scholarly journals Paclitaxel Magnetic Core–Shell Nanoparticles Based on Poly(lactic acid) Semitelechelic Novel Block Copolymers for Combined Hyperthermia and Chemotherapy Treatment of Cancer

Pharmaceutics ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 213 ◽  
Author(s):  
Evi Christodoulou ◽  
Maria Nerantzaki ◽  
Stavroula Nanaki ◽  
Panagiotis Barmpalexis ◽  
Kleoniki Giannousi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lactic Acid ◽  
Block Copolymers ◽  
Polymeric Nanoparticles ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Poly Lactic Acid ◽  
Average Particle ◽  
Chemotherapy Treatment ◽  
Cytotoxicity Studies

Magnetic hybrid inorganic/organic nanocarriers are promising alternatives for targeted cancer treatment. The present study evaluates the preparation of manganese ferrite magnetic nanoparticles (MnFe2O4 MNPs) encapsulated within Paclitaxel (PTX) loaded thioether-containing ω-hydroxyacid-co-poly(d,l-lactic acid) (TEHA-co-PDLLA) polymeric nanoparticles, for the combined hyperthermia and chemotherapy treatment of cancer. Initially, TEHA-co-PDLLA semitelechelic block copolymers were synthesized and characterized by 1H-NMR, FTIR, DSC, and XRD. FTIR analysis showed the formation of an ester bond between the two compounds, while DSC and XRD analysis showed that the prepared copolymers were amorphous. MnFe2O4 MNPs of relatively small crystallite size (12 nm) and moderate saturation magnetization (64 emu·g−1) were solvothermally synthesized in the sole presence of octadecylamine (ODA). PTX was amorphously dispersed within the polymeric matrix using emulsification/solvent evaporation method. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and transmission electron microscopy showed that the MnFe2O4 nanoparticles were effectively encapsulated within the drug-loaded polymeric nanoparticles. Dynamic light scattering measurements showed that the prepared nanoparticles had an average particle size of less than 160 nm with satisfactory yield and encapsulation efficiency. Diphasic PTX in vitro release over 18 days was observed while PTX dissolution rate was mainly controlled by the TEHA content. Finally, hyperthermia measurements and cytotoxicity studies were performed to evaluate the magnetic response, as well as the anticancer activity and the biocompatibility of the prepared nanocarriers.

scholarly journals Analysis of Gas Permeability Characteristics of Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Amita Bhatia ◽  
Rahul K. Gupta ◽  
Sati N. Bhattacharya ◽  
Hyoung Jin Choi
Keyword(s):  
Lactic Acid ◽  
Gas Permeability ◽  
Average Particle Size ◽  
Barrier Property ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
Clay Nanocomposites ◽  
Average Particle ◽  
Butylene Succinate ◽  
Morphological Studies

Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

scholarly journals Poly(l-Lactic Acid)-co-poly(Butylene Adipate) New Block Copolymers for the Preparation of Drug-Loaded Long Acting Injectable Microparticles

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 930
Author(s):  
Vasiliki Karava ◽  
Aggeliki Siamidi ◽  
Marilena Vlachou ◽  
Evi Christodoulou ◽  
Nikolaos D. Bikiaris ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Block Copolymers ◽  
In Vitro Dissolution ◽  
Sem Images ◽  
Exterior Surface ◽  
Erosion Rates ◽  
Cytotoxicity Studies ◽  
Release Data ◽  
Long Acting

The present study evaluates the use of newly synthesized poly(l-lactic acid)-co-poly(butylene adipate) (PLA/PBAd) block copolymers as microcarriers for the preparation of aripiprazole (ARI)-loaded long acting injectable (LAI) formulations. The effect of various PLA to PBAd ratios (95/5, 90/10, 75/25 and 50/50 w/w) on the enzymatic hydrolysis of the copolymers showed increasing erosion rates by increasing the PBAd content, while cytotoxicity studies revealed non-toxicity for all prepared biomaterials. SEM images showed the formation of well-shaped, spherical MPs with a smooth exterior surface and no particle’s agglomeration, while DSC and pXRD data revealed that the presence of PBAd in the copolymers favors the amorphization of ARI. FTIR spectroscopy showed the formation of new ester bonds between the PLA and PBAd parts, while analysis of the MP formulations showed no molecular drug–polyester matrix interactions. In vitro dissolution studies suggested a highly tunable biphasic extended release, for up to 30 days, indicating the potential of the synthesized copolymers to act as promising LAI formulations, which will maintain a continuous therapeutic level for an extended time period. Lastly, several empirical and mechanistic models were also tested, with respect to their ability to fit the experimental release data.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

scholarly journals Commercial Cokes and Graphites as Anode Materials for Lithium - Ion Cells

