scholarly journals Optimization of Islet Microencapsulation with Thin Polymer Membranes for Long-Term Stability

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 755 ◽  
Author(s):  
Shota Toda ◽  
Artin Fattah ◽  
Kenta Asawa ◽  
Naoko Nakamura ◽  
Kristina N. Ekdahl ◽  
...  
Keyword(s):  
Polymer Membranes ◽  
Polymer Membrane ◽  
Membrane Stability ◽  
Host Immune System ◽  
Layer By Layer ◽  
Molecular Weights ◽  
Long Term Stability ◽  
Layer Membrane ◽  
Cell Microencapsulation ◽  
Poly Ethylene

Microencapsulation of islets can protect against immune reactions from the host immune system after transplantation. However, sufficient numbers of islets cannot be transplanted due to the increase of the size and total volume. Therefore, thin and stable polymer membranes are required for the microencapsulation. Here, we undertook the cell microencapsulation using poly(ethylene glycol)-conjugated phospholipid (PEG-lipid) and layer-by-layer membrane of multiple-arm PEG. In order to examine the membrane stability, we used different molecular weights of 4-arm PEG (10k, 20k and 40k)-Mal to examine the influence on the polymer membrane stability. We found that the polymer membrane made of 4-arm PEG(40k)-Mal showed the highest stability on the cell surface. Also, the polymer membrane did not disturb the insulin secretion from beta cells.

scholarly journals Testing the Performance of Various Polymeric Antiscalants for Mitigation of Sb-Rich Precipitates Mimicking Stibnite-Based Geothermal Deposits

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Celal Çiftçi ◽  
Emre Karaburun ◽  
Serhat Tonkul ◽  
Alper Baba ◽  
Mustafa M. Demir ◽  
...  
Keyword(s):  
Power Plants ◽  
Vinyl Pyrrolidone ◽  
Poly Vinyl Alcohol ◽  
Poly Ethylene Glycol ◽  
Molecular Weights ◽  
Geothermal Fields ◽  
The World ◽  
Testing Potential ◽  
Poly Ethylene ◽  
Poly Vinyl Pyrrolidone

Scaling is frequently observed in geothermal fields and reduces the energy harvesting of power plants. Recently, Sb-rich deposits have developed in many fields around the world. Various polymeric macromolecules have been used as antiscalants to mitigate the formation of scale. Testing potential commercial antiscalants in field conditions is a tedious and costly process. The artificial synthesis of geothermal deposits in the lab is a more practical and economical way to test the performance of antiscalants. This study obtained a Sb-rich deposit by refluxing SbCl3 and Na2S·3H2O in 18 h. The product was found to be a mixture of Sb2O3 and Sb2S3. We examined the performance of antiscalants such as poly(ethylene glycol), poly(vinyl pyrrolidone), Gelatin, and poly(vinyl alcohol) of various molecular weights at 5 to 100 ppm. The formation of Sb2S3 is suppressed in the presence of the polymeric antiscalants. The dosage was found to be critical for the solubilization of Sb-rich deposits. Gelatin of 5 ppm showed the highest performance under the conditions employed in this study. While low dosages improve the concentration of [Sb3+], high dosages are required to increase the solubility of [S2-]. Moreover, the amount of deposit is reduced by 12.4% compared to the reference (in the absence of any polymeric molecules). Thus, comparatively, Gelatin shows the most promising performance among the molecules employed.

scholarly journals Sizing and Thermal Stability of Prepared Tetraaminophthalocyaninatocopper(II) Derivatives-grafted Polymers

2016 ◽  
Vol 13 (2) ◽  
pp. 221-234
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thermal Stability ◽  
Ethylene Glycol ◽  
Group Analysis ◽  
Condensation Polymerization ◽  
Grafted Polymers ◽  
Poly Ethylene Glycol ◽  
Molecular Weights ◽  
Poly Ethylene ◽  
Thermal Stability Of ◽  
End Group

Different polymers were prepared by condensation polymerization of sebacic anhydride and adipic anhydride with ethylene glycol and poly(ethylene glycol). Their number average molecular weights were determined by end group analysis. Then, they were grafted on the prepared phthalocyaninatocopper(II) compounds with the general formula (NH2)4PcCu(II) having amino groups of 3,3',3'',3'''- or 4,4',4'',4'''- positions. All prepared polymers, compounds, and phthalocyaninatocopper(II)-grafted polymers were characterized by FTIR. The sizing measurements were carried out in 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) compounds with and without grafting polymers. The results showed that the grafting process led to decreasing in particle size and increasing in surface area. The grafting process was reflected positively on the thermal degradation of 3,3',3'',3'''- (NH2)4PcCu(II) and 4,4',4'',4'''- (NH2)4PcCu(II) grafted polymers. They had higher thermal stability accompanied with higher char residue and T50% weight loss with 3,3',3'',3'''-(NH2)4PcCu(II) and their grafted polymers being the best.

