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Search Results: 1 - 10 of 14719 matches for " Poly( -glutamic acid) "
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An Anionic Polymer Incorporating Low Amounts of Hydrophobic Residues Is a Multifunctional Surfactant. Part 2: Emulsification, Moisture Absorption, and Moisture Retention of Alkyl Esterified Poly-γ-Glutamic Acid  [PDF]
Makoto Urai, Tomoko Aizawa, Mutsuyasu Nakajima, Michio Sunairi
Advances in Chemical Engineering and Science (ACES) , 2015, DOI: 10.4236/aces.2015.52020
Abstract: In the accompanying paper (Part 1), we showed that the fatty acid moiety and the acidity of the polysaccharide-backbone of a fatty acid-containing polysaccharide might be involved in its emul-sification, moisture absorption, and moisture retention abilities. In this study, we synthesized alkyl esterified poly-γ-glutamic acid (PGA) with various chain lengths and degrees of substitution of the alkyl moieties to examine how hydrophobic groups incorporated in the anionic polymer contribute to enhanced emulsification, moisture absorption, and moisture retention. With a low degree of alkylation of PGA, these abilities were drastically improved. To improve the moisture absorption of PGA, alkylation with a short chain length is effective in forming interspaces between PGA chains to trap water molecules. Hydrophobic-hydrophilic balance may also be important to improve the emulsification and moisture retention abilities of PGA alkylates. To the best of our knowledge, this is the first report of the relationship between the structure and the multifunctional abilities of an anionic polymer incorporated with a small amount of hydrophobic residue. PGA alkylates, as well as fatty acid-containing polysaccharides, have potential use as multifunctional surfactants throughout various industries.
Eletrodo modificado com filme de poli aminoácido para determina??o de hidrazina em água de caldeira
Brugnera, M. F.;Santos, D. P.;Zanoni, M. V. B.;
Eclética Química , 2006, DOI: 10.1590/S0100-46702006000400010
Abstract: glassy carbon electrodes were modified by films of poly glutamic acid (pag) obtained after electropolymerization of the glutamic acid in ph 7.0 phosphate buffer solution under successive voltammetric scans from -0.8 v to +2.0 v. the modified electrode were applied for determination of hydrazine, which is pre-concentrated on the electrode surface by interaction of free carboxylic groups bearing in the pag film and amino group of hydrazine. although, hydrazine is not electrochemically oxidized on bare electrode, a well defined peak is observed at + 0.57 v with great analytical potentiality. linear calibration graphs were obtained for hydrazine at concentrations from 4 x 10-5 to 1 x 10-3 mol l-1, using differential pulse voltammetry. detection limit was calculated and values around 1.2 x 10-6 mol l-1 were obtained. the proposed method was applied to the determination of hydrazine in samples collected from industrial kettle with recovery of around 94 %.
