly journals Plasmon Resonance of Silver Nanoparticles as a Method of Increasing Their Antibacterial Action

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 80 ◽  
Author(s):  
Alexander Vasil’kov ◽  
Ruslan Dovnar ◽  
Siarhei Smotryn ◽  
Nikolai Iaskevich ◽  
Alexander Naumkin
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
Plasmon Resonance ◽  
Photoelectron Spectroscopy ◽  
Antibacterial Properties ◽  
Petri Dish ◽  
Aureus Strain ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray

In this article, a series of silver-containing dressings are prepared by metal-vapor synthesis (MVS), and their antibacterial properties are investigated. The antibacterial activity of the dressings containing silver nanoparticles (AgNPs) against some Gram-positive, and Gram-negative microorganisms (Staphylococcus aureus, Staphylococcus haemolyticus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Moraxella spp.) has been determined. Based on the plasmon resonance frequency of these nanoparticles, the frequency of laser irradiation of the dressing was chosen. The gauze bandage examined showed pronounced antibacterial properties, especially to Staphylococcus aureus strain. When 470 nm laser radiation, with a power of 5 mW, was applied for 5 min, 4 h after inoculating the Petri dish, and placing a bandage containing silver nanoparticles on it, the antibacterial effect of the latter significantly increased—both against Gram-positive and Gram-negative microorganisms. The structure and chemical composition of the silver-containing nanocomposite were studied by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). The synthesized AgNPs demonstrate narrow and monomodal particle size distribution with an average size of 1.75 nm. Atoms of metal in Ag/bandage system are mainly in Ag0 state, and the oxidized atoms are in the form of Ag-Ag-O groups.

scholarly journals Silver Nanoparticles Synthesized with Rumex hymenosepalus: A Strategy to Combat Early Mortality Syndrome (EMS) in a Cultivated White Shrimp

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Francisco Javier Alvarez-Cirerol ◽  
Marco Antonio López-Torres ◽  
Ericka Rodríguez-León ◽  
César Rodríguez-Beas ◽  
Aaron Martínez-Higuera ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Antibacterial Properties ◽  
Early Mortality ◽  
White Shrimp ◽  
Ros Generation ◽  
Early Mortality Syndrome ◽  
Selected Area Electron Diffraction ◽  
Worldwide Production ◽  
Vis Spectroscopy

Early Mortality Syndrome (EMS) or Acute Hepatopancreatic Necrosis Syndrome (AHPNS) is a disease produced by gram-negative bacteria Vibrio parahaemolyticus (V. parahaemolyticus), which has caused declines in worldwide production of a white shrimp Litopenaeus vannamei (L. vannamei). In this work, we propose the implementation of silver nanoparticles (AgNPs) synthesized with Rumex hymenosepalus (Rh) extract as an alternative on V. parahaemolyticus control. AgNPs were characterized by UV-Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). AgNP mean sizes by DLS were 80.82±1.16 nm and sizes between 2 and 10 nm by TEM, with a zeta potential of −47.72±1.05 mV. This study evaluated AgNPs and Rh antimicrobial capacity on V. parahaemolyticus at different concentrations; the minimum inhibitory concentration (MIC) found was 25 μg/mL for AgNPs and 220 μg/mL for Rh. Additionally, were carried out time-kill curves and reactive oxygen species (ROS) generation for 1 and 4 MIC. Both concentrations (MIC) were tested for toxicity on Artemia nauplii from Artemia franciscana (A. franciscana), because nauplii were used as biocarriers for AgNPs and Rh extract on L. vannamei. Once the shrimp were treated, they were challenged with Vibrio infection and it was found that those who were treated with both agents showed greater survival than the control. V. parahaemolyticus and postlarval samples were taken from the bioassay and fixed and prepared for TEM and SEM in order to search NPs in internal structure of bacteria and the hepatopancreatic area of shrimps; AgNPs were detected in both cases. AgNPs and Rh extract show antibacterial properties on the infected shrimp with V. parahaemolyticus. The action mechanisms are interaction with the bacterial membrane and ROS generation; these effects are produced by both agents.

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