scholarly journals Effects of the electrosprayed polycaprolactone microparticles morphology on the polycaprolactone degradation

2019 ◽  
Vol 3 (2) ◽  
pp. 65-73
Author(s):  
Nguyen-Vu Viet Linh ◽  
Nguyen Quoc Viet ◽  
Huynh Dai Phu
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Protein Delivery ◽  
Gel Permeation Chromatography ◽  
Processing Parameters ◽  
The Body ◽  
Processing Parameter ◽  
Gel Permeation ◽  
Polymeric Microparticles ◽  
Scanning Electron

The polycaprolactone (PCL) microparticles fabricated by electrospray technique have been studied and applied in drug and protein delivery system. The degradation of PCL and the release of drug/protein from the polymeric microparticles (MPs) were desired to happen simultaneously. When the new dosage was administrated, the PCL MPs were degraded and eliminated out of the body. This research indicated that the degradation of PCL was influenced by the various morphology of electrosprayed microparticles. The different sizes of 11.8 μm and 5.17 μm and the various shapes of the PCL MPs such as hollow, porous and wrinkle particles and spheres were investigated the PCL degradation in the PBS solution, at pH 7.4. The morphology of PCL MPs was designed by controlling the polymer solution and the electrosprayed processing parameters such as the flow rate and collecting distance. Scanning electron microscopy and gel permeation chromatography were order to determine the change of the morphology and number molecule weight (Mn) of PCL MPs. The porous, distorted and smaller particles reduced the Mn faster than the microspheres because of the larger surface area of MPs contacted with PBS solution. After 77 days, PCL MPs which were fabricated by the processing parameter, including 2.5% PCL in DCM, flow rate of 0.8 mL/h, voltage of 18 kV, collecting distance of 25 cm, reduced 49.96% molecular weight (decreasing from Mn= 80,438 g/mol to 40,225 g/mol).  

scholarly journals TAYLOR CONE–JET MODE IN THE FABRICATION OF ELECTROSPRAYED MICROSPHERES

2018 ◽  
Vol 55 (1B) ◽  
pp. 216 ◽  
Author(s):  
Viet Linh Nguyen - Vu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polymer Solution ◽  
Flow Rate ◽  
Applied Voltage ◽  
Processing Parameters ◽  
Taylor Cone ◽  
Sem Micrographs ◽  
Scanning Electron

In this study, electrospray modes were investigated to clarify their effects on the morphology and size of polycaprolactone (PCL) particles. The result indicated that electrosprayed microspheres with homogeneous and stable morphology were fabricated by using cone–jet mode and suitable electrospray processing parameters. Besides, the PCL solution was created by dissolving in dichloromethane with different concentrations such as 3.5%, 4%, 4.5% and 5%. The scanning electron microscopy (SEM) micrographs pointed that electrosprayed PCL microspheres were formed by using 4.5 % polymer solution. In addition, the reproducible and homogeneous morphology of PCL microparticles were obtained at the following set of parameters: applied voltage of 18 kV, flow rate of 1.5 mL/h and distance tip to collector of 20 cm. Moreover, at the collecting distance of 15–25 cm, the flow rate of 1.2–1.8 mL/h and applied voltage of 18 kV the cone–jet mode was generated. It was an effective electrospray mode to create stable and homogeneous microspheres.

scholarly journals Manilkara zapota (Linn.) Seeds: A Potential Source of Natural Gum

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Sudarshan Singh ◽  
Sunil B. Bothara
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Gel Permeation Chromatography ◽  
X Ray Diffraction ◽  
X Ray ◽  
Manilkara Zapota ◽  
Gel Permeation ◽  
Scanning Electron

Mucilage isolated from seeds of Manilkara zapota (Linn.) P. Royen syn. is a plant growing naturally in the forests of India. This mucilage is yet to be commercially exploited, and characterized as polymer. Various physicochemical methods like particle size analysis, scanning electron microscopy, thermal analysis, gel permeation chromatography, X-ray diffraction spectrometry, zeta potential, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy have been employed to characterize this gum in the present study. Particle size analyses suggest that mucilage has particle size in nanometer. Scanning electron microscopy analysis suggests that the mucilage has irregular particle size. The glass transition temperature of the gum was observed to be 138°C and 136°C by differential scanning calorimetry and differential thermal analysis, respectively. The thermogravimetric analysis suggested that mucilage had good thermal stability. The average molecular weight of mucilage was determined to be 379180, by gel permeation chromatography, while the viscosity of mucilage was observed to be 219.1 cP. The X-ray diffraction spectrometry pattern of the mucilage indicates a completely amorphous structure. Elemental analysis of the gum revealed the contents of carbon, hydrogen, nitrogen, and sulfur to be 80.9 (%), 10.1 (%), 1.58 (%), and 512 (mg/kg), respectively. Mucilage had specific content of calcium, magnesium, potassium, lower concentrations of aluminum, cadmium, cobalt, lead, and nickel. The major functional groups identified from FT-IR spectrum include 3441 cm−1 (–OH), 1660 cm−1 (Alkenyl C–H & C=C Stretch), 1632 cm−1 (–COO–), 1414 cm−1 (–COO–), and 1219 cm−1 (–CH3CO). Analysis of mucilage by paper chromatography and 1D NMR, indicated the presence of rhamnose, xylose, arabinose, mannose, and fructose.