1997 ◽  
Vol 496 ◽  
Author(s):  
David J. Derwin ◽  
Kim Kinoshita ◽  
Tri D. Tran ◽  
Peter Zaleski
Keyword(s):  
Electron Microscopy ◽  
Ethylene Carbonate ◽  
Average Particle Size ◽  
Chemical Properties ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Bet Surface Area ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
Wide Range

AbstractSeveral types of carbonaceous materials from Superior Graphite Co. were investigated for lithium ion intercalation. These commercially available cokes, graphitized cokes and graphites have a wide range of physical and chemical properties. The coke materials were investigated in propylene carbonate based electrolytes and the graphitic materials were studied in ethylene carbonate / dimethyl solutions to prevent exfoliation. The reversible capacities of disordered cokes are below 230 mAh / g and those for many highly ordered synthetic (artificial) and natural graphites approached 372 mAh / g (LiC6). The irreversible capacity losses vary between 15 to as much as 200 % of reversible capacities for various types of carbon. Heat treated cokes with the average particle size of 10 microns showed marked improvements in reversible capacity for lithium intercalation. The electrochemical characteristics are correlated with data obtained from scanning electron microscopy (SEM), high resolution transmission electron microscopy (TAM), X - ray diffraction (XRD) and BET surface area analysis. The electrochemical performance, availability, cost and manufacturability of these commercial carbons will be discussed.

Study on the synthesis of antibacterial plastic by using silver nanoparticles doped in zeolite framework

2021 ◽  
Vol 6 (1) ◽  
pp. 32-36
Author(s):  
Anh Quoc Le ◽  
Van Phu Dang ◽  
Ngoc Duy Nguyen ◽  
Kim Lan Nguyen Thi ◽  
Kim Lang Vo Thi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Average Particle Size ◽  
Bactericidal Effect ◽  
Ethanol Solution ◽  
Average Particle ◽  
Γ Irradiation ◽  
Zeolite Framework ◽  
Ion Exchange Reaction ◽  
Transmission Electron

Silver nanoparticles (AgNPs) doped in the zeolite framework (AgNPs/Z) were successfully synthesized by γ-irradiation in ethanol solution of silver ion-zeolite (Ag+/Z) prepared by ion exchange reaction between silver nitrate (AgNO3) and zeolite 4A. The effects of the Ag+ concentration and irradiation dose on the formation of AgNPs/Z were also investigated. AgNPs/Z with the silver content of about 10,000 ppm and the average particle size of AgNPs of about 27 nm was characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM). Firstly, AgNPs/Z was added into PP resins for creation of PP-AgNPs/Z masterbatch (Ag content of ~10.000 ppm) and then PP-AgNPs/Z plastics were preapared by mixing masterbatch with PP resins. The antibacterial activity of the PP-AgNPs/Z plastics was investigated against Gram-negative bacteria Escherichia coli (E. coli). The results showed that PP-AgNPs/Z plastic contained 100 ppm of Ag possessed a high antibacterial property, namely the bactericidal effect was more than 96 % on the platic surface. In conclusion, possessing many advantages such as: vigorously antibacterial effect and good dispersion in plastic matrix, AgNPs/Z is promising to be applied as bactericidal agent for plastic industry.

scholarly journals Phase analysis and corrosion behavior of brazing Cu/Al dissimilar metal joint with BAl88Si filler metal

2021 ◽  
Vol 10 (1) ◽  
pp. 1318-1328
Author(s):  
Hua Yu ◽  
Liangliang Zhang ◽  
Shuai Li ◽  
Fangfang Cai ◽  
Yunpeng Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Salt Spray ◽  
Ternary Eutectic ◽  
Average Particle Size ◽  
Testing Machine ◽  
Joint Interface ◽  
Average Particle ◽  
Automatic Production ◽  
Brazed Joint

Abstract To meet the requirements of automatic production, a new type of green BAl88Si cored solder was developed. The lap brazing experiments were carried out with copper and aluminum as brazing substrates. The microstructure, phase composition, and corrosion behavior of solder joint interface were studied by field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, electron backscattering diffraction, tensile testing machine, and electrochemical workstation. The results show that the brazing joint of Cu/BAl88Si/Al is metallurgical bonding, and the brazing joint of Cu/BAl88Si/Al is composed of Cu9Al4, CuAl2, a-Al, (CuAl2 + a-Al + Si) ternary eutectic. In addition, there is no obvious preference for each grain in the brazing joint, and there are S texture {123}<634>, Copper texture {112}<111>, and Brass texture {110}<112>. The interface of Cu9Al4/CuAl2 is a non-coherent crystal plane and does not have good lattice matching. The average particle size of CuAl2 is 11.95 µm and that of Al is 28.3 µm. However, the kernel average misorientation (KAM) value at the brazed joint interface is obviously higher than that at the brazed joint interface copper, so the defect density at the brazed joint interface aluminum is higher than that at the brazed joint interface copper. At the same time, due to poor corrosion resistance at the interface on the aluminum side of the brazed joint, serious corrosion spots and corrosion cracks occur at the same time, which leads to the shear performance of the brazed joint decreasing by about 75% after salt spray test for 240 h.