Development of a Freeze-Dried Skin Care Product Composed of Hyaluronic Acid and Poly(γ-Glutamic Acid) Containing Bioactive Components for Application after Chemical Peels  [PDF]
Yuka Isago, Ryusuke Suzuki, Eri Isono, Yuya Noguchi, Yoshimitsu Kuroyanagi
Open Journal of Regenerative Medicine (OJRM) , 2014, DOI: 10.4236/ojrm.2014.33006
Abstract: Eight types of spongy sheet were prepared by freeze-drying aqueous solutions of hyaluronic acid (HA) and poly(γ-glutamic acid) (PGA) with or without bioactive components including vitamin C derivative (VC), glucosylceramide (GC), and epidermal growth factor (EGF). Spongy sheets were categorized into the following groups: Group I (HA/PGA), Group II (HA/PGA + VC), Group III (HA/PGA + GC), Group IV (HA/PGA + VC, GC), Group V (HA/PGA + EGF), Group VI (HA/PGA + VC, EGF), Group VII (HA/PGA + GC, EGF), and Group VIII (HA/PGA + VC, GC, EGF). In the first experiment, we examined fibroblast proliferation in conditioned medium that had been prepared by immersing each spongy sheet in a conventional culture medium. EGF-incorporating spongy sheets (Groups V-VIII) enhanced fibroblast proliferation more than EGF-free spongy sheets (Groups I-IV). In the second experiment, cytokine production by fibroblasts was evaluated using a wound surface model. This involved elevation of fibroblasts-incorporating collagen gel sheets to the air-liquid interface, on which a spongy sheet (Groups I, IV, V and VIII) was placed and cultured for 1 week. EGF-incorporating spongy sheets (Groups V and VIII) enhanced the production of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by fibroblasts more than EGF-free spongy sheets (Groups I and IV). The effect of these four types of spongy sheet on wounds was investigated in animal experiments. Chemical peel was performed by contacting 50% trichloroacetic acid (TCA) on the dorsal region of mice, after which a spongy sheet was placed, and the wound condition was then observed in a two-week period. Angiogenesis was facilitated to a greater degree in Group VIII compared with Groups I, IV and V. This finding indicates that Group VIII spongy sheet is a promising aid for skin recovery after chemical peel.
Nanosecond T-Jump Experiment in Poly(glutamic acid): A Circular Dichroism Study
Lucille Mendon?a,Fran?ois Hache
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms13022239
Abstract: Poly(glutamic acid) has been studied with a nanosecond T-jump experiment. A new experimental set-up based on the frequency-quadrupling of an 82 MHz Titanium-Sapphire laser allows rapid CD measurements to be performed. Combining time-resolved absorption and circular dichroism at 204 and 220 nm, we are able to measure precisely the unfolding relaxation time as well as the helical fraction evolution. We show that only CD at 220 nm is relevant to observe the unfolding of an alpha helix whereas no change is observed for CD at 204 nm. Conversely, both absorptions yield information on the dynamics of the process.
The Existing Studies on Biosynthesis of Poly( -glutamic acid) by Fermentation
Food and Public Health , 2013, DOI: 10.5923/j.fph.20130301.04
Abstract: Poly( -glutamic acid) known as -PGA, is a polymer that releases the nonessential amino acid glutamic acid upon hydrolysis. The application of poly( -glutamic acid) has increased in past year, as has the research to optimise its production methods with less-expensive processes, for example, the use of new substrate carbon and nitrogen sources for the fermentation processes. The following work reports the study of different fermentation processes for -PGA production and their implementation with regard to the fermentation and nutritional requirements of the studied microorganisms.
Synthesis and micellization behavior of stimuli-responsive polypeptide hybrid triblock copolymer
JingYi Rao,ZhiYuan Zhu,ShiYong Liu
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0244-x
Abstract: Polypeptide hybrid triblock copolymer, poly(L-glutamic acid)-b-poly(propylene oxide)-b-poly (L-glutamic acid) (PLGA-b-PPO-b-PLGA), was synthesized by the ring-opening polymerization of benzyl-L-glutamic N-carboxyanhydride (BLG-NCA) using poly(propylene glycol) bis(2-aminopropyl ether) as initiator, followed by the subsequent deprotection step. The obtained double hydrophilic triblock copolymer exhibits “schizophrenic” micellization behavior in aqueous solution upon dually playing with solution pH and temperature. The multi-responsive micellization behavior of this polypeptide hybrid triblock copolymer has been thoroughly investigated by 1H NMR, laser light scattering (LLS), temperature-dependent optical transmittance, and circular dichroism spectroscopy (CD).