scholarly journals ELECTROSPRAY METHOD: PROCESSING PARAMETERS INFLUENCE ON MORPHOLOGY AND SIZE OF PCL PARTICLES

2018 ◽  
Vol 55 (1B) ◽  
pp. 209
Author(s):  
Linh Viet Nguyen Vu
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Drug Carrier ◽  
Processing Parameters ◽  
Release Profile ◽  
Polymeric Microparticles ◽  
Size And Morphology ◽  
Imagej Software ◽  
H 20 ◽  
Scanning Electron

The polymeric microparticles using electrospray technique have been used effectively as the drug carrier, whereby controlled release of drug. The electrosprayed particles morphology and size dictated the degradation of polymer matrix, therefore they influenced the release profile from drug loaded microparticles. The effects of electrospray processing parameters (flow rate, applied voltage and distance from the tip of needle to collector) on morphology and size of polycaprolactone (PCL) particles were investigated by scanning electron microscopy (SEM) and ImageJ software. In this research, the PCL solution was prepared by dissolving PCL in Dichloromethane at 4.5 % solution. In addition, processing parameters such as the flow rate (0.5 mL/h, 1 mL/h, 1.5 mL/h, 2 mL/h and 4 mL/h), the applied voltage (15 kV, 18 kV and 24 kV) and the collecting distance (15 cm, 20 cm, and 25 cm) were changed to examine the effects of them on size and morphology of PCL particles. The results indicated that at the suitable electrospraying parameters (18 kV, 1.5 mL/h, 20–25 cm), microparticles have obtained the uniform and stable morphology while at higher flow rate (2 mL/h and 4 mL/h), the particles were deformed and had bigger size. 

scholarly journals Effect of Various Temperatures on Bletillae Rhizoma Polysaccharide Extraction and Physicochemical Properties

2018 ◽  
Vol 9 (1) ◽  
pp. 116 ◽  
Author(s):  
Xiaoyan Long ◽  
Quan Yan ◽  
Linwei Peng ◽  
Xinyue Liu ◽  
Xuegang Luo
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Extraction Temperature ◽  
X Ray Diffraction ◽  
Simple Process ◽  
X Ray ◽  
Gel Permeation ◽  
Scanning Electron

Six fractional polysaccharides were prepared by water extraction and alcohol precipitation under controlled temperature from bletillae rhizoma, a traditional Chinese medicine. Based on this, yields of bletillae rhizome polysaccharides (RBPs) were obtained. The extracting temperature impacted the characteristics of the fractional polysaccharides. The fractional polysaccharides were characterized by glucomannan (GM) content, thermal stability, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), and x-ray diffraction (XRD). For the analysis, 2.0% w/v dispersions of the six fractional polysaccharides were prepared and their flow behaviors were evaluated using a rotational rheometer. The results showed that increased extraction temperature led to increased GM extraction yields and extraction rate, but GM content was relative stable (over 90%). The average molecular weight (Mw) of fractional polysaccharides obtained at 30, 40, 50, 60, 70, and 80 °C was 3.598 × 104, 4.188 × 104, 8.632 × 104, 8.850 × 104, 2.372 × 105, and 3.081 × 105 g/mol, respectively. SEM revealed that fractional polysaccharides had a porous structure of different sizes and densities. Thermal analysis, FTIR, and XRD results indicated that extraction temperature affects the structure and moisture content of fractional polysaccharides. All results showed that the extraction temperature has an obvious impact on the morphology, molecular weight, and polydispersity of the RBPs. This simple process is a promising method for the preparation of fractional polysaccharides.

Electropolymerization of Dialkoxythiophenes and its Morphologies

2011 ◽  
Vol 332-334 ◽  
pp. 1840-1843 ◽  
Author(s):  
Sheng Chen ◽  
Shi Jian Tu ◽  
Yue Chuan Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Electrochemical Deposition ◽  
Supporting Electrolyte ◽  
Gel Permeation Chromatography ◽  
Polymerization Process ◽  
Two Dimensional ◽  
Gel Permeation ◽  
Scanning Electron

Dialkoxysubstitued thiophene monomers were synthesized by the nucleophilic substitution and transetherification reactions. Electrochemical homopolymerization of 3,4-dioctyloxythiophene (DOOT), copolymerization of 3,4-dimethoxythiophene (DMOT) with DOOT were carried out via potentiodynamic and galvanostat methods in the supporting electrolyte. The polymers were characterized via cyclic voltammetry (CV), scanning electron microscopy (SEM), gel permeation chromatography (GPC). In the polymerization process, the electroactive copolymer was formed on the electrode surface with the Eonset(ox) at 970mV, which is 20mV higher than that of DOOT. The Eredox of the copolymer was approximately 15mV higher than that of POOT. The momorphology studies indicated that the electrochemical deposition of P(DMOT-co-DOOT) proceeds via a mechanism of nucleation and two-dimensional (2-D) growth.

