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Sample records for acid polyethylene glycol

  1. Polyethylene Glycol 3350

    MedlinePlus

    Polyethylene glycol 3350 is used to treat occasional constipation. Polyethylene glycol 3350 is in a class of medications ... Polyethylene glycol 3350 comes as a powder to be mixed with a liquid and taken by mouth. ...

  2. Polyethylene glycol plus ascorbic acid for bowel preparation in chronic kidney disease.

    PubMed

    Lee, Jae Min; Keum, Bora; Yoo, In Kyung; Kim, Seung Han; Choi, Hyuk Soon; Kim, Eun Sun; Seo, Yeon Seok; Jeen, Yoon Tae; Chun, Hoon Jai; Lee, Hong Sik; Um, Soon Ho; Kim, Chang Duck; Kim, Myung Gyu; Jo, Sang Kyung

    2016-09-01

    The safety of polyethylene glycol plus ascorbic acid has not been fully investigated in patients with renal insufficiency. High-dose ascorbic acid could induce hyperoxaluria, thereby causing tubule-interstitial nephritis and renal failure. This study aims to evaluate the safety and efficacy of polyethylene glycol plus ascorbic acid in patients with chronic kidney disease.We retrospectively reviewed prospectively collected data on colonoscopy in patients with impaired renal function. Patients were divided into 2 groups: 2 L polyethylene glycol plus ascorbic acid (n = 61) and 4 L polyethylene glycol (n = 80). The safety of the 2 groups was compared by assessing the differences in laboratory findings before and after bowel cleansing.The laboratory findings were not significantly different before and after the administration of 2 L polyethylene glycol plus ascorbic acid or 4 L polyethylene glycol. In both groups, the estimated glomerular filtration rate was not influenced by the administration of the bowel-cleansing agent. Patients' reports on tolerance and acceptability were better in the 2 L polyethylene glycol plus ascorbic acid group than in the 4 L polyethylene glycol group.The 2 L polyethylene glycol plus ascorbic acid solution is a safe choice for bowel preparation before colonoscopy in patients with impaired renal function. PMID:27603372

  3. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  4. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  5. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  6. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  7. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  8. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of methacrylic acid-methyl methacrylate- polyethylene glycol monomethyl ether methacrylate graft copolymer when used as an inert ingredient in a pesticide chemical formulation. Akzo Noel Surface Chemistry LLC submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an......

  9. Polyethylene Glycol 3350

    MedlinePlus

    Polyethylene glycol 3350 comes as a powder to be mixed with a liquid and taken by mouth. It is usually taken once a day as needed for up to ... to produce a bowel movement.To use the powder, follow these steps: If you are using polyethylene ...

  10. Polyethylene Glycol Propionaldehydes

    NASA Technical Reports Server (NTRS)

    Harris, Joe M.; Sedaghat-Herati, Mohammad R.; Karr, Laurel J.

    1992-01-01

    New class of compounds derived from polyethylene glycol (PEG's) namely, PEG-propionaldehydes, offers two important advantages over other classes of PEG aldehyde derivatives: compounds exhibit selective chemical reactivity toward amino groups and are stable in aqueous environment. PEG's and derivatives used to couple variety of other molecules, such as, to tether protein molecules to surfaces. Biotechnical and biomedical applications include partitioning of two phases in aqueous media; immobilization of such proteins as enzymes, antibodies, and antigens; modification of drugs; and preparation of protein-rejecting surfaces. In addition, surfaces coated with PEG's and derivatives used to control wetting and electroosmosis. Another potential application, coupling to aminated surfaces.

  11. 40 CFR 721.10505 - Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, mixed mono- and... Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12-16-alkyl... identified as phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol...

  12. 40 CFR 721.10505 - Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, mixed mono- and... Phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol mono-C12-16-alkyl... identified as phosphoric acid, mixed mono- and diesters with 2-ethyl-1-hexanol and polyethylene glycol...

  13. [Determination of isophthalic acid in polyethylene glycol terephthalate fiber by high performance liquid chromatography].

    PubMed

    Wang, R; Wang, X Y; Tang, C J; Li, L P

    2001-07-01

    The isophthalic acid(IPA) is present in polyethylene glycol terephthalate(PET) at small level, but plays an important role for the properties of polyester fiber. Thus the PET sample was hydrolysated by 100 g/L of sodium hydrate in methanol at 70 degrees C during 10 h and finally assayed by HPLC. A reversed-phase high performance liquid chromatographic method for the separation of isophthalic acid from terephthalic acid(TPA) has been developed. The operating conditions were Novapak C18 column, methanol-water(15:85, V/V)(pH3) as mobile phase with the flow rate of 1.0 mL/min and UV detection wavelength at 254 nm. PMID:12545507

  14. Poly(ethylene glycol)-poly(lactic-co-glycolic acid) based thermosensitive injectable hydrogels for biomedical applications.

    PubMed

    Alexander, Amit; Ajazuddin; Khan, Junaid; Saraf, Swarnlata; Saraf, Shailendra

    2013-12-28

    Stimuli triggered polymers provide a variety of applications related with the biomedical fields. Among various stimuli triggered mechanisms, thermoresponsive mechanisms have been extensively investigated, as they are relatively more convenient and effective stimuli for biomedical applications. In a contemporary approach for achieving the sustained action of proteins, peptides and bioactives, injectable depots and implants have always remained the thrust areas of research. In the same series, Poloxamer based thermogelling copolymers have their own limitations regarding biodegradability. Thus, there is a need to have an alternative biomaterial for the formulation of injectable hydrogel, which must remain biocompatible along with safety and efficacy. In the same context, poly(ethylene glycol) (PEG) based copolymers play a crucial role as a biomedical material for biomedical applications, because of their biocompatibility, biodegradability, thermosensitivity and easy controlled characters. This review stresses on the physicochemical property, stability and composition prospects of smart PEG/poly(lactic-co-glycolic acid) (PLGA) based thermoresponsive injectable hydrogels, recently utilized for biomedical applications. The manuscript also highlights the synthesis scheme and stability characteristics of these copolymers, which will surely help the researchers working in the same area. We have also emphasized the applied use of these smart copolymers along with their formulation problems, which could help in understanding the possible modifications related with these, to overcome their inherent associated limitations. PMID:24144918

  15. Poly(lactic acid) / Poly(ethylene glycol) blends: Mechanical, thermal and morphological properties

    NASA Astrophysics Data System (ADS)

    Bijarimi, M.; Ahmad, S.; Rasid, R.; Khushairi, M. A.; Zakir, M.

    2016-04-01

    The poly(lactic acid) (PLA) was melt blended with linear polyethylene glycol (PEG) in an effort to increase the toughness of PLA. Melt blending was carried out in an internal mixer at 180 °C mixing temperature with 50 rpm for 15 minutes. The blends were characterized in terms of mechanical, thermal and morphological properties. It was found that tensile and flexural strength, stiffness and notched Izod impact strength decreased significantly when the PEG was added to the PLA matrix at 2.5-10% of PEG concentrations. Both glass transition and melting temperatures (Tg and Tm) lowered as the concentration of PEG was increased. Moreover, it was noted that the PLA/PEG blends showed a lower onset and peak degradation temperatures but with lower final degradation temperature as compared to the neat PLA. The morphological analysis revealed that the PEG was dispersed as droplets in the PLA matrix with a clear boundary between PLA matrix and PEG phases.

  16. Fabrication of poly hydroxybutyrate-polyethylene glycol-folic acid nanoparticles loaded by paclitaxel.

    PubMed

    Rezaei, Fatemeh; Rafienia, Mohammad; Keshvari, Hamid; Sattary, Mansooreh; Naeimi, Mitra; Keyvani, Hossein

    2016-01-01

    In this study drug (paclitaxel)-loaded nanoparticles of poly hydroxybutyrate-polyethylene glycol-folic acid (PHB-PEG-FOL) were prepared by using an oil-in-water (O/W) emulsion-solvent evaporation method. The functionalization and conjugation steps in the chemical synthesis were confirmed using Fourier transform infrared (FTIR) and nuclear magnetic resonance tests ((1)H NMR). Morphology of nanoparticles was evaluated by scanning electron microscopy (SEM). Nanoparticles were characterized by particle size analyzer. Between two samples containing drug, the lower doses showed more homogeneous distribution, and the lowest aggregation. The drug release profiles showed a two-phase release including initial rapid release and a continuous release. MG63 cells were used to evaluate cytotoxicity. The cytotoxicity of PHB-PEG-FOL nanoparticles with drug against cancer cells was much higher and longer than free drug sample. These nanoparticles were successfully synthesized as a novel system for targeted drug delivery against cancer cells. PMID:26234551

  17. Improving of bowel cleansing effect for polyethylene glycol with ascorbic acid using simethicone

    PubMed Central

    Yoo, In Kyung; Jeen, Yoon Tae; Kang, Seung Hun; Lee, Jae Hyung; Kim, Seung Han; Lee, Jae Min; Choi, Hyuk Soon; Kim, Eun Sun; Keum, Bora; Chun, Hoon Jai; Lee, Hong Sik; Kim, Chang Duck

    2016-01-01

    Abstract Background and Aim: Low-volume polyethylene glycol with ascorbic acid (PEG-Asc) use is reported to be as safe and effective as traditional 4-L polyethylene glycol use. However, PEG-Asc produces bubbles, which cause problems during colonoscopy. Data on the effects of using antifoaming agents such as simethicone with PEG-Asc are lacking. The aim of this CONSORT-prospective, randomized, observer-blinded, controlled trial is to compare the quality of bowel preparation and compliance between PEG-Asc users and PEG-Asc plus simethicone users. Methods: Adult outpatients aged 18 to 80 years undergoing colonoscopy were recruited to the study. Two hundred sixty patients were randomly assigned to 1 of 2 treatment arms, PEG-Asc or PEG-Asc plus simethicone. The primary outcome measure was the bowel cleansing quality using Boston bowel preparation scale and bubble scores. The secondary outcome measures were patient tolerability and doctor tolerability. Results: The simethicone group showed superior cleansing results (6–9 Boston scale scores: 99% vs. 84%, <5% bubble scores: 96% vs. 49%, P < 0.001) and fewer gastrointestinal symptoms (abdominal fullness: 24% vs. 55%, colicky pain: 5% vs. 24%, P < 0.001) than the non-simethicone group. Moreover, endoscopist fatigue during colonoscopy was lower in the simethicone group than in the non-simethicone group (1.31 ± 0.75 vs. 2.97 ± 2.14, P < 0.001). Conclusion: PEG-Asc plus simethicone use was more effective and associated with better patient and endoscopist tolerance than PEG-Asc use. Therefore, this combination is recommended as one of the promising methods for bowel preparation before colonoscopy. PMID:27428209

  18. Preventing corona effects: multiphosphonic acid poly(ethylene glycol) copolymers for stable stealth iron oxide nanoparticles.

    PubMed

    Torrisi, V; Graillot, A; Vitorazi, L; Crouzet, Q; Marletta, G; Loubat, C; Berret, J-F

    2014-08-11

    When dispersed in biological fluids, engineered nanoparticles are selectively coated with proteins, resulting in the formation of a protein corona. It is suggested that the protein corona is critical in regulating the conditions of entry into the cytoplasm of living cells. Recent reports describe this phenomenon as ubiquitous and independent of the nature of the particle. For nanomedicine applications, however, there is a need to design advanced and cost-effective coatings that are resistant to protein adsorption and that increase the biodistribution in vivo. In this study, phosphonic acid poly(ethylene glycol) copolymers were synthesized and used to coat iron oxide particles. The copolymer composition was optimized to provide simple and scalable protocols as well as long-term stability in culture media. It is shown that polymers with multiple phosphonic acid functionalities and PEG chains outperform other types of coating, including ligands, polyelectrolytes, and carboxylic acid functionalized PEG. PEGylated particles exhibit moreover exceptional low cellular uptake, of the order of 100 femtograms of iron per cell. The present approach demonstrates that the surface chemistry of engineered particles is a key parameter in the interactions with cells. It also opens up new avenues for the efficient functionalization of inorganic surfaces. PMID:25046557

  19. Oleanolic acid liposomes with polyethylene glycol modification: promising antitumor drug delivery

    PubMed Central

    Gao, Dawei; Tang, Shengnan; Tong, Qi

    2012-01-01

    Background Oleanolic acid is a pentacyclic triterpene present in many fruits and vegetables, and has received much attention on account of its biological properties. However, its poor solubility and low bioavailability limit its use. The objective of this study was to encapsulate oleanolic acid into nanoliposomes using the modified ethanol injection method. Methods The liposomes contain a hydrophobic oleanolic acid core, an amphiphilic soybean lecithin monolayer, and a protective hydrophilic polyethylene glycol (PEG) coating. During the preparation process, the formulations described were investigated by designing 34 orthogonal experiments as well as considering the effects of different physical characteristics. The four factors were the ratios of drug to soybean phosphatidylcholine (w/w), cholesterol (w/w), PEG-2000 (w/w), and temperature of phosphate-buffered saline at three different levels. We identified the optimized formulation which showed the most satisfactory lipid stability and particle formation. The morphology of the liposomes obtained was determined by transmission electron microscopy and atomic force microscopy. The existence of PEG in the liposome component was validated by Fourier transform infrared spectrum analysis. Results The PEGylated liposomes dispersed individually and had diameters of around 110–200 nm. Encapsulation efficiency was more than 85%, as calculated by high-performance liquid chromatography and Sephadex® gel filtration. Furthermore, when compared with native oleanolic acid, the liposomal formulations showed better stability in vitro. Finally, the cytotoxicity of the oleanolic acid liposomes was evaluated using a microtiter tetrazolium assay. Conclusion These results suggest that PEGylated liposomes would serve as a potent delivery vehicle for oleanolic acid in future cancer therapy. PMID:22848175

  20. Multifunctional ligands based on dihydrolipoic acid and polyethylene glycol to promote biocompatibility of quantum dots.

    PubMed

    Susumu, Kimihiro; Mei, Bing C; Mattoussi, Hedi

    2009-01-01

    One of the common strategies to promote the transfer of quantum dots (QDs) to buffer media and to couple them to biological molecules has relied on cap exchange. We have shown previously that dihydrolipoic acid (DHLA) and polyethylene glycol (PEG)-appended DHLA can effectively replace the native ligands on CdSe-ZnS QDs. Here we explain in detail the synthesis of a series of modular ligands made of the DHLA-PEG motif appended with terminal functional groups. This design allows easy coupling of biomolecules and dyes to the QDs. The ligands are modular and each is comprised of three units: a potential biological functional group (biotin, carboxylic acid and amine) and a DHLA appended at the ends of a short PEG chain, where PEG promotes water solubility and DHLA provides anchoring onto the QD. The resulting QDs are stable over a broad pH range and accessible to simple bioconjugation techniques, such as avidin-biotin binding. PMID:19265801

  1. Time Dependence of Material Properties of Polyethylene Glycol Hydrogels Chain Extended with Short Hydroxy Acid Segments

    PubMed Central

    Barati, Danial; Moeinzadeh, Seyedsina; Karaman, Ozan; Jabbari, Esmaiel

    2014-01-01

    The objective of this work was to investigate the effect of chemical composition and segment number (n) on gelation, stiffness, and degradation of hydroxy acid-chain-extended star polyethylene glycol acrylate (SPEXA) gels. The hydroxy acids included glycolide (G,), L-lactide (L), p-dioxanone (D) and -caprolactone (C). Chain-extension generated water soluble macromers with faster gelation rates, lower sol fractions, higher compressive moduli, and a wide-ranging degradation times when crosslinked into a hydrogel. SPEGA gels with the highest fraction of inter-molecular crosslinks had the most increase in compressive modulus with n whereas SPELA and SPECA had the lowest increase in modulus. SPEXA gels exhibited a wide range of degradation times from a few days for SPEGA to a few weeks for SPELA, a few months for SPEDA, and many months for SPECA. Marrow stromal cells and endothelial progenitor cells had the highest expression of vasculogenic markers when co-encapsulated in the faster degrading SPELA gel. PMID:25267858

  2. Nanomolar CFTR inhibition by pore-occluding divalent polyethylene glycol-malonic acid hydrazides.

    PubMed

    Sonawane, N D; Zhao, Dan; Zegarra-Moran, Olga; Galietta, Luis J V; Verkman, A S

    2008-07-21

    Inhibitors of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel have potential application as antisecretory therapy in cholera. We synthesized mono- and divalent CFTR inhibitors consisting of a malonic acid hydrazide (MalH) coupled via a disulfonic stilbene linker to polyethylene glycols (PEGs; 0.2-100 kDa). IC50 values for CFTR inhibition were 10-15 microM for the monovalent MalH-PEGs, but substantially lower for divalent MalH-PEG-MalH compounds, decreasing from 1.5 to 0.3 microM with increasing PEG size and showing positive cooperativity. Whole-cell patch-clamp showed voltage-dependent CFTR block with inward rectification. Outside-out patch-clamp showed shortened single-channel openings, indicating CFTR pore block from the extracellular side. Luminally added MalH-PEG-MalH blocked by >90% cholera toxin-induced fluid secretion in mouse intestinal loops (IC50 approximately 10 pmol/loop), and greatly reduced mortality in a suckling mouse cholera model. These conjugates may provide safe, inexpensive antisecretory therapy. PMID:18635008

  3. Antitumor drug effect of betulinic acid mediated by polyethylene glycol modified liposomes.

    PubMed

    Liu, Yanping; Gao, Dawei; Zhang, Xuwu; Liu, Zhiwei; Dai, Kun; Ji, Bingshuo; Wang, Qianqian; Luo, Liyao

    2016-07-01

    Betulinic acid (BA), as a natural pentacyclic lupine-type triterpene, principally derives from bark of white birch, due to its potent pharmacological properties and low side-effect, which has been demonstrated a prominent efficiency on cancer therapy. However, the poor solubility and low bioavailability limit its pharmaceutical effect. Herein, we reported the rapid efficient synthesis of the polyethylene glycol modified (PEGylated) BA liposomes using ethanol injection technique for the first time. In the study, hydrophobic BA was encapsulated in the lipid bilayer of liposomes, meanwhile hydrophilic PEG layer covered the surface of liposomes. The mean diameter of PEGylated BA liposomes was 142nm, which can effectively accumulate in the tumor tissues. In vitro drug release study showed that the PEGylated BA liposomes had a better sustained drug release effect than BA liposomes. The PEGylated BA liposomes also exhibited a better tumor inhibitory effect compared with those of free BA or BA liposomes in vitro and in vivo experiments. Therefore, the PEGylated BA liposomes could serve as a better alternative for the cancer therapy in future. PMID:27127036

  4. Bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400, and polyethylene glycol 1000 against selected microorganisms

    PubMed Central

    Nalawade, Triveni Mohan; Bhat, Kishore; Sogi, Suma H. P.

    2015-01-01

    Aim: The aim of the present study was to evaluate the bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400 (PEG 400), and polyethylene glycol 1000 (PEG 1000) against selected microorganisms in vitro. Materials and Methods: Five vehicles, namely propylene glycol, glycerine, PEG 400, PEG 1000, and combination of propylene glycol with PEG 400, were tested for their bactericidal activity. The minimum bactericidal concentration was noted against four standard strains of organisms, i.e. Streptococcus mutans American Type Culture Collection (ATCC) 25175, Streptococcus mutans ATCC 12598, Enterococcus faecalis ATCC 35550, and Escherichia coli ATCC 25922, using broth dilution assay. Successful endodontic therapy depends upon thorough disinfection of root canals. In some refractory cases, routine endodontic therapy is not sufficient, so intracanal medicaments are used for proper disinfection of canals. Intracanal medicaments are dispensed with vehicles which aid in increased diffusion through the dentinal tubules and improve their efficacy. Among the various vehicles used, glycerine is easily available, whereas others like propylene glycol and polyethylene glycol have to be procured from appropriate sources. Also, these vehicles, being viscous, aid in sustained release of the medicaments and improve their handling properties. The most commonly used intracanal medicaments like calcium hydroxide are ineffective on many microorganisms, while most of the other medicaments like MTAD (Mixture of Tetracycline, an Acid, and a Detergent) and Triple Antibiotic Paste (TAP) consist of antibiotics which can lead to development of antibiotic resistance among microorganisms. Thus, in order to use safer and equally effective intracanal medicaments, newer alternatives like chlorhexidine gluconate, ozonized water, etc., are being explored. Similarly, the five vehicles mentioned above are being tested for their antimicrobial activity in this study. Results: All vehicles

  5. Biocompatibility and functional performance of a polyethylene glycol acid-grafted cellulosic membrane for hemodialysis.

    PubMed

    Sirolli, V; Di Stante, S; Stuard, S; Di Liberato, L; Amoroso, L; Cappelli, P; Bonomini, M

    2000-06-01

    In order to improve the biochemical reactivity of the cellulose polymer, which is mainly attributed to the presence of surface hydroxyl groups, derivatized cellulosic membranes have been engineered replacing or masking some or all of the hydroxyl groups in the manufacturing process of the membrane. The present study was set up to analyze both biocompatibility and functional performance of two different derivatized cellulosic membranes (cellulose diacetate; polyethylene glycol, PEG, acid-grafted cellulose) as compared to a synthetic membrane (polymethylmethacrylate, PMMA). Cellulose diacetate is prepared by substituting hydroxyl groups with acetyl groups; PEG cellulose is obtained by grafting PEG chains onto the cellulosic polymer with a smaller amount of substitution than cellulose diacetate. While the three dialyzers provided similar urea and creatinine removal, the dialyzer containing cellulose diacetate showed a reduced ability to remove 32-microglobulin compared to that containing PEG cellulose or PMMA. A transient reduction in leukocyte count was observed for both derivatized cellulosic membranes. The neutrophil and monocyte counts throughout the entire dialysis session showed a closer parallelism with the cellular expression of the adhesive receptor CD 15s (sialyl-Lewis x molecule) than with CD11b/CD18 expression. Platelet activation, as indicated by the percentage of cells expressing the activation markers CD62P (P-selectin) and CD63 (gp53), occurred with all membranes at 15 min of dialysis and also with PMMA at 30 min. An increased formation of platelet-neutrophil and platelet-monocyte coaggregates was found at 15 and 30 min during dialysis with cellulose diacetate and PMMA but not with PEG cellulose. Generally in concomitance with the increase in platelet-neutrophil coaggregates, an increased hydrogen peroxide production by neutrophils occurred. Our results indicate that derivatizing cellulose may represent a useful approach to improve the biocompatibility

  6. Poly(ethylene glycol)-co-methacrylamide-co-acrylic acid based nanogels for delivery of doxorubicin.

    PubMed

    Kumar, Parveen; Behl, Gautam; Sikka, Manisha; Chhikara, Aruna; Chopra, Madhu

    2016-10-01

    Polymeric nanogels have been widely explored for their potential application as delivery carriers for cancer therapeutics. The ability of nanogels to encapsulate therapeutics by simple diffusion mechanism and the ease of their fabrication to impart target specificity in addition to their ability to get internalized into target cells make them good candidates for drug delivery. The present study aims to investigate the applicability of poly(ethylene glycol)-co-methacrylamide-co-acrylic acid (PMA)-based nanogels as a viable option for the delivery of doxorubicin (DOX). The nanogels were synthesized by free radical polymerization in an inverse mini-emulsion and characterized by nuclear magnetic resonance spectroscopy ((1)H NMR), Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction and differential scanning calorimetry. DOX was physically incorporated into the nanogels (PMA-DOX) and the mechanism of its in vitro release was studied. TEM experiment revealed spherical morphology of nanogels and the hydrodynamic diameter of the neat nanogels was in the range of 160 ± 46.95 nm. The size of the nanogels increased from 235.1 ± 28.46 to 403.7 ± 89.89 nm with the increase in drug loading capacity from 4.68 ± 0.03 to 13.71 ± 0.01%. The sustained release of DOX was observed upto 80 h and the release rate decreased with increased loading capacity following anomalous release mechanism as indicated by the value of diffusion exponent (n = 0.64-0.75) obtained from Korsmeyer-Peppas equation. Further, cytotoxicity evaluation of PMA-DOX nanogels on HeLa cells resulted in relatively higher efficacy (IC50~5.88 μg/mL) as compared to free DOX (IC50~7.24 μg/mL) thus demonstrating that the preparation is potentially a promising drug delivery carrier. PMID:27383582

  7. Microporous Poly(L-Lactic Acid) Membranes Fabricated by Polyethylene Glycol Solvent-Cast/Particulate Leaching Technique

    PubMed Central

    Selvam, Shivaram; Chang, Wenji V.; Nakamura, Tamako; Samant, Deedar M.; Thomas, Padmaja B.; Trousdale, Melvin D.; Mircheff, Austin K.; Schechter, Joel E.

    2009-01-01

    With the eventual goal of developing a tissue-engineered tear secretory system, we found that primary lacrimal gland acinar cells grown on solid poly(L-lactic acid) (PLLA) supports expressed the best histiotypic morphology. However, to be able to perform vectorial transport functions, epithelia must be supported by a permeable substratum. In the present study, we describe the use of a solvent-cast/particulate leaching technique to fabricate microporous PLLA membranes (mpPLLAm) from PLLA/polyethylene glycol blends. Scanning electron microscopy revealed pores on both the air-cured (∼4 μm) and glass-cured sides (<2 μm) of the mpPLLAm. Diffusion studies were performed with mpPLLAm fabricated from 57.1% PLLA/42.9% polyethylene glycol blends to confirm the presence of channelized pores. The data reveal that glucose, L-tryptophan, and dextran (a high molecular weight glucose polymer) readily permeate mpPLLAm. Diffusion of the immunoglobulin G through the mpPLLAm decreased with time, suggesting the possible adsorption and occlusion of the pores. Cells cultured on the mpPLLAm (57.1/42.9 wt%) grew to subconfluent monolayers but retained histiotypic morphological and physiological characteristics of lacrimal acinar cells in vivo. Our results suggest that mpPLLAm fabricated using this technique may be useful as a scaffold for a bioartificial lacrimal gland device. PMID:19260769

  8. Infrared and Raman studies on polylactide acid and polyethylene glycol-400 blend

    NASA Astrophysics Data System (ADS)

    Yuniarto, Kurniawan; Purwanto, Yohanes Aris; Purwanto, Setyo; Welt, Bruce A.; Purwadaria, Hadi Karia; Sunarti, Titi Candra

    2016-04-01

    As a biodegradableplastic, polylactideacid (PLA) can be blended with polyethylene glycol (PEG) to form a polymer blend because PEG has a good miscibility with PLA. Furthermore, this paper study the functional groups of PLA-PEG400 blend using direct casting to produce matrix film. Fourier Transform Infrared (FTIR) and Raman spectroscopy was used to identify alteration of functional group PLA-PEG400 blend. Absorbance and frequency wavenumber were used to observe any changing among functional group. In general, PLA-PEG blend did not produce a new configuration or chemical properties although some functional groups tended to decrease. PLA-PEG400 film spectra showed a similaritycompared to those of neat PLA because of each pristine polymer. However, FTIR and Raman investigated reducing carbonyl group of PLA with PEG400 addition and followed improving CH-COC bonding. Methyl group represented CH3symmetricchanged both the shift and absorbance.FTIR and Raman spectroscopy observed increasing hydrogen bonding with increasing PEG400 addition where a largest was found at PEG 10% and appeared at frequency range from 3400 cm-1 to 3600 cm-1. According to PEG400 addition, a FTIR measuredenhancing crystalline region.

  9. Effects of one-seed juniper and polyethylene glycol on intake, rumen fermentation, and plasma amino acids in sheep and goats fed supplemental protein and tannins.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We tested the effect of polyethylene glycol (PEG) on juniper and total intake, rumen fermentation, and plasma amino acids (AA) of 12 does and 12 ewes fed sudangrass and basal diets containing 10% quebracho tannins with no protein supplement (Control; 5% CP) or high rumen degradable (RDP 15% CP) or u...

  10. Biodegradable Poly (Lactic-co-Glycolic Acid)-Polyethylene Glycol Nanocapsules: An Efficient Carrier for Improved Solubility, Bioavailability, and Anticancer Property of Lutein.

    PubMed

    Arunkumar, Ranganathan; Prashanth, Keelara Veerappa Harish; Manabe, Yuki; Hirata, Takashi; Sugawara, Tatsuya; Dharmesh, Shylaja Mallaiah; Baskaran, Vallikannan

    2015-06-01

    Lutein bioavailability is limited because of its poor aqueous solubility. In this study, lutein-poly (lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG) nanocapsules were prepared to improve the solubility, bioavailability, and anticancer property of lutein. The scanning electron microscopy and dynamic light scattering examination revealed that the nanocapsules are smooth and spherical with size ranging from 80 to 500 nm (mean = 200 nm). In vitro lutein release profile from nanocapsules showed controlled sustainable release (66%) up to 72 h. Aqueous solubility of lutein nanocapsules was much higher by 735-fold than the lutein. Fourier transform infrared spectroscopy analyses showed no chemical interaction among PLGA, PEG, and lutein, indicating possible weak intermolecular forces like hydrogen bonds. X-ray diffraction revealed lutein is distributed in a disordered amorphous state in nanocapsules. Postprandial plasma kinetics (area under the curve) of an oral dose of lutein from nanocapsules was higher by 5.4-fold compared with that of micellar lutein (control). The antiproliferative effect of lutein from nanocapsules (IC50 value, 10.9 μM) was higher (43.6%) than the lutein (IC50 value, 25 μM). Results suggest that PLGA-PEG nanocapsule is an efficient carrier for enhancing hydrophilicity, bioavailability, and anticancer property of lipophilic molecules such as lutein. PMID:25824524

  11. Self-assembled poly(ethylene glycol)-co-acrylic acid microgels to inhibit bacterial colonization of synthetic surfaces.

