scholarly journals Fabrication of Core-Shell PLGA-Chitosan Microparticles Using Electrospinning: Effects of Polymer Concentration

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Nguyen Thi Hiep ◽  
Nguyen Dai Hai ◽  
Vo Van Toi
Keyword(s):  
Glycolic Acid ◽  
Polymer Concentration ◽  
Core Shell ◽  
The Core ◽  
Ft Ir ◽  
Ejection Speed ◽  
Diphenyl Tetrazolium Bromide ◽  
Product Outcome ◽  
Labeling Method ◽  
Fluorescence Observation

This investigation aims to fabricate the core-shell microparticles composed of poly(lactic-co-glycolic acid) and chitosan (PLGA-CS MPs) using electrospinning. The challenge of using electrospinning is that it has many parameters which change product outcome if any single parameter is changed. However, the advantage of this system is that we can fabricate either micro/nanofibers or micro/nanoparticles. To learn about the effect of liquid concentration, the electrospinning parameters (voltage, needle sizes, distance from needle to collector, and ejection speed) were fixed while the concentration of PLGA or chitosan was varied. The results showed that PLGA microparticles can be fabricated successfully when the concentration of PLGA is smaller than 10 wt%. Presence of the chitosan shell was confirmed by zeta potential measurements, FT-IR, optical observation, and fluorescence observation. Thickness of the chitosan shell can be controlled by changing the concentration of chitosan and measured by fluorescamine labeling method. Moreover, SEM observation showed that concentration of chitosan affected the size of PLGA-CS microparticles. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay test showed that PLGA-CS microparticles possess excellent biocompatibility.

scholarly journals Synthesis and Control of the Shell Thickness of Polyaniline and Polypyrrole Half Hollow Spheres Using the Polystyrene Cores

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Su-Ryeon Yun ◽  
Gyeong-Ok Kim ◽  
Chan Woo Lee ◽  
Nam-Ju Jo ◽  
Yongku Kang ◽  
...  
Keyword(s):  
Shell Thickness ◽  
Hollow Spheres ◽  
Core Shell ◽  
Chemical Structures ◽  
The Core ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Core Shell Structure ◽  
And Control ◽  
Ft Ir Spectroscopy

Polyaniline (Pani) and polypyrrole (Ppy) half hollow spheres with different shell thicknesses were successfully synthesized by three steps process using polystyrene (PS) as the core. The PS core was synthesized by emulsion polymerization. Aniline and pyrrole monomers were polymerized on the surface of the PS core. The shells of Pani and Ppy were fabricated by adding different amounts of aniline and pyrrole monomers. PS cores were dissolved and removed from the core shell structure by solvent extraction. The thicknesses of the Pani and Ppy half hollow spheres were observed by FE-SEM and FE-TEM. The chemical structures of the Pani and Ppy half hollow spheres were characterized by FT-IR spectroscopy and UV-Vis spectroscopy. The shell thicknesses of the Pani half hollow spheres were 30.2, 38.0, 42.2, 48.2, and 52.4 nm, while the shell thicknesses of the Ppy half hollow spheres were 16.0, 22.0, 27.0, and 34.0 nm. The shell thicknesses of Pani and Ppy half hollow spheres linearly increased as the amount of the monomer increased. Therefore, the shell thickness of the Pani and Ppy half hollow spheres can be controlled in these ranges.

Preparation and Characterization of Core-Shell Latex Containing PDMS in the Shell

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Baotan Zhang ◽  
Bailing Liu ◽  
Shunsheng Cao ◽  
Xiaobo Deng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrophobic Surface ◽  
Water Repellency ◽  
Atomic Ratio ◽  
Core Shell ◽  
Seeded Emulsion Polymerization ◽  
The Core ◽  
Static Contact ◽  
Ft Ir ◽  
Shell Particles

AbstractIn this paper, the composite latex particles with a polyacrylate (PA) core and a polydimethylsiloxane (PDMS) shell via 3-(methacryloxypropyl)- trimethoxy silane (MPS) as the medium to link the core and shell were prepared by semicontinuous seeded emulsion polymerization and were characterized by transmission electron microscopy (TEM), FT-IR, particle size analyzer and X-ray photoelectron spectroscopy (XPS). The TEM images indicated that the particles containing organic siloxane (D-40) displayed an evident core/shell structure. Additionally, the study by FT-IR and XPS also revealed that D4 could be grafted onto the surface of polyacrylate core because there appeared the characteristic peaks of Si-O-Si group and Si 2s and Si 2p in the spectra of FT-IR and XPS respectively. Besides, the atomic ratio of C/Si on the surface of the core/shell particles (D-40) was close to the ratio of C/Si in the latex of pure PDMS that could prove the PA particles were fully covered by PDMS and the properties of PDMS should be embodied in a maximal level. In order to testify the result, the surface properties of the films produced from the core/shell particles were also investigated by the static contact angle method. Compared with the copolymer of PA, the core/shell particles were more effective to create hydrophobic surface, so, the introduction of D4 was capable of obvious increase in water repellency.

