scholarly journals Characterization of Alginate/Silver Nanobiocomposites Synthesized by Solution Plasma Process and Their Antimicrobial Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Sangwoo Nam ◽  
D. MubarakAli ◽  
Jungwan Kim
Keyword(s):  
Antimicrobial Properties ◽  
Spherical Shape ◽  
Sem Analysis ◽  
Human Pathogens ◽  
Plasma Process ◽  
Tem Analysis ◽  
3D Scaffolds ◽  
Vis Spectroscopy ◽  
The Matrix ◽  
Almost All

Solution plasma process (SPP) was adopted to prepare alginate/silver nanoparticle (AL/AgNP) biocomposites. The biocomposites were synthesized in solutions of varying concentrations of AgNO3(1−5 mM) and alginate (0.1−0.3%, w/w) by discharging plasma for 7 min at 800 V with 30 kHz frequency using a pulsed unipolar power supply. The AL/AgNP emulsion was fabricated into 3D scaffolds by freeze drying and lyophilization and then stabilized by cross-linking via UV irradiation. UV-Vis spectroscopy of the biocomposites showed a characteristic absorbance at the maximum of 415–440 nm with increase in the intensity of the peaks as the concentration of AgNO3increased. FE-SEM analysis showed that the 3D scaffolds had microporous structures with fine and uniform pores of 3–9 ± 2.0 μm in diameter. TEM analysis revealed that AgNPs in the biocomposites were in spherical shape with size range of 5–40±2.0 nm (AL0.3/Ag5) and well distributed in the matrix. The AL/AgNP biocomposites showed microbicidal activity against 9 human pathogens with MIC of 9.6–21 μg/mL for bacteria and 85–425 μg/mL for fungi. Almost all of theE. colicells (99.8%) were killed by the treatment with 42.5 μg/mL of AgNPs at room temperature for 1 h.

scholarly journals The Development of the Innovative Synthesis Methodology of Albumin Nanoparticles Supported by Their Physicochemical, Cytotoxic and Hemolytic Evaluation

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4386
Author(s):  
Sonia Kudłacik-Kramarczyk ◽  
Anna Drabczyk ◽  
Magdalena Głąb ◽  
Paweł Gajda ◽  
Anna Czopek ◽  
...  
Keyword(s):  
Spherical Shape ◽  
Dermal Fibroblasts ◽  
Albumin Concentration ◽  
Salting Out ◽  
Tem Analysis ◽  
Albumin Nanoparticles ◽  
Vis Spectroscopy ◽  
Physicochemical Evaluation ◽  
Normal Human ◽  
Synthesis Methodology

Many studies are being performed to develop effective carriers for controlled cytostatic delivery wherein albumin is a promising material due to its tendency to accumulate near cancer cells. The novelty of this work involves the development of the synthesis methodology of albumin nanoparticles and their biological and physicochemical evaluation. Albumin particles were obtained via the salt-induced precipitation and K3PO4 was used as a salting-out agent. Various concentrations of protein and salting-out agent solutions were mixed using a burette or a syringe system. It was proved that the size of the particles depended on the concentrations of the reagents and the methodology applied. As a result of a process performed using a burette and 2 M K3PO4, albumin spheres having a size 5–25 nm were obtained. The size of nanospheres and their spherical shape was confirmed via TEM analysis. The use of a syringe system led to preparation of particles of large polydispersity. The highest albumin concentration allowing for synthesis of homogeneous particles was 2 g/L. The presence of albumin in spheres was confirmed via the FT-IR technique and UV-Vis spectroscopy. All samples showed no cytotoxicity towards normal human dermal fibroblasts and no hemolytic properties against human erythrocytes (the hemolysis did not exceed 2.5%).

scholarly journals Synthesis and characterization of Fe3O4@SiO2 sub-nano core/shell with SiO2 derived from rice husk ash