Synthesis, characterization, and biological evaluation of poly(L-γ-glutamyl-glutamine)-paclitaxel nanoconjugate
Sang Van, Sanjib K Das, Xinghe Wang, et al
International Journal of Nanomedicine , 2010, DOI: http://dx.doi.org/10.2147/IJN.S13482
Abstract: thesis, characterization, and biological evaluation of poly(L-γ-glutamyl-glutamine)-paclitaxel nanoconjugate Rapid Communication (6639) Total Article Views Authors: Sang Van, Sanjib K Das, Xinghe Wang, et al Published Date October 2010 Volume 2010:5 Pages 825 - 837 DOI: http://dx.doi.org/10.2147/IJN.S13482 Sang Van1, Sanjib K Das1, Xinghe Wang1, Zhongling Feng1, Yi Jin1, Zheng Hou1, Fu Chen1, Annie Pham1, Nan Jiang1, Stephen B Howell2, Lei Yu1 1Nitto Denko Technical Corporation, Oceanside, CA, USA; 2Moores Cancer Center, University of California, La Jolla, San Diego, CA, USA Abstract: The purpose of this study was to develop a novel, highly water-soluble poly(L-γ-glutamyl-glutamine)-paclitaxel nanoconjugate (PGG-PTX) that would improve the therapeutic index of paclitaxel (PTX). PGG-PTX is a modification of poly(L-glutamic acid)-paclitaxel conjugate (PGA-PTX) in which an additional glutamic acid has been added to each glutamic side chain in the polymer. PGG-PTX has higher water-solubility and faster dissolution than PGA-PTX. Unlike PGA-PTX, PGG-PTX self-assembles into nanoparticles, whose size remains in the range of 12–15 nm over the concentration range from 25 to 2,000 μg/mL in saline. Its critical micellar concentration in saline was found to be ~25 μg/mL. The potency of PGG-PTX when tested in vitro against the human lung cancer H460 cell line was comparable to other known polymer-PTX conjugates. However, PGG-PTX possesses lower toxicity compared with PGA-PTX in mice. The maximum tolerated dose of PGG-PTX was found to be 350 mg PTX/kg, which is 2.2-fold higher than the maximum tolerated dose of 160 mg PTX/kg reported for the PGA-PTX. This result indicates that PGG-PTX was substantially less toxic in vivo than PGA-PTX.
Synthesis and micellization behavior of stimuli-responsive polypeptide hybrid triblock copolymer

JingYi Rao,ZhiYuan Zhu,ShiYong Liu,

科学通报(英文版) , 2009,
Abstract: Polypeptide hybrid triblock copolymer, poly(L-glutamic acid)-b-poly(propylene oxide)-b-poly (L-glutamic acid) (PLGA-b-PPO-b-PLGA), was synthesized by the ring-opening polymerization of benzyl-L-glutamic N-carboxyanhydride (BLG-NCA) using poly(propylene glycol) bis(2-aminopropyl ether) as initiator, followed by the subsequent deprotection step. The obtained double hydrophilic triblock copolymer exhibits “schizophrenic” micellization behavior in aqueous solution upon dually playing with solution pH and temperature. The multi-responsive micellization behavior of this polypeptide hybrid triblock copolymer has been thoroughly investigated by 1H NMR, laser light scattering (LLS), temperature-dependent optical transmittance, and circular dichroism spectroscopy (CD). Supported by the National Natural Science Foundation of China (Grant Nos. 20534020, 20674079, and 20874092)
In vitro removal of toxic heavy metals by poly(γ-glutamic acid)-coated superparamagnetic nanoparticles
Inbaraj BS, Chen BH
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S34396
Abstract: vitro removal of toxic heavy metals by poly(γ-glutamic acid)-coated superparamagnetic nanoparticles Original Research (2004) Total Article Views Authors: Inbaraj BS, Chen BH Published Date August 2012 Volume 2012:7 Pages 4419 - 4432 DOI: http://dx.doi.org/10.2147/IJN.S34396 Received: 30 May 2012 Accepted: 26 June 2012 Published: 10 August 2012 Baskaran Stephen Inbaraj,1 Bing-Huei Chen1,2 1Department of Food Science, 2Graduate Institute of Medicine, Fu Jen University, Taipei, Taiwan Background: Chelation therapy involving organic chelators for treatment of heavy metal intoxication can cause cardiac arrest, kidney overload, mineral deficiency, and