Interpolymer complexes of poly(sulfonic acid)s and poly(ethylene oxide): an unexpected association

Soft Matter ◽  
2019 ◽  
Vol 15 (45) ◽  
pp. 9318-9324
Author(s):  
Liliana Maldonado ◽  
Gabriel Debais ◽  
Federico Davia ◽  
Lucila P. Méndez De Leo ◽  
Mario Tagliazucchi
Keyword(s):  
Aqueous Solution ◽  
Ethylene Oxide ◽  
Sulfonic Acid ◽  
Layer By Layer ◽  
Interpolymer Complexes ◽  
Layer Deposition ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Hydrogen Bonded

Poly(sulfonic acid)s and poly(ethylene oxide) unexpectedly form novel hydrogen-bonded interpolymer complexes in aqueous solution and on surfaces by layer-by-layer deposition.

scholarly journals Poloxamer Hydrogels for Biomedical Applications

Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 671 ◽  
Author(s):  
Eleonora Russo ◽  
Carla Villa
Keyword(s):  
Drug Delivery ◽  
Ethylene Oxide ◽  
Propylene Oxide ◽  
Biomedical Application ◽  
Aqueous Environment ◽  
Molecular Weights ◽  
Long Time ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Concentration Threshold

This review article focuses on thermoresponsive hydrogels consisting of poloxamers which are of high interest for biomedical application especially in drug delivery for ophthalmic, injectable, transdermal, and vaginal administration. These hydrogels remain fluid at room temperature but become more viscous gel once they are exposed to body temperature. In this way, the gelling system remains at the topical level for a long time and the drug release is controlled and prolonged. Poloxamers are synthetic triblock copolymers of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO), also commercially known as Pluronics®, Synperonics® or Lutrol®. The different poloxamers cover a range of liquids, pastes, and solids, with molecular weights and ethylene oxide–propylene oxide weight ratios varying from 1100 to 14,000 and 1:9 to 8:2, respectively. Concentrated aqueous solutions of poloxamers form thermoreversible gels. In recent years this type of gel has arouse interest for tissue engineering. Finally, the use of poloxamers as biosurfactants is evaluated since they are able to form micelles in an aqueous environment above a concentration threshold known as critical micelle concentration (CMC). This property is exploited for drug delivery and different therapeutic applications.

Construction of antibacterial poly(ethylene terephthalate) films via layer by layer assembly of chitosan and hyaluronic acid

2016 ◽  
Vol 143 ◽  
pp. 35-43 ◽  
Author(s):  
Sara del Hoyo-Gallego ◽  
Leyre Pérez-Álvarez ◽  
Flor Gómez-Galván ◽  
Erlantz Lizundia ◽  
Ivo Kuritka ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Ethylene Terephthalate ◽  
Layer By Layer ◽  
Layer By Layer Assembly ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Layer Assembly

scholarly journals Synthetic scheme to improve the solid content of biodegradable waterborne polyurethane by changing the association relationships of hydrophilic fragments

RSC Advances ◽  
2020 ◽  
Vol 10 (48) ◽  
pp. 28680-28694 ◽  
Author(s):  
Zhihui Yang ◽  
Guangfeng Wu
Keyword(s):  
Ethylene Glycol ◽  
Waterborne Polyurethane ◽  
Solid Content ◽  
Synthetic Method ◽  
High Solid Content ◽  
Poly Ethylene Glycol ◽  
High Solid ◽  
Molecular Weights ◽  
Waterborne Polyurethanes ◽  
Poly Ethylene

A synthetic method was developed to prepare biodegradable waterborne polyurethanes (BHPUs) with a high solid content by introducing different molecular weights of poly(ethylene glycol) (PEG) into poly(ε-caprolactone) (PCL)-based polyurethanes.

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