2020 ◽  
pp. 52-56
Author(s):  
Luong Huynh Vu Thanh, Tran Nguyen Phuong Lan Luong
Keyword(s):  
Spherical Shape ◽  
Xrd Analysis ◽  
Research Process ◽  
Infrared Spectrometry ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ft Ir

This study aims to synthesize and characterize Fe3O4@SiO2 sub-nanoparticles (SNPs) with high saturation magnetization (SM). The research process was conducted in simple and environmentally friendly conditions. The results of ultraviolet-visible (UV-Vis) spectroscopy and X-ray diffraction (XRD) analysis presented that the Fe3O4@SiO2 SNPs were well formed and the phase change of Fe3O4 NPs did not happen in Fe3O4@SiO2 SNPs. Transmission electron microscope (TEM) analysis showed that the Fe3O4@SiO2 SNPs are in a fairly spherical shape with a core/shell structure and a diameter in a range of 100 nm to 500 nm. Fourier transform infrared spectrometry (FT-IR) spectra of Fe3O4@SiO2 SNPs presented some absorption peaks indicating the existence of Si-O-Si, O-Si-O, Fe-O and Fe-O-Si. The SM of Fe3O4 particles and Fe3O4@SiO2 SNPs determined via vibrating sample magnetometer (VSM) were 50.9 emu.g−1 and 19.5 emu.g−1, respectively. All the above results provide clear evidence that the Fe3O4 particles were coated by SiO2 to form sub-nano core/shell with great SM.

Geraniol and cinnamaldehyde as natural antibacterial additives for poly(lactic acid) and their plasticizing effects

2019 ◽  
Vol 40 (1) ◽  
pp. 38-48
Author(s):  
Mert Akgün ◽  
İhsan Başaran ◽  
Salih C. Suner ◽  
Ayhan Oral
Keyword(s):  
Lactic Acid ◽  
Antibacterial Activities ◽  
Mechanical Tests ◽  
Sem Analysis ◽  
Diffusion Method ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Disk Diffusion Method ◽  
Vis Spectroscopy ◽  
The Matrix

Abstract The main goal of this study is to prepare antibacterial poly(lactic acid) (PLA) containing cinnamaldehyde and geraniol and to evaluate the antibacterial activity and assess the changes of physical properties of the PLA films. Cinnamaldehyde- and geraniol-incorporated (10%, 20%, 30%, and 50% v/w) PLA films were prepared via solution-casting. While preparing these films, plasticizers were not added to the matrix. Antibacterial activities of these films against Escherichia coli and Staphylococcus aureus were investigated by the disk diffusion method. Thermal degradation characteristics were analyzed via thermogravimetric analysis (TGA), glass transition, crystallization, and melting temperatures, and enthalpies of the films were determined from differential scanning calorimetry (DSC) scans. Tensile strength and elongation-at-break values of neat PLA and antibacterial-compound-containing films were evaluated and compared after the mechanical tests. Moreover, the changes in the polymer morphology were observed by SEM analysis, and opacity of the films was determined by UV-vis spectroscopy. Our results showed that both compounds provided antibacterial effect to the PLA, with cinnamaldehyde being more effective than geraniol. Moreover, plasticization effects of the compounds were confirmed by DSC analysis.

scholarly journals Electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) solution

2013 ◽  
Vol 78 (12) ◽  
pp. 2087-2098 ◽  
Author(s):  
Rade Surudzic ◽  
Zeljka Jovanovic ◽  
Natasa Bibic ◽  
Branislav Nikolic ◽  
Vesna Miskovic-Stankovic
Keyword(s):  
Silver Nanoparticles ◽  
Electrochemical Synthesis ◽  
Vinyl Alcohol ◽  
Spherical Shape ◽  
Constant Current ◽  
Poly Vinyl Alcohol ◽  
Tem Analysis ◽  
Constant Current Density ◽  
Synthesis Time ◽  
Vis Spectroscopy