    PubMed

    Wang, Qichen; Uzunoglu, Emel; Wu, Yong; Libera, Matthew

    2012-05-01

    We explored the use of self-assembled microgels to inhibit the bacterial colonization of synthetic surfaces both by modulating surface cell adhesiveness at length scales comparable to bacterial dimensions (∼1 μm) and by locally storing/releasing an antimicrobial. Poly(ethylene glycol) [PEG] and poly(ethylene glycol)-co-acrylic acid [PEG-AA] microgels were synthesized by suspension photopolymerization. Consistent with macroscopic gels, a pH dependence of both zeta potential and hydrodynamic diameter was observed in AA-containing microgels but not in pure PEG microgels. The microgels were electrostatically deposited onto poly(l-lysine) (PLL) primed silicon to form submonolayer surface coatings. The microgel surface density could be controlled via the deposition time and the microgel concentration in the parent suspension. In addition to their intrinsic antifouling properties, after deposition, the microgels could be loaded with a cationic antimicrobial peptide (L5) because of favorable electrostatic interactions. Loading was significantly higher in PEG-AA microgels than in pure PEG microgels. The modification of PLL-primed Si by unloaded PEG-AA microgels reduced the short-term (6 h) S. epidermidis surface colonization by a factor of 2, and the degree of inhibition increased when the average spacing between microgels was reduced. Postdeposition L5 peptide loading into microgels further reduced bacterial colonization to the extent that, after 10 h of S. epidermidis culture in tryptic soy broth, the colonization of L5-loaded PEG-AA microgel-modified Si was comparable to the very small level of colonization observed on macroscopic PEG gel controls. The fact that these microgels can be deposited by a nonline-of-sight self-assembly process and hinder bacterial colonization opens the possibility of modifying the surfaces of topographically complex biomedical devices and reduces the rate of biomaterial-associated infection. PMID:22519439

  12. Liver-targeting Resibufogenin-loaded poly(lactic-co-glycolic acid)-d-α-tocopheryl polyethylene glycol 1000 succinate nanoparticles for liver cancer therapy

    PubMed Central

    Chu, Qiuchen; Xu, Hong; Gao, Meng; Guan, Xin; Liu, Hongyan; Deng, Sa; Huo, Xiaokui; Liu, Kexin; Tian, Yan; Ma, Xiaochi

    2016-01-01

    Liver cancer remains a major problem around the world. Resibufogenin (RBG) is a major bioactive compound that was isolated from Chansu (also called toad venom or toad poison), which is a popular traditional Chinese medicine that is obtained from the skin secretions of giant toads. RBG has strong antitumor effects, but its poor aqueous solubility and its cardiotoxicity have limited its clinical use. The aim of this study was to formulate RBG-loaded poly(lactic-co-glycolic acid) (PLGA)-d-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RPTN) to enhance the treatment of liver cancer. RPTN, RBG-loaded PLGA nanoparticle (RPN), and RBG/coumarin-6-loaded PLGA-d-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RCPTN) were prepared. The cellular uptake of RCPTN by HepG2 and HCa-F cells was analyzed using confocal laser scanning microscopy. Apoptosis was induced in HepG2 cells by RPTN, RBG solution (RS), and 5-fluorouracil solution (used as the negative controls), as assayed using flow cytometry. LD50 (median lethal dose) values were determined for RS and RPTN, and the liver-targeting properties were determined for RCPTN in intravenously injected mice. A pharmacokinetic study was conducted in rats, and the in vivo therapeutic effects of RPTN, RPN, and RS were examined in a mouse tumor model. The results showed that RCPTN simultaneously delivered both coumarin-6 and RBG into HepG2 and HCa-F cells. The ratio of apoptotic cells was increased in the RPTN group. The LD50 for RPTN was 2.02-fold higher than the value for RS. Compared to RS, RPTN and RPN both showed a significant difference in vivo not only in the pharmacodynamic study but also in anticancer efficacy, and RPTN performed much better than RPN. The detection indexes for drug concentration and fluorescence inversion microscopy images both demonstrated that RCPTN was much better at targeting the liver than RS. The liver-targeting RPTN, which displayed enhanced pharmacological effects and

  13. Liver-targeting Resibufogenin-loaded poly(lactic-co-glycolic acid)-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticles for liver cancer therapy.

    PubMed

    Chu, Qiuchen; Xu, Hong; Gao, Meng; Guan, Xin; Liu, Hongyan; Deng, Sa; Huo, Xiaokui; Liu, Kexin; Tian, Yan; Ma, Xiaochi

    2016-01-01

    Liver cancer remains a major problem around the world. Resibufogenin (RBG) is a major bioactive compound that was isolated from Chansu (also called toad venom or toad poison), which is a popular traditional Chinese medicine that is obtained from the skin secretions of giant toads. RBG has strong antitumor effects, but its poor aqueous solubility and its cardiotoxicity have limited its clinical use. The aim of this study was to formulate RBG-loaded poly(lactic-co-glycolic acid) (PLGA)-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RPTN) to enhance the treatment of liver cancer. RPTN, RBG-loaded PLGA nanoparticle (RPN), and RBG/coumarin-6-loaded PLGA-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RCPTN) were prepared. The cellular uptake of RCPTN by HepG2 and HCa-F cells was analyzed using confocal laser scanning microscopy. Apoptosis was induced in HepG2 cells by RPTN, RBG solution (RS), and 5-fluorouracil solution (used as the negative controls), as assayed using flow cytometry. LD50 (median lethal dose) values were determined for RS and RPTN, and the liver-targeting properties were determined for RCPTN in intravenously injected mice. A pharmacokinetic study was conducted in rats, and the in vivo therapeutic effects of RPTN, RPN, and RS were examined in a mouse tumor model. The results showed that RCPTN simultaneously delivered both coumarin-6 and RBG into HepG2 and HCa-F cells. The ratio of apoptotic cells was increased in the RPTN group. The LD50 for RPTN was 2.02-fold higher than the value for RS. Compared to RS, RPTN and RPN both showed a significant difference in vivo not only in the pharmacodynamic study but also in anticancer efficacy, and RPTN performed much better than RPN. The detection indexes for drug concentration and fluorescence inversion microscopy images both demonstrated that RCPTN was much better at targeting the liver than RS. The liver-targeting RPTN, which displayed enhanced pharmacological effects and

  14. Multiplex Immunoassay Platforms Based on Shape-Coded Poly(ethylene glycol) Hydrogel Microparticles Incorporating Acrylic Acid

    PubMed Central

    Park, Saemi; Lee, Hyun Jong; Koh, Won-Gun

    2012-01-01

    A suspension protein microarray was developed using shape-coded poly(ethylene glycol) (PEG) hydrogel microparticles for potential applications in multiplex and high-throughput immunoassays. A simple photopatterning process produced various shapes of hydrogel micropatterns that were weakly bound to poly(dimethylsiloxane) (PDMS)-coated substrates. These micropatterns were easily detached from substrates during the washing process and were collected as non-spherical microparticles. Acrylic acids were incorporated into hydrogels, which could covalently immobilize proteins onto their surfaces due to the presence of carboxyl groups. The amount of immobilized protein increased with the amount of acrylic acid due to more available carboxyl groups. Saturation was reached at 25% v/v of acrylic acid. Immunoassays with IgG and IgM immobilized onto hydrogel microparticles were successfully performed with a linear concentration range from 0 to 500 ng/mL of anti-IgG and anti-IgM, respectively. Finally, a mixture of two different shapes of hydrogel microparticles immobilizing IgG (circle) and IgM (square) was prepared and it was demonstrated that simultaneous detection of two different target proteins was possible without cross-talk using same fluorescence indicator because each immunoassay was easily identified by the shapes of hydrogel microparticles. PMID:22969408

  15. Osmotic effects of polyethylene glycol.

    PubMed

    Schiller, L R; Emmett, M; Santa Ana, C A; Fordtran, J S

    1988-04-01

    Polyethylene glycol (PEG) has been used to increase the osmotic pressure of fluids used to cleanse the gastrointestinal tract. However, little is known about its osmotic activity. To investigate this activity systematically, solutions of PEG of differing molecular weights were made and subjected to measurement of osmolality by both freezing point depression and vapor pressure osmometry. Measured osmolality was increasingly greater than predicted from average molecular weight as PEG concentration increased. Measurement of sodium activity in NaCl/PEG solutions by means of an ion-selective electrode suggested that the higher than expected osmolality could be due in part to interactions that, in effect, sequestered water from the solution. Osmolality was consistently greater by freezing point osmometry than by vapor pressure osmometry. To determine which osmometry method reflected biologically relevant osmolality, normal subjects underwent steady-state total gut perfusion with an electrolyte solution containing 105 g/L of PEG 3350. This produced rectal effluent that was hypertonic by freezing point osmometry but isotonic by vapor pressure osmometry. Assuming that luminal fluid reaches osmotic equilibrium with plasma during total gut perfusion, this result suggests that the vapor pressure osmometer accurately reflects the biologically relevant osmolality of intestinal contents. We conclude that PEG exerts more of an osmotic effect than would be predicted from its molecular weight. This phenomenon may reflect interactions between PEG and water molecules that alter the physical chemistry of the solution and sequester water from the solution. PMID:3345895

  16. A new formulation of curcumin using poly (lactic-co-glycolic acid)—polyethylene glycol diblock copolymer as carrier material

    NASA Astrophysics Data System (ADS)

    Phuong Tuyen Dao, Thi; Hoai Nguyen, To; To, Van Vinh; Ho, Thanh Ha; Nguyen, Tuan Anh; Chien Dang, Mau

    2014-09-01

    The aim of this study is to fabricate a nanoparticle formulation of curcumin using a relatively new vehicle as the matrix polymer: poly(lactic-co-glycolic acid) (PLGA)- polyethylene glycol (PEG) diblock copolymer, and to investigate the effects of the various processing parameters on the characteristics of nanoparticles (NPs). We successfully synthesized the matrix polymer of PLGA-PEG by conjugation of PLGA copolymer with a carboxylate end group to a heterobifunctional amine-PEG-methoxy using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide as conjugation crosslinkers. The composition of the formed product (PLGA-PEG) was characterized with 500 MHz 1H nuclear magnetic resonance (NMR). The conjugation of PLGA-PEG was confirmed using Fourier transform infrared (FTIR) spectrum study. This diblock copolymer was then used to prepare the curcumin-loaded NPs through nanoprecipitation technique. With this method, we found that the size distribution depends on the type of solvent, the concentration of polymer and the concentration of surfactant. The particle size and size distribution were measured by dynamic light scattering (DLS). Transmission electron microscope (TEM) and scanning electron microscope (SEM) were used to confirm the size, structure and morphology of the successfully prepared NPs. All of our results showed that they are spherical and quite homologous with mean diameter around of 100-300 nm. Further, we evaluated encapsulation efficiency and some characteristics of NPs through high performance liquid chromatography (HPLC) analyses, zeta-potential measurements and x-ray diffraction studies. The HPLC analyses were performed to determine the amount of curcumin entrapped in NPs. The zeta-potential measurements confirmed the stability of NPs and the successful encapsulation of curcumin within NPs and the x-ray diffraction patterns showed the disordered-crystalline phase of curcumin inside the polymeric matrix.

  17. Synthesis and Characterization of Silicate Ester Prodrugs and Poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) Block Copolymers for Formulation into Prodrug-Loaded Nanoparticles

    NASA Astrophysics Data System (ADS)

    Wohl, Adam Richard

    Fine control of the physical and chemical properties of customized materials is a field that is rapidly advancing. This is especially critical in pursuits to develop and optimize novel nanoparticle drug delivery. Specifically, I aim to apply chemistry concepts to test the hypothesis "Silicate ester prodrugs of paclitaxel, customized to have the proper hydrophobicity and hydrolytic lability, can be formulated with well-defined, biocompatible, amphiphilic block copolymers into nanoparticles that are effective drugs." Chapter 1 briefly describes the context and motivation of the scientific pursuits described in this thesis. In Chapter 2, a family of model silicate esters is synthesized, the hydrolysis rate of each compound is benchmarked, and trends are established based upon the steric bulk and leaving group ability of the silicate substituents. These trends are then applied to the synthesis of labile silicate ester prodrugs in Chapter 3. The bulk of this chapter focuses on the synthesis, hydrolysis, and cytotoxicity of prodrugs based on paclitaxel, a widely used chemotherapeutic agent. In Chapter 4, a new methodology for the synthesis of narrowly dispersed, "random" poly(lactic-co-glycolic acid) polymers by a constant infusion of the glycolide monomer is detailed. Using poly(ethylene glycol) as a macroinitiator, amphiphilic block copolymers were synthesized. Co-formulating a paclitaxel silicate and an amphiphilic block copolymer via flash nanoprecipitation led to highly prodrug-loaded, kinetically trapped nanoparticles. Studies to determine the structure, morphology, behavior, and efficacy of these nanoparticles are described in Chapter 5. Efforts to develop a general strategy for the selective end-functionalization of the polyether block of these amphiphilic block copolymers are discussed in Chapter 6. Examples of this strategy include functionalization of the polyether with an azide or a maleimide. Finally, Chapter 7 provides an outlook for future development of

  18. Conjugation of cell-penetrating peptides with poly(lactic-co-glycolic acid)-polyethylene glycol nanoparticles improves ocular drug delivery

    PubMed Central

    Vasconcelos, Aimee; Vega, Estefania; Pérez, Yolanda; Gómara, María J; García, María Luisa; Haro, Isabel

    2015-01-01

    In this work, a peptide for ocular delivery (POD) and human immunodeficiency virus transactivator were conjugated with biodegradable poly(lactic-co-glycolic acid) (PGLA)–polyethylene glycol (PEG)-nanoparticles (NPs) in an attempt to improve ocular drug bioavailability. The NPs were prepared by the solvent displacement method following two different pathways. One involved preparation of PLGA NPs followed by PEG and peptide conjugation (PLGA-NPs-PEG-peptide); the other involved self-assembly of PLGA-PEG and the PLGA-PEG-peptide copolymer followed by NP formulation. The conjugation of the PEG and the peptide was confirmed by a colorimetric test and proton nuclear magnetic resonance spectroscopy. Flurbiprofen was used as an example of an anti-inflammatory drug. The physicochemical properties of the resulting NPs (morphology, in vitro release, cell viability, and ocular tolerance) were studied. In vivo anti-inflammatory efficacy was assessed in rabbit eyes after topical instillation of sodium arachidonate. Of the formulations developed, the PLGA-PEG-POD NPs were the smaller particles and exhibited greater entrapment efficiency and more sustained release. The positive charge on the surface of these NPs, due to the conjugation with the positively charged peptide, facilitated penetration into the corneal epithelium, resulting in more effective prevention of ocular inflammation. The in vitro toxicity of the NPs developed was very low; no ocular irritation in vitro (hen’s egg test–chorioallantoic membrane assay) or in vivo (Draize test) was detected. Taken together, these data demonstrate that PLGA-PEG-POD NPs are promising vehicles for ocular drug delivery. PMID:25670897

  19. Paclitaxel distribution in poly(ethylene glycol) / poly(lactide-co-glycolic acid) blends and its release visualized by coherent anti-Stokes Raman scattering microscopy

    PubMed Central

    Kang, Eunah; Robinson, Joshua; Park, Kinam; Cheng, Ji-Xin

    2007-01-01

    Mechanisms underlying the release of paclitaxel (PTX) from poly(ethylene glycol)/poly(lactic-co-glycolic acid) (PEG/PLGA) blends were investigated by coherent anti-Stokes Raman scattering (CARS) microscopy. PLGA, PEG, and PTX were selectively imaged by using the resonant CARS signal from the CH3, CH2, and aromatic CH stretch vibrations, respectively. Phase segregation was observed in PLGA films containing 10 to 40 wt.% PEG in the absence of PTX loading. The PEG phase existed in the form of crystalline fibers in the (8:2, weight ratio) and (7:3) PLGA/PEG films. CARS observation indicated that PTX preferentially partitioned into the PEG domains in the (9:1) and (8:2) PLGA/PTX films, but exhibited a uniform mixing with both PLGA and PEG in the (7:3) PLGA/PEG film. The solid dispersion of PTX into PEG domains was attributed to a strong interaction between PTX and PEG, supported by the disappearance of PEG crystallization in the PTX-loaded PLGA/PEG film evidenced through X-ray diffraction analysis. PTX release was induced by exposing the film to an aqueous solution and monitored in real time by CARS and two-photon fluorescence microscopy. Fast dissolution of both PEG and PTX was observed at the film surface. Upon infiltration of water into the film, the PEG domains rearranged into ring structures enriched by both PTX and PEG. The CARS data provided a visual evidence explaining the accelerated burst release followed by more sustained release of PTX from the PLGA/PEG films as measured by HPLC. PMID:17574291

  20. Complexes of Imidazole with Poly(ethylene glycol) as a Corrosion Inhibitor for Carbon Steel in Sulphuric Acid

    NASA Astrophysics Data System (ADS)

    Salimi, Saeed; Nasr-Esfahani, Mojtaba; Umoren, Saviour A.; Saebnoori, Ehsan

    2015-12-01

    The inhibiting action of polyethylene glycol and imidazole (PEG/IMZ)) complexes prepared by a simple deprotonation procedure on carbon steel corrosion in 0.5 mol/L sulphuric acid was evaluated using the weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques complemented by surface analysis using scanning electron microscopy. The inhibiting effect of the PEG/IMZ complexes on carbon steel corrosion was compared with the non-complex forms. Results obtained show that PEG/IMZ complex is a very effective corrosion inhibitor of carbon steel in the acid environment. The inhibition efficiency increased with the increase in the temperature and also with increasing percentage of imidazole in the complex. Corrosion inhibition occurs by virtue of adsorption of PEG/IMZ complexes on the steel surface which was found to follow the Temkin adsorption isotherm model. The PEG/IMZ complexes function as a mixed-type inhibitor. Results from all the methods employed are in a reasonably good agreement.

  1. Poly(acrylic acid)/polyethylene glycol hygrogel prepared by using gamma-ray irradiation for mucosa adhesion

    NASA Astrophysics Data System (ADS)

    Nho, Young-Chang; Park, Jong-Seok; Shin, Jung-Woong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Gwon, Hui-Jeong; Khil, Myung-Seob; Lee, Deok-Won; Ahn, Sung-Jun

    2015-01-01

    A buccal delivery system provides a much milder environment for drug delivery compared to an oral delivery which presents a hostile environment for drugs, especially proteins and polypeptides, owing to acid hydrolysis. Local delivery in an oral cavity has particular applications in the treatment of toothaches, periodontal disease, and bacterial infections. Poly(acrylic acid) (PAA)-based hydrogels prepared using a chemical initiator have been attempted for a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, PAA and polyethylene glycol (PEG) were selected to prepare using a radiation process a bioadhesive hydrogel for adhesion to mucosal surfaces. PAA and PEG were dissolved in purified water to prepare a homogeneous PAA/PEG solution, and the solution was then irradiated using an electron beam at dose up to 70 kGy to make the hydrogels. Their physical properties, such as gel percent, swelling percent, and adhesive strength to mucosal surfaces, were investigated. In this experiment, various amounts of PEG were incorporated into the PAA to enhance the mucoadhesive property of the hydrogels. The effect of the molecular weight of PEG on the mucoadhesion was also examined.

  2. Polyethylene glycol enhanced protein refolding.

    PubMed

    Cleland, J L; Builder, S E; Swartz, J R; Winkler, M; Chang, J Y; Wang, D I

    1992-09-01

    Previous studies on the refolding of recombinant bovine carbonic anhydrase B (CAB) indicated that polyethylene glycol (PEG) significantly enhanced the recovery of active protein by reducing aggregation. To further test the ability of PEG to enhance refolding, three recombinant human proteins, deoxyribonuclease (rhDNAse), tissue plasminogen activator (rhtPA), and interferon-gamma (rhIFN-gamma) were refolded in the presence of PEG (3350 MW). rhDNAse produced from CHO cells was denatured in 7.2 M urea and refolded by rapid dilution to 4.0 M urea and 0.20 mg/ml protein. When a final PEG to rhDNAse molar ratio of 5 to 1 (0.1 milligram PEG, 3350 MW) was used in the dilution buffer, refolding was improved by 30% to yield complete recovery of active protein. Impure E. coli derived inclusion body preparations of rhDNAse were solubilized in 8 M urea and refolded by dilution to 4 M urea and 0.10 mg/ml protein. Refolding with a dilution buffer which yielded a final PEG to rhDNAse molar ratio of 10 to 1 (0.1 milligram PEG, 3350 MW) resulted in a three-fold increase in the recovery of active protein. When PEG was used in the dilution buffer, aggregation of rhDNAse did not occur during refolding in either case. rhtPA produced from CHO cells was denatured in 5 M guanidine hydrochloride (GuHCl) and refolded by rapid dilution to 0.10 M GuHCl and 0.20 mg/ml protein.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1368998

  3. Biocompatibility of poly(ethylene glycol) and poly(acrylic acid) interpenetrating network hydrogel by intrastromal implantation in rabbit cornea.

    PubMed

    Zheng, Luo Luo; Vanchinathan, Vijay; Dalal, Roopa; Noolandi, Jaan; Waters, Dale J; Hartmann, Laura; Cochran, Jennifer R; Frank, Curtis W; Yu, Charles Q; Ta, Christopher N

    2015-10-01

    We evaluated the biocompatibility of a poly(ethylene glycol) and poly(acrylic acid) (PEG/PAA) interpenetrating network hydrogel designed for artificial cornea in a rabbit model. PEG/PAA hydrogel measuring 6 mm in diameter was implanted in the corneal stroma of twelve rabbits. Stromal flaps were created with a microkeratome. Randomly, six rabbits were assigned to bear the implant for 2 months, two rabbits for 6 months, two rabbits for 9 months, one rabbit for 12 months, and one rabbit for 16 months. Rabbits were evaluated monthly. After the assigned period, eyes were enucleated, and corneas were processed for histology and immunohistochemistry. There were clear corneas in three of six rabbits that had implantation of hydrogel for 2 months. In the six rabbits with implant for 6 months or longer, the corneas remained clear in four. There was a high rate of epithelial defect and corneal thinning in these six rabbits. One planned 9-month rabbit developed extrusion of implant at 4 months. The cornea remained clear in the 16-month rabbit but histology revealed epithelial in-growth. Intrastromal implantation of PEG/PAA resulted in a high rate of long-term complications. PMID:25778285

  4. Alpha-tocopheryl polyethylene glycol succinate-emulsified poly(lactic-co-glycolic acid) nanoparticles for reversal of multidrug resistance in vitro.

    PubMed

    Wang, Ying; Guo, Miao; Lu, Yu; Ding, Li-Ying; Ron, Wen-Ting; Liu, Ya-Qing; Song, Fei-Fei; Yu, Shu-Qin

    2012-12-14

    Multidrug resistance (MDR) is one of the factors in the failure of anticancer chemotherapy. In order to enhance the anticancer effect of P-glycoprotein (P-gp) substrates, inhibition of the P-gp efflux pump on MDR cells is a good tactic. We designed novel multifunctional drug-loaded alpha-tocopheryl polyethylene glycol succinate (TPGS)/poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPGS/PLGA/SN-38 NPs; SN-38 is 7-ethyl-10-hydroxy-camptothecin), with TPGS-emulsified PLGA NPs as the carrier and modulator of the P-gp efflux pump and SN-38 as the model drug. TPGS/PLGA/SN-38 NPs were prepared using a modified solvent extraction/evaporation method. Physicochemical characterizations of TPGS/PLGA/SN-38 NPs were in conformity with the principle of nano-drug delivery systems (nDDSs), including a diameter of about 200 nm, excellent spherical particles with a smooth surface, narrow size distribution, appropriate surface charge, and successful drug-loading into the NPs. The cytotoxicity of TPGS/PLGA/SN-38 NPs to MDR cells was increased by 3.56 times compared with that of free SN-38. Based on an intracellular accumulation study relative to the time-dependent uptake and efflux inhibition, we suggest novel mechanisms of MDR reversal of TPGS/PLGA NPs. Firstly, TPGS/PLGA/SN-38 NPs improved the uptake of the loaded drug by clathrin-mediated endocytosis in the form of unbroken NPs. Simultaneously, intracellular NPs escaped the recognition of P-gp by MDR cells. After SN-38 was released from TPGS/PLGA/SN-38 NPs in MDR cells, TPGS or/and PLGA may modulate the efflux microenvironment of the P-gp pump, such as mitochondria and the P-gp domain with an ATP-binding site. Finally, the controlled-release drug entered the nucleus of the MDR cell to induce cytotoxicity. The present study showed that TPGS-emulsified PLGA NPs could be functional carriers in nDDS for anticancer drugs that are also P-gp substrates. More importantly, to enhance the therapeutic effect of P-gp substrates, this work

  5. Alpha-tocopheryl polyethylene glycol succinate-emulsified poly(lactic-co-glycolic acid) nanoparticles for reversal of multidrug resistance in vitro

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Guo, Miao; Lu, Yu; Ding, Li-Ying; Ron, Wen-Ting; Liu, Ya-Qing; Song, Fei-Fei; Yu, Shu-Qin

    2012-12-01

    Multidrug resistance (MDR) is one of the factors in the failure of anticancer chemotherapy. In order to enhance the anticancer effect of P-glycoprotein (P-gp) substrates, inhibition of the P-gp efflux pump on MDR cells is a good tactic. We designed novel multifunctional drug-loaded alpha-tocopheryl polyethylene glycol succinate (TPGS)/poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPGS/PLGA/SN-38 NPs; SN-38 is 7-ethyl-10-hydroxy-camptothecin), with TPGS-emulsified PLGA NPs as the carrier and modulator of the P-gp efflux pump and SN-38 as the model drug. TPGS/PLGA/SN-38 NPs were prepared using a modified solvent extraction/evaporation method. Physicochemical characterizations of TPGS/PLGA/SN-38 NPs were in conformity with the principle of nano-drug delivery systems (nDDSs), including a diameter of about 200 nm, excellent spherical particles with a smooth surface, narrow size distribution, appropriate surface charge, and successful drug-loading into the NPs. The cytotoxicity of TPGS/PLGA/SN-38 NPs to MDR cells was increased by 3.56 times compared with that of free SN-38. Based on an intracellular accumulation study relative to the time-dependent uptake and efflux inhibition, we suggest novel mechanisms of MDR reversal of TPGS/PLGA NPs. Firstly, TPGS/PLGA/SN-38 NPs improved the uptake of the loaded drug by clathrin-mediated endocytosis in the form of unbroken NPs. Simultaneously, intracellular NPs escaped the recognition of P-gp by MDR cells. After SN-38 was released from TPGS/PLGA/SN-38 NPs in MDR cells, TPGS or/and PLGA may modulate the efflux microenvironment of the P-gp pump, such as mitochondria and the P-gp domain with an ATP-binding site. Finally, the controlled-release drug entered the nucleus of the MDR cell to induce cytotoxicity. The present study showed that TPGS-emulsified PLGA NPs could be functional carriers in nDDS for anticancer drugs that are also P-gp substrates. More importantly, to enhance the therapeutic effect of P-gp substrates, this work

  6. Polymeric compositions incorporating polyethylene glycol as a phase change material

    DOEpatents

    Salyer, Ival O.; Griffen, Charles W.

    1989-01-01

    A polymeric composition comprising a polymeric material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the composition is useful in making molded and/or coated materials such as flooring, tiles, wall panels and the like; paints containing polyethylene glycols or end-capped polyethylene glycols are also disclosed.

  7. Preparation of Porous Core-Shell Poly L-Lactic Acid/Polyethylene Glycol Superfine Fibres Containing Drug.

    PubMed

    Yang, Wenjing; He, Nongyue; Fu, Juan; Li, Zhiyang; Ji, Xuyuan

    2015-12-01

    In this paper, poly L-lactic acid (PLLA) blended with polyethylene glycol (PEG) was dissolved in methylene dichloride solution as the shell solution, and rapamycin (RAPA), was encapsulated inside the core of PLLA micro/nano fibres as a model drug. The effects of the blending ratio of PLLA to PEG, the concentration of the electrospinning solution, the voltage, the flow rate, and the encapsulation efficiency were studied. Uniform and porous RAPA-Loading PLLA fibres were obtained when the ratio of PLLA to PEG was 7/3, the concentration of PLLA was 3%, the applied voltage was 7.5 kV, and the pump speed was V(core) = 0.1 mL/h, V(shell) = 1 mL/h, repectively. The average diameter of PLLA fibres increased with the gradual increase in PLLA concentration. FTIR results showed that RAPA was successfully encapsulated into the core-co-shell PLLA fibres. Meanwhile, the RAPA-loading of coaxial electrospun PLLA fibres was significantly higher than that of the blending electrospun fibres. It was also found that the porous core-shell PLLA/PEG blending superfine fibres could regulate the appearance of pore on the surface of superfine fibres by adjusting the electrospinning parameters. The porous PLLA/PEG blending fibres can be used as drug carriers and, to improve the single way of drug release depending on the degradation of shell material to meet different need. It will be a remarkable breakthrough in the area for sustained and controlled release drug delivery system. PMID:26682434

  8. Polyethylene glycol-electrolyte solution (PEG-ES)

    MedlinePlus

    Polyethylene glycol-electrolyte solution (PEG-ES) is used to empty the colon (large intestine, bowel) before a ... Polyethylene glycol-electrolyte solution (PEG-ES) comes as a powder to mix with water and take by ...