scholarly journals Preparation and characterization of domperidone nanoparticles for dissolution improvement

2018 ◽  
Vol 27 (1) ◽  
pp. 39-52
Author(s):  
Mohammed Sabar Al-lami ◽  
Malath H. Oudah ◽  
Firas A. Rahi
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Methyl Cellulose ◽  
Precipitation Method ◽  
Average Particle ◽  
Antisolvent Precipitation ◽  
Stirring Time

This study was carried out to prepare and characterize domperidone nanoparticles to enhance solubility and the release rate. Domperidone is practically insoluble in water and has low and an erratic bioavailability range from 13%-17%. The domperidone nanoparticles were prepared by solvent/antisolvent precipitation method at different polymer:drug ratios of 1:1 and 2:1 using different polymers and grades of poly vinyl pyrolidone, hydroxy propyl methyl cellulose and sodium carboxymethyl cellulose as stabilizers. The effect of polymer type, ratio of polymer:drug, solvent:antisolvent ratio, stirring rate and stirring time on the particle size, were investigated and found to have a significant (p? 0.05) effect on particle size. The best formula was obtained with lowest average particle size of 84.05. This formula was studied for compatibility by FTIR and DSC, surface morphology by FESEM and crystalline state by XRPD. Then domperidone nanoparticles were formulated into a simple capsule dosage form in order to study of the in vitro release of drug from nanoparticles in comparison raw drug and mixture of polymer:drug ratios of 2:1. The release of domperidone from best formula was highly improved with a significant (p? 0.05) increase.

Ni/MWCNT-Supported Palladium Nanoparticles as Magnetic Catalysts for Selective Oxidation of Benzyl Alcohol

2013 ◽  
Vol 66 (5) ◽  
pp. 564 ◽  
Author(s):  
Mingmei Zhang ◽  
Qian Sun ◽  
Zaoxue Yan ◽  
Junjie Jing ◽  
Wei Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Benzyl Alcohol ◽  
Bimetallic Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray ◽  
Oxidation Of Benzyl Alcohol ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Well dispersed Pd@Ni bimetallic nanoparticles on multi-walled carbon nanotubes (Pd@Ni/MWCNT) are prepared and used as catalysts for the oxidation of benzyl alcohol. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy analysis, and X-ray diffraction were performed to characterise the synthesised catalyst. The results show a uniform dispersion of Pd@Ni nanoparticles on MWCNT with an average particle size of 4.0 nm. The as synthesised catalyst was applied to the oxidation of benzyl alcohol. A 99 % conversion of benzyl alcohol and a 98 % selectivity of benzaldehyde were achieved by using the Pd@Ni/MWCNT (Pd: 0.2 mmol) catalyst with water as a solvent and H2O2 as oxidant at 80°C. The catalytic activity of Pd@Ni/MWCNT towards benzyl alcohol is higher than that of a Pd/MWCNT catalyst at the same Pd loadings. The catalyst can be easily separated due to its magnetic properties.

Catalytic Reduction of Nitrobenzene Using Silver Nanoparticles Embedded Calcium Alginate Film

2019 ◽  
Vol 19 (11) ◽  
pp. 7487-7492 ◽  
Author(s):  
Supriya ◽  
Jayanta Kumar Basu ◽  
Sonali Sengupta
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Sodium Borohydride ◽  
Calcium Alginate ◽  
Catalytic Reduction ◽  
Average Particle Size ◽  
Catalyst Loading ◽  
Average Particle ◽  
Transmission Electron

Synthesis of silver nanoparticles embedded on calcium alginate film and the catalytic property of this film in the reduction of nitrobenzene with sodium borohydride are demonstrated in this work. Natural polymer alginate acts as effective reducing and stabilizing agent in synthesis of silver nanoparticles. Effect of different parameters on the preparation of silver nanoparticles, such as, temperature, concentration of silver precursor and heating time was investigated. As-prepared silver nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, UV-Vis spectrometry, and atomic absorption spectrometry. Transmission electron microscopy analysis con-firms the formation of silver nanoparticles with particles size range of 3–19 nm and average particle size was found to be 10±4 nm. Effect of concentration of nitrobenzene and sodium borohydride, catalyst loading and temperature on the catalytic reduction of nitrobenzene was studied. Reusability of catalyst was examined in this reduction reaction and the catalyst shows good activity up to 10th run.

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