In this work silver/poly(vinyl alcohol), Ag/PVA, colloid dispersions were obtained by electrochemical reduction of Ag+ ions. The electrochemical synthesis of silver nanoparticles in the aqueous solutions of 5 and 10 wt. % PVA, containing 0.1 M KNO3 and 3.9 mM AgNO3, was performed at constant current density of 25 mA cm-2, and during synthesis time of 10 min. The presence of silver nanoparticles was confirmed by UV-vis spectroscopy. Cyclic voltammetry analysis and FTIR spectroscopy indicated the interactions between silver nanoparticles and PVA molecules. TEM analysis confirmed spherical shape of the obtained silver nanoparticles, with the mean diameter of 15 ? 9 nm.

scholarly journals Microwave Mediated Fast Synthesis of Silver Nanoparticles and Investigation of Their Antibacterial Activities for Gram-Positive and Gram-Negative Microorganisms

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 666
Author(s):  
Faheem Ahmed ◽  
Suliman Yousef AlOmar ◽  
Fadwa Albalawi ◽  
Nishat Arshi ◽  
Sourabh Dwivedi ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Infections ◽  
Antibacterial Properties ◽  
Spherical Shape ◽  
Ammonium Bromide ◽  
Face Centered Cubic ◽  
Gram Positive ◽  
Tem Analysis ◽  
Gram Negative ◽  
Vis Spectroscopy

Herein, a simple one-step microwave irradiation technique has been used to synthesize the silver nanoparticles using silver nitrate (AgNO3) solution and cetyltrimethyl ammonium bromide (CTAB) as a stabilizing agent. The crystals of as-prepared nanoparticles were studied using X-ray diffraction (XRD) and a selected area electron diffraction (SAED) pattern, confirming the single-phase face-centered cubic structure. The optical property measured using UV-Vis spectroscopy shows an absorption maximum at 420 nm, which also confirms the formation of silver nanoparticles. Transmission electron microscopy (TEM) analysis revealed that the silver nanoparticles have a spherical shape with an average diameter of ~6 nm. The antibacterial properties of silver nanoparticles were investigated using both Gram-positive and Gram-negative microorganisms, such as Staphylococcus aureus, Pseudomonas aeruginosa, andEscherichia coli. Klebsiella pneumoniae, and Candida albicans. Results showed a highest zone of inhibition of about 35 mm against P. aeruginosa as compared with E. coli (21 mm), S. aureus (30 mm), K. pneumonia (28 mm), and C. albicans (29 mm). These studies suggested that silver nanoparticles prepared by this fast and effective method might be developed as antibacterial agents against an extensive range of microorganisms to control and stop the spreading and persistence of bacterial infections.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

A technique for preparing semiconductor cross sections for both TEM and SEM analysis

1989 ◽  
Vol 47 ◽  
pp. 712-713
Author(s):  
Stanley J. Klepeis ◽  
J.P. Benedict ◽  
R.M Anderson
Keyword(s):  
Sample Preparation ◽  
Cross Section ◽  
Cross Sections ◽  
Sem Analysis ◽  
Preparation Technique ◽  
Ion Milling ◽  
Tem Analysis ◽  
Polished Cross Section ◽  
Area Of Interest ◽  
Polished Side

The ability to prepare a cross-section of a specific semiconductor structure for both SEM and TEM analysis is vital in characterizing the smaller, more complex devices that are now being designed and manufactured. In the past, a unique sample was prepared for either SEM or TEM analysis of a structure. In choosing to do SEM, valuable and unique information was lost to TEM analysis. An alternative, the SEM examination of thinned TEM samples, was frequently made difficult by topographical artifacts introduced by mechanical polishing and lengthy ion-milling. Thus, the need to produce a TEM sample from a unique,cross-sectioned SEM sample has produced this sample preparation technique.The technique is divided into an SEM and a TEM sample preparation phase. The first four steps in the SEM phase: bulk reduction, cleaning, gluing and trimming produces a reinforced sample with the area of interest in the center of the sample. This sample is then mounted on a special SEM stud. The stud is inserted into an L-shaped holder and this holder is attached to the Klepeis polisher (see figs. 1 and 2). An SEM cross-section of the sample is then prepared by mechanically polishing the sample to the area of interest using the Klepeis polisher. The polished cross-section is cleaned and the SEM stud with the attached sample, is removed from the L-shaped holder. The stud is then inserted into the ion-miller and the sample is briefly milled (less than 2 minutes) on the polished side. The sample on the stud may then be carbon coated and placed in the SEM for analysis.