  9. Bioinspired insights into silicic acid stabilization mechanisms: the dominant role of polyethylene glycol-induced hydrogen bonding.

    PubMed

    Preari, Melina; Spinde, Katrin; Lazic, Joëlle; Brunner, Eike; Demadis, Konstantinos D

    2014-03-19

    Mono- and disilicic acids were stabilized by uncharged polyethylene glycols (PEGs) in silica-supersaturated solutions (the starting solution contained 500 ppm/8.3 mM sodium orthosilicate, Na2SiO3·5H2O, expressed as SiO2) at pH = 7, most likely by hydrogen bonding between the silanol groups and -CH2-CH2-O-ether moieties. The stabilization was monitored by measuring molybdate-reactive silica and also by a combination of liquid- and solid-state (29)Si NMR spectroscopy. It depends on PEG concentration (20-100 ppm) and molecular weight (1550-20,000 Da). Two narrow (29)Si NMR signals characteristic for monosilicic acid (Q(0)) and disilicic acid (Q(1)) can be observed in (29)Si NMR spectra of solutions containing PEG 10000 with intensities distinctly higher than the control, that is, in the absence of PEG. Silica-containing precipitates are observed in the presence of PEG, in contrast to the gel formed in the absence of PEG. These precipitates exhibit similar degrees of silica polycondensation as found in the gel as can be seen from the (29)Si MAS NMR spectra. However, the (2)D HETCOR spectra show different (1)H NMR signal shifts: The signal due to H-bonded SiOH/H2O, which is found at 6 ppm in the control, is shifted to ~7 ppm in the PEG-containing precipitate. This indicates the formation of slightly stronger H-bonds than in the control sample, most likely between PEG and the silica species. The presence of PEG in these precipitates is unequivocally proven by (13)C CP MAS NMR spectroscopy. The (13)C signal of PEG significantly shifts and is much narrower in the precipitates as compared to the pristine PEG, indicating that PEG is embedded into the silica or at least bound to its surface (or both), and not phase separated. FT-IR spectra corroborate the above arguments. The H-bonding between silanol and ethereal O perturbs the band positions attributed to vibrations involving the O atom. This work may invoke an alternative way to envision silica species stabilization

  10. 21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyethylene glycol (400) monolaurate. 178.3760... SANITIZERS Certain Adjuvants and Production Aids § 178.3760 Polyethylene glycol (400) monolaurate. Polyethylene glycol (400) monolaurate containing not more than 0.1 percent by weight of ethylene...

  11. 21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyethylene glycol (400) monolaurate. 178.3760 Section 178.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Production Aids § 178.3760 Polyethylene glycol (400) monolaurate. Polyethylene glycol (400)...

  12. 21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyethylene glycol (400) monolaurate. 178.3760... SANITIZERS Certain Adjuvants and Production Aids § 178.3760 Polyethylene glycol (400) monolaurate. Polyethylene glycol (400) monolaurate containing not more than 0.1 percent by weight of ethylene...

  13. 21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyethylene glycol (400) monolaurate. 178.3760... SANITIZERS Certain Adjuvants and Production Aids § 178.3760 Polyethylene glycol (400) monolaurate. Polyethylene glycol (400) monolaurate containing not more than 0.1 percent by weight of ethylene...

  14. Thermo-mechanical properties of poly ε-caprolactone/poly L-lactic acid blends: addition of nalidixic acid and polyethylene glycol additives.

    PubMed

    Douglas, P; Albadarin, Ahmad B; Al-Muhtaseb, Ala'a H; Mangwandi, Chirangano; Walker, G M

    2015-05-01

    The search for ideal biomaterials is still on-going for tissue regeneration. In this study, blends of poly ε-caprolactone (PCL) with poly l-lactic acid (PLLA), nalidixic acid (NA) and polyethylene glycol (PEG) were prepared. Mechanical and thermal properties of the blends were investigated by tensile and flexural analysis, DSC, TGA, WXRD, MFI, BET, SEM and hot stage optical microscopy. Results showed that the loading of PLLA caused a significant decrease in tensile strength and almost total eradication of the elongation at break of PCL matrix, especially after PEG and NA addition. Increased stiffness was also noted with additional NA, PEG and PLLA, resulting in an increase in the flexural modulus of the blends. Isothermal degradation indicated that bulk PCL, PLLA and the blends were thermally stable at 200°C for the duration of 2h making extrusion of the blends at this temperature viable. Morphological study showed that increasing the PLLA content and addition of the very low viscosity PEG and powder NA decreased the Melt Flow Indexer and increased the viscosity. At the higher temperature, the PLLA begins to soften and eventually melts allowing for increased flow and, coupling this with, the natural increase in MFI caused by temperature is enhanced further. The PEG and NA addition increased dramatically the pore volume which is important for cell growth and flow transport of nutrients and metabolic waste. PMID:25725403

  15. pH-Responsive Polyethylene Glycol Monomethyl Ether-ε-Polylysine-G-Poly (Lactic Acid)-Based Nanoparticles as Protein Delivery Systems

    PubMed Central

    Liu, Huiqin; Li, Yijia; Yang, Rui; Gao, Xiujun; Ying, Guoguang

    2016-01-01

    The application of poly(lactic acid) for sustained protein delivery is restricted by the harsh pH inside carriers. In this study, we synthesized a pH-responsive comb-shaped block copolymer, polyethylene glycol monomethyl ether-ε-polylysine-g-poly (lactic acid) (PEP)to deliver protein (bovine serum albumin (BSA)). The PEP nanoparticles could automatically adjust the internal pH to a milder level, as shown by the quantitative ratio metric results. The circular dichroism spectra showed that proteins from the PEP nanoparticles were more stable than those from poly(lactic acid) nanoparticles. PEP nanoparticles could achieve sustained BSA release in both in vitro and in vivo experiments. Cytotoxicity results in HL-7702 cells suggested good cell compatibility of PEP carriers. Acute toxicity results showed that the PEP nanoparticles induced no toxic response in Kunming mice. Thus, PEP nanoparticles hold potential as efficient carriers for sustained protein release. PMID:27467072

  16. 40 CFR 721.6493 - Amidoamine modified polyethylene glycol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amidoamine modified polyethylene... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical... as an amidoamine modified polyethylene glycol (PMN P-99-0645) is subject to reporting under...

  17. 40 CFR 721.6493 - Amidoamine modified polyethylene glycol (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Amidoamine modified polyethylene... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical... as an amidoamine modified polyethylene glycol (PMN P-99-0645) is subject to reporting under...

  18. 40 CFR 721.6493 - Amidoamine modified polyethylene glycol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Amidoamine modified polyethylene... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical... as an amidoamine modified polyethylene glycol (PMN P-99-0645) is subject to reporting under...

  19. 40 CFR 721.6493 - Amidoamine modified polyethylene glycol (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Amidoamine modified polyethylene... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical... as an amidoamine modified polyethylene glycol (PMN P-99-0645) is subject to reporting under...

  20. 40 CFR 721.6493 - Amidoamine modified polyethylene glycol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Amidoamine modified polyethylene... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical... as an amidoamine modified polyethylene glycol (PMN P-99-0645) is subject to reporting under...

  1. Radioprotection by polyethylene glycol-protein complexes in mice

    SciTech Connect

    Gray, B.H.; Stull, R.W.

    1983-03-01

    Polyethylene glycol of about 5000 D was activated with cyanuric chloride, and the activated compound was complexed to each of three proteins. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase were each radioprotectants when administered prophylactically to female B6CBF1 mice before irradiation. The dose reduction factor for these mice was 1.2 when 5000 units of polyethylene glycol-catalase was administered before /sup 60/Co irradiation. Female B6CBF1 mice administered prophylactic intravenous injections of catalase, polyethylene glycol-albumin, or heat-denatured polyethylene glycol-catalase had survival rates similar to phosphate-buffered saline-injected control mice following /sup 60/Co irradiation. Polyethylene glycol-superoxide dismutase and polyethylene glycol-catalase have radioprotective activity in B6CBF1 mice, which appears to depend in part on enzymatic activities of the complex. However, no radioprotective effect was observed in male C57BL/6 mice injected with each polyethylene glycol-protein complex at either 3 or 24 hr before irradiation. The mechanism for radioprotection by these complexes may depend in part on other factors.

  2. Characterization of Polyethylene Glycol Modified Hemoglobins

    NASA Astrophysics Data System (ADS)

    Salazar, Gil; Barr, James; Morgan, Wayne; Ma, Li

    2011-03-01

    Polyethylene glycol modified hemoglobins (PEGHbs) was characterized by liquid chromatography and fluorescence methods. We prepared four samples of two different molecular weight PEG, 5KDa and 20KDa, modified bovine and human hemoglobin. We studied the oxygen affinities, stabilities, and peroxidase activities of PEGHbs. We have related oxygen affinities with different degrees of modifications. The data showed that the modification on the beta subunits was less stable than that of the alpha subunits on the human Hb based samples especially. We also compared peroxidase activities among different modified PEGHbs.

  3. Low volume polyethylene glycol with ascorbic acid, sodium picosulfate-magnesium citrate, and clear liquid diet alone prior to small bowel capsule endoscopy

    PubMed Central

    Rayner-Hartley, Erin; Alsahafi, Majid; Cramer, Paula; Chatur, Nazira; Donnellan, Fergal

    2016-01-01

    AIM: To compare low volume polyethylene glycol with ascorbic acid, sodium picosulfate-magnesium citrate and clear liquid diet alone as bowel preparation prior to small bowel capsule endoscopy (CE). METHODS: We retrospectively collected all CE studies done from December 2011 to July 2013 at a single institution. CE studies were reviewed only if low volume polyethylene glycol with ascorbic acid, sodium picosulfate-magnesium citrate or clear liquid diet alone used as the bowel preparation. The studies were then reviewed by the CE readers who were blinded to the preparation type. Cleanliness and bubble burden were graded independently within the proximal, middle and distal small bowel using a four-point scale according to the percentage of small bowel mucosa free of debris/bubbles: grade 1 = over 90%, grade 2 = between 90%-75%, grade 3 = between 50%-75%, grade 4 = less than 50%. Data are expressed as mean ± SEM. ANOVA and Fishers exact test were used where appropriate. P values < 0.05 were considered statistically significant. RESULTS: A of total of 123 CE studies were reviewed. Twenty-six studies were excluded from analysis because of incomplete small bowel examination. In the remaining studies, 39 patients took low volume polyethylene glycol with ascorbic acid, 31 took sodium picosulfate-magnesium citrate and 27 took a clear liquid diet alone after lunch on the day before CE, followed by overnight fasting in all groups. There was no significant difference in small bowel cleanliness (1.98 ± 0.09 vs 1.84 ± 0.08 vs 1.76 ± 0.08) or small bowel transit time (213 ± 13 vs 248 ± 14 ± 225 ± 19 min) for clear liquid diet alone, MoviPrep and Pico-Salax respectively. The bubble burden in the mid small bowel was significantly higher in the MoviPrep group (1.6 ± 0.1 vs 1.9 ± 0.1 vs 1.6 ± 0.1, P < 0.05). However this did not result in a significant difference in diagnosis of pathology. CONCLUSION: There was no significant difference in small bowel cleanliness or

  4. Preparation of tissue engineering porous scaffold with poly(lactic acid) and polyethylene glycol solution blend by solvent-casting/particulate-leaching

    NASA Astrophysics Data System (ADS)

    Huang, Ran; Zhu, Xiaomin; Zhao, Tingting; Wan, Ajun

    2014-12-01

    Polyethylene glycol/poly(lactic acid) solution blend is employed as the raw materials to prepare porous scaffold of potential usage in tissue engineering. The solution blend can be naturally introduced in the classical solvent casting/particular leaching technique in porous matrix preparation. The PEG presence is to modify the degradation behavior of scaffolds to fit particular requirements in tissue engineering. The porous matrix of PEG/PLA with various weight ratios are made with pores size ˜ 250 μ m. The SEM characterizations have been done to investigate the porous morphology of products, the results indicate that though with the clear semi-miscibility feature of PEG/PLA blends, the macro-structure is not significantly affected by the PEG content percentage. The degradation results show an enhanced weight loss rate with the presence of PEG as expected.

  5. Arginine-glycine-aspartic acid-polyethylene glycol-polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture.

    PubMed

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    2016-01-01

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine-glycine-aspartic acid (RGD) peptide. Our studies demonstrate that RGD-polyethylene glycol (PEG)-PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT-MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system. PMID:27621619

  6. A Polymeric Prodrug of 5-Fluorouracil-1-Acetic Acid Using a Multi-Hydroxyl Polyethylene Glycol Derivative as the Drug Carrier

    PubMed Central

    Sun, Xun; Gong, Tao; Zhang, Zhirong

    2014-01-01

    Purpose Macromolecular prodrugs obtained by covalently conjugating small molecular drugs with polymeric carriers were proven to accomplish controlled and sustained release of the therapeutic agents in vitro and in vivo. Polyethylene glycol (PEG) has been extensively used due to its low toxicity, low immunogenicity and high biocompatibility. However, for linear PEG macromolecules, the number of available hydroxyl groups for drug coupling does not change with the length of polymeric chain, which limits the application of PEG for drug conjugation purposes. To increase the drug loading and prolong the retention time of 5-fluorouracil (5-Fu), a macromolecular prodrug of 5-Fu, 5-fluorouracil-1 acid-PAE derivative (5-FA-PAE) was synthesized and tested for the antitumor activity in vivo. Methods PEG with a molecular weight of 38 kDa was selected to synthesize the multi-hydroxyl polyethylene glycol derivative (PAE) through an addition reaction. 5-fluorouracil-1 acetic acid (5-FA), a 5-Fu derivative was coupled with PEG derivatives via ester bond to form a macromolecular prodrug, 5-FA-PAE. The in vitro drug release, pharmacokinetics, in vivo distribution and antitumor effect of the prodrug were investigated, respectively. Results The PEG-based prodrug obtained in this study possessed an exceedingly high 5-FA loading efficiency of 10.58%, much higher than the maximum drug loading efficiency of unmodified PEG with the same molecular weight, which was 0.98% theoretically. Furthermore, 5-FA-PAE exhibited suitable sustained release in tumors. Conclusion This study provides a new approach for the development of the delivery to tumors of anticancer agents with PEG derivatives. PMID:25389968

  7. Hydration of polyethylene glycol-grafted liposomes.

    PubMed

    Tirosh, O; Barenholz, Y; Katzhendler, J; Priev, A

    1998-03-01

    This study aimed to characterize the effect of polyethylene glycol of 2000 molecular weight (PEG2000) attached to a dialkylphosphatidic acid (dihexadecylphosphatidyl (DHP)-PEG2000) on the hydration and thermodynamic stability of lipid assemblies. Differential scanning calorimetry, densitometry, and ultrasound velocity and absorption measurements were used for thermodynamic and hydrational characterization. Using a differential scanning calorimetry technique we showed that each molecule of PEG2000 binds 136 +/- 4 molecules of water. For PEG2000 covalently attached to the lipid molecules organized in micelles, the water binding increases to 210 +/- 6 water molecules. This demonstrates that the two different structural configurations of the PEG2000, a random coil in the case of the free PEG and a brush in the case of DHP-PEG2000 micelles, differ in their hydration level. Ultrasound absorption changes in liposomes reflect mainly the heterophase fluctuations and packing defects in the lipid bilayer. The PEG-induced excess ultrasound absorption of the lipid bilayer at 7.7 MHz for PEG-lipid concentrations over 5 mol % indicates the increase in the relaxation time of the headgroup rotation due to PEG-PEG interactions. The adiabatic compressibility (calculated from ultrasound velocity and density) of the lipid bilayer of the liposome increases monotonically with PEG-lipid concentration up to approximately 7 mol %, reflecting release of water from the lipid headgroup region. Elimination of this water, induced by grafted PEG, leads to a decrease in bilayer defects and enhanced lateral packing of the phospholipid acyl chains. We assume that the dehydration of the lipid headgroup region in conjunction with the increase of the hydration of the outer layer by grafting PEG in brush configuration are responsible for increasing thermodynamic stability of the liposomes at 5-7 mol % of PEG-lipid. At higher PEG-lipid concentrations, compressibility and partial volume of the lipid phase

  8. Water potential of aqueous polyethylene glycol.

    PubMed

    Steuter, A A

    1981-01-01

    Water potential (Psiomega) values were determined for aqueous colloids of four molecular sizes of polyethylene glycol (PEG) using freezing-point depression and vapor-pressure deficit methods. A significant third-order interaction exists between the method used to determine Psiomega, PEG molecular size, and concentration. At low PEG concentrations, freezing-point depression measurements result in higher (less negative) values for Psiomega than do vapor-pressure deficit measurements. The reverse is true at high concentrations. PEG in water does not behave according to van't Hoff's law. Psiomega is related to molality for a given PEG but not linearly. Moreover, Psiomega varies with the molecular size of the PEG. It is suggested that the Psiomega of PEG in water may be controlled primarily by the matric forces of ethylene oxide subunits of the PEG polymer. The term matricum is proposed for PEG in soil-plant-water relation studies. PMID:16661635

  9. Effective Antisense Gene Regulation via Noncationic, Polyethylene Glycol Brushes.

    PubMed

    Lu, Xueguang; Jia, Fei; Tan, Xuyu; Wang, Dali; Cao, Xueyan; Zheng, Jiamin; Zhang, Ke

    2016-07-27

    Negatively charged nucleic acids are often complexed with polycationic transfection agents before delivery. Herein, we demonstrate that a noncationic, biocompatible polymer, polyethylene glycol, can be used as a transfection vector by forming a brush polymer-DNA conjugate. The brush architecture provides embedded DNA strands with enhanced nuclease stability and improved cell uptake. Because of the biologically benign nature of the polymer component, no cytotoxicity was observed. This approach has the potential to address several long-lasting challenges in oligonucleotide therapeutics. PMID:27420413

  10. Urinary excretion of polyethylene glycol 3350 and sulfate after gut lavage with a polyethylene glycol electrolyte lavage solution.

    PubMed

    Brady, C E; DiPalma, J A; Morawski, S G; Santa Ana, C A; Fordtran, J S

    1986-06-01

    Ingestion of an electrolyte lavage solution containing polyethylene glycol 3350 and sulfate is an effective method of cleansing the colon for diagnostic studies. Polyethylene glycol and sulfate are considered poorly absorbed from the gastrointestinal tract. Because of the quantities administered, concern exists about potential toxicity of absorption of even a small percentage, particularly for polyethylene glycol. We measured the urinary excretion of both polyethylene glycol and sulfate in normal subjects and inflammatory bowel patients. Absorption of polyethylene glycol can be assessed by measuring recovery in urine, as 85%-96% of an intravenous load is excreted in urine. Similarly, appreciable sulfate absorption would exceed renal tubular reabsorption and result in increased urinary excretion. Mean percent polyethylene glycol load recovered in urine was minimal and similar for normal (0.06%) and inflammatory bowel (0.09%) subjects. Urinary sulfate excretion after lavage was also similar for both groups and was not different from baseline. These results do not suggest the likelihood of toxicity due to polyethylene glycol 3350 or sulfate absorption during gut lavage with this solution. PMID:3699408

  11. In vivo toxicity and immunogenicity of wheat germ agglutinin conjugated poly(ethylene glycol)-poly(lactic acid) nanoparticles for intranasal delivery to the brain

    SciTech Connect

    Liu Qingfeng; Shao Xiayan; Chen Jie; Shen Yehong; Feng Chengcheng; Gao Xiaoling; Zhao Yue; Li Jingwei; Zhang Qizhi Jiang, Xinguo

    2011-02-15

    Biodegradable polymer-based nanoparticles have been widely studied to deliver therapeutic agents to the brain after intranasal administration. However, knowledge as to the side effects of nanoparticle delivery system to the brain is limited. The aim of this study was to investigate the in vivo toxicity and immunogenicity of wheat germ agglutinin (WGA) conjugated poly(ethylene glycol)-poly(lactic acid) nanoparticles (WGA-NP) after intranasal instillation. Sprague-Dawley rats were intranasally given WGA-NP for 7 continuous days. Amino acid neurotransmitters, lactate dehydrogenase (LDH) activity, reduced glutathione (GSH), acetylcholine, acetylcholinesterase activity, tumor necrosis factor {alpha} (TNF-{alpha}) and interleukin-8 (IL-8) in rat olfactory bulb (OB) and brain were measured to estimate the in vivo toxicity of WGA-NP. Balb/C mice were intranasally immunized by WGA-NP and then WGA-specific antibodies in serum and nasal wash were detected by indirect ELISA. WGA-NP showed slight toxicity to brain tissue, as evidenced by increased glutamate level in rat brain and enhanced LDH activity in rat OB. No significant changes in acetylcholine level, acetylcholinesterase activity, GSH level, TNF-{alpha} level and IL-8 level were observed in rat OB and brain for the WGA-NP group. WGA-specific antibodies in mice serum and nasal wash were not increased after two intranasal immunizations of WGA-NP. These results demonstrate that WGA-NP is a safe carrier system for intranasal delivery of therapeutic agents to the brain.

  12. Redox-labelled poly(ethylene glycol) used as a diffusion probe in poly(ethylene glycol) melts

    SciTech Connect

    Haas, O.; Velasquez, C.; Porat, Z.

    1995-12-01

    Ferrocene labelled monomethyl poly(ethylene glycol) MPEG with molecular weights of 1900 and 750 was prepared and used as an electrochemical diffusion probe in poly(ethylene glycol) melts. Cyclic voltammetry and chronoamperometry were used in connection with microdisk electrodes to measure the diffusion coefficient of redox tagged molecules using melted poly(ethylene glycol) as a solvent. The molecular weight of the solvent polymer was 750, 2000 and 20000. Results from the temperature dependency of the diffusion process and of the viscosity and conductivity of the polymer electrolyte are presented and discussed.

  13. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... substituted polyethylene glycol (generic). 721.7255 Section 721.7255 Protection of Environment ENVIRONMENTAL... substituted polyethylene glycol (generic). (a) Chemical substance and significant new uses subject to... substituted polyethylene glycol with substituted polyethylene glycol (PMN P-01-833) is subject to...

  14. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... substituted polyethylene glycol (generic). 721.7255 Section 721.7255 Protection of Environment ENVIRONMENTAL... substituted polyethylene glycol (generic). (a) Chemical substance and significant new uses subject to... substituted polyethylene glycol with substituted polyethylene glycol (PMN P-01-833) is subject to...

  15. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substituted polyethylene glycol (generic). 721.7255 Section 721.7255 Protection of Environment ENVIRONMENTAL... substituted polyethylene glycol (generic). (a) Chemical substance and significant new uses subject to... substituted polyethylene glycol with substituted polyethylene glycol (PMN P-01-833) is subject to...

  16. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... substituted polyethylene glycol (generic). 721.7255 Section 721.7255 Protection of Environment ENVIRONMENTAL... substituted polyethylene glycol (generic). (a) Chemical substance and significant new uses subject to... substituted polyethylene glycol with substituted polyethylene glycol (PMN P-01-833) is subject to...

  17. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... substituted polyethylene glycol (generic). 721.7255 Section 721.7255 Protection of Environment ENVIRONMENTAL... substituted polyethylene glycol (generic). (a) Chemical substance and significant new uses subject to... substituted polyethylene glycol with substituted polyethylene glycol (PMN P-01-833) is subject to...

  18. Crystallization studies of polyethylene -poly(ethylene glycol) graft copolymers

    NASA Astrophysics Data System (ADS)

    Mark, P. R.; Hovey, G. E.; Murthy, N. S.; Breitenkamp, K.; Kade, M.; Emerick, T.

    2006-03-01

    Structure and crystallization behavior of three copolymers obtained by grafting poly (ethylene glycol) (PEG) chains to polyethylene (PE) main chain was investigated by variable temperature x-ray diffraction and thermal analysis. The results show that PEG side chains and PE main chains crystallize into separate domains. This is especially true when grafted chains are long (50 and 100 repeat units), in which the PEG domains are same as in PEG homopolymer both in structure and in melting behavior. In the copolymer with shorter chains (25 repeat units), the PEG crystals are not distinct and melting is broad. The PEG domains can be dissolved in water or ethanol without altering the mechanical integrity of the film. PE crystallites in both samples are similar to that in PE homopolymer. For instance, the thermal expansion of the basal cell plane (a- and b-axes) of the PE domains agrees well with that of PE homopolymer over the entire temperature range from ambient to melt. However, the chain-axis dimension PE-lattice in the copolymer is shorter by ˜ 0.05 å and the basal dimensions are larger by ˜ 0.05 å. The changes in these dimensions due to the changes in the length of the grafted PEG chains were investigated.

  19. Fabrication of honeycomb-structured poly(ethylene glycol)-block-poly(lactic acid) porous films and biomedical applications for cell growth

    NASA Astrophysics Data System (ADS)

    Yao, Bingjian; Zhu, Qingzeng; Yao, Linli; Hao, Jingcheng

    2015-03-01

    A series of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) copolymers with a hydrophobic PLA block of different molecular weights and a fixed length hydrophilic PEG were synthesized successfully and characterized. These amphiphilic block copolymers were used to fabricate honeycomb-structured porous films using the breath figure (BF) templating technique. The surface topology and composition of the highly ordered pattern film were further characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. The results indicated that the PEG-to-PLA block molecular weight ratio influenced the BF film surface topology. The film with the best ordered pores was obtained with a PEG-to-PLA ratio of 2.0 × 103:3.0 × 104. The self-organization of the hydrophilic PEG chains within the pores was confirmed by XPS and fluorescence labeled PEG. A model is proposed to elucidate the stabilization process of the amphiphilic PEG-PLA aggregated architecture on the water droplet-based templates. In addition, GFP-U87 cell viability has been investigated by MTS test and the cell morphology on the honeycomb-structured PEG-PLA porous film has been evaluated using phase-contrast microscope. This porous film is shown to be suitable as a matrix for cell growth.

  20. Does Polyethylene Glycol (PEG) Plus Ascorbic Acid Induce More Mucosal Injuries than Split-Dose 4-L PEG during Bowel Preparation?

    PubMed Central

    Kim, Min Sung; Park, Jongha; Park, Jae hyun; Kim, Hyung Jun; Jang, Hyun Jeong; Joo, Hee Rin; Kim, Ji Yeon; Choi, Joon Hyuk; Heo, Nae Yun; Park, Seung Ha; Kim, Tae Oh; Yang, Sung Yeon

    2016-01-01

    Background/Aims The aims of this study were to compare the bowel-cleansing efficacy, patient affinity for the preparation solution, and mucosal injury between a split dose of poly-ethylene glycol (SD-PEG) and low-volume PEG plus ascorbic acid (LV-PEG+Asc) in outpatient scheduled colonoscopies. Methods Of the 319 patients, 160 were enrolled for SD-PEG, and 159 for LV-PEG+Asc. The bowel-cleansing efficacy was rated according to the Ottawa bowel preparation scale. Patient affinity for the preparation solution was assessed using a questionnaire. All mucosal injuries observed during colonoscopy were biopsied and histopathologically reviewed. Results There was no significant difference in bowel cleansing between the groups. The LV-PEG+Asc group reported better patient acceptance and preference. There were no significant differences in the incidence or characteristics of the mucosal injuries between the two groups. Conclusions Compared with SD-PEG, LV-PEG+Asc exhibited equivalent bowel-cleansing efficacy and resulted in improved patient acceptance and preference. There was no significant difference in mucosal injury between SD-PEG and LV-PEG+Asc. Thus, the LV-PEG+Asc preparation could be used more effectively and easily for routine colonoscopies without risking significant mucosal injury. PMID:26260754

  1. Efficient anti-tumor effect of photodynamic treatment with polymeric nanoparticles composed of polyethylene glycol and polylactic acid block copolymer encapsulating hydrophobic porphyrin derivative.

    PubMed

    Ogawara, Ken-ichi; Shiraishi, Taro; Araki, Tomoya; Watanabe, Taka-ichi; Ono, Tsutomu; Higaki, Kazutaka

    2016-01-20

    To develop potent and safer formulation of photosensitizer for cancer photodynamic therapy (PDT), we tried to formulate hydrophobic porphyrin derivative, photoprotoporphyrin IX dimethyl ester (PppIX-DME), into polymeric nanoparticles composed of polyethylene glycol and polylactic acid block copolymer (PN-Por). The mean particle size of PN-Por prepared was around 80nm and the zeta potential was determined to be weakly negative. In vitro phototoxicity study for PN-Por clearly indicated the significant phototoxicity of PN-Por for three types of tumor cells tested (Colon-26 carcinoma (C26), B16BL6 melanoma and Lewis lung cancer cells) in the PppIX-DME concentration-dependent fashion. Furthermore, it was suggested that the release of PppIX-DME from PN-Por would gradually occur to provide the sustained release of PppIX-DME. In vivo pharmacokinetics of PN-Por after intravenous administration was evaluated in C26 tumor-bearing mice, and PN-Por exhibited low affinity to the liver and spleen and was therefore retained in the blood circulation for a long time, leading to the efficient tumor disposition of PN-Por. Furthermore, significant and highly effective anti-tumor effect was confirmed in C26 tumor-bearing mice with the local light irradiation onto C26 tumor tissues after PN-Por injection. These findings indicate the potency of PN-Por for the development of more efficient PDT-based cancer treatments. PMID:26593985

  2. AS1411 Aptamer-Decorated Biodegradable Polyethylene Glycol-Poly(lactic-co-glycolic acid) Nanopolymersomes for the Targeted Delivery of Gemcitabine to Non-Small Cell Lung Cancer In Vitro.

    PubMed

    Alibolandi, Mona; Ramezani, Mohammad; Abnous, Khalil; Hadizadeh, Farzin

    2016-05-01

    Molecularly targeted drug delivery systems represent a novel therapeutic strategy in the treatment of different cancers. In the present study, we have developed gemcitabine (GEM)-loaded AS1411 aptamer surface-decorated polyethylene glycol-poly(lactic-co-glycolic acid) nanopolymersome (Apt-GEM-NP) to target nucleolin-overexpressing non-small cell lung cancer (NSCLC; A549). The prepared Apt-GEM-NP showed average particle size of 128 ± 5.23 nm and spherical morphology with encapsulation efficiency and loading content of 95.32 ± 2.37% and 8.61 ± 0.27%, respectively. Apt-GEM-NP exhibited a controlled release pattern. A sustained release of drug in physiological conditions will greatly improve the chemotherapeutic efficiency of a system. Enhanced cellular uptake and the cytotoxicity of aptamer-conjugated nanoparticles (NPs) in A549 cancer cells obviously verified nucleolin-mediated receptor-based active targeting. Nucleolin-mediated internalization of the targeted polymeric NP was further confirmed by flow cytometry and fluorescence microscopy. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay clearly showed the enhanced cell proliferation inhibitory effect of AS1411-conjugated NP on account of the selective delivery of GEM to the nucleolin-overexpressing cancer cells. Our results showed that AS1411 aptamer conjugation on the surface of NP could be a potential treatment strategy for A549 as a nucleolin-overexpressing cell line. This suggests that AS1411-GEM-NPs could be potentially used for the treatment of NSCLC. PMID:27039356

  3. Activation of Cytosolic Pyruvate Kinase by Polyethylene Glycol.

    PubMed Central

    Podesta, F. E.; Plaxton, W. C.

    1993-01-01

    Homogeneous cytosolic pyruvate kinase from endosperm of germinating castor oil (Ricinus communis L. cv Hale) seeds was potently activated by polyethylene glycol. The addition of 5% (w/v) polyethylene glycol to the pyruvate kinase reaction mixture caused a 2.6-fold increase in maximal velocity and 12.5- and 2-fold reductions in Km values for phosphoenolpyruvate and ADP, respectively. Glycerol, ethylene glycol, and bovine serum albumin also enhanced pyruvate kinase activity, albeit to a lesser extent than polyethylene glycol. The addition of 5% (w/v) polyethylene glycol to the elution buffer during high-performance gel filtration chromatography of purified cytosolic pyruvate kinase helped to stabilize the active heterotetrameric native structure of the enzyme. A higher degree of inhibition by MgATP, but lower sensitivity to the inhibitors 3-phosphoglycerate and fructose- 1,6-bisphosphate, was also observed in the presence of 5% (w/v) polyethylene glycol. It is concluded that (a) plant cytosolic pyruvate kinase activity and regulation, like that of other regulatory pyruvate kinases, is modified by extreme dilution in the assay medium, probably as a result of deaggregation of the native tetrameric enzyme, and (b) ATP is probably the major metabolic effector of germinating castor endosperm cytosolic pyruvate kinase in vivo. PMID:12231936

  4. Activation of Cytosolic Pyruvate Kinase by Polyethylene Glycol.

    PubMed

    Podesta, F. E.; Plaxton, W. C.

    1993-09-01

    Homogeneous cytosolic pyruvate kinase from endosperm of germinating castor oil (Ricinus communis L. cv Hale) seeds was potently activated by polyethylene glycol. The addition of 5% (w/v) polyethylene glycol to the pyruvate kinase reaction mixture caused a 2.6-fold increase in maximal velocity and 12.5- and 2-fold reductions in Km values for phosphoenolpyruvate and ADP, respectively. Glycerol, ethylene glycol, and bovine serum albumin also enhanced pyruvate kinase activity, albeit to a lesser extent than polyethylene glycol. The addition of 5% (w/v) polyethylene glycol to the elution buffer during high-performance gel filtration chromatography of purified cytosolic pyruvate kinase helped to stabilize the active heterotetrameric native structure of the enzyme. A higher degree of inhibition by MgATP, but lower sensitivity to the inhibitors 3-phosphoglycerate and fructose- 1,6-bisphosphate, was also observed in the presence of 5% (w/v) polyethylene glycol. It is concluded that (a) plant cytosolic pyruvate kinase activity and regulation, like that of other regulatory pyruvate kinases, is modified by extreme dilution in the assay medium, probably as a result of deaggregation of the native tetrameric enzyme, and (b) ATP is probably the major metabolic effector of germinating castor endosperm cytosolic pyruvate kinase in vivo. PMID:12231936

  5. Pulmonary surfactant adsorption is increased by hyaluronan or polyethylene glycol.

    PubMed

    Taeusch, H William; Dybbro, Eric; Lu, Karen W

    2008-04-01

    In acute lung injuries, inactivating agents may interfere with transfer (adsorption) of pulmonary surfactants to the interface between air and the aqueous layer that coats the interior of alveoli. Some ionic and nonionic polymers reduce surfactant inactivation in vitro and in vivo. In this study, we tested directly whether an ionic polymer, hyaluronan, or a nonionic polymer, polyethylene glycol, enhanced adsorption of a surfactant used clinically. We used three different methods of measuring adsorption in vitro: a modified pulsating bubble surfactometer; a King/Clements device; and a spreading trough. In addition we measured the effects of both polymers on surfactant turbidity, using this assay as a nonspecific index of aggregation. We found that both hyaluronan and polyethylene glycol significantly increased the rate and degree of surfactant material adsorbed to the surface in all three assays. Hyaluronan was effective in lower concentrations (20-fold) than polyethylene glycol and, unlike polyethylene glycol, hyaluronan did not increase apparent aggregation of surfactant. Surfactant adsorption in the presence of serum was also enhanced by both polymers regardless of whether hyaluronan or polyethylene glycol was included with serum in the subphase or added to the surfactant applied to the surface. Therefore, endogenous polymers in the alveolar subphase, or exogenous polymers added to surfactant used as therapy, may both be important for reducing inactivation of surfactant that occurs with various lung injuries. PMID:18065212

  6. A single dose of dexamethasone encapsulated in polyethylene glycol-coated polylactic acid nanoparticles attenuates cisplatin-induced hearing loss following round window membrane administration

    PubMed Central

    Sun, Changling; Wang, Xueling; Zheng, Zhaozhu; Chen, Dongye; Wang, Xiaoqin; Shi, Fuxin; Yu, Dehong; Wu, Hao

    2015-01-01

    This study aimed to investigate the sustained drug release properties and hearing protection effect of polyethylene glycol-coated polylactic acid (PEG-PLA) stealth nanoparticles loaded with dexamethasone (DEX). DEX was fabricated into PEG-PLA nanoparticles using an emulsion and evaporation technique, as previously reported. The DEX-loaded PEG-PLA nanoparticles (DEX-NPs) had a hydrodynamic diameter of 130±4.78 nm, and a zeta potential of −26.13±3.28 mV. The in vitro release of DEX from DEX-NPs lasted 24 days in phosphate buffered saline (pH 7.4), 5 days in artificial perilymph (pH 7.4), and 1 day in rat plasma. Coumarin 6-labeled NPs placed onto the round window membrane (RWM) of guinea pigs penetrated RWM quickly and accumulated to the organs of Corti, stria vascularis, and spiral ganglion cells after 1 hour of administration. The DEX-NPs locally applied onto the RWM of guinea pigs by a single-dose administration continuously released DEX in 48 hours, which was significantly longer than the free DEX that was cleared out within 12 hours after administration at the same dose. Further functional studies showed that locally administrated single-dose DEX-NPs effectively preserved outer hair cells in guinea pigs after cisplatin insult and thus significantly attenuated hearing loss at 4 kHz and 8 kHz frequencies when compared to the control of free DEX formulation. Histological analyses indicated that the administration of DEX-NPs did not induce local inflammatory responses. Therefore, prolonged delivery of DEX by PEG-PLA nanoparticles through local RWM diffusion (administration) significantly protected the hair cells and auditory function in guinea pigs from cisplatin toxicity, as determined at both histological and functional levels, suggesting the potential therapeutic benefits in clinical applications. PMID:25999718

  7. Superparamagnetic iron oxide--loaded poly(lactic acid)-D-alpha-tocopherol polyethylene glycol 1000 succinate copolymer nanoparticles as MRI contrast agent.

    PubMed

    Prashant, Chandrasekharan; Dipak, Maity; Yang, Chang-Tong; Chuang, Kai-Hsiang; Jun, Ding; Feng, Si-Shen

    2010-07-01

    We developed a strategy to formulate supraparamagnetic iron oxides (SPIOs) in nanoparticles (NPs) of biodegradable copolymer made up of poly(lactic acid) (PLA) and d-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS) for medical imaging by magnetic resonance imaging (MRI) of high contrast and low side effects. The IOs-loaded PLA-TPGS NPs (IOs-PNPs) were prepared by the single emulsion method and the nanoprecipitation method. Effects of the process parameters such as the emulsifier concentration, IOs loading in the nanoparticles, and the solvent to non-solvent ratio on the IOs distribution within the polymeric matrix were investigated and the formulation was then optimized. The transmission electron microscopy (TEM) showed direct visual evidence for the well dispersed distribution of the IOs within the NPs. We further investigated the biocompatibility and cellular uptake of the IOs-PNPs in vitro with MCF-7 breast cancer cells and NIH-3T3 mouse fibroblast in close comparison with the commercial IOs imaging agent Resovist. MRI imaging was further carried out to investigate the biodistribution of the IOs formulated in the IOs-PNPs, especially in the liver to understand the liver clearance process, which was also made in close comparison with Resovist. We found that the PLA-TPGS NPs formulation at the clinically approved dose of 0.8 mg Fe/kg could be cleared within 24 h in comparison with several weeks for Resovist. Xenograft tumor model MRI confirmed the advantages of the IOs-PNPs formulation versus Resovist through the enhanced permeation and retention (EPR) effect of the tumor vasculature. PMID:20434210

  8. Synthesis and self-assembly of biodegradable polyethylene glycol-poly (lactic acid) diblock copolymers as polymersomes for preparation of sustained release system of doxorubicin

    PubMed Central

    Alibolandi, Mona; Sadeghi, Fatemeh; Sazmand, Seyed Hossein; Shahrokhi, Seyed Mohammad; Seifi, Mahmoud; Hadizadeh, Farzin

    2015-01-01

    Introduction: The copolymer of polyethylene glycol (PEG) and polyesters has many interesting properties, such as amphiphilicity, biocompatibility, biodegradability, and self-assembly in an aqueous environment. Diblock copolymers of PEG-polyester can form different structures such as micelles, polymersome, capsules or micro-container in an aqueous environment according to the length of their blocks. Materials and Methods: Herein, a series of poly (lactic acid) (PLA) and PEG diblock copolymers were synthesized through the ring-opening polymerization. The polymerization reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The corresponding copolymers were implemented for the formation of polymersome structures using film rehydration method. Impact of methoxy PEG chain length and hydrophobic weight fraction on particle size of polymersomes were studied, and the proper ones were selected for loading of doxorubicin (DOX) via pH gradient method. Results and Discussion: Results obtained from 1HNMR and GPC revealed that microwave irradiation is a simple and reliable method for the synthesis of PEG-PLA copolymers. Further analysis indicated the copolymer with relative molecular weight of PLA to PEG ratios of 3 or fEo ~ 25% produced the smallest size polymersomes. Polymersomes prepared from PEG5000 to PLA15000 were more capable in loading and sustained release of DOX than those prepared from PEG2000 to PLA6000. Conclusion: In conclusion copolymers of PEG/PLA with fOE ~25% and relatively higher molecular weight are more suitable for encapsulation and providing sustained release of DOX. PMID:26258054

  9. The surface grafting of graphene oxide with poly(ethylene glycol) as a reinforcement for poly(lactic acid) nanocomposite scaffolds for potential tissue engineering applications.

    PubMed

    Zhang, Chunmei; Wang, Liwei; Zhai, Tianliang; Wang, Xinchao; Dan, Yi; Turng, Lih-Sheng

    2016-01-01

    Graphene oxide (GO) was incorporated into poly(lactic acid) (PLA) as a reinforcing nanofiller to produce composite nanofibrous scaffolds using the electrospinning technique. To improve the dispersion of GO in PLA and the interfacial adhesion between the filler and matrix, GO was surface-grafted with poly(ethylene glycol) (PEG). Morphological, thermal, mechanical, and wettability properties, as well as preliminary cytocompatibility with Swiss mouse NIH 3T3 cells of PLA, PLA/GO, and PLA/GO-g-PEG electrospun nanofibers, were characterized. Results showed that the average diameter of PLA/GO-g-PEG electrospun nanofibers decreased with filler content. Both GO and GO-g-PEG improved the thermal stability of PLA, but GO-g-PEG was more effective. The water contact angle test of the nanofiber mats showed that the addition of GO in PLA did not change the surface wettability of the materials, but PLA/GO-g-PEG samples exhibited improved wettability with lower water contact angles. The tensile strength of the composite nanofiber mats was improved with the addition of GO, and it was further enhanced when GO was surface grafted with PEG. This suggested that improved interfacial adhesion between GO and PLA was achieved by grafting PEG onto the GO. The cell viability and proliferation results showed that the cytocompatibility of PLA was not compromised with the addition of GO and GO-g-PEG. With enhanced mechanical properties as well as good wettability and cytocompatibility, PLA/GO-g-PEG composite nanofibers have the potential to be used as scaffolds in tissue engineering. PMID:26409231

  10. Cisplatin Loaded Poly(L-glutamic acid)-g-Methoxy Poly(ethylene glycol) Complex Nanoparticles for Potential Cancer Therapy: Preparation, In Vitro and In Vivo Evaluation.

    PubMed

    Yu, Haiyang; Tang, Zhaohui; Li, Mingqiang; Song, Wantong; Zhang, Dawei; Zhang, Ying; Yang, Yan; Sun, Hai; Deng, Mingxiao; Chen, Xuesi

    2016-01-01

    A series of novel polypeptide-based graft copolymer poly(L-glutamic acid)-graft-methoxy poly(ethylene glycol) (PLG-g-mPEG) was synthesized through a Steglich esterification reaction of PLG with mPEG. The structure of the copolymers was confirmed by nuclear magnetic resonance spectra (NMR) and gel permeation chromatography (GPC). MTT assay demonstrated that the PLG-g-mPEGs had good cell compatibility. The unreacted carboxyl groups of the PLG-g-mPEGs were used to complex cisplatin to form polymer-metal complex nanoparticles (CDDP/PLG-g-mPEG) for cancer therapy. The average hydrodynamic radius of the CDDP/PLG-g-mPEG nanoparticles was inr the range of 14-25 nm, which was beneficial for solid tumor targeting delivery. A sustained release without initial burst was achieved for the CDDP/PLG-g-mPEG nanoparticles, indicating that the CDDP-loaded nanoparticles had great potential to suppress the drug release in blood circulation before the nanoparticles had arrived at targeting tumors. The CDDP/PLG-g-mPEG nanoparticles showed a much longer blood retention profile as compared with the free CDDP. This indicated that the CDDP-loaded nanoparticles had much more opportunity to accumulate in tumor tissue by exerting the EPR effect. In vitro tests demonstrated that the CDDP/PLG-g-mPEG nanoparticles could inhibit the proliferation of HeLa, MCF-7 and A549 cancer cells. At equal dose (4 mg kg(-1)), the CDDP/PLG-g-mPEG nanoparticles showed comparable in vivo antitumor efficacy and significantly lower systemic toxicity as compared with free cis-Diaminedichloroplatinum (cisplatin, CDDP) in MCF-7 tumor bearing mice. These suggested that the CDDP/PLG-g-mPEG nanoparticle drug delivery system had a great potential to be used for cancer therapy. PMID:27301173

  11. Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Brullot, W.; Reddy, N. K.; Wouters, J.; Valev, V. K.; Goderis, B.; Vermant, J.; Verbiest, T.

    2012-06-01

    Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles were obtained by a facile protocol and thoroughly characterized. Superparamagnetic iron oxide nanoparticles synthesized using a modified forced hydrolysis method were functionalized with polyethylene glycol silane (PEG silane), precipitated and dried. These functionalized particles are dispersable in a range of solvents and concentrations depending on the desired properties. Examples of tunable properties are magnetic behavior, optical and magneto-optical response, thermal features and rheological behavior. As such, PEG silane functionalized particles represent a platform for the development of new materials that have broad applicability in e.g. biomedical, industrial or photonic environments. Magnetic, optical, magneto-optical, thermal and rheological properties of several ferrofluids based on PEG coated particles with different concentrations of particles dispersed in low molecular mass polyethylene glycol were investigated, establishing the applicability of such materials.

  12. Nanocomplexes based on amphiphilic hyaluronic acid derivative and polyethylene glycol-lipid for ginsenoside rg3 delivery.

    PubMed

    Lee, Jae-Young; Yang, Heejung; Yoon, In-Soo; Kim, Sang-Bum; Ko, Seung-Hak; Shim, Jae-Seong; Sung, Sang Hyun; Cho, Hyun-Jong; Kim, Dae-Duk

    2014-10-01

    Hybrid nanocomplex formulations, based on amphiphilic hyaluronic acid-ceramide (HACE) and lipids, were fabricated for the delivery of 20(S)-ginsenoside Rg 3 [(S)-Rg3]. Nanocomplexes with less than 200 nm mean diameter, narrow size distribution, spherical shape, and negative zeta potential were prepared. The maintenance of the structural stability of the hybrid nanocomplexes in the blood stream was demonstrated by measuring their particle size in serum. Nanocomplexes based on HACE, phosphatidylcholine (PC), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-PEG) showed a sustained drug release profile compared with other formulations. Blank nanocomplexes exhibited negligible cytotoxicity within the tested concentration range in A549 human lung adenocarcinoma cells. The cellular uptake efficiency of hybrid nanocomplexes was improved compared with the HACE-based nanoparticles probably because of interactions between lipids and the cellular membrane. The results of a pharmacokinetic study in rats revealed decreased in vivo clearance of (S)-Rg3, especially in the HACE/PC/DSPE-PEG-based hybrid nanocomplex (F3) group. The hybrid nanostructure and the outer PEG chain likely contributed to improve in vivo performance of the F3 group. Thus, these developed hybrid nanocomplexes could serve as good candidates for tumor-targeted delivery of anticancer agents. PMID:25112537

  13. Molecularly uniform poly(ethylene glycol) certified reference material

    NASA Astrophysics Data System (ADS)

    Takahashi, Kayori; Matsuyama, Shigetomo; Kinugasa, Shinichi; Ehara, Kensei; Sakurai, Hiromu; Horikawa, Yoshiteru; Kitazawa, Hideaki; Bounoshita, Masao

    2015-02-01

    A certified reference material (CRM) for poly(ethylene glycol) with no distribution in the degree of polymerization was developed. The degree of polymerization of the CRM was accurately determined to be 23. Supercritical fluid chromatography (SFC) was used to separate the molecularly uniform polymer from a standard commercial sample with wide polydispersity in its degree of polymerization. Through the use of a specific fractionation system coupled with SFC, we are able to obtain samples of poly(ethylene glycol) oligomer with exact degrees of polymerization, as required for a CRM produced by the National Metrology Institute of Japan.

  14. MICROWAVE-ACCELERATED SUZUKI CROSS-COUPLING REACTION IN POLYETHYLENE GLYCOL (PEG)

    EPA Science Inventory

    Polyethylene glycol (PEG) is found to be an inexpensive and nontoxic reaction medium for the microwave-assisted Suzuki cross-coupling of arylboronic acids with aryl halides. This environmentally friendly microwave protocol offers the ease of operation and enables the recyclabilit...

  15. Pharmacokinetics, biodistribution and in vivo efficacy of cisplatin loaded poly(L-glutamic acid)-g-methoxy poly(ethylene glycol) complex nanoparticles for tumor therapy.

    PubMed

    Yu, Haiyang; Tang, Zhaohui; Zhang, Dawei; Song, Wantong; Zhang, Ying; Yang, Yan; Ahmad, Zaheer; Chen, Xuesi

    2015-05-10

    Platinum-based polymeric nano-drugs, especially cisplatin-loaded polymeric nanoparticles (CDDP-NPs), have been extensively exploited for the treatment of solid tumors. However, it is still unclear what role the processing procedure and the properties of the polymeric carrier materials may play in influencing the plasma pharmacokinetics, biodistribution and in vivo efficacy of CDDP-NPs. In this study, a series of poly(l-glutamic acid)-g-methoxy poly(ethylene glycol) (PLG-g-mPEG) copolymers were synthesized for the preparation of CDDP-loaded PLG-g-mPEG (CDDP/PLG-g-mPEG) nanoparticles. All of the parameters, including PLG molecular weight, mPEG/PLG weight ratio, mPEG chain length, ultrafiltration purification and cisplatin loading content, were found to have a significant influence on the plasma pharmacokinetics of the CDDP/PLG-g-mPEG nanoparticles. The blood circulation time of the nanoparticles was prolonged with increases in PLG molecular weight, mPEG/PLG weight ratio, mPEG chain length and CDDP loading content. The use of ultrafiltration purification could prolong the blood circulation time of the nanoparticles as well. Experiments to measure the pharmacokinetics and biodistribution demonstrated that the selected CDDP/PLG-g-mPEG nanoparticles, NP10, had a long blood circulation time and could achieve selective and significant accumulation in Lewis lung carcinoma (LLC) tumors. The platinum plasma concentrations in the LLC tumor-bearing mice receiving NP10 remained up to 46-fold higher than that of mice receiving equivalent doses of free CDDP. In addition, the plasma area under the concentration time curve (AUC) of NP10 was 31-fold higher than that of free CDDP in 48h. The platinum concentration ratio of NP10 to free CDDP in tumors reached as high as 9.4. The tumor AUC ratio of NP10 to CDDP was 6. Using a mouse C26 tumor model, here we demonstrate that NP10 improves the safety and tolerance in vivo when compared to CDDP and effectively inhibits the growth of C26

  16. 21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyethylene glycol (mean molecular weight 200-9..., PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3750 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene glycol identified in this section may be safely used as...

  17. 21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyethylene glycol (mean molecular weight 200-9..., PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3750 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene glycol identified in this section may be safely used as...

  18. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Polyethylene glycol (400) mono- and dioleate. 573... DRINKING WATER OF ANIMALS Food Additive Listing § 573.800 Polyethylene glycol (400) mono- and dioleate. (a) The food additive polyethylene glycol (400) mono- and dioleate meets the following...

  19. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Polyethylene glycol (400) mono- and dioleate. 573... DRINKING WATER OF ANIMALS Food Additive Listing § 573.800 Polyethylene glycol (400) mono- and dioleate. (a) The food additive polyethylene glycol (400) mono- and dioleate meets the following...

  20. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Polyethylene glycol (400) mono- and dioleate. 573... DRINKING WATER OF ANIMALS Food Additive Listing § 573.800 Polyethylene glycol (400) mono- and dioleate. (a) The food additive polyethylene glycol (400) mono- and dioleate meets the following...

  1. Fluorescein prototropism within poly(ethylene glycol)s and their aqueous mixtures.

    PubMed

    Bhagi, Ambika; Pandey, Shubha; Pandey, Ashish; Pandey, Siddharth

    2013-05-01

    Depending on the solubilizing milieu and conditions, fluorescein may exist in one or more of its many prototropic forms [cationic, neutral (zwitterionic, quinoid, and lactone), monoanionic (phenolate and carboxylate), and dianionic]. Fluorescein prototropism is investigated in liquid poly(ethylene glycol)s (PEGs) of different average molecular weight (MW) and their aqueous mixtures using UV-vis absorbance along with static and time-resolved fluorescence spectroscopic techniques. Information regarding various prototropic forms of fluorescein in up to 30 wt % different average MW PEG-added aqueous buffers at varying pH reveals that addition of PEG causes lactonization of fluorescein in the milieu; higher the average MW of PEG, the more the lactonization is. Neat PEG200, PEG400, and PEG600 are found to support the dianionic form of fluorescein, while PEG1000 supports the neutral lactonized form. It is demonstrated that various prototropic forms of fluorescein may be generated within PEGs by addition of adequate amounts of acidic aqueous buffer. Significant bathochromic shift in absorbance and fluorescence band maxima of dianionic fluorescein as concentration of PEG200 is increased correlates well with hydrogen bond accepting basicity, hydrogen bond donating acidity, and dipolarity/polarizability of the aqueous PEG200 mixture. Interestingly, fluorescence emission from the cationic form of fluorescein is observed from dilute aqueous acidic media in the presence of high concentration of PEG200, whereas the fluorescence emission from cation in the absence of PEG200 is observed only from aqueous solutions of very high acidity (>5 M [H(+)]). Excited-state intensity decay is also used to support this outcome. It is proposed that, in the presence of a small amount of acid in PEG200, a highly acidic water-rich solvation microenvironment is formed around fluorescein, which converts its dianionic form to cationic form and considerably hinders the rapid deprotonation of the

  2. 21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ethylene oxide and water with a mean molecular weight of 200 to 9,500. (2) It contains no more than 0.2... the total ethylene and diethylene glycol content of polyethylene glycols having mean molecular weights... and diethylene glycol content of polyethylene glycols having mean molecular weights below...

  3. 21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ethylene oxide and water with a mean molecular weight of 200 to 9,500. (2) It contains no more than 0.2... the total ethylene and diethylene glycol content of polyethylene glycols having mean molecular weights... and diethylene glycol content of polyethylene glycols having mean molecular weights below...

  4. Comparison of Polyethylene Glycol-Electrolyte Solution vs Polyethylene Glycol-3350 for the Treatment of Fecal Impaction in Pediatric Patients

    PubMed Central

    Boles, Erin E.; Gaines, Cameryn L.

    2015-01-01

    OBJECTIVES: The objective of this study was to evaluate the safety and efficacy of polyethylene glycol-electrolyte solution vs polyethylene glycol-3350 for the treatment of fecal impaction in pediatric patients. METHODS: A retrospective, observational, institutional review board–approved study was conducted over a 1-year time period. Patients were included in the study if they were admitted to the hospital with a diagnosis of fecal impaction or constipation and were treated with either polyethylene glycol-electrolyte solution (PEG-ES) or polyethylene glycol-3350 (PEG-3350). Patients were excluded if they were discharged prior to resolution of treatment and/or did not receive PEG-ES or PEG-3350. RESULTS: Fifty-one patients (ranging in age from 1 month to 15 years) were evaluated: 23 patients received PEG-ES and 28 patients received PEG-3350. Sex, race, age, and weight were not statistically different between the 2 groups. Resolution of fecal impaction was not significantly different between PEG-ES vs PEG-3350 (87% and 86%, respectively; p = 0.87). There was only 1 reported side effect with PEG-3350, vs 11 reported side effects with PEG-ES (p < 0.01). CONCLUSIONS: Theses results suggest that PEG-3350 is as effective as PEG-ES for the treatment of fecal impaction in pediatric patients and is associated with fewer side effects. PMID:26170773

  5. 21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyethylene glycol (mean molecular weight 200-9... Adjuvants and Production Aids § 178.3750 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene... chapter. (c) The provisions of paragraph (b) of this section are not applicable to polyethylene...

  6. Polyethylene Glycol (PEG)-Induced Anaphylactic Reaction During Bowel Preparation

    PubMed Central

    2015-01-01

    Barium enema is used to screen patients with gastrointestinal bleeding who do not want to undergo colonoscopy. Polyethylene glycol (PEG) is usually the bowel preparation of choice. Few allergic reactions from this product have been reported; these include urticaria, angioedema, and anaphylaxis. Reactions are thought to result from a small amount of PEG crossing the intestinal mucosa, which, in some patients, is sufficient to provoke an anaphylactic reaction. PMID:26203443

  7. Cementitious building material incorporating end-capped polyethylene glycol as a phase change material

    DOEpatents

    Salyer, Ival O.; Griffen, Charles W.