anemia. Methods: In this study, superparamagnetic iron oxide nanoparticles (SPIONs) modified with an edible biopolymer poly(γ-glutamic acid) (PGA) were synthesized by coprecipitation method, characterized and evaluated for their removal efficiency of heavy metals from a metal solution, and simulated gastrointestinal fluid (SGIF). Results: Instrumental characterization of bare- and PGA-SPIONs revealed 7% coating of PGA on SPIONs with a spherical shape and an iron oxide spinel structure belonging to magnetite. The particle sizes as determined from transmission electron microscopy images were 8.5 and 11.7 nm for bare- and PGA-SPIONs, respectively, while the magnetization values were 70.3 and 61.5 emu/g. Upon coating with PGA, the zeta potentials were shifted from positive to negative at most of the environmental pH (3–8) and biological pH (1–8), implying good dispersion in aqueous suspension and favorable conditions for heavy metal removal. Batch studies showed rapid removal of lead and cadmium with the kinetic rates estimated by pseudo-second-order model being 0.212 and 0.424 g/mg min, respectively. A maximum removal occurred in the pH range 4–8 in deionized water and 5–8 in SGIF corresponding to most gastrointestinal pH except for the stomach. Addition of different ionic strengths (0.001–1 M sodium acetate) and essential metals (Cu, Fe, Zn, Mg, Ca, and K) did not show any marked influence on lead removal by PGA-SPIONs, but significantly reduced the binding of cadmium. Compared to deionized water, the lead removal from SGIF was high at all pH with the Langmuir monolayer removal capacity being 98.70 mg/g for the former and 147.71 mg/g for the latter. However, a lower cadmium removal capacity was shown for SGIF (23.15 mg/g) than for deionized water (31.13 mg/g). Conclusion: These results suggest that PGA-SPIONs could be used as a metal chelator for clinical treatment of metal poisoning.
Mesenchymal stem cell recruitment by stromal derived factor-1-delivery systems based on chitosan/poly(γ-glutamic acid) polyelectrolyte complexes
RM Gon?alves,JC Antunes,MA Barbosa
European Cells and Materials (ECM) , 2012,
Abstract: Human mesenchymal stem cells (hMSCs) have an enormous potential for tissue engineering and cell-based therapies. With a potential of differentiation into multiple lineages and immune-suppression, these cells play a key role in tissue remodelling and regeneration.Here a method of hMSC recruitment is described, based on the incorporation of a chemokine in Chitosan (Ch)/Poly(γ-glutamic acid) (γ-PGA) complexes. Ch is a non-toxic, cationic polysaccharide widely investigated. γ-PGA is a hydrophilic, non-toxic, biodegradable and negatively charged poly-amino acid. Ch and γ-PGA, being oppositely charged, can be combined through electrostatic interactions. These biocompatible structures can be used as carriers for active substances and can be easily modulated in order to control the delivery of drugs, proteins, DNA, etc.Using the layer-by-layer method, Ch and γ-PGA were assembled into polyelectrolyte multilayers films (PEMs) with thickness of 120 nm. The chemokine stromal-derived factor-1 (SDF-1) was incorporated in these complexes and was continuously released during 120 h. The method of SDF-1 incorporation is of crucial importance for polymers assembly into PEMs and for the release kinetics of this chemokine. The Ch/γ-PGA PEMs with SDF-1 were able to recruit hMSCs, increasing the cell migration up to 6 fold to a maximum of 16.2 ± 4.9 cells/mm2. The controlled release of SDF-1 would be of great therapeutic value in the process of hMSC homing to injured tissues. This is the first study suggesting Ch/γ-PGA PEMs as SDF-1 reservoirs to recruit hMSCs, describing an efficient method of chemokine incorporation that allows a sustained released up to 5 days and that can be easily scaled-up.
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