Study on Preparation and Properties of Coaxial Electrospun PLGA/Gelatin Fibers

2021 ◽  
Vol 1032 ◽  
pp. 35-41
Author(s):  
Jia Li ◽  
Shuai Lin ◽  
Yue Long Ma ◽  
Xian Hua Xu ◽  
Wei Zheng ◽  
...  
Keyword(s):  
Glycolic Acid ◽  
Coaxial Electrospinning ◽  
Electrospun Fibers ◽  
Core Shell ◽  
High Porosity ◽  
Large Specific Surface Area ◽  
The Core ◽  
Acid Copolymer ◽  
Biomedical Field ◽  
Core Shell Structure

The coaxial electrospun fibers with large specific surface area, high porosity and core-shell structure have been great applied in biomedical field, especially as drug delivery carriers. In this paper, PLGA(polylactic acid/glycolic acid copolymer) was used as the core and the mixture of PLGA and gelatin was used as the shell. PLGA/gelatin fiber was prepared by coaxial electrospinning technology. The effects of different parameters on the surface morphology and the diameter of fibers were investigated.

Bifunctional Fe3O4@SiO2@Eu-Polyoxometalates Nanoparticles and Study on their Magnetism and Luminescence

2011 ◽  
Vol 284-286 ◽  
pp. 2224-2229 ◽  
Author(s):  
Hong Yan Zhang ◽  
Jun Wang ◽  
Shao Hua Fan
Keyword(s):  
Electron Microscopy ◽  
Luminescence Spectroscopy ◽  
Core Shell ◽  
Silica Spheres ◽  
Stöber Method ◽  
The Core ◽  
Transmission Electron ◽  
Ft Ir ◽  
Shell Particles ◽  
The Stöber Method

In this paper, we report the synthesis of the bifunctional Fe3O4@SiO2@Eu-polyoxometalates particles. The magnetite nanoparticles (Fe3O4) homogeneously coated with silica spheres prepared with the Stöber method. The so-obtained Fe3O4@SiO2 core/shell particles were modified by 3-aminopropyltriethoxysilane and finally grafted with the luminescent Europium -polyoxometalates. The core-shell particles were characterized by scanning electron microscopy, transmission electron microscopy, FT-IR, UV, magnetism and luminescence spectroscopy. The results indicated that the core-shell particles show both interesting luminescence and magnetic properties.

Facile Synthesis and In Vitro Biological Screening of Pd@SiO2 Core–Shell Nanoparticles

2019 ◽  
Vol 19 (6) ◽  
pp. 3536-3543 ◽  
Author(s):  
K Rajasekar ◽  
A Dinesh ◽  
M Durka ◽  
K Muthukumaravel
Keyword(s):  
Dna Binding ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Core Shell ◽  
Light Illumination ◽  
Shell Nanoparticles ◽  
The Core ◽  
Ft Ir ◽  
Core Shell Nanoparticles

In this study, semiconductor core–shell Pd@SiO2 nanoparticles (NPs) were prepared by Stober’s method. The prepared final products were characterized by XRD, FT-IR, SEM, HR-TEM and EDX techniques. Cell viability of Pd@SiO2 NPs against HeLa cell line was screened by MTT assay. The present study indicates that the core–shell Pd@SiO2 NPs are extremely stable along with very high photodynamic efficiency under LED light illumination. The antibacterial activities of core– shell Pd@SiO2 NPs were determined with Escherichia coli and Staphylococcus aureus by agar diffusion method. DNA binding affinity of the core–shell Pd@SiO2 NPs towards CT-DNA was also investigated. The observed results showed that SiO2 supported on the surface of Pd NPs not only prevented aggregation, but also proved the enhanced antimicrobial and DNA binding propensities than the free Pd NPs.

Coaxial nanofibers from poly(caprolactone)/ poly(vinyl alcohol)/Thyme and their antibacterial properties

2016 ◽  
Vol 47 (5) ◽  
pp. 834-852 ◽  
Author(s):  
Pantea Koushki ◽  
S Hajir Bahrami ◽  
Marziyeh Ranjbar-Mohammadi
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Vinyl Alcohol ◽  
Polymer Concentration ◽  
Antibacterial Properties ◽  
Poly Vinyl Alcohol ◽  
Core Shell ◽  
Operational Parameters ◽  
The Core ◽  
Poly Caprolactone

Today, with substantial global demand from patients suffering from wounds and burns, the wound care sector has gained great deal of interest in medical industry. Herein, coaxial electrospun poly(caprolactone)/poly(vinyl alcohol) core–shell nanofibers incorporated with Thyme extract in the core structure were prepared using coaxial electrospinning, and the effect of various operational parameters such as polymer concentration, applied voltage, flow rate, distance, and Thyme concentration on nanofiber diameter were studied. Physical and mechanical properties of the nanofibers were determined by analytical techniques. The results revealed that desired nanofibers with uniform surface morphology and acceptable tensile strength could be obtained at applied voltage of 15 kV, needle tip-target of 13 cm, core flow rate of 0.2 mL/h, and shell flow rate of l mL/h. Moreover, MTT assay shows that the nanofibers are highly biocompatible regardless of Thyme encapsulation. Antibacterial activities of the prepared core–shell nanofibers were also examined against two bacteria—gram-positive Staphylococcus and gram-negative Escherichia. Encapsulation of 5% (w/v) Thyme extract concentration in the core–shell poly(caprolactone)/poly(vinyl alcohol) nanofibers led to high antibacterial activity of the produced nanofibers.