scholarly journals Efficient determination and pesticide control by means of immobilization of acetylcholinesterase

2017 ◽  
Vol 36 (1) ◽  
Author(s):  
Elvan Hasanoğlu Özkan ◽  
Nurdan Kurnaz Yetim ◽  
Murat Gümüş ◽  
Nurşen Sarı ◽  
Ali Dişli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Gel Permeation Chromatography ◽  
Condensation Method ◽  
Gel Permeation ◽  
Tetrazole Derivatives ◽  
Scanning Electron

Supports involving tetrazole (o/m/p-F-Tet-1H) were prepared to detect pesticides. This novel te-trazole including fluorine in different positions was attached to nanoparticles (2AEPS-(o/m/p-F-Tet-1H)) by a condensation method. Primarily, the tetrazole derivatives were characterized by 1H-NMR,13C-NMR and LC-MS. Then, nanoparticles were prepared by a condensation method in non-aqueous medium and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, gel permeation chromatography. The enzymatic properties of immobilized acetylcholinesterase (AChE) were investigated for the determination of phosmet. This research is the first example.

scholarly journals Synthesis of functionalized polyisobutylene and its block copolymers with D,L-lactide

2019 ◽  
pp. 40-50
Author(s):  
Pavel A. Nikishau ◽  
Evgenii A. Ksendzov ◽  
Dmitriy I. Shiman ◽  
Ludmila V. Gaponik ◽  
Sergei V. Kostjuk
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nmr Spectroscopy ◽  
Block Copolymers ◽  
Gel Permeation Chromatography ◽  
Optimal Conditions ◽  
Gel Permeation ◽  
Scanning Electron

Method of reactive polyisobutylene modification by various alkoxybenzenes (anisole and 4-phenoxybutanol) was proposed to form functionalized polyisobutylenes. Polymerization of D,L-lactide was explored on the 4-phenoxybutanol/1,5,7-triazabicyclo[4.4.0]dec-5-ene system. It led to determination of optimal conditions for gaining of poly(isobutylene-b-D,L-lactide). Such copolymers (Mn = 14 300 g/mol and Mn = 36 600 g/mol, Mw /  Mn ≤ 2.5) which were obtained by the polymerization of D,L-lactide on polyisobutylene macroinitiator shows microphase ordering. Formation of the block copolymers is confirmed by 1Н NMR spectroscopy, gel permeation chromatography, and scanning electron microscopy.

Preparation of Alcohol-Preserved Larvae of Culicidae (Diptera) for Scanning Electron Microscopy

1972 ◽  
Vol 3 (3) ◽  
pp. 181-188 ◽  
Author(s):  
Christine Dahl
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Body ◽  
Taxonomic Studies ◽  
Scanning Electron ◽  
Sem Studies

AbstractA method for preparation of alcohol-preserved culicid larvae for Scanning Electron Microscope (SEM) studies is described. It is based on dehydration by ethanol-xylol and fast evaporation of xylol in +8o° C. for ten minutes. For taxonomic studies such as examination of pecten teeth, comb scales and microtrichiae in magnifications up to 6oooX the method is suitable. For studies of receptor structures on hair-tufts and microstructures of the body integument alcohol preserved material is less satisfactory. The microstructure of the comb scales is figured and their function discussed. Differences in the ultrastructure of the abdominal hair-tufts are pointed out.

Gel permeation chromatography: The effect of flow rate on efficiency. II

1983 ◽  
Vol 28 (2) ◽  
pp. 473-483 ◽  
Author(s):  
Jau-Yi Chuang ◽  
Julian F. Johnson ◽  
Anthony R. Cooper
Keyword(s):  
Flow Rate ◽  
Gel Permeation Chromatography ◽  
Gel Permeation

scholarly journals Synthesis, Characterization and Properties of Antibacterial Polyurethanes

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 213
Author(s):  
Jihua Duan ◽  
Guichang Jiang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Gray Mold ◽  
Proton Nuclear Magnetic Resonance ◽  
Step Method ◽  
Chemical Structures ◽  
Physically Crosslinked ◽  
Scanning Electron

Novel physically crosslinked polyurethane (PUII), based on isophorone diisocyanates, was prepared by a conventional two-step method. The chemical structures of the PUII were characterized by fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM) and DSC. The PUII hydrogels were subjected to solvent-induced self-assembly in THF + water to construct a variety of morphologies. The self-assembly morphology of the PUII was observed by scanning electron microscopy (SEM). The PUII films with different amounts (0.2%, 0.4%, 0.6%, 0.8%, 1.0%) of 1,3,5-Tris(2-hydroxyethyl)hexahydro-1,3,5-triazine (TNO) were challenged with Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Gray mold. The results showed that when a small amount of antibacterial agent were added, the antibacterial effect of films on Botrytis cinerea was more obvious. The mechanical evaluation shows that the antimicrobial polyurethane films exhibit good mechanical properties.

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