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

Utilizing Nanoprobing and Circuit Diagnostics to Identify Key Failure Mechanism of Otherwise Nonvisible Defects in 20 nm Logic Devices

2014 ◽  
Author(s):  
M.K. Dawood ◽  
C. Chen ◽  
P.K. Tan ◽  
S. James ◽  
P.S. Limin ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Contact Layer ◽  
Fault Isolation ◽  
Tem Analysis ◽  
Logic Devices ◽  
Technology Advancement ◽  
Transmission Electron ◽  
Voltage Contrast ◽  
Almost All ◽  
20 Nm

Abstract In this work, we present two case studies on the utilization of advanced nanoprobing on 20nm logic devices at contact layer to identify the root cause of scan logic failures. In both cases, conventional failure analysis followed by inspection of passive voltage contrast (PVC) failed to identify any abnormality in the devices. Technology advancement makes identifying failure mechanisms increasingly more challenging using conventional methods of physical failure analysis (PFA). Almost all PFA cases for 20nm technology node devices and beyond require Transmission Electron Microscopy (TEM) analysis. Before TEM analysis can be performed, fault isolation is required to correctly determine the precise failing location. Isolated transistor probing was performed on the suspected logic NMOS and PMOS transistors to identify the failing transistors for TEM analysis. In this paper, nanoprobing was used to isolate the failing transistor of a logic cell. Nanoprobing revealed anomalies between the drain and bulk junction which was found to be due to contact gouging of different severities.

Morphology and Mechanical Properties of Polyethylene Terephthalate/Ethylene Propylene Diene Monomer (PET/EPDM) in the Presence of Nanoclay

2020 ◽  
Vol 57 (3) ◽  
pp. 249-259
Author(s):  
Baifen Liu ◽  
Mohammad Mirjalili ◽  
Peiman Valipour ◽  
Sajad Porzal ◽  
shirin Nourbakhsh
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Thermal Destruction ◽  
Processing Temperature ◽  
Tem Analysis ◽  
Maximum Stiffness ◽  
Cloisite 30B ◽  
Nano Clay ◽  
The Matrix ◽  
Sample Maximum

This research deals with the mechanical properties, microstructure, and interrelations of triple nanocomposite based on PET/EPDM/Nanoclay. These properties were examined in different percentages of PET/EPDM blend with compatibilizer (Styrene-Ethylene/Butylene-Styrene)-G-(Maleic anhydrate) (SEBS-g-MAH). Results showed that the addition of 15% SEBS-g-MAH improved the toughness and impact strength of this nanocomposite. SEM micrographs indicated the most stable fuzzy microstructure in a 50/50 mixture of scattered phases of EPDM/SEBS-g-MAH. The effects of percentages of 1, 3, 5, 7 nanoclay Cloisite 30B (C30B) on the improvement of the properties were evaluated. With the addition of nano clay, the toughness and impact strength was reduced. Thermal destruction of nanoclay in processing temperature led to the decreasing dispersion of clay plates in the matrix and a reduction in the distances of nano clay plates in the composite compared to pure nano clay. XRD and TEM analysis was used to demonstrate the results. By adding 1% of nanoclay to the optimal sample, maximum stiffness, and Impact strength, among other nanocomposites, was achieved.

Sign in / Sign up

Export Citation Format

Share Document