scholarly journals Synthesis and Characterization of LiZn Ferrite-Coated CNT via a Sol-Gel Method

2006 ◽  
Vol 15 (5) ◽  
pp. 096369350601500
Author(s):  
Sun Chang ◽  
Sun Kangning
Keyword(s):  
Sol Gel ◽  
Surface Oxidation ◽  
Core Shell ◽  
Oxidation Treatment ◽  
Gel Method ◽  
Sol Gel Method ◽  
The Core ◽  
Ft Ir ◽  
Effect Of Surface

A novel CNTs-based composite, LiZn ferrite (Li0.435Zn0.195Fe2.37 O4) coated CNTs core-shell nanostructure, was successfully prepared by a sol-gel method. The core-shell hetero-nanostructure have confirmed by TEM and XRD. The effect of surface oxidation treatment of MWNTs was investigated by FT-IR. The result showed that MWNTs functionalized with–COOH and –OH, etc. groups form an efficient matrix for the growth of LiZn ferrite crystals.

Thermo-Chemical Reactions of Modified PAN Fibers during Heat-Treatment Process

2006 ◽  
Vol 11-12 ◽  
pp. 73-76 ◽  
Author(s):  
Yi Wang ◽  
Jie Liu ◽  
Jie Ying Liang
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Chemical Reactions ◽  
Treatment Process ◽  
Core Shell ◽  
Heat Treatment Process ◽  
Cyclization Reactions ◽  
The Core ◽  
Ft Ir ◽  
Pan Fibers

Thermo-chemical reactions of modified PAN fibers during heat-treatment process were systematically studied by DSC, FT-IR, EA, XPS, etc. Comparing with original PAN fibers, chemical reactions, structures and elemental compositions of fibers modified with potassium permanganate (KMnO4) were all changed at a certain extent. KMnO4 had reduced the activation energy of cyclization reactions, decreased the area and widened the peak of exothermic curve, decreased the velocity of cyclization reaction, increased the oxygen content about 67%, hence increased C-O-C and C=O groups and the core/shell ratio.

Preparation and Characterization of SiO2-PMMA with Different Shell Thickness Using AGET ATRP

2013 ◽  
Vol 634-638 ◽  
pp. 1951-1954 ◽  
Author(s):  
Lei Zhang ◽  
Guo Wei Zhou ◽  
Min Nan Zhao
Keyword(s):  
Electron Transfer ◽  
1H Nmr ◽  
Shell Thickness ◽  
Silica Surface ◽  
Core Shell ◽  
Aget Atrp ◽  
The Core ◽  
Ft Ir ◽  
Shell Composite

Monodispersed SiO2-core/PMMA-shell composite nanospheres have been prepared via activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) mediated by an iron (III) catalyst. By simply adjusting the amount of monomer, the shell thickness of products can easily be tuned. Samples were characterized by FT-IR, TEM, 1H NMR. The results showed that the sphere structure kept unchanging after grafting. FT-IR and 1H NMR measurements show that the polymer was grafted on the silica surface successfully. TEM results for composite nanospheres suggested the core-shell-like structure of the hybrid nanoparticle.

The Preparation of Core-Shell Type Acrylic-Polyurethane Composite Emulsions for Pigment Printing

2011 ◽  
Vol 332-334 ◽  
pp. 387-390
Author(s):  
Chun Lei Xu ◽  
Yi Hu ◽  
Jin Qiang Liu ◽  
Sheng Peng Wang ◽  
Shao Min Qu ◽  
...  
Keyword(s):  
Shell Structure ◽  
Core Shell ◽  
Seeded Emulsion Polymerization ◽  
Acrylic Polymer ◽  
The Core ◽  
Polyurethane Composite ◽  
Transmission Electron ◽  
Ft Ir ◽  
Core Shell Structure ◽  
Acrylic Polyurethane

Vinyl-endblocked polyurethanes were prepared from polyether diols(N210), isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and 2-hydroxyethyl acrylate (HEA). The core-shell structure acrylic-polyurethane composite emulsion was prepared by seeded emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) using the polyurethanes emulsions as seeded emulsions. The core and shell regions were occupied by acrylic polymer and polyurethane, respectively. Because polyurethanes were vinyl-endblocked, acrylic monomers could graft partially to them. The formation of core-shell structure was observed by transmission electron microscopy (TEM). The structure and properties of dried film were studied by Fourier-transform infrared spectroscopy (FT-IR) and TGA.

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