    1986-01-01

    A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

  8. Electrochemical measurements of diffusion coefficients of redox-labeled poly(ethylene glycol) dissolved in poly(ethylene glycol) melts

    SciTech Connect

    Haas, O.; Velazquez, C.S.; Porat, Z.; Murray, R.W.

    1995-10-12

    Ferrocene labeled monomethoxy-poly(ethylene glycol)s (MPEG) with molecular weights of 1900 and 750 were used as redox probe solutes in poly(ethylene glycol) melt solvents of molecular weight 750, 2000, and 20000. Cyclic voltammetry and chronoamperometry at microdisk electrodes were employed to measure the diffusion coefficients of the redox probes, which were independent of the probe concentration and varied between 10{sup -7} and 10{sup -10} cm{sup 2}/s. Diffusional activation barrier results also suggest that the ferrocene label does not significantly influence the diffusivity of the probe molecule in the host solvent. Activation barrier, viscosity, and ionic conductivity results show that the LiClO{sub 4} electrolyte does not influence the diffusion barrier or viscosity as long as the ether O/Li{sup +} ratio is >=250 (ca. 0.1 M) which is still a sufficient electrolyte concentration to allow quantitative electrochemical diffusion measurements. 21 refs., 7 figs., 2 tabs.

  9. Complete Genome Sequence of Polypropylene Glycol- and Polyethylene Glycol-Degrading Sphingopyxis macrogoltabida Strain EY-1

    PubMed Central

    Nagata, Yuji; Numata, Mitsuru; Tsuchikane, Kieko; Hosoyama, Akira; Yamazoe, Atsushi; Tsuda, Masataka; Fujita, Nobuyuki; Kawai, Fusako

    2015-01-01

    Strain EY-1 was isolated from a microbial consortium growing on a random polymer of ethylene oxide and propylene oxide. Strain EY-1 grew on polyethylene glycol and polypropylene glycol and identified as Sphingopyxis macrogoltabida. Here, we report the complete genome sequence of Sphingopyxis macrogoltabida EY-1. The genome of strain EY-1 is comprised of a 4.76-Mb circular chromosome, and five plasmids. The whole finishing was conducted in silico, with aids of computational tools GenoFinisher and AceFileViewer. Strain EY-1 is available from Biological Resource Center, National Institute of Technology and Evaluation (Tokyo, Japan) (NITE). PMID:26634754

  10. Effects of hypochlorous acid exposure on the rejection of salt, polyethylene glycols, boron and arsenic(V) by nanofiltration and reverse osmosis membranes.

    PubMed

    Do, Van Thanh; Tang, Chuyang Y; Reinhard, Martin; Leckie, James O

    2012-10-15

    The separation layer of polyamide-based (PA) thin film composite (TFC) membranes can be modified by active chlorine species. The PA-TFC membranes, NF90, BW30 and NF270, were exposed to different concentrations of sodium hypochlorite (NaOCl) at pH 5 for 24 h. Elemental composition obtained from X-ray Photoelectron Spectroscopy (XPS) showed that the chlorine content in the PA layer increased with the chlorine concentrations. Treatment of membranes with 10 ppm Cl increased the membrane hydrophilicity. By contrast, when treated with 1000 ppm Cl or more, the membranes became less hydrophilic. Water permeability values for all 3 membrane types declined with increased chlorine concentrations. Filtration of polyethylene glycols (PEGs) with molecular weights of 200, 400 and 600 Daltons (Da) was performed to investigate the influence of chlorine treatment on membrane molecular weight cut off (MWCO) and rejection by size exclusion. Treatment with 10 and 100 ppm Cl lowered the MWCO while treatment with higher concentrations increased the MWCO. All chlorinated membranes experienced higher NaCl rejection compared to virgin ones. The performance of NF90 was tested with respect to the rejection of inorganic contaminants including boron (H(3)BO(3)) and arsenic (H(2)AsO(4)(-)). The boron rejection results paralleled PEG rejection whereas those for arsenic followed NaCl rejection patterns. The changes in membrane performance due to chlorine treatment were explained in terms of competing mechanisms: membrane tightening, bond cleavage by N-chlorination and chlorination promoted polyamide hydrolysis. PMID:22818949

  11. Effect of tocopheryl polyethylene glycol succinate on the percutaneous penetration of minoxidil from water/ethanol/polyethylene glycol 400 solutions.

    PubMed

    Sheu, Ming-Thau; Wu, An-Bang; Lin, Keng-Ping; Shen, Chao-Hui; Ho, Hsiu-O

    2006-06-01

    We described to achieve the local retention of minoxidil which has penetrated the skin with minimization of its absorption into the general circulation and elimination of local irritation induced by propylene glycol. The effect of tocopheryl polyethylene glycol succinate (TPGS) on the penetration flux of minoxidil and its retention in the skin from topical minoxidil formulations consisting of water, alcohol, and polyethylene glycol 400 was characterized by an experimental design of ten solvent formulations in this study. Results show that the addition of TPGS was only able to improve the solubility of minoxidil in those solvent systems containing higher proportions of water and PEG 400, and the extent of improvement was also more profound with the addition of TPGS at concentrations higher than 5%. For those solvent systems containing a higher fraction of alcohol, an insignificant change in minoxidil solubility with increasing added amounts of TPGS was noted even with the tendency to decrease the solubility of minoxidil with higher amounts of TPGS. Increasing the amount of TPGS added gradually increased the flux and the corrected flux from solvent formulations with a lower solubility parameter, but decreased those from solvent systems with a higher solubility parameter. With the addition of TPGS, solvent formulation F6 (alcohol:PEG 400 of 50:50) was demonstrated to be the optimal choice by having an improved local effect and a reduced systemic effect compared to the reference of 2% Regaine((R)). Tocopheryl polyethylene glycol succinate (TPGS) was mainly retained locally in the stratum corneum, and the amount was proportional to the increase in the amount of TPGS added to these ten solvent formulations. PMID:16720414

  12. Fermentative degradation of nonionic surfactants and polyethylene glycol by enrichment cultures and by pure cultures of homoacetogenic and propionate-forming bacteria.

    PubMed Central

    Wagener, S; Schink, B

    1988-01-01

    Linear alkyl ethoxylates (polyethylene glycol alkyl ethers) were fermented completely to methane and CO2 in enrichment cultures inoculated with anoxic sewage sludge. Long-chain fatty acids were released as intermediates. No degradation was found with polypropylene glycol and polypropylene glycol-containing surfactants. Two types of primary ethoxylate-degrading bacteria were isolated and characterized. Both degraded polyethylene glycols with molecular weights of 1,000 completely. Strain KoB35 fermented polyethylene glycol, ethoxyethanol, and lactate to acetate and propionate and was assigned to the described species Pelobacter propionicus. Strain KoB58 converted polyethylene glycol and many other substrates to acetate only and was assigned to the genus Acetobacterium. The pathways of anaerobic degradation of nonionic surfactants are discussed with respect to their limitations and the various groups of bacteria involved. Images PMID:3355141

  13. Vorinostat with sustained exposure and high solubility in poly(ethylene glycol)-b-poly(DL-lactic acid) micelle nanocarriers: characterization and effects on pharmacokinetics in rat serum and urine.

    PubMed

    Mohamed, Elham A; Zhao, Yunqi; Meshali, Mahasen M; Remsberg, Connie M; Borg, Thanaa M; Foda, Abdel Monem M; Takemoto, Jody K; Sayre, Casey L; Martinez, Stephanie E; Davies, Neal M; Forrest, M Laird

    2012-10-01

    The histone deacetylase inhibitor suberoylanilide hydroxamic acid, known as vorinostat, is a promising anticancer drug with a unique mode of action; however, it is plagued by low water solubility, low permeability, and suboptimal pharmacokinetics. In this study, poly(ethylene glycol)-b-poly(DL-lactic acid) (PEG-b-PLA) micelles of vorinostat were developed. Vorinostat's pharmacokinetics in rats was investigated after intravenous (i.v.) (10 mg/kg) and oral (p.o.) (50 mg/kg) micellar administrations and compared with a conventional polyethylene glycol 400 solution and methylcellulose suspension. The micelles increased the aqueous solubility of vorinostat from 0.2 to 8.15 ± 0.60 and 10.24 ± 0.92 mg/mL at drug to nanocarrier ratios of 1:10 and 1:15, respectively. Micelles had nanoscopic mean diameters of 75.67 ± 7.57 and 87.33 ± 8.62 nm for 1:10 and 1:15 micelles, respectively, with drug loading capacities of 9.93 ± 0.21% and 6.91 ± 1.19%, and encapsulation efficiencies of 42.74 ± 1.67% and 73.29 ± 4.78%, respectively. The micelles provided sustained exposure and improved pharmacokinetics characterized by a significant increase in serum half-life, area under curve, and mean residence time. The micelles reduced vorinostat clearance particularly after i.v. dosing. Thus, PEG-b-PLA micelles significantly improved the p.o. and i.v. pharmacokinetics and bioavailability of vorinostat, which warrants further investigation. PMID:22806441

  14. The effect of glycerol, propylene glycol and polyethylene glycol 400 on the partition coefficient of benzophenone-3 (oxybenzone).

    PubMed

    Mbah, C J

    2007-01-01

    Sunscreen products are widely used to protect the skin from sun-related deleterious effects. The objective of the study was to investigate the potential effect of glycerol, propylene glycol and polyethylene glycol 400 on dermal absorption of oxybenzone by studying their effects on its partition coefficient. The partition coefficient was evaluated in a chloroform-water system at room temperature. It was found that glycerol and propylene glycol decreased the partition coefficient of oxybenzone, while an increase in partition coefficient was observed with polyethylene glycol 400. The findings suggest that polyethylene glycol 400 in contrast to glycerol and propylene glycol has the potential of increasing the vehicle-skin partition coefficient of oxybenzone when cosmetic products containing such an UV absorber are topically applied to the skin. PMID:17294811

  15. Polyethylene glycol-based homologated ligands for nicotinic acetylcholine receptors☆

    PubMed Central

    Scates, Bradley A.; Lashbrook, Bethany L.; Chastain, Benjamin C.; Tominaga, Kaoru; Elliott, Brandon T.; Theising, Nicholas J.; Baker, Thomas A.; Fitch, Richard W.

    2010-01-01

    A homologous series of polyethylene glycol (PEG) monomethyl ethers were conjugated with three ligand series for nicotinic acetylcholine receptors. Conjugates of acetylaminocholine, the cyclic analog 1-acetyl-4,4-dimethylpiperazinium, and pyridyl ether A-84543 were prepared. Each series was found to retain significant affinity at nicotinic receptors in rat cerebral cortex with tethers of up to six PEG units. Such compounds are hydrophilic ligands which may serve as models for fluorescent/affinity probes and multivalent ligands for nAChR. PMID:19006672

  16. GLYCOLIC - FORMIC ACID FLOWSHEET DEVELOPMENT

    SciTech Connect

    Pickenheim, B.; Stone, M.; Newell, J.

    2010-11-08

    Flowsheet testing was performed to further develop the nitric/glycolic/formic acid flowsheet as an alternative to the nitric/formic flowsheet currently being processed at the DWPF. This new flowsheet has shown that mercury can be removed in the Sludge Receipt and Adjustment Tank (SRAT) with minimal hydrogen generation. All other processing objectives were also met, including greatly reducing the Slurry Mix Evaporator (SME) product yield stress as compared to the baseline nitric/formic flowsheet. Eight runs were performed in total, including the baseline run. The baseline nitric/formic flowsheet run was extremely difficult to process under existing DWPF acceptance criteria with this simulant at the HM levels of noble metals. While nitrite was destroyed and mercury was removed to near the DWPF limit, the rheology of the SRAT and SME products were well above design basis and hydrogen generation far exceeded the DWPF limit. In addition, mixing during the SME cycle was very poor. In this sense, the nitric/glycolic/formic acid flowsheet represents a significant upgrade over the current flowsheet. In the nitric/glycolic/formic flowsheet runs, mercury was successfully removed with almost no hydrogen generation and the SRAT and SME products yield stresses were within process limits or previously processed ranges. It is recommended that DWPF continue to support development of the nitric/glycolic/formic flowsheet. Although experience is limited at this time, this flowsheet meets or outperforms the current flowsheet in many regards, including off-gas generation, mercury removal, product rheology and general ease of processing. Additional flowsheet testing will allow for a more thorough understanding of the chemistry and effectiveness of the flowsheet over a range of sludge compositions and formic/glycolic ratios. This testing will also show whether the REDOX and metal solubility concerns with this change in the flowsheet can be addressed by just adjusting the volumes of

  17. Particle Size Control of Polyethylene Glycol Coated Fe Nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivasan, B.; Bonder, M. J.; Zhang, Y.; Gallo, D.; Hadjipanayis, G. C.

    2006-03-01

    Recent interest in Fe nanoparticles with high magnetization is driven by their potential use in biomedical applications such as targeted drug delivery, MRI contrast enhancement and hyperthermia treatment of cancer. This study looks at the use of a polyethylene glycol (PEG) solution to mediate the particle size and therefore control the coercivity of the resulting nanoparticles. Iron nanoparticles were synthesized using an aqueous sodium borohydride reduction of ferrous chloride by a simultaneous introduction of reagents in a Y- junction. The resulting product was collected in a vessel containing a 15 mg/ml carboxyl terminated polyethylene glycol (cPEG) in ethyl alcohol solution located under the Y junction. By varying the length of tubing below the Y junction, the particle size was varied from 5-25 nm. X-ray diffraction data indicates the presence of either amorphous Fe-B or crystalline alpha Fe, depending on the molar ratio of reagents. Magnetic measurements indicate the particles are ferromagnetic with values of coercivity ranging from 200-500 Oe and a saturation magnetization in range of 70-110 emu/g. The XRD shows that the particles are not affected by the polymer coating.

  18. Synthesis and properties of oligodeoxyribonucleotide-polyethylene glycol conjugates.

    PubMed Central

    Jäschke, A; Fürste, J P; Nordhoff, E; Hillenkamp, F; Cech, D; Erdmann, V A

    1994-01-01

    Pools of oligonucleotide conjugates consisting of 10-400 different molecular species were synthesized. The conjugates contained a varying number of ethylene glycol units attached to 3'-terminal, 5'-terminal and internal positions of the oligonucleotides. Conjugate synthesis was performed by phosphoramidite solid phase chemistry using suitably protected polyethylene glycol phosphoramidites and PEG-derivatized solid supports containing polydisperse PEGs of various molecular weight ranges. The pools were analyzed and fractionated by chromatographic and electrophoretic techniques, and the composition of isolated conjugates was revealed by matrix-assisted laser desorption/ionization mass spectrometry. The number and attachment sites of coupled ethylene glycol units greatly influence the hydrophobicity of the conjugates, as well as their electrophoretic mobilities. Conjugation had little effect on the hybridization behavior of oligonucleotide conjugates with unmodified complementary oligonucleotide strands. Melting temperatures were between 67 and 73 degrees C, depending on the size and number of coupled PEG chains, compared to 68 degrees C for the unmodified duplex. Conjugates with PEG coupled to both 3'- and 5'-terminal positions showed a more than 10-fold increase in exonuclease stability. PMID:7984434

  19. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.800 Polyethylene glycol (400) mono- and dioleate. (a) The food additive polyethylene glycol (400) mono- and dioleate meets the following...

  20. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.800 Polyethylene glycol (400) mono- and dioleate. (a) The food additive polyethylene glycol (400) mono- and dioleate meets the following...

  1. 21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyethylene glycol (mean molecular weight 200-9... molecular weight 200-9,500). Polyethylene glycol identified in this section may be safely used as a... conditions: (a) The additive is an addition polymer of ethylene oxide and water with a mean molecular...

  2. 21 CFR 178.3750 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyethylene glycol (mean molecular weight 200-9... molecular weight 200-9,500). Polyethylene glycol identified in this section may be safely used as a... conditions: (a) The additive is an addition polymer of ethylene oxide and water with a mean molecular...

  3. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., potassium salt. 721.3900 Section 721.3900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.3900 Alkyl polyethylene glycol phosphate, potassium salt. (a) Chemical... as alkyl polyethylene glycol phosphate, potassium salt (P-90-481), is subject to reporting under...

  4. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., potassium salt. 721.3900 Section 721.3900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.3900 Alkyl polyethylene glycol phosphate, potassium salt. (a) Chemical... as alkyl polyethylene glycol phosphate, potassium salt (P-90-481), is subject to reporting under...

  5. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., potassium salt. 721.3900 Section 721.3900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.3900 Alkyl polyethylene glycol phosphate, potassium salt. (a) Chemical... as alkyl polyethylene glycol phosphate, potassium salt (P-90-481), is subject to reporting under...

  6. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., potassium salt. 721.3900 Section 721.3900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.3900 Alkyl polyethylene glycol phosphate, potassium salt. (a) Chemical... as alkyl polyethylene glycol phosphate, potassium salt (P-90-481), is subject to reporting under...

  7. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., potassium salt. 721.3900 Section 721.3900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.3900 Alkyl polyethylene glycol phosphate, potassium salt. (a) Chemical... as alkyl polyethylene glycol phosphate, potassium salt (P-90-481), is subject to reporting under...

  8. 40 CFR 721.10546 - Pentenylated polyethylene glycol sulfate salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... sulfate salt (generic). 721.10546 Section 721.10546 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10546 Pentenylated polyethylene glycol sulfate salt... identified generically as pentenylated polyethylene glycol sulfate salt (PMN P-04-340) is subject...

  9. 40 CFR 721.10546 - Pentenylated polyethylene glycol sulfate salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sulfate salt (generic). 721.10546 Section 721.10546 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10546 Pentenylated polyethylene glycol sulfate salt... identified generically as pentenylated polyethylene glycol sulfate salt (PMN P-04-340) is subject...

  10. Horseradish Peroxidase Inactivation: Heme Destruction and Influence of Polyethylene Glycol

    PubMed Central

    Mao, Liang; Luo, Siqiang; Huang, Qingguo; Lu, Junhe

    2013-01-01

    Horseradish peroxidase (HRP) mediates efficient conversion of many phenolic contaminants and thus has potential applications for pollution control. Such potentially important applications suffer however from the fact that the enzyme becomes quickly inactivated during phenol oxidation and polymerization. The work here provides the first experimental data of heme consumption and iron releases to support the hypothesis that HRP is inactivated by heme destruction. Product of heme destruction is identified using liquid chromatography with mass spectrometry. The heme macrocycle destruction involving deprivation of the heme iron and oxidation of the 4-vinyl group in heme occurs as a result of the reaction. We also demonstrated that heme consumption and iron releases resulting from HRP destruction are largely reduced in the presence of polyethylene glycol (PEG), providing the first evidence to indicate that heme destruction is effectively suppressed by co-dissolved PEG. These findings advance a better understanding of the mechanisms of HRP inactivation. PMID:24185130

  11. The effect of polyethylene glycol on shellac stability

    NASA Astrophysics Data System (ADS)

    Khairuddin; Pramono, Edi; Budi Utomo, Suryadi; Wulandari, Viki; A'an Zahrotul, W.; Clegg, Francis

    2016-02-01

    The effect of polyethylene glycol (PEG) having amolecular weight of 1000 and 2000 on shellac stability has been investigated in this research. The shellac was shellac wax free, and the solvent was ethanol 96%. Shellac films were prepared by solventevaporationmethod. The stability of shellac was investigated using insoluble solid test, Fourier Transform Infra Red (FTIR), Thermogravimetry Analyzer (TGA), and Water Vapour Transmission Rate (WVTR). The results showed that stability of shellac decreased after heating at 125oC for 10,30,90,and 180 minutes, and storing for 1 month at 27 oC and 85 relative humidity (RH). PEG improved the stability, and the most stable effect was achieved through PEG1000.

  12. Simulation of polyethylene glycol and calcium-mediated membrane fusion

    SciTech Connect

    Pannuzzo, Martina; De Jong, Djurre H.; Marrink, Siewert J.; Raudino, Antonio

    2014-03-28

    We report on the mechanism of membrane fusion mediated by polyethylene glycol (PEG) and Ca{sup 2+} by means of a coarse-grained molecular dynamics simulation approach. Our data provide a detailed view on the role of cations and polymer in modulating the interaction between negatively charged apposed membranes. The PEG chains cause a reduction of the inter-lamellar distance and cause an increase in concentration of divalent cations. When thermally driven fluctuations bring the membranes at close contact, a switch from cis to trans Ca{sup 2+}-lipid complexes stabilizes a focal contact acting as a nucleation site for further expansion of the adhesion region. Flipping of lipid tails induces subsequent stalk formation. Together, our results provide a molecular explanation for the synergistic effect of Ca{sup 2+} and PEG on membrane fusion.

  13. Polyethylene glycol diffusion in ex vivo skin tissue

    NASA Astrophysics Data System (ADS)

    Genin, V. D.; Tuchina, D. K.; Bashkatov, A. N.; Genina, E. A.; Tuchin, V. V.

    2015-11-01

    Optical clearing of the rat skin under the action of polyethylene glycol (PEG) with molecular weight 300 and 400 Dalton was studied ex vivo. The collimated transmittance was measured at the wavelength range 500-900 nm. It was found that collimated transmittance of skin samples increased, whereas weight, thickness and area of the samples decreased during PEG penetration in skin tissue. A mechanism of the optical clearing under the action of PEG is discussed. Taking into account the kinetics of volume and thickness of the skin samples, diffusion coefficient of PEGs in skin tissue has been estimated as (1.83±2.22)×10-6 cm2/s and (1.70±1.47)×10-6 cm2/s for PEG-300 and PEG-400, respectively. The presented results can be useful for enhancement of many methods of laser therapy and optical diagnostics of skin diseases and localization of subcutaneous neoplasms.

  14. Effects of sterilization on poly(ethylene glycol) hydrogels.

    PubMed

    Kanjickal, Deenu; Lopina, Stephanie; Evancho-Chapman, M Michelle; Schmidt, Steven; Donovan, Duane

    2008-12-01

    The past few decades have witnessed a dramatic increase in the development of polymeric biomaterials. These biomaterials have to undergo a sterilization procedure before implantation. However, many sterilization procedures have been shown to profoundly affect polymer properties. Poly(ethylene glycol) hydrogels have gained increasing importance in the controlled delivery of therapeutics and in tissue engineering. We evaluated the effect of ethylene oxide (EtO), hydrogen peroxide (H(2)O(2)), and gamma sterilization of poly(ethylene glycol) hydrogels on properties relevant to controlled drug delivery and tissue engineering. We observed that the release of cyclosporine (CyA) (an immunosuppressive drug that is effective in combating tissue rejection following organ transplantation) was significantly affected by the type of sterilization. However, that was not the case with rhodamine B, a dye. Hence, the drug release characteristics were observed to be dependent not only on the sterilization procedure but also on the type of agent that needs to be delivered. In addition, differences in the swelling ratios for the sterilized and unsterilized hydrogels were statistically significant for 1:1 crosslinked hydrogels derived from the 8000 MW polymer. Significant differences were also observed for gamma sterilization for 1:1 crosslinked hydrogels derived from the 3350 MW polymer and also the 2:1 crosslinked hydrogels derived from the 8000 MW polymer. Atomic force microscopy (AFM) studies revealed that the roughness parameter for the unsterilized and EtO-sterilized PEG hydrogels remained similar. However, a statistically significant reduction of the roughness parameter was observed for the H(2)O(2) and gamma-sterilized samples. Electron spin resonance (ESR) studies on the unsterilized and the sterilized samples revealed the presence of the peroxy and the triphenyl methyl carbon radical in the samples. The gamma and the H(2)O(2)-sterilized samples were observed to have a much

  15. Fabrication of poly(ethylene glycol) hydrogel microstructures using photolithography.

    PubMed

    Revzin, A; Russell, R J; Yadavalli, V K; Koh, W G; Deister, C; Hile, D D; Mellott, M B; Pishko, M V

    2001-09-01

    The fabrication of hydrogel microstructures based upon poly(ethylene glycol) diacrylates, dimethacrylates, and tetraacrylates patterned photolithographically on silicon or glass substrates is described. A silicon/silicon dioxide surface was treated with 3-(trichlorosilyl)propyl methacrylate to form a self-assembled monolayer (SAM) with pendant acrylate groups. The SAM presence on the surface was verified using ellipsometry and time-of-flight secondary ion mass spectrometry. A solution containing an acrylated or methacrylated poly(ethylene glycol) derivative and a photoinitiator (2,2-dimethoxy-2-phenylacetophenone) was spin-coated onto the treated substrate, exposed to 365 nm ultraviolet light through a photomask, and developed with either toluene, water, or supercritical CO2. As a result of this process, three-dimensional, cross-linked PEG hydrogel microstructures were immobilized on the surface. Diameters of cylindrical array members were varied from 600 to 7 micrometers by the use of different photomasks, while height varied from 3 to 12 micrometers, depending on the molecular weight of the PEG macromer. In the case of 7 micrometers diameter elements, as many as 400 elements were reproducibly generated in a 1 mm2 square pattern. The resultant hydrogel patterns were hydrated for as long as 3 weeks without delamination from the substrate. In addition, micropatterning of different molecular weights of PEG was demonstrated. Arrays of hydrogel disks containing an immobilized protein conjugated to a pH sensitive fluorophore were also prepared. The pH sensitivity of the gel-immobilized dye was similar to that in an aqueous buffer, and no leaching of the dye-labeled protein from the hydrogel microstructure was observed over a 1 week period. Changes in fluorescence were also observed for immobilized fluorophore labeled acetylcholine esterase upon the addition of acetyl acholine. PMID:12448421

  16. Fabrication of poly(ethylene glycol) hydrogel microstructures using photolithography

    NASA Technical Reports Server (NTRS)

    Revzin, A.; Russell, R. J.; Yadavalli, V. K.; Koh, W. G.; Deister, C.; Hile, D. D.; Mellott, M. B.; Pishko, M. V.

    2001-01-01

    The fabrication of hydrogel microstructures based upon poly(ethylene glycol) diacrylates, dimethacrylates, and tetraacrylates patterned photolithographically on silicon or glass substrates is described. A silicon/silicon dioxide surface was treated with 3-(trichlorosilyl)propyl methacrylate to form a self-assembled monolayer (SAM) with pendant acrylate groups. The SAM presence on the surface was verified using ellipsometry and time-of-flight secondary ion mass spectrometry. A solution containing an acrylated or methacrylated poly(ethylene glycol) derivative and a photoinitiator (2,2-dimethoxy-2-phenylacetophenone) was spin-coated onto the treated substrate, exposed to 365 nm ultraviolet light through a photomask, and developed with either toluene, water, or supercritical CO2. As a result of this process, three-dimensional, cross-linked PEG hydrogel microstructures were immobilized on the surface. Diameters of cylindrical array members were varied from 600 to 7 micrometers by the use of different photomasks, while height varied from 3 to 12 micrometers, depending on the molecular weight of the PEG macromer. In the case of 7 micrometers diameter elements, as many as 400 elements were reproducibly generated in a 1 mm2 square pattern. The resultant hydrogel patterns were hydrated for as long as 3 weeks without delamination from the substrate. In addition, micropatterning of different molecular weights of PEG was demonstrated. Arrays of hydrogel disks containing an immobilized protein conjugated to a pH sensitive fluorophore were also prepared. The pH sensitivity of the gel-immobilized dye was similar to that in an aqueous buffer, and no leaching of the dye-labeled protein from the hydrogel microstructure was observed over a 1 week period. Changes in fluorescence were also observed for immobilized fluorophore labeled acetylcholine esterase upon the addition of acetyl acholine.

  17. Polymer adsorption on platinum: surface coverage determination using iodide-125. [Polyethylene glycol terephthalate

    SciTech Connect

    Ellis, T.M.; Van de Mark, M.R.; mi, FL

    1981-10-01

    Adsorption of iodide-125, a ..gamma.. emitter, was used as a quantitative methodology for polymer adsorption surface coverage analysis. Adsorption of I-125 on clean platinum produced surface elemental ratios of I:Pt of 1:4. The technique was applied to the adsorption of polyethylene glycol terephthalate from trifluoroacetic acid on platinum flags with a 2-cm/sup 2/ surface area. This polymer adsorption is approximated by a logarithmic relationship similar to the Temkin isotherm. Polymer coverage attained up to 99.6% of the surface.

  18. A thermosensitive hydrogel based on biodegradable amphiphilic poly(ethylene glycol) polycaprolactone poly(ethylene glycol) block copolymers

    NASA Astrophysics Data System (ADS)

    Gong, Chang Yang; Qian, Zhi Yong; Liu, Cai Bing; Juan Huang, Mei; Gu, Ying Chun; Wen, Yan Jun; Kan, Bing; Wang, Ke; Dai, Mei; Li, Xing Yi; Gou, Ma Ling; Tu, Ming Jing; Wei, Yu Quan

    2007-06-01

    A series of low molecular weight poly(ethylene glycol)-polycaprolactone-poly(ethylene glycol) (PEG-PCL-PEG) biodegradable block copolymers were successfully synthesized using isophorone diisocyanate (IPDI) as the coupling agent, and were characterized using 1H NMR and Fourier transform infrared spectroscopy. The aqueous solutions of the PEG-PCL-PEG copolymers displayed a special thermosensitive gel-sol transition when the concentration was above the corresponding critical gel concentration. Gel-sol phase diagrams were recorded using the test-tube-inversion method; they depended on the hydrophilic/hydrophobic balance in the macromolecular structure, as well as some other factors, including the heating history, volume, and the ageing time of the copolymer aqueous solutions and dissolution temperature of the copolymers. As a result, the gel-sol transition temperature range could be altered, which might be very useful for application in injectable drug delivery systems. This work was financially supported by the Chinese Key Basic Research Program (2004CB518800 and 2004CB518807), and the Sichuan Key Project of Science and Technology (06(05SG022-021-02)).

  19. Poly(ethylene glycol) grafted chitosan as new copolymer material for oral delivery of insulin

    NASA Astrophysics Data System (ADS)

    Ho, Thanh Ha; Thanh Le, Thi Nu; Nguyen, Tuan Anh; Chien Dang, Mau

    2015-09-01

    A new scheme of grafting poly (ethylene glycol) onto chitosan was proposed in this study to give new material for delivery of insulin over oral pathway. First, methoxy poly(ethylene glycol) amine (mPEGa MW 2000) were grafted onto chitosan (CS) through multiples steps to synthesize the grafting copolymer PEG-g-CS. After each synthesis step, chitosan and its derivatives were characterized by FTIR, 1H NMR Then, insulin loaded PEG-g-CS nanoparticles were prepared by cross-linking of CS with sodium tripolyphosphate (TPP). Same insulin loaded nanoparticles using unmodified chitosan were also prepared in order to compare with the modified ones. Results showed better protecting capacity of the synthesized copolymer over original CS. CS nanoparticles (10 nm of size) were gel like and high sensible to temperature as well as acidic environment while PEG-g-CS nanoparticles (200 nm of size) were rigid and more thermo and pH stable.

  20. Poly(ethylene glycol)-functionalized polymeric microchips for capillary electrophoresis.

    PubMed

    Sun, Xuefei; Li, Dan; Lee, Milton L

    2009-08-01

    Recently, we reported the synthesis, fabrication, and preliminary evaluation of poly(ethylene glycol) (PEG)-functionalized polymeric microchips that are inherently resistant to protein adsorption without surface modification in capillary electrophoresis (CE). In this study, we investigated the impact of cross-linker purity and addition of methyl methacrylate (MMA) as a comonomer on CE performance. Impure poly(ethylene glycol) diacrylate (PEGDA) induced electroosmotic flow (EOF) and increased the separation time, while the addition of MMA decreased the separation efficiency to approximately 25% of that obtained using microchips fabricated without MMA. Resultant improved microchips were evaluated for the separation of fluorescent dyes, amino acids, peptides, and proteins. A CE efficiency of 4.2 x 10(4) plates for aspartic acid in a 3.5 cm long microchannel was obtained. Chiral separation of 10 different D,L-amino acid pairs was obtained with addition of a chiral selector (i.e., beta-cyclodextrin) in the running buffer. Selectivity (alpha) and resolution (R(s)) for D,L-leucine were 1.16 and 1.64, respectively. Good reproducibility was an added advantage of these PEG-functionalized microchips. PMID:19572700

  1. Hemoglobin precipitation by polyethylene glycols leads to underestimation of membrane pore sizes.

    PubMed

    Quijano, Jairo C; Lemeshko, Victor V

    2008-12-01

    The size of pores formed in the plasma membrane by various substances is frequently determined using polyethylene glycols as osmotic protectants. In this work, we have found that the size of pores formed by saponin in the red blood cell membrane determined by hemolysis versus molecular weight of polyethylene glycol was different to that estimated by light dispersion of cell suspensions. After complete swelling of cells induced by saponin in semiisotonic salt media containing 150 mOsm PEG-4000 or PEG-3000, a significant increase in the light absorbance at 640 nm was developed resulting from the formation of hemoglobin precipitates. Easily sedimenting aggregates were also formed when the supernatant of lysed cells was added to the equiosmotic solutions of polyethylene glycols with molecular weight higher than 1000. We suggest that the real size of large pores could be underestimated due to the phenomenon of hemoglobin precipitation by polyethylene glycols. PMID:18692020

  2. Partitioning of differently sized poly(ethylene glycol)s into OmpF porin.

    PubMed Central

    Rostovtseva, Tatiana K; Nestorovich, Ekaterina M; Bezrukov, Sergey M

    2002-01-01

    To understand the physics of polymer equilibrium and dynamics in the confines of ion channel pores, we study partitioning of poly(ethylene glycol)s (PEGs) of different molecular weights into the bacterial porin, OmpF. Thermodynamic and kinetic parameters of partitioning are deduced from the effects of polymer addition on ion currents through single OmpF channels reconstituted into planar lipid bilayer membranes. The equilibrium partition coefficient is inferred from the average reduction of channel conductance in the presence of PEG; rates of polymer exchange between the pore and the bulk are estimated from PEG-induced conductance noise. Partition coefficient as a function of polymer weight is best fitted by a "compressed exponential" with the compression factor of 1.65. This finding demonstrates that PEG partitioning into the OmpF channel pore has sharper dependence on polymer molecular weight than predictions of hard-sphere, random-flight, or scaling models. A 1360-Da polymer separates regimes of partitioning and exclusion. Comparison of its characteristic size with the size of a 2200-Da polymer previously found to separate these regimes for the alpha-toxin shows good agreement with the x-ray structural data for these channels. The PEG-induced conductance noise is compatible with the polymer mobility reduced inside the OmpF pore by an order of magnitude relatively to its value in bulk solution. PMID:11751305

  3. Safety Evaluation of Polyethylene Glycol (PEG) Compounds for Cosmetic Use

    PubMed Central

    Shin, Chan Young; Kim, Kyu-Bong

    2015-01-01

    Polyethylene glycols (PEGs) are products of condensed ethylene oxide and water that can have various derivatives and functions. Since many PEG types are hydrophilic, they are favorably used as penetration enhancers, especially in topical dermatological preparations. PEGs, together with their typically nonionic derivatives, are broadly utilized in cosmetic products as surfactants, emulsifiers, cleansing agents, humectants, and skin conditioners. The compounds studied in this review include PEG/PPG-17/6 copolymer, PEG-20 glyceryl triisostearate, PEG-40 hydrogenated castor oil, and PEG-60 hydrogenated castor oil. Overall, much of the data available in this review are on PEGylated oils (PEG-40 and PEG-60 hydrogenated castor oils), which were recommended as safe for use in cosmetics up to 100% concentration. Currently, PEG-20 glyceryl triisostearate and PEGylated oils are considered safe for cosmetic use according to the results of relevant studies. Additionally, PEG/PPG-17/6 copolymer should be further studied to ensure its safety as a cosmetic ingredient. PMID:26191379

  4. Fluoroalkylated polyethylene glycol as potential surfactant for perfluorocarbon emulsion.

    PubMed

    Peng, C A; Hsu, Y C

    2001-11-01

    So far, perfluorocarbon (PFC) emulsions have been manufactured based mainly on two surfactants, Pluronic F-68 and egg yolk phospholipids (EYP) for clinical use. However, they have been documented to induce inflammatory or allergic responses when PFC emulsions were injected into human bloodstream. The cause of these side effects is associated with the phagocytosis of emulsified PFC microparticles by cells such as macrophages. In order to lessen the side effects, it is logic to develop surfactants, which are more phagocytosis-resistant and biocompatible. In this study, a perfluoroalkylated polyethylene glycol (R(F)-PEG) surfactant was synthesized by reacting perfluorooctanoyl chloride (C7F15COCl) with PEG of molecular weigh 8000. Both R(F)-PEG 8000 and EYP were used to make PFC emulsions separately by an ultrasonic homogenizer. Individual PFC emulsions were then incubated with mouse macrophage J774A.1 cells to examine the degree of phagocytosis. From microscopic observation of cell morphology, our results showed that the process of phagocytosis was retarded to a large extend using the R(F)-PEG surfactant. We also harnessed 19F-NMR to quantitatively detect the amount of PFC emulsions phagocytosed by J774A.1 cells. 19F-NMR result was consistent with the qualitative microscopic observation aforementioned. PMID:11795633

  5. Micropallet arrays with poly(ethylene glycol) walls.

    PubMed

    Wang, Yuli; Salazar, Georgina To'a; Pai, Jeng-Hao; Shadpour, Hamed; Sims, Christopher E; Allbritton, Nancy L

    2008-05-01

    Arrays of releasable micropallets with surrounding walls of poly(ethylene glycol) (PEG) were fabricated for the patterning and sorting of adherent cells. PEG walls were fabricated between the SU-8 pallets using a simple, mask-free strategy. By utilizing the difference in UV-transmittance of glass and SU-8, PEG monomer was selectively photopolymerized in the space surrounding the pallets. Since the PEG walls are composed of a cross-linked structure, the stability of the walls is independent of the pallet array geometry and the properties of the overlying solution. Even though surrounded with PEG walls, the individual pallets were detached from the array by the mechanical force generated by a focused laser pulse, with a release threshold of 6 microJ. Since the PEG hydrogels are repellent to protein adsorption and cell attachment, the walls localized cell growth to the pallet top surface. Cells grown in the microwells formed by the PEG walls were released by detaching the underlying pallet. The released cells/pallets were collected, cultured and clonally expanded. The micropallet arrays with PEG walls provide a platform for performing single cell analysis and sorting on chip. PMID:18432343

  6. Optical clearing of skin tissue ex vivo with polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Tuchina, D. K.; Genin, V. D.; Bashkatov, A. N.; Genina, E. A.; Tuchin, V. V.

    2016-01-01

    Alterations of the optical and structural (weight, thickness, and square) parameters of skin caused by polyethylene glycol (PEG) with molecular weights of 300 and 400 Da were studied experimentally. The objects of the study were ex vivo skin samples of albino laboratory rats. Collimated transmittance of the skin was measured in the wavelength range 500-900 nm. As a result of exposure to the agents, an increase in the collimated transmittance and a decrease in weight, thickness, and square of skin samples were observed. Analysis of the kinetics of parameters alterations allowed us to measure the diffusion coefficient of the agents in the skin as (1.83 ± 2.22) × 10-6 and (1.70 ± 1.47) × 10-6 cm2/s for PEG-300 and PEG-400, respectively, and the rate of alterations of the structural parameters. The results obtained in this study can be used for the improvement of existing and development of new methods of noninvasive diagnostics and therapy of subcutaneous diseases.

  7. Immediate-type hypersensitivity to polyethylene glycols: a review.

    PubMed

    Wenande, E; Garvey, L H

    2016-07-01

    Polyethylene glycols (PEGs) or macrogols are polyether compounds widely used in medical and household products. Although generally considered biologically inert, cases of mild to life-threatening immediate-type PEG hypersensitivity are reported with increasing frequency. Nevertheless, awareness of PEG's allergenic potential remains low, due to a general lack of suspicion towards excipients and insufficient product labelling. Information on immediate-type reactions to PEG is limited to anecdotal reports, and the potential for PEG sensitization and cross-sensitization to PEGylated drugs and structurally related derivatives is likely underestimated. Most healthcare professionals have no knowledge of PEG and thus do not suspect PEG's as culprit agents in hypersensitivity reactions. In consequence, patients are at risk of misdiagnosis and commonly present with a history of repeated, severe reactions to a range of unrelated products in hospital and at home. Increased awareness of PEG prevalence, PEG hypersensitivity, and improved access to PEG allergy testing, should facilitate earlier diagnosis and reduce the risk of inadvertent re-exposure. This first comprehensive review provides practical information for allergists and other healthcare professionals by describing the clinical picture of 37 reported cases of PEG hypersensitivity since 1977, summarizing instances where PEG hypersensitivity should be considered and proposing an algorithm for diagnostic management. PMID:27196817

  8. Microfluidic Valves Made From Polymerized Polyethylene Glycol Diacrylate

    PubMed Central

    Rogers, Chad I.; Oxborrow, Joseph B.; Anderson, Ryan R.; Tsai, Long-Fang; Nordin, Gregory P.; Woolley, Adam T.

    2013-01-01

    Pneumatically actuated, non-elastomeric membrane valves fabricated from polymerized polyethylene glycol diacrylate (poly-PEGDA) have been characterized for temporal response, valve closure, and long-term durability. A ~100 ms valve opening time and a ~20 ms closure time offer valve operation as fast as 8 Hz with potential for further improvement. Comparison of circular and rectangular valve geometries indicates that the surface area for membrane interaction in the valve region is important for valve performance. After initial fabrication, the fluid pressure required to open a closed circular valve is ~50 kPa higher than the control pressure holding the valve closed. However, after ~1000 actuations to reconfigure polymer chains and increase elasticity in the membrane, the fluid pressure required to open a valve becomes the same as the control pressure holding the valve closed. After these initial conditioning actuations, poly-PEGDA valves show considerable robustness with no change in effective operation after 115,000 actuations. Such valves constructed from non-adsorptive poly-PEGDA could also find use as pumps, for application in small volume assays interfaced with biosensors or impedance detection, for example. PMID:24357897

  9. Intramolecular Hydrogen Bonds in Low-Molecular-Weight Polyethylene Glycol.

    PubMed

    Kozlowska, Mariana; Goclon, Jakub; Rodziewicz, Pawel

    2016-04-18

    We used static DFT calculations to analyze, in detail, the intramolecular hydrogen bonds formed in low-molecular-weight polyethylene glycol (PEG) with two to five repeat subunits. Both red-shifted O-H⋅⋅⋅O and blue-shifting C-H⋅⋅⋅O hydrogen bonds, which control the structural flexibility of PEG, were detected. To estimate the strength of these hydrogen bonds, the quantum theory of atoms in molecules was used. Car-Parrinello molecular dynamics simulations were used to mimic the structural rearrangements and hydrogen-bond breaking/formation in the PEG molecule at 300 K. The time evolution of the H⋅⋅⋅O bond length and valence angles of the formed hydrogen bonds were fully analyzed. The characteristic hydrogen-bonding patterns of low-molecular-weight PEG were described with an estimation of their lifetime. The theoretical results obtained, in particular the presence of weak C-H⋅⋅⋅O hydrogen bonds, could serve as an explanation of the PEG structural stability in the experimental investigation. PMID:26864943

  10. Coarse-grained models for aqueous polyethylene glycol solutions.

    PubMed

    Choi, Eunsong; Mondal, Jagannath; Yethiraj, Arun

    2014-01-01

    A new coarse-grained force field is developed for polyethylene glycol (PEG) in water. The force field is based on the MARTINI model but with the big multipole water (BMW) model for the solvent. The polymer force field is reparameterized using the MARTINI protocol. The new force field removes the ring-like conformations seen in simulations of short chains with the MARTINI force field; these conformations are not observed in atomistic simulations. We also investigate the effect of using parameters for the end-group that are different from those for the repeat units, with the MARTINI and BMW/MARTINI models. We find that the new BMW/MARTINI force field removes the ring-like conformations seen in the MARTINI models and has more accurate predictions for the density of neat PEG. However, solvent-separated-pairs between chain ends and slow dynamics of the PEG reflect its own artifacts. We also carry out fine-grained simulations of PEG with bundled water clusters and show that the water bundling can lead to ring-like conformations of the polymer molecules. The simulations emphasize the pitfalls of coarse-graining several molecules into one site and suggest that polymer-solvent systems might be a stringent test for coarse-grained force fields. PMID:24350686

  11. Enhanced toxicity and cellular uptake of methotrexate-conjugated nanoparticles in folate receptor-positive cancer cells by decorating with folic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate.

    PubMed

    Junyaprasert, Varaporn Buraphacheep; Dhanahiranpruk, Sirithip; Suksiriworapong, Jiraphong; Sripha, Kittisak; Moongkarndi, Primchanien

    2015-12-01

    Folic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS-FOL) decorated methotrexate (MTX)-conjugated nanoparticles were developed for targeted delivery of MTX to folate receptor-expressed tumor cells. The synthesis of TPGS-FOL followed 3-step process. Firstly, the terminal hydroxyl group of TPGS was converted to sulfonyl chloride using mesyl chloride in comparison with nosyl and tosyl chlorides. The highest conversion efficiency and yield were obtained by mesyl chloride due to the formation of higher reactive intermediate in a presence of triethylamine. Secondly, the substitution of sulfonyl group by sodium azide produced considerably high yield with conversion efficiency of over 90%. Lastly, the coupling reaction of azido-substituted TPGS and propargyl folamide by click reaction resulted in 96% conjugation efficiency without polymer degradation. To fabricate the folate receptor-targeted nanoparticles, 10 and 20%mol MTX-conjugated PEGylated poly(ϵ-caprolactone) nanoparticles were decorated with TPGS-FOL. The size and size distribution of MTX-conjugated nanoparticles relatively increased with %MTX. The MTX release from the nanoparticles was accelerated in acidic medium with an increase of %MTX but retarded in physiological pH medium. The decoration of TPGS-FOL onto the nanoparticles slightly enlarged the size and size distribution of the nanoparticles; however, it did not affect the surface charge. The cytotoxicity and cellular uptake of MCF-7 cells demonstrated that 10% MTX-conjugated nanoparticles and FOL-decorated nanoparticles possessed higher toxicity and uptake efficiency than 20% MTX-conjugated nanoparticles and undecorated nanoparticles, respectively. The results indicated that FOL-10% MTX-conjugated nanoparticles exhibited potential targeted delivery of MTX to folate receptor-expressed cancer cells. PMID:26433645

  12. Vorinostat with Sustained Exposure and High Solubility in Poly(ethylene glycol)-b-poly(DL-lactic acid) Micelle Nanocarriers: Characterization and Effects on Pharmacokinetics in Rat Serum and Urine

    PubMed Central

    Mohamed, Elham A.; Zhao, Yunqi; Meshali, Mahasen M.; Remsberg, Connie M.; Borg, Thanaa M.; Foda, Abdel Monem M.; Takemoto, Jody K.; Sayre, Casey; Martinez, Stephanie; Davies, Neal M.; Forrest, M. Laird

    2015-01-01

    The histone deacetylase inhibitor suberoylanilide hydroxamic acid, known as vorinostat, is a promising anti-cancer drug with a unique mode of action; however, it is plagued by low water solubility, low permeability, and suboptimal pharmacokinetics. In this study, poly(ethylene glycol)-b-poly(DL-lactic acid) (PEG-b-PLA) micelles of vorinostat were developed. Vorinostat’s pharmacokinetics in rats were investigated after intravenous (i.v.) (10 mg/kg) and oral (50 mg/kg) micellar administrations and compared to a conventional PEG400 solution and methylcellulose suspension. The micelles increased the aqueous solubility of vorinostat from 0.2 mg/ml to 8.15 ± 0.60 mg/ml and 10.24 ± 0.92 mg/ml at drug to nanocarrier ratios of 1:10 and 1:15, respectively. Micelles had nanoscopic mean diameters of 75.67 ± 7.57 nm and 87.33 ± 8.62 nm for 1:10 and 1:15 micelles, respectively, with drug loading capacities of 9.93 ± 0.21% and 6.91 ± 1.19 %, and encapsulation efficiencies of 42.74 ± 1.67% and 73.29 ± 4.78%, respectively. The micelles provided sustained exposure and improved pharmacokinetics characterized by a significant increase in serum half-life, area under curve, and mean residence time. The micelles reduced vorinostat clearance particularly after i.v. dosing. Thus, PEG-b-PLA micelles significantly improved the oral and intravenous pharmacokinetics and bioavailability of vorinostat, which warrants further investigation. PMID:22806441

  13. Separation of polyethylene glycols and amino-terminated polyethylene glycols by high-performance liquid chromatography under near critical conditions.

    PubMed

    Wei, Y-Z; Zhuo, R-X; Jiang, X-L

    2016-05-20

    The separation and characterization of polyethylene glycols (PEGs) and amino-substituted derivatives on common silica-based reversed-phase packing columns using isocratic elution is described. This separation is achieved by liquid chromatography under the near critical conditions (LCCC), based on the number of amino functional end groups without obvious effect of molar mass for PEGs. The mobile phase is acetonitrile in water with an optimal ammonium acetate buffer. The separation mechanism of PEG and amino-substituted PEG under the near LCCC on silica-based packing columns is confirmed to be ion-exchange interaction. Under the LCCC of PEG backbone, with fine tune of buffer concentration, the retention factor ratios for benzylamine and phenol in buffered mobile phases, α(benzylamine/phenol)-values, were used to assess the ion-exchange capacity on silica-based reversed-phase packing columns. To the best of our knowledge, this is the first report on separation of amino-functional PEGs independent of the molar mass by isocratic elution using common C18 or phenyl reversed-phase packing columns. PMID:27102303

  14. 40 CFR 721.10360 - 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol mono...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-(triethoxysilyl)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (generic). 721.10360... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene...

  15. 40 CFR 721.10360 - 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol mono...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-(triethoxysilyl)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (generic). 721.10360... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene...

  16. 40 CFR 721.10360 - 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol mono...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-(triethoxysilyl)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (generic). 721.10360... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene...

  17. Recent advances in crosslinking chemistry of biomimetic poly(ethylene glycol) hydrogels

    PubMed Central

    Lin, Chien-Chi

    2015-01-01

    The design and application of biomimetic hydrogels have become an important and integral part of modern tissue engineering and regenerative medicine. Many of these hydrogels are prepared from synthetic macromers (e.g., poly(ethylene glycol) or PEG) as they provide high degrees of tunability for matrix crosslinking, degradation, and modification. For a hydrogel to be considered biomimetic, it has to recapitulate key features that are found in the native extracellular matrix, such as the appropriate matrix mechanics and permeability, the ability to sequester and deliver drugs, proteins, and or nucleic acids, as well as the ability to provide receptor-mediated cell-matrix interactions and protease-mediated matrix cleavage. A variety of chemistries have been employed to impart these biomimetic features into hydrogel crosslinking. These chemistries, such as radical-mediated polymerizations, enzyme-mediated crosslinking, bio-orthogonal click reactions, and supramolecular assembly, may be different in their crosslinking mechanisms but are required to be efficient for gel crosslinking and ligand bioconjugation under aqueous reaction conditions. The prepared biomimetic hydrogels should display a diverse array of functionalities and should also be cytocompatible for in vitro cell culture and/or in situ cell encapsulation. The focus of this article is to review recent progress in the crosslinking chemistries of biomimetic hydrogels with a special emphasis on hydrogels crosslinked from poly(ethylene glycol)-based macromers. PMID:26029357

  18. Actively targeting D-α-tocopheryl polyethylene glycol 1000 succinate-poly(lactic acid) nanoparticles as vesicles for chemo-photodynamic combination therapy of doxorubicin-resistant breast cancer.

    PubMed

    Jiang, Di; Gao, Xiaoling; Kang, Ting; Feng, Xingye; Yao, Jianhui; Yang, Mengshi; Jing, Yixian; Zhu, Qianqian; Feng, Jingxian; Chen, Jun

    2016-02-01

    Drug resistance is the major reason for therapeutic failure during cancer treatment. Chemo-photodynamic combination therapy has potential to improve the treatment efficiency in drug-resistant cancers, but is limited by the incompatible physical properties of the photosensitizer with a chemo-drug and poor accumulation of both drugs into the inner areas of the tumor. Herein, a novel drug delivery system was designed by incorporating the photosensitizer, chlorine 6, chemically in the shell and the chemo-drug, doxorubicin, physically in the core of D-α-tocopheryl polyethylene glycol 1000 succinate-poly(lactic acid) (TPGS-PLA) nanoparticles with a targeting ligand, tLyp-1 peptide, decorated over the surface (tLyp-1-NP). This nanoparticle with a high drug loading capacity of both the photosensitizer and chemo-drug is expected to realize chemo-photodynamic combination therapy of drug-resistant cancer and simultaneously achieve the specific deep penetration and accumulation of drugs into the inner areas of tumor. tLyp-1-NP was prepared via a nanoprecipitation method and it exhibited a uniformly spherical morphology with a size of approximately 130 nm. After appropriate irradiation, tLyp-1-NP showed high cellular uptake and strong cytotoxicity in both human umbilical vein endothelial cells (HUVEC cells) and doxorubicin-resistant human breast adenocarcinoma cells (MCF-7/ADR cells) in vitro. After intravenous administration, compared with the unmodified NPs, tLyp-1-NP was found to have superior tumor targeting ability and more potent reversion of doxorubicin-resistant cancer. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and the hematoxylin and eosin staining of the treated tumors further demonstrated the anti-tumor efficacy of tLyp-1-NP in the presence of a laser. These observations collectively suggest the potential of tLyp-1-NP for the actively targeting chemo-photodynamic combination therapy of drug-resistant cancer. PMID:26785758

  19. Preparation, in vitro and in vivo evaluation of polymeric nanoparticles based on hyaluronic acid-poly(butyl cyanoacrylate) and D-alpha-tocopheryl polyethylene glycol 1000 succinate for tumor-targeted delivery of morin hydrate.

    PubMed

    Abbad, Sarra; Wang, Cheng; Waddad, Ayman Yahia; Lv, Huixia; Zhou, Jianping

    2015-01-01

    Herein, we describe the preparation of a targeted cellular delivery system for morin hydrate (MH), based on a low-molecular-weight hyaluronic acid-poly(butyl cyanoacrylate) (HA-PBCA) block copolymer. In order to enhance the therapeutic effect of MH, D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) was mixed with HA-PBCA during the preparation process. The MH-loaded HA-PBCA "plain" nanoparticle (MH-PNs) and HA-PBCA/TPGS "mixed" nanoparticles (MH-MNs) were concomitantly characterized in terms of loading efficiency, particle size, zeta potential, critical aggregation concentration, and morphology. The obtained MH-PNs and MH-MNs exhibited a spherical morphology with a negative zeta potential and a particle size less than 200 nm, favorable for drug targeting. Remarkably, the addition of TPGS resulted in about 1.6-fold increase in drug-loading. The in vitro cell viability experiment revealed that MH-MNs enhanced the cytotoxicity of MH in A549 cells compared with MH solution and MH-PNs. Furthermore, blank MNs containing TPGS exhibited selective cytotoxic effects against cancer cells without diminishing the viability of normal cells. In addition, the cellular uptake study indicated that MNs resulted in 2.28-fold higher cellular uptake than that of PNs, in A549 cells. The CD44 receptor competitive inhibition and the internalization pathway studies suggested that the internalization mechanism of the nanoparticles was mediated mainly by the CD44 receptors through a clathrin-dependent endocytic pathway. More importantly, MH-MNs exhibited a higher in vivo antitumor potency and induced more tumor cell apoptosis than did MH-PNs, following intravenous administration to S180 tumor-bearing mice. Overall, the results imply that the developed nanoparticles are promising vehicles for the targeted delivery of lipophilic anticancer drugs. PMID:25609946

  20. Preparation, in vitro and in vivo evaluation of polymeric nanoparticles based on hyaluronic acid-poly(butyl cyanoacrylate) and D-alpha-tocopheryl polyethylene glycol 1000 succinate for tumor-targeted delivery of morin hydrate

    PubMed Central

    Abbad, Sarra; Wang, Cheng; Waddad, Ayman Yahia; Lv, Huixia; Zhou, Jianping

    2015-01-01

    Herein, we describe the preparation of a targeted cellular delivery system for morin hydrate (MH), based on a low-molecular-weight hyaluronic acid-poly(butyl cyanoacrylate) (HA-PBCA) block copolymer. In order to enhance the therapeutic effect of MH, D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) was mixed with HA-PBCA during the preparation process. The MH-loaded HA-PBCA “plain” nanoparticle (MH-PNs) and HA-PBCA/TPGS “mixed” nanoparticles (MH-MNs) were concomitantly characterized in terms of loading efficiency, particle size, zeta potential, critical aggregation concentration, and morphology. The obtained MH-PNs and MH-MNs exhibited a spherical morphology with a negative zeta potential and a particle size less than 200 nm, favorable for drug targeting. Remarkably, the addition of TPGS resulted in about 1.6-fold increase in drug-loading. The in vitro cell viability experiment revealed that MH-MNs enhanced the cytotoxicity of MH in A549 cells compared with MH solution and MH-PNs. Furthermore, blank MNs containing TPGS exhibited selective cytotoxic effects against cancer cells without diminishing the viability of normal cells. In addition, the cellular uptake study indicated that MNs resulted in 2.28-fold higher cellular uptake than that of PNs, in A549 cells. The CD44 receptor competitive inhibition and the internalization pathway studies suggested that the internalization mechanism of the nanoparticles was mediated mainly by the CD44 receptors through a clathrin-dependent endocytic pathway. More importantly, MH-MNs exhibited a higher in vivo antitumor potency and induced more tumor cell apoptosis than did MH-PNs, following intravenous administration to S180 tumor-bearing mice. Overall, the results imply that the developed nanoparticles are promising vehicles for the targeted delivery of lipophilic anticancer drugs. PMID:25609946

  1. Distraction induced Enterogenesis: A unique mouse model using polyethylene glycol

    PubMed Central

    Okawada, Manabu; Maria, Haytham Mustafa; Teitelbaum, Daniel H.

    2011-01-01

    Background/Purpose Recent studies have demonstrated that the small intestine can be lengthened by applying mechanical forces to the bowel lumen – distraction-induced enterogenesis. However, the mechanisms which account for this growth are unknown, and might be best examined using a mouse model. The purpose of this study is to establish the feasibility of developing distractive-induced small bowel growth in mouse. Methods 12-week old C57BL/6J mice had a jejunal segment taken out of continuity, and distended with polyethylene glycol (PEG: 3350 KDa); this group was compared to a control group without stretching. Segment length and diameter were measured intra-operatively and after 5 days. Villus height, crypt depth, muscle thickness in the isolated segment were assessed. Rate of epithelial cell proliferation (5-bromo-2-deoxyuridine: BrdU incorporation) in crypt was also examined. The mucosal mRNA expression of targeted factors were performed to investigate potential mechanisms of which might lead to distraction-induced enterogenesis. Results At harvest, the PEG-stretch group showed a significant increase in length and diameter versus controls. Villus height, crypt depth and muscular layer thickness increased in the PEG group. The PEG group also showed significantly increased rates of epithelial cell proliferation versus controls. Real-time PCR showed a trend toward higher β-catenin and c-myc mRNA expression in the PEG stretched group; however, this difference was not statistically significant. Conclusions Radial distraction-induced enterogenesis with PEG is a viable method for increasing small intestinal length and diameter. This model may provide a new method for studying the mechanisms leading to distraction-induced enterogenesis. PMID:21605872

  2. Interaction between water and poly(vinylpyrrolidone) containing polyethylene glycol.

    PubMed

    Hamaura, T; Newton, J M

    1999-11-01

    Information on the interaction between water and polymers is indispensable for manufacturing solid dispersion of a drug by hot-melt extrusion because this interaction affects various properties of the water-polymer mixtures, such as their viscoelastic properties. In this study, poly(vinylpyrrolidone) K30 (PVP) containing 0%, 10%, and 20% poly(ethylene glycol) 400 (PEG) was used as model amorphous polymers. The interaction of water with these polymers was assessed by the evaluation of the glass transition temperature (Tg), the point on the isotherm corresponding to the weight of sorbed water required to form a complete monolayer on the solid surface (apparent Wm), and the maximal amount of nonfreezing water, which were measured by differential scanning calorimetry and water sorption isotherms. In all of the systems with a water content below a certain water fraction (0.1 for PVP, 0.12 for PVP-PEG 10%, and 0.16 for PVP-PEG 20%), the Tg values were successfully predicted using theoretical equations, whereas the experimental Tg values were higher than predicted for those with a water content above these water fraction levels. In addition, these values of water fraction are similar to the apparent W(m) values determined using the Guggenheim-Anderson-DeBoer (GAB) equation (0.110, 0.117, and 0.147 weight fraction of water for PVP, PVP-PEG 10%, and PVP-PEG 20%, respectively). Nonfreezing water is detected above 0.47, 0.49, and 0.51 weight fraction of water for PVP, PVP-PEG 10%, and PVP-PEG 20%, respectively. Miscibility between water and PVP or PVP-PEG seems to change according to the water content in the system. All parameters increase with the concentration of PEG in the sample. This may be explained by the fact that PEG has a larger number of polymer repeating units, which may therefore interact with water more than PVP. PMID:10564074

  3. Myocardial matrix-polyethylene glycol hybrid hydrogels for tissue engineering

    NASA Astrophysics Data System (ADS)

    Grover, Gregory N.; Rao, Nikhil; Christman, Karen L.

    2014-01-01

    Similar to other protein-based hydrogels, extracellular matrix (ECM) based hydrogels, derived from decellularized tissues, have a narrow range of mechanical properties and are rapidly degraded. These hydrogels contain natural cellular adhesion sites, form nanofibrous networks similar to native ECM, and are biodegradable. In this study, we expand the properties of these types of materials by incorporating poly(ethylene glycol) (PEG) into the ECM network. We use decellularized myocardial matrix as an example of a tissue specific ECM derived hydrogel. Myocardial matrix-PEG hybrids were synthesized by two different methods, cross-linking the proteins with an amine-reactive PEG-star and photo-induced radical polymerization of two different multi-armed PEG-acrylates. We show that both methods allow for conjugation of PEG to the myocardial matrix by gel electrophoresis and infrared spectroscopy. Scanning electron microscopy demonstrated that the hybrid materials still contain a nanofibrous network similar to unmodified myocardial matrix and that the fiber diameter is changed by the method of PEG incorporation and PEG molecular weight. PEG conjugation also decreased the rate of enzymatic degradation in vitro, and increased material stiffness. Hybrids synthesized with amine-reactive PEG had gelation rates of 30 min, similar to the unmodified myocardial matrix, and incorporation of PEG did not prevent cell adhesion and migration through the hydrogels, thus offering the possibility to have an injectable ECM hydrogel that degrades more slowly in vivo. The photo-polymerized radical systems gelled in 4 min upon irradiation, allowing 3D encapsulation and culture of cells, unlike the soft unmodified myocardial matrix. This work demonstrates that PEG incorporation into ECM-based hydrogels can expand material properties, thereby opening up new possibilities for in vitro and in vivo applications.

  4. A course-grained model for polyethylene glycol polymer

    SciTech Connect

    Nicholson, Don M; Wang, Qifei; Keffer, David J

    2011-01-01

    A coarse-grained (CG) model of polyethylene glycol (PEG) was developed and implemented in CG molecular dynamics (MD) simulations of PEG chains with degree of polymerization (DP) 20 and 40. In the model, two repeat units of PEG are grouped as one CG bead. Atomistic MD simulation of PEG chains with DP = 20 was first conducted to obtain the bonded structural probability distribution functions (PDFs) and nonbonded pair correlation function (PCF) of the CG beads. The bonded CG potentials are obtained by simple inversion of the corresponding PDFs. The CG nonbonded potential is parameterized to the PCF using both an inversion procedure based on the Ornstein-Zernike equation with the Percus-Yevick approximation (OZPY{sup -1}) and a combination of OZPY{sup -1} with the iterative Boltzmann inversion (IBI) method (OZPY{sup -1}+IBI). As a simple one step method, the OZPY{sup -1} method possesses an advantage in computational efficiency. Using the potential from OZPY{sup -1} as an initial guess, the IBI method shows fast convergence. The coarse-grained molecular dynamics (CGMD) simulations of PEG chains with DP = 20 using potentials from both methods satisfactorily reproduce the structural properties from atomistic MD simulation of the same systems. The OZPY{sup -1}+IBI method yields better agreement than the OZPY{sup -1} method alone. The new CG model and CG potentials from OZPY{sup -1}+IBI method was further tested through CGMD simulation of PEG with DP = 40 system. No significant changes are observed in the comparison of PCFs from CGMD simulations of PEG with DP = 20 and 40 systems indicating that the potential is independent of chain length.

  5. Detection of poly(ethylene glycol) residues from nonionic surfactants in surface water by1h and13c nuclear magnetic resonance spectrometry

    USGS Publications Warehouse

    Leenheer, J.A.; Wershaw, R. L.; Brown, P.A.; Noyes, T.I.

    1991-01-01

    ??? Poly(ethylene glycol) (PEG) residues were detected in organic solute isolates from surface water by 1H nuclear magnetic resonance spectrometry (NMR), 13C NMR spectrometry, and colorimetric assay. PEG residues were separated from natural organic solutes in Clear Creek, CO, by a combination of methylation and chromatographic procedures. The isolated PEG residues, characterized by NMR spectrometry, were found to consist of neutral and acidic residues that also contained poly(propylene glycol) moieties. The 1H NMR and the colorimetric assays for poly(ethylene glycol) residues were done on samples collected in the lower Mississippi River and tributaries between St. Louis, MO, and New Orleans, LA, in July-August and November-December 1987. Aqueous concentrations for poly(ethylene glycol) residues based on colorimetric assay ranged from undetectable to ???28 ??g/L. Concentrations based on 1H NMR spectrometry ranged from undetectable to 145 ??g/L.

  6. Detection of poly(ethylene glycol) residues from nonionic surfactants in surface water by sup 1 H and sup 13 C nuclear magnetic resonance spectrometry

    SciTech Connect

    Leenheer, J.A.; Wershaw, R.L.; Brown, P.A.; Noyes, T.I. )

    1991-01-01

    Poly(ethylene glycol) (PEG) residues were detected in organic solute isolates from surface water by {sup 1}H nuclear magnetic resonance spectrometry (NMR), {sup 13}C NMR spectrometry, and colorimetric assay. PEG residues were separated from natural organic solutes in Clear Creek, CO, by a combination of methylation and chromatographic procedures. The isolated PEG residues, characterized by NMR spectrometry, were found to consist of neutral and acidic residues that also contained poly(propylene glycol) moieties. The {sup 1}H NMR and the colorimetric assays for poly(ethylene glycol) residues were done on samples collected in the lower Mississippi River and tributaries between S. Louis, MO, and New Orleans, LA, in July-August and November-December 1987. Aqueous concentrations for poly(ethylene glycol) residues based on colorimetric assay ranged from undetectable to {approximately}28 {mu}g/L. Concentrations based on {sup 1}H NMR spectrometry ranged from undetectable to 145 {mu}g/L.

  7. Polyethylene glycol gold-nanoparticles: Facile nanostructuration of doxorubicin and its complex with DNA molecules for SERS detection

    NASA Astrophysics Data System (ADS)

    Spadavecchia, Jolanda; Perumal, Ramesh; Casale, Sandra; Krafft, Jean-Marc; Methivier, Christophe; Pradier, Claire-Marie

    2016-03-01

    We report the synthesis of dicarboxylic acid-terminated polyethylene-glycol (PEG)-gold nanoparticles by a simple one-step method, and their further use to form nanostructured surfaces for biomolecule immobilization. The synthesized nano-scale particles were conjugated with probe/target oligonucleotides in order to evaluate intercalation phenomenon in the presence of doxorubicin drug via surface enhanced Raman spectroscopy (SERS) analysis.

  8. Tumor Acidity-Induced Sheddable Polyethylenimine-Poly(trimethylene carbonate)/DNA/Polyethylene Glycol-2,3-Dimethylmaleicanhydride Ternary Complex for Efficient and Safe Gene Delivery.

    PubMed

    Zhao, Caiyan; Shao, Leihou; Lu, Jianqing; Deng, Xiongwei; Wu, Yan

    2016-03-16

    Amphiphilic PEI derivatives/DNA complexes are widely used for DNA delivery, but they are unstable in vivo and have cytotoxicity due to the excess cationic charge. PEGylation of cationic complexes can improve sterical stability and biocompatibility. However, PEGylation significantly inhibits cellular uptake and endosomal escape. In this work, sheddable ternary complexes were developed by coating a tumor acidity-sensitive β-carboxylic amide functionalized PEG layer on the binary complexes of amphiphilic cationic polyethylenimine-poly(trimethylene carbonate) nanoparticles/DNA (PEI-PTMC/DNA). Such sheddable ternary complexes markedly reduced their nonspecific interactions with serum protein in the bloodstream and obtained minimal cytotoxicity due to the protection of the PEG shell. At the tumor site, the PEG layer was deshielded by responding to the tumor acidic microenvironment and the positively charged complexes re-exposed that had higher affinity with negatively charged cell membranes. Meanwhile the positively charged complexes facilitated endosomal escape. Accordingly, this delivery system improved the biocompatibility of gene-loaded complexes and enhanced the gene transfection efficiency. Such PEGylated complexes with the ability to deshield the PEG layer at the target tissues hold great promise for efficient and safe gene delivery in vivo. PMID:26904916

  9. Norway spruce embryogenesis: changes in carbohydrate profile, structural development and response to polyethylene glycol.

    PubMed

    Hudec, Lukáš; Konrádová, Hana; Hašková, Anna; Lipavská, Helena

    2016-05-01

    Two unrelated, geographically distinct, highly embryogenic lines of Norway spruce (Picea abies (L.) Karst.) were analysed to identify metabolic traits characteristic for lines with good yields of high-quality embryos. The results were compared with corresponding characteristics of a poorly productive line (low embryo yield, scarce high-quality embryos). The following carbohydrate profiles and spectra during maturation, desiccation and germination were identified as promising characteristics for line evaluation: a gradual decrease in total soluble carbohydrates with an increasing sucrose : hexose ratio during maturation; accumulation of raffinose family oligosaccharides resulting from desiccation and their rapid degradation at the start of germination; and a decrease in sucrose, increase in hexoses and the appearance of pinitol with proceeding germination. We propose that any deviation from this profile in an embryonic line is a symptom of inferior somatic embryo development. We further propose that a fatty acid spectrum dominated by linoleic acid (18 : 2) was a common feature of healthy spruce somatic embryos, although it was quite different from zygotic embryos mainly containing oleic acid (18 : 1). The responses of the lines to osmotic stress were evaluated based on comparison of control (without osmoticum) and polyethylene glycol (PEG)-exposed (PEG 4000) variants. Although genetically distinct, both highly embryogenic lines responded in a very similar manner, with the only difference being sensitivity to high concentrations of PEG. At an optimum PEG concentration (3.75 and 5%), which was line specific, negative effects of PEG on embryo germination were compensated for by a higher maturation efficiency so that the application of PEG at an appropriate concentration improved the yield of healthy germinants per gram of initial embryonal mass and accelerated the process. Polyethylene glycol application, however, resulted in no improvement of the poorly

  10. Design, preparation and characterization of cyclic RGDfK peptide modified poly(ethylene glycol)-block-poly(lactic acid) micelle for targeted delivery.

    PubMed

    Li, Caixia; Wang, Wenlong; Xi, Yuewei; Wang, Jiexin; Chen, Jian-Feng; Yun, Jimmy; Le, Yuan

    2016-07-01

    Molecular targeted cancer therapy is a promising strategy to overcome the lack of specificity of anticancer drug. While the binding of c(RGDfK) (cyclic Arginine-Glycine-Aspartic acid-Phenylalanine-Lysine) to αvβ3 over-expressed on tumor cell has been validated, the underlying interaction remains poorly understood. In this work, docking calculation was applied to investigate the interactions between c(RGDfK)/c(RGDfK)-PEG and αvβ3. The calculated results indicated that c(RGDfK) interacted with αvβ3 mainly by electrostatic interaction, stabilization interaction, and hydrophobic interaction. Conjugation of PEG chain to the c(RGDfK) weakened the binding affinity of c(RGDfK) to αvβ3. Accordingly, docetaxel(DTX)-loaded target micelles (c(RGDfK)-PEG-PLA/PEG-PLA/DTX) were designed, characterized and evaluated using HeLa cells. In vitro release studies demonstrated both target and non-target micelles displayed almost the same profiles, which best fit in Ritger-Peppas model. Cellular uptake and MTT studies revealed that the target micelles with the presence of c(RGDfK) were more efficiently taken up by HeLa cells and significantly improved the cytotoxicity compared to that of non-target micelles. Cell inhibition rate of target micelles was improved by 20% after 24h. Our findings suggest that target micelles may be a potential anticancer drug delivery system in the treatment of integrin αvβ3 over-expressed on tumor cell. PMID:27127057

  11. Engineering Poly(ethylene glycol) Materials to Promote Cardiogenesis

    NASA Astrophysics Data System (ADS)

    Smith, Amanda Walker

    Heart failure is one of the leading causes of death worldwide, and the current costs of treatment put a significant economic burden on our societies. After an infarction, fibrotic tissue begins to form as part of the heart failure cascade. Current options to slow this process include a wide range of pharmaceutical agents, and ultimately the patient may require a heart transplant. Innovative treatment approaches are needed to bring down costs and improve quality of life. The possibility of regenerating or replacing damaged tissue with healthy cardiomyocytes is generating considerable excitement, but there are still many obstacles to overcome. First, while cell injections into the myocardium have demonstrated slight improvements in cardiac function, the actual engraftment of transplanted cells is very low. It is anticipated that improving engraftment will boost outcomes. Second, cellular differentiation and reprogramming protocols have not yet produced cells that are identical to adult cardiomyocytes, and immunogenicity continues to be a problem despite the advent of autologously derived induced pluripotent stem cells. This dissertation will explore biomaterials approaches to addressing these two obstacles. Tissue engineering scaffolds may improve cell engraftment by providing bioactive factors, preventing cell anoikis, and reducing cell washout by blood flow. Poly(ethylene glycol) (PEG) is often used as a coating to reduce implant rejection because it is highly resistant to protein adsorption. Because fibrosis of a material in contact with the myocardium could cause arrhythmias, PEG materials are highly relevant for cardiac tissue engineering applications. In Chapter 2, we describe a novel method for crosslinking PEG microspheres around cells to form a scaffold for tissue engineering. We then demonstrate that HL-1 cardiomyocyte viability and phenotype are retained throughout the fabrication process and during the first 7 weeks of culture. In the third chapter of the

  12. Effect of sodium chloride on solute-solvent interactions in aqueous polyethylene glycol-sodium sulfate two-phase systems.

    PubMed

    da Silva, Nuno R; Ferreira, Luisa A; Madeira, Pedro P; Teixeira, José A; Uversky, Vladimir N; Zaslavsky, Boris Y

    2015-12-18

    Partition behavior of eight small organic compounds and six proteins was examined in poly(ethylene glycol)-8000-sodium sulfate aqueous two-phase systems containing 0.215M NaCl and 0.5M osmolyte (sorbitol, sucrose, TMAO) and poly(ethylene glycol)-10000-sodium sulfate-0.215M NaCl system, all in 0.01M sodium phosphate buffer, pH 6.8. The differences between the solvent properties of the coexisting phases (solvent dipolarity/polarizability, hydrogen bond donor acidity, and hydrogen bond acceptor basicity) were characterized with solvatochromic dyes using the solvatochromic comparison method. Differences between the electrostatic properties of the phases were determined by analysis of partitioning of sodium salts of dinitrophenylated (DNP-) amino acids with aliphatic alkyl side-chain. The partition coefficients of all compounds examined (including proteins) were described in terms of solute-solvent interactions. The results obtained in the study show that solute-solvent interactions of nonionic organic compounds and proteins in polyethylene glycol-sodium sulfate aqueous two-phase system change in the presence of NaCl additive. PMID:26615710

  13. Poly(ethylene glycol)-polypeptide Copolymer Micelles for Therapeutic Agent Delivery.

    PubMed

    Cheng, Yilong

    2016-01-01

    Poly(ethylene glycol)-polypeptide (PEG-polypeptide) based polymeric micelles as therapeutic agent carriers have received considerable interest due to their advanced achievements in clinical trials. Polypeptides not only show well-defined secondary structure (alfa-helix and beta-sheet) and good biocompatibility, but can also be functionalized with various groups by direct N-carboxyanhydrides (NCAs) polymerization or further modification. Additionally, the ionizable side chains enable them to deliver diverse therapeutic agents, such as negative nucleic acid and positive doxorubicin. In this review, we firstly summarized the synthetic methods of amphiphilic copolymers PEG-polypeptide, and emphatically discussed recent progress on their applications as nanocarriers for therapeutic agents from following aspects: PEG-nonionic polypeptide copolymer micelles, PEG-anionic polypeptide micelles, and PEGcationic polypeptide micelles. PMID:26696015

  14. Highly conductive polymer electrolyte membranes modified with polyethylene glycol-bis-carbamate

    NASA Astrophysics Data System (ADS)

    Fu, Guopeng; Dempsey, Janel; Kyu, Thein

    By virtue of its non-flammability and chemical stability, polyethylene glycol (PEG) networks have shown potential application in all solid-state polymer electrolyte membranes (PEM). However, room temperature ionic conductivity of these PEG based PEMs is inherently low. Plasticization of these PEMs is needed to improve the ionic conductivity. It was demonstrated by this group that small-molecule plasticizers such as succinonitrile, ethylene carbonate, or urea-carbamate can boost ionic conductivity of solid-state polymer electrolyte membranes. Polyethylene glycol bis-carbamate (PEGBC) was synthesized via condensation reaction of polyethylene glycol diamine and ethylene carbonate. The PEGBC modified PEM has shown higher ionic conductivity relative to the unmodified PEM. Moreover, PEGBC modified PEM has a better thermal stability relative to ethylene carbonate based liquid electrolyte with enhanced ionic conductivity. Supported by NSF-DMR 1161070, 1502543 and REU 1359321.

  15. Sorption of adamantanes on polyethylene glycol-modified graphitized thermal soot

    NASA Astrophysics Data System (ADS)

    Yashkin, S. N.; Ageeva, Yu. A.

    2014-04-01

    The thermodynamic characteristics of sorption of adamantane and its functional derivatives on graphitized thermal soot (GTS) modified with polyethylene glycol Carbowax 20M were determined by equilibrium gas chromatography. The resulting thermodynamic characteristics were analyzed and compared with the data measured for adamantanes on the surface of nonmodified GTS and polyethylene glycol deposited on an inert substrate. The solid carbon substrate was shown to affect the character of intermolecular interactions in the GTS-modifier system and the retention of framework compounds under the conditions of gas, liquid, and solid-state chromatography.

  16. Microgels of polyaspartamide and poly(ethylene glycol) derivatives obtained by γ-irradiation

    NASA Astrophysics Data System (ADS)

    Pitarresi, Giovanna; Licciardi, Mariano; Craparo, Emanuela Fabiola; Calderaro, Elio; Spadaro, Giuseppe; Giammona, Gaetano

    2002-09-01

    The copolymer PHG based on α, β-poly( N-2-hydroxyethyl)- DL-aspartamide (PHEA) functionalized with glycidyl methacrylate has been exposed in aqueous solution to a γ-ray source at different irradiation doses (2, 2.5 and 3.5 kGy), alone or in combination with poly(ethylene glycol)dimethacrylate (PEGDMA) or poly(ethylene glycol)diacrylate (PEGDA). The irradiation produces microgel systems that have been characterized by viscosity measurements. Lyophilization of microgels gives rise to samples able to swell instantaneously in water whereas their treatment with acetone produces swellable microparticles that have been characterized.

  17. Green polymer chemistry VIII: synthesis of halo-ester-functionalized poly(ethylene glycol)s via enzymatic catalysis.

    PubMed

    Castano, Marcela; Seo, Kwang Su; Kim, Eun Hye; Becker, Matthew L; Puskas, Judit E

    2013-09-01

    Halo-ester-functionalized poly(ethylene glycol)s (PEGs) are successfully prepared by the transesterification of alkyl halo-esters with PEGs using Candida antarctica lipase B (CALB) as a biocatalyst under the solventless conditions. Transesterifications of chlorine, bromine, and iodine esters with tetraethylene glycol monobenzyl ether (BzTEG) are quantitative in less than 2.5 h. The transesterification of halo-esters with PEGs are complete in 4 h. (1) H and (13) C NMR spectroscopy with MALDI-ToF and ESI mass spectrometry confirm the structure and purity of the products. This method provides a convenient and "green" process to effectively produce halo-ester PEGs. PMID:23877930

  18. Hydrophilic polysulfone film prepared from polyethylene glycol monomethylether via coupling graft

    NASA Astrophysics Data System (ADS)

    Du, Ruikui; Gao, Baojiao; Li, Yanbin

    2013-06-01

    In the presence of acid-acceptor Na2CO3, the nucleophilic substitution between chloromethylated polysulfone (CMPSF) and polyethylene glycol monomethylether (PEGME) was conducted. Polyethylene glycol (PEG) was coupling-grafted onto the side chains of polysulfone (PSF) so that the graft copolymer PSF-g-PEG was prepared and the hydrophilic modification of polysulfone membrane material was realized. The chemical structure of PSF-g-PEG was characterized by FTIR and 1H NMR. The influence of the main factors on the coupling graft reaction was investigated. The water static contact angle of PSF-g-PEG membrane was determined and its property of resisting protein pollution was examined by using bovine serum albumin (BSA) as a model protein. The experimental results show that the coupling graft reaction between CMPSF and PEGME can proceed successfully, and the reaction of chloromethyl groups of CMPSF with the hydroxyl end groups of PEGME is a typical SN1 nucleophilic substitution reaction. The polarity of the solvents and the reaction temperature greatly influence the reaction. The suitable solvent is dimethyl acetamide with stronger polarity and 70 °C is a suitable reaction temperature. After reaction of 36 h, the grafting degree of PEG can reach 48 g/100 g and the product yield is about 73.6%. The contact angle of PSF-g-PEG membrane declines rapidly with the increase of PEG grafting degree, displaying the obvious enhancement of the hydrophilicity. The adsorption capacity of BSA on PSF-g-PEG membrane decreases remarkably with the increase of PEG grafting degree, showing excellent antifouling ability of PSF-g-PEG membrane for proteins.

  19. Hepatocyte-targeting gene transfer mediated by galactosylated poly(ethylene glycol)-graft-polyethylenimine derivative

    PubMed Central

    Wang, Yuqiang; Su, Jing; Cai, Wenwei; Lu, Ping; Yuan, Lifen; Jin, Tuo; Chen, Shuyan; Sheng, Jing

    2013-01-01

    Biscarbamate cross-linked polyethylenimine derivative (PEI-Et) has been reported as a novel nonviral vector for efficient and safe gene transfer in our previous work. However, it had no cell-specificity. To achieve specific delivery of genes to hepatocytes, galactosylated poly(ethylene glycol)-graft-polyethylenimine derivative (GPE) was prepared through modification of PEI-Et with poly(ethylene glycol) and lactobionic acid, bearing a galactose group as a hepatocyte-targeting moiety. The composition of GPE was characterized by proton nuclear magnetic resonance. The weight-average molecular weight of GPE measured with a gel permeation chromatography instrument was 9489 Da, with a polydispersity of 1.44. GPE could effectively condense plasmid DNA (pDNA) into nanoparticles. Gel retardation assay showed that GPE/pDNA complexes were completely formed at weigh ratios (w/w) over 3. The particle size of GPE/pDNA complexes was 79–100 nm and zeta potential was 6–15 mV, values which were appropriate for cellular uptake. The morphology of GPE/pDNA complexes under atomic force microscopy appeared spherical and uniform in size, with diameters of 53–65 nm. GPE displayed much higher transfection efficiency than commercially available PEI 25 kDa in BRL-3A cell lines. Importantly, GPE showed good hepatocyte specificity. Also, the polymer exhibited significantly lower cytotoxicity compared to PEI 25 kDa at the same concentration or weight ratio in BRL-3A cell lines. To sum up, our results indicated that GPE might carry great potential in safe and efficient hepatocyte-targeting gene delivery. PMID:23576866

  20. Hepatocyte-targeting gene transfer mediated by galactosylated poly(ethylene glycol)-graft-polyethylenimine derivative.

    PubMed

    Wang, Yuqiang; Su, Jing; Cai, Wenwei; Lu, Ping; Yuan, Lifen; Jin, Tuo; Chen, Shuyan; Sheng, Jing

    2013-01-01

    Biscarbamate cross-linked polyethylenimine derivative (PEI-Et) has been reported as a novel nonviral vector for efficient and safe gene transfer in our previous work. However, it had no cell-specificity. To achieve specific delivery of genes to hepatocytes, galactosylated poly(ethylene glycol)-graft-polyethylenimine derivative (GPE) was prepared through modification of PEI-Et with poly(ethylene glycol) and lactobionic acid, bearing a galactose group as a hepatocyte-targeting moiety. The composition of GPE was characterized by proton nuclear magnetic resonance. The weight-average molecular weight of GPE measured with a gel permeation chromatography instrument was 9489 Da, with a polydispersity of 1.44. GPE could effectively condense plasmid DNA (pDNA) into nanoparticles. Gel retardation assay showed that GPE/pDNA complexes were completely formed at weigh ratios (w/w) over 3. The particle size of GPE/pDNA complexes was 79-100 nm and zeta potential was 6-15 mV, values which were appropriate for cellular uptake. The morphology of GPE/pDNA complexes under atomic force microscopy appeared spherical and uniform in size, with diameters of 53-65 nm. GPE displayed much higher transfection efficiency than commercially available PEI 25 kDa in BRL-3A cell lines. Importantly, GPE showed good hepatocyte specificity. Also, the polymer exhibited significantly lower cytotoxicity compared to PEI 25 kDa at the same concentration or weight ratio in BRL-3A cell lines. To sum up, our results indicated that GPE might carry great potential in safe and efficient hepatocyte-targeting gene delivery. PMID:23576866

  1. Platelet responses to dynamic biomaterial surfaces with different poly(ethylene glycol) and polyrotaxane molecular architectures constructed on gold substrates.

    PubMed

    Kakinoki, Sachiro; Yui, Nobuhiko; Yamaoka, Tetsuji

    2013-11-01

    Four different dynamic biomaterial surfaces with different molecular architectures were prepared using two hydrophilic polymers: poly(ethylene glycol) and polyrotaxanes containing α-cyclodextrin. Either one or both terminals of the poly(ethylene glycol) or polyrotaxanes were immobilized onto a gold substrate via Au-S bonds, resulting in poly(ethylene glycol)-graft, polyrotaxanes-graft, poly(ethylene glycol)-loop, and polyrotaxanes-loop structures. Human platelet adhesion was suppressed more effectively on the graft surfaces than on the loop surfaces for both poly(ethylene glycol) and polyrotaxanes due to the high mobility of graft polymer chains with a free terminal. Moreover, the platelets adhered to the polyrotaxane surfaces much less than the poly(ethylene glycol) surfaces, possibly because of the mobile nature of the α-cyclodextrin molecules that were threaded on the poly(ethylene glycol) chain. Actin filament assembly in adherent platelets was also greatly prevented on the poly(ethylene glycol)/polyrotaxanes-graft surfaces in comparison with the corresponding loop surfaces. A clear correlation between the numbers and areas of adherent platelets on these surfaces suggests that platelet adhesion and activation were dominated by the platelet GPIIb/IIIa-adsorbed fibrinogen interaction. These results indicate that both of the different modes of dynamic features, sliding/rotation of α-cyclodextrin and polymer chain mobility, effectively suppressed platelet adhesion in spite of the similar hydrophilicity. This research affords a novel chemical strategy for designing hemocompatible biomaterial surfaces. PMID:23048065

  2. 40 CFR 721.10472 - 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10472 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products. (a) Chemical substance and... with epichlorohydrin-polyethylene glycol reaction products. 721.10472 Section 721.10472 Protection...

  3. 40 CFR 721.10472 - 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10472 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products. (a) Chemical substance and... with epichlorohydrin-polyethylene glycol reaction products. 721.10472 Section 721.10472 Protection...

  4. Polyethylene glycol binding alters human telomere G-quadruplex structure by conformational selection

    PubMed Central

    Buscaglia, Robert; Miller, M. Clarke; Dean, William L.; Gray, Robert D.; Lane, Andrew N.; Trent, John O.; Chaires, Jonathan B.

    2013-01-01

    Polyethylene glycols (PEGs) are widely used to perturb the conformations of nucleic acids, including G-quadruplexes. The mechanism by which PEG alters G-quadruplex conformation is poorly understood. We describe here studies designed to determine how PEG and other co-solutes affect the conformation of the human telomeric quadruplex. Osmotic stress studies using acetonitrile and ethylene glycol show that conversion of the ‘hybrid’ conformation to an all-parallel ‘propeller’ conformation is accompanied by the release of about 17 water molecules per quadruplex and is energetically unfavorable in pure aqueous solutions. Sedimentation velocity experiments show that the propeller form is hydrodynamically larger than hybrid forms, ruling out a crowding mechanism for the conversion by PEG. PEGs do not alter water activity sufficiently to perturb quadruplex hydration by osmotic stress. PEG titration experiments are most consistent with a conformational selection mechanism in which PEG binds more strongly to the propeller conformation, and binding is coupled to the conformational transition between forms. Molecular dynamics simulations show that PEG binding to the propeller form is sterically feasible and energetically favorable. We conclude that PEG does not act by crowding and is a poor mimic of the intranuclear environment, keeping open the question of the physiologically relevant quadruplex conformation. PMID:23804761

  5. Controlling microencapsulation and release of micronized proteins using poly(ethylene glycol) and electrospraying.

    PubMed

    Bock, Nathalie; Dargaville, Tim R; Woodruff, Maria A

    2014-07-01

    The fabrication of tailored microparticles for delivery of therapeutics is a challenge relying upon a complex interplay between processing parameters and materials properties. The emerging use of electrospraying allows better tailoring of particle morphologies and sizes than current techniques, critical to reproducible release profiles. While dry encapsulation of proteins is essential for the release of active therapeutics from microparticles, it is currently uncharacterized in electrospraying. To this end, poly(ethylene glycol) (PEG) was assessed as a micronizing and solubilizing agent for dry protein encapsulation and release from electrosprayed particles made from polycaprolactone (PCL). The physical effect of PEG in protein-loaded poly(lactic-co-glycolic acid) (PLGA) particles was also studied, for comparison. The addition of 5-15 wt% PEG 6 kDa or 35 kDa resulted in reduced PCL particle sizes and broadened distributions, which could be improved by tailoring the electrospraying processing parameters, namely by reducing polymer concentration and increasing flow rate. Upon micronization, protein particle size was reduced to the micrometer domain, resulting in homogenous encapsulation in electrosprayed PCL microparticles. Microparticle size distributions were shown to be the most determinant factor for protein release by diffusion and allowed specific control of release patterns. PMID:24657821

  6. Actively targeting d-α-tocopheryl polyethylene glycol 1000 succinate-poly(lactic acid) nanoparticles as vesicles for chemo-photodynamic combination therapy of doxorubicin-resistant breast cancer

    NASA Astrophysics Data System (ADS)

    Jiang, Di; Gao, Xiaoling; Kang, Ting; Feng, Xingye; Yao, Jianhui; Yang, Mengshi; Jing, Yixian; Zhu, Qianqian; Feng, Jingxian; Chen, Jun

    2016-01-01

    Drug resistance is the major reason for therapeutic failure during cancer treatment. Chemo-photodynamic combination therapy has potential to improve the treatment efficiency in drug-resistant cancers, but is limited by the incompatible physical properties of the photosensitizer with a chemo-drug and poor accumulation of both drugs into the inner areas of the tumor. Herein, a novel drug delivery system was designed by incorporating the photosensitizer, chlorine 6, chemically in the shell and the chemo-drug, doxorubicin, physically in the core of d-α-tocopheryl polyethylene glycol 1000 succinate-poly(lactic acid) (TPGS-PLA) nanoparticles with a targeting ligand, tLyp-1 peptide, decorated over the surface (tLyp-1-NP). This nanoparticle with a high drug loading capacity of both the photosensitizer and chemo-drug is expected to realize chemo-photodynamic combination therapy of drug-resistant cancer and simultaneously achieve the specific deep penetration and accumulation of drugs into the inner areas of tumor. tLyp-1-NP was prepared via a nanoprecipitation method and it exhibited a uniformly spherical morphology with a size of approximately 130 nm. After appropriate irradiation, tLyp-1-NP showed high cellular uptake and strong cytotoxicity in both human umbilical vein endothelial cells (HUVEC cells) and doxorubicin-resistant human breast adenocarcinoma cells (MCF-7/ADR cells) in vitro. After intravenous administration, compared with the unmodified NPs, tLyp-1-NP was found to have superior tumor targeting ability and more potent reversion of doxorubicin-resistant cancer. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and the hematoxylin and eosin staining of the treated tumors further demonstrated the anti-tumor efficacy of tLyp-1-NP in the presence of a laser. These observations collectively suggest the potential of tLyp-1-NP for the actively targeting chemo-photodynamic combination therapy of drug-resistant cancer.Drug resistance is the

  7. 21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyethylene glycol (mean molecular weight 200-9,500). 172.820 Section 172.820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR...

  8. 21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyethylene glycol (mean molecular weight 200-9,500). 172.820 Section 172.820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR...

  9. One step synthesis of C-dots by microwave mediated caramelization of poly(ethylene glycol).

    PubMed

    Jaiswal, Amit; Ghosh, Siddhartha Sankar; Chattopadhyay, Arun

    2012-01-11

    A rapid, simple and one step microwave mediated method for synthesizing C-dots using poly(ethylene glycol) (PEG) as a precursor and passivating agent is reported. The C-dots possessed low cytotoxicity, were amenable to separation by electrophoresis, photostable and entered cancer cells, making them suitable candidates for bioimaging and biolabelling. PMID:22075768

  10. Molar Mass and Second Virial Coefficient of Polyethylene Glycol by Vapor Pressure Osmometry

    ERIC Educational Resources Information Center

    Schwinefus, Jeffrey J.; Checkal, Caleb; Saksa, Brian; Baka, Nadia; Modi, Kalpit; Rivera, Carlos

    2015-01-01

    In this laboratory experiment, students determine the number-average molar masses and second virial coefficients of polyethylene glycol (PEG) polymers ranging in molar mass from 200 to 1500 g mol[superscript -1] using vapor pressure osmometry (VPO). Students assess VPO in relation to accurate molar mass calculations of PEG polymers. Additionally,…

  11. Importance of poly(ethylene glycol) conformation for the synthesis of silver nanoparticles in aqueous solution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the formation of silver nanoparticles (NPs) using silver nitrate in a poly(ethylene glycol) (PEG) aqueous solution, which acts as both a reducing and stabilizing agent, the PEG chain structure was found to play a significant role. Even though PEG 100 (100 kg/mol) has limited reducing sites of hyd...

  12. Development of biodegradable and injectable macromers based on poly(ethylene glycol) and diacid monomers.

    PubMed

    Kim, Jinku; Yaszemski, Michael J; Lu, Lichun

    2009-09-15

    Novel biodegradable injectable poly(ethylene glycol)-(PEG) based macromers were synthesized by reacting low-molecular weight PEG (MW: 200) and dicarboxylic acids such as sebacic acid or terephthalic acid. Chemical structures of the resulting polymers were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy characterizations. Differential scanning calorimetry (DSC) showed that these polymers were completely amorphous above room temperature. After photopolymerization, dynamic elastic shear modulus of the crosslinked polymers was up to 1.5 MPa and compressive modulus was up to 2.2 MPa depending on the polymer composition. The in vitro degradation study showed that mass losses of these polymers were gradually decreased over 23 weeks of period in simulated body fluid. By incorporating up to 30 wt % of 2-hydroxyethyl methylmethacrylate (HEMA) into the crosslinking network, the dynamic elastic modulus and compressive modulus was significantly increased up to 7.2 and 3.2 MPa, respectively. HEMA incorporation also accelerated the degradation as indicated by substantially higher mass loss of up to 27% after 20 weeks of incubation. Cytocompatability studies using osteoblasts and neural cells revealed that cell metabolic activity on these polymers with or without HEMA was close to the control tissue culture polystyrene. The PEG-based macromers developed in this study may be useful as scaffolds or cell carriers for tissue engineering applications. PMID:18655146

  13. Carbohydrate-mediated polyethylene glycol conjugation of TSH improves its pharmacological properties.

    PubMed

    Park, Anna; Honey, Denise M; Hou, Lihui; Bird, Julie J; Zarazinski, Christine; Searles, Michelle; Braithwaite, Christian; Kingsbury, Jonathan S; Kyazike, Josephine; Culm-Merdek, Kerry; Greene, Ben; Stefano, James E; Qiu, Huawei; McPherson, John M; Pan, Clark Q

    2013-03-01

    Thyrogen (thyrotropin alfa for injection), recombinant human TSH (rhTSH), has been successfully used to enhance diagnostic radioiodine scanning and thyroglobulin testing in the follow-up of patients with thyroid cancer and as an adjunctive treatment for radioiodine thyroid remnant ablation. However, the short half-life of rhTSH in the circulation requires a multidose regimen. We developed novel sialic acid-mediated and galactose-mediated conjugation chemistries for targeting polyethylene glycol (PEG) to the three N-linked glycosylation sites on the protein, to prolong plasma half-life by eliminating kidney filtration and potential carbohydrate-mediated clearance. Conjugates of different PEG sizes and copy numbers were screened for reaction yield, TSH receptor binding, and murine phamacokinetics/pharmacodynamics studies. The best performing of these products, a 40-kDa mono-PEGylated sialic acid-mediated conjugate, exhibited a 3.5-fold longer duration of action than rhTSH in rats, as a 5-fold lower affinity was more than compensated by a 23-fold extension of circulation half-life. Biochemical characterization confirmed conjugation through the sialic acids. Correlation of PEG distribution on the three N-linked glycosylation sites and the PEG effect on receptor binding supported the previously reported structure-function relationship of rhTSH glycosylation. This long-acting rhTSH has the potential to significantly improve patient convenience and provider flexibility while reducing potential side effects associated with a sudden elevation of serum TSH. PMID:23389953

  14. Biodegradable Poly(Ethylene Glycol) Hydrogels Based on a Self-Elimination Degradation Mechanism

    PubMed Central

    Deshmukh, Manjeet; Singh, Yashveer; Gunaseelan, Simi; Gao, Dayuan; Stein, Stanley; Sinko, Patrick J.

    2010-01-01

    Two vinyl sulfone functionalized crosslinkers were developed for the purpose of preparing degradable poly(ethylene glycol) (PEG) hydrogels (EMXL and GABA-EMXL hydrogels). A self-elimination degradation mechanism in which an N-terminal residue of a glutamine is converted to pyroglutamic acid with subsequent release of diamino PEG (DAP) is proposed. The hydrogels were formed via Michael addition by mixing degradable or nondegradable crosslinkers and copolymer {4% w/v; poly[PEG-alt-poly(mercapto-succinic acid)]} at room temperature in phosphate buffer (PB, pH=7.4). Hydrogel degradation was characterized by assessing diamino PEG release and examining morphological changes as well as the swelling and weight loss ratio under physiological conditions (37 °C). Degradation of EMXL and GABA-EMXL hydrogels occurred by surface erosion (confirmed by SEM). GABA-EMXL degradation was significantly faster (~3-fold) than EMXL; however, the degradation of both hydrogels in mouse plasma was 12-times slower than in PBS. The slower degradation rate in plasma as compared to buffer is consistent with the presence of γ-glutamyltransferase, γ-glutamylcyclotransferase and/or glutaminyl cyclase (QC), which have been shown to suppress pyroglutamic acid formation. The current studies suggest that EMXL and GABA-EMXL hydrogels may have biomedical applications where 1 to 2 week degradation timeframes are optimal. PMID:20561680

  15. Surface patterned pH-sensitive fluorescence using β-cyclodextrin functionalized poly(ethylene glycol).

    PubMed

    Kim, Sung Han; Sharker, Shazid Md; In, Insik; Park, Sung Young

    2016-08-20

    This paper reports the development of a pH-responsive molecular pattern that shows specific and selective affinity for particular host-guest interactions, and its use as a pH fluorescent sensor. The pH-responsive boronate ester is formed via interactions between the diol group of β-cyclodextrin (CD) and phenylboronic acid of poly(ethylene glycol), and is strategically designed to allow reversible formation of a molecular lining pattern. Printing on a versatile substrate provides a method to monitor the positioning of different molecules by using a pH-responsive boronate ester, allowing specific host-guest interactions on any surface. Confocal laser scanning microscopy, fluorescence spectroscopy, and (1)H NMR results indicate that the assembled CD monolayer can be removed by washing with an acidic pH buffer, demonstrating the presence of a boronate ester connective bridge, which is acid labile. Therefore, visualization of the pH-responsive fluorescence sensor using a rhodamine-CD complex allows straightforward discrimination between different molecules on any substrate, thus facilitating application of this sensor in clinical diagnostics and environmental monitoring. PMID:27178950

  16. Permeabilization of ultraviolet-irradiated chinese hamster cells with polyethylene glycol and introduction of ultraviolet endonuclease from Micrococcus luteus

    SciTech Connect

    Yarosh, D.B.; Setlow, R.B.

    1981-03-01

    Chinese hamster V-79 cells were made permeable by treatment with polyethylene glycol and then incubated with a Micrococcus luteus extract containing ultraviolet-specific endonuclease activity. This treatment introduced nicks in irradiated, but not in unirradiated, deoxyribonucleic acid. The nicks remained open for at least 3 h; there was no loss of endonuclease-sensitive sites, and no excision of dimers as measured by chromatography was detected. In addition, there was no increase in ultraviolet resistance in treated cells. This suggests that the absence of a significant amount of excision repair in rodent cells is due to the lack of both incision and excision capacity.

  17. Synergistic effect of polyethylene glycol with arginine on the prevention of heat-induced aggregation of lysozyme

    NASA Astrophysics Data System (ADS)

    Tomita, S.; Hamada, H.; Nagasaki, Y.; Shiraki, K.

    2008-03-01

    . Arginine (Arg) is a commonly used additive to prevent protein aggregation and inactivation in denaturing solutions. This paper presents new findings on the synergistic effect on the prevention of heat-induced aggregation of lysozyme using Arg in combination with polyethylene glycol (PEG). The synergistic enhancement was observed in the presence of Arg with amphiphilic polymers, such as PEG6000, PEG20000, and poly(vinyl pyrrolidone), while it was not observed with hydrophilic polymers, such as PEG200, Poly(acrylic acid), poly(vinyl alcohol), dextran, and Ficoll 70.

  18. Effect of Short Chain Poly(ethylene glycol)s on the Hydration Structure and Dynamics around Human Serum Albumin.

    PubMed

    Samanta, Nirnay; Luong, Trung Quan; Das Mahanta, Debasish; Mitra, Rajib Kumar; Havenith, Martina

    2016-01-26

    We report the changes in the hydration dynamics around a globular protein, human serum albumin (HSA), in the presence of two short chain crowding agents, namely poly(ethylene glycol)s (PEG 200 and 400). The change in the network water structure is investigated using FTIR spectroscopy in the far-infrared (FIR) frequency range. Site specific changes are obtained by time-resolved fluorescence spectroscopic technique using the intrinsic fluorophore tryptophan (Trp214) of HSA. The collective hydration dynamics of HSA in the presence of PEG molecules are obtained using terahertz (THz) time domain spectroscopy (TTDS) and high intensity p-Ge THz measurements. Our study affirms a considerable perturbation of HSA hydration beyond a critical concentration of PEG. PMID:26720549

  19. Pressure and temperature dependence of excess enthalpies of methanol + tetraethylene glycol dimethyl ether and methanol + polyethylene glycol dimethyl ether 250

    SciTech Connect

    Lopez, E.R.; Coxam, J.Y.; Fernandez, J.; Grolier, J.P.E.

    1999-12-01

    The excess molar enthalpies at 323.15 K, 373.15 K, and 423.15 K, at 8 MPa, are reported for the binary mixtures methanol + tetraethylene glycol dimethyl ether (TEGDME) and methanol + poly(ethylene glycol) dimethyl ether 250 (PEGDME 250). Excess molar enthalpies were determined with a Setaram C-80 calorimeter equipped with a flow mixing cell. For both systems, the excess enthalpies are positive over the whole composition range, increasing with temperature. The H{sup E}(x) curves are slightly asymmetrical, and their maxima are skewed toward the methanol-rich region. The excess enthalpies slightly change with the pressure, the sign of this change being composition-dependent. In the case of mixtures with TEGDME, the experimental H{sup E} values have been compared with those predicted with the Gmehling et al. version of UNIFAC (Dortmund) and the Nitta-Chao and DISQUAC group contribution models.

  20. Ultrasound responsive block copolymer micelle of poly(ethylene glycol)-poly(propylene glycol) obtained through click reaction.

    PubMed

    Li, Fayong; Xie, Chuan; Cheng, Zhengang; Xia, Hesheng

    2016-05-01

    The well-defined amphiphilic poly(ethylene glycol)-block-poly(propylene glycol) copolymer containing 1, 2, 3-triazole moiety and multiple ester bonds (PEG-click-PPG) was prepared by click reaction strategy. The PEG-click-PPG copolymer can self-assemble into spherical micelles in aqueous solution. It is found that high intensity focused ultrasound (HIFU) can open the copolymer PEG-click-PPG micelles and trigger the release of the payload in the micelle. The multiple ester bonds introduced in the junction point of the copolymer chain through click reactions were cleaved under HIFU, and leads to the disruption of the copolymer micelle and fast release of loaded cargo. The click reaction provides a convenient way to construct ultrasound responsive copolymer micelles with weak bonds. PMID:26703197

  1. Glycolic acid peel therapy - a current review.

    PubMed

    Sharad, Jaishree

    2013-01-01

    Chemical peels have been time-tested and are here to stay. Alpha-hydroxy peels are highly popular in the dermatologist's arsenal of procedures. Glycolic acid peel is the most common alpha-hydroxy acid peel, also known as fruit peel. It is simple, inexpensive, and has no downtime. This review talks about various studies of glycolic acid peels for various indications, such as acne, acne scars, melasma, postinflammatory hyperpigmentation, photoaging, and seborrhea. Combination therapies and treatment procedure are also discussed. Careful review of medical history, examination of the skin, and pre-peel priming of skin are important before every peel. Proper patient selection, peel timing, and neutralization on-time will ensure good results, with no side effects. Depth of the glycolic acid peel depends on the concentration of the acid used, the number of coats applied, and the time for which it is applied. Hence, it can be used as a very superficial peel, or even a medium depth peel. It has been found to be very safe with Fitzpatrick skin types I-IV. All in all, it is a peel that is here to stay. PMID:24399880

  2. Recent development of poly(ethylene glycol)-cholesterol conjugates as drug delivery systems.

    PubMed

    He, Zhi-Yao; Chu, Bing-Yang; Wei, Xia-Wei; Li, Jiao; Edwards, Carl K; Song, Xiang-Rong; He, Gu; Xie, Yong-Mei; Wei, Yu-Quan; Qian, Zhi-Yong

    2014-07-20

    Poly(ethylene glycol)-cholesterol (PEG-Chol) conjugates are composed of "hydrophilically-flexible" PEG and "hydrophobically-rigid" Chol molecules. PEG-Chol conjugates are capable of forming micelles through molecular self-assembly and they are also used extensively for the PEGylation of drug delivery systems (DDS). The PEGylated DDS have been shown to display optimized physical stability properties in vitro and longer half-lives in vivo when compared with non-PEGylated DDS. Cell uptake studies have indicated that PEG-Chol conjugates are internalized via clathrin-independent pathways into endosomes and Golgi apparatus. Acid-labile PEG-Chol conjugates are also able to promote the content release of PEGylated DDS when triggered by dePEGylation at acidic conditions. More importantly, biodegradable PEG-Chol molecules have been shown to decrease the "accelerated blood clearance" phenomenon of PEG-DSPE. Ligands, peptides or antibodies which have been modified with PEG-Chols are oftentimes used to formulate active targeting DDS, which have been shown in many systems recently to enhance the efficacy and lower the adverse effects of drugs. Production of PEG-Chol is simple and efficient, and production costs are relatively low. In conclusion, PEG-Chol conjugates appear to be very promising multifunctional biomaterials for many uses in the biomedical sciences and pharmaceutical industries. PMID:24768727

  3. Poly(ethylene glycol)-based multidentate oligomers for biocompatible semiconductor and gold nanocrystals.

    PubMed

    Palui, Goutam; Na, Hyon Bin; Mattoussi, Hedi

    2012-02-01

    We have developed a new set of multifunctional multidentate OligoPEG ligands, each containing a central oligomer on which were laterally grafted several short poly(ethylene glycol) (PEG) moieties appended with either thioctic acid (TA) or terminally reactive groups. Reduction of the TAs (e.g., in the presence of NaBH(4)) provides dihydrolipoic acid (DHLA)-appended oligomers. Here the insertion of PEG segments in the ligand structure promotes water solubility and reduces nonspecific interactions, while TA and DHLA groups provide multidentate anchoring onto Au nanoparticles (AuNPs) and ZnS-overcoated semiconductor quantum dots (QDs), respectively. The synthetic route involves simple coupling chemistry using N,N-dicylohexylcarbodiimide (DCC). Water-soluble QDs and AuNPs capped with these ligands were prepared via cap exchange. As prepared, the nanocrystals dispersions were aggregation-free, homogeneous, and stable for extended periods of time over pH ranging from 2 to 14 and in the presence of excess electrolyte (2 M NaCl). The new OligoPEG ligands also allow easy integration of tunable functional and reactive groups within their structures (e.g., azide or amine), which imparts surface functionalities to the nanocrystals and opens up the possibility of bioconjugation with specific biological molecules. The improved colloidal stability combined with reactivity offer the possibility of using the nanocrystals as biological probes in an array of complex and biologically relevant media. PMID:22201293

  4. Development of electrically conductive oligo(polyethylene glycol) fumarate-polypyrrole hydrogels for nerve regeneration.

    PubMed

    Runge, M Brett; Dadsetan, Mahrokh; Baltrusaitis, Jonas; Ruesink, Terry; Lu, Lichun; Windebank, Anthony J; Yaszemski, Michael J

    2010-11-01

    Electrically conductive hydrogel composites consisting of oligo(polyethylene glycol) fumarate (OPF) and polypyrrole (PPy) were developed for applications in nerve regeneration. OPF-PPy scaffolds were synthesized using three different anions: naphthalene-2-sulfonic acid sodium salt (NSA), dodecylbenzenesulfonic acid sodium salt (DBSA), and dioctyl sulfosuccinate sodium salt (DOSS). Scaffolds were characterized by ATR-FTIR, XPS, AFM, dynamic mechanical analysis, electrical resistivity measurements, and swelling experiments. OPF-PPy scaffolds were shown to consist of up to 25 mol % polypyrrole with a compressive modulus ranging from 265 to 323 kPa and a sheet resistance ranging from 6 to 30 × 10(3) Ohms/square. In vitro studies using PC12 cells showed OPF-PPy materials had no cytotoxicity and PC12 cells showed distinctly better cell attachment and an increase in the percent of neurite bearing cells on OPF-PPy materials compared to OPF. The neurite lengths of PC12 cells were significantly higher on OPF-PPyNSA and OPF-PPyDBSA. These results show that electrically conductive OPF-PPy hydrogels are promising candidates for future applications in nerve regeneration. PMID:20942380

  5. Development of Electrically Conductive Oligo(polyethylene Glycol) Fumarate-Polypyrrole Hydrogels for Nerve Regeneration

    PubMed Central

    Runge, M. Brett; Dadsetan, Mahrokh; Baltrusaitis, Jonas; Ruesink, Terry; Lu, Lichun; Windebank, Anthony J.; Yaszemski, Michael J.

    2014-01-01

    Electrically conductive hydrogel composites consisting of oligo(polyethylene glycol) fumarate (OPF) and polypyrrole (PPy) were developed for applications in nerve regeneration. OPF-PPy scaffolds were synthesized using three different anions: naphthalene-2-sulfonic acid sodium salt (NSA), dodecylbenzenesulfonic acid sodium salt (DBSA), and dioctyl sulfosuccinate sodium salt (DOSS). Scaffolds were characterized by ATR-FTIR, XPS, AFM, dynamic mechanical analysis, electrical resistivity measurements, and swelling experiments. OPF-PPy scaffolds were shown to consist of up to 25 mol% polypyrrole with a compressive modulus ranging from 265 to 323 kPa and a sheet resistance ranging from 6 to 30 × 103 Ohms/square. In vitro studies using PC12 cells showed OPF-PPy materials had no cytotoxicity and PC12 cells showed distinctly better cell attachment and an increase in the percent of neurite bearing cells on OPF-PPy materials compared to OPF. The neurite lengths of PC12 cells were significantly higher on OPF-PPyNSA and OPF-PPyDBSA. These results show that electrically conductive OPF-PPy hydrogels are promising candidates for future applications in nerve regeneration. PMID:20942380

  6. Extraction of actinides into aqueous polyethylene glycol solutions from carbonate media in the presence of alizarin complexone

    SciTech Connect

    Molochnikova, N.P.; Frenkel', V.Ya.; Myasoedov, B.F.; Shkinev, V.M.; Spivakov, B.Ya.; Zolotov, Yu.A.

    1987-01-01

    Actinide extraction in a two-phase aqueous system based on polyethylene glycol from carbonate solutions of various compositions in presence of alizarin complexone is studied. It is shown that the nature of the alkali metals affects actinide extraction into the polyethylene glycol phase. Tri- and tetravalent actinides are extracted maximally from sodium carbonate solutions. Separation of actinides in different oxidation states is more effective in potassium carbonate solutions. The behavior of americium in different oxidation states in the system carbonate-polyethylene glycol-complexone is studied. The possibility of extraction separation of microamount of americium(V) from curium in carbonate solutions in presence of alizarin complexone is shown.

  7. Effects of polyalkylene glycols and fatty acid soaps on properties of synthetic lubricating-cooling fluids

    SciTech Connect

    Stulii, A.A.

    1983-01-01

    The lack of any effect of the polyalkylene glycols on the series of properties of the fatty acid soaps was confirmed by replacing the PEG-35 in the synthetic lubricating-cooling fluid (LCF) by a polyethylene glycol with a molecular weight of 400 or 6000, a propylene oxide oligomer with a molecular weight of 700, or a copolymer of ethylene and propylene oxides (Pluronic 44, Pluriol PE-6400, Hydropol 200). Attempts to select surfactants and optimal concentrations in synthetic LCFs based on polyalkylene glycols. Indicates that of the studied soaps, those of the most interest are the triethanolamine soaps of individual C/sub 6/-C/sub 10/ fatty acids and commercial mixed C/sub 7/-C/sub 9/ synthetic fatty acids. Finds that the polyalkylene glycols and the indicated soaps supplement each other, imparting the required set of properties to the LCF.

  8. Synthesis, Characterization, and Size Control of Zinc Sulfide Nanoparticles Capped by Poly(ethylene glycol)

    NASA Astrophysics Data System (ADS)

    Allehyani, S. H. A.; Seoudi, R.; Said, D. A.; Lashin, A. R.; Abouelsayed, A.

    2015-11-01

    Zinc sulfide nanoparticles with controllable size were synthesized by chemical precipitation. Results from transmission electron microscopy and x-ray powder diffraction showed the samples were grown with the cubic phase. Particle size was varied by varying the molar ratio of zinc chloride to sodium sulfide in the presence of poly(ethylene glycol). The optical band gap was calculated on the basis of ultraviolet-visible spectroscopy and ranged from 4.13 to 4.31 eV depending on particle size. Surface passivation and adsorption of poly (ethylene glycol) on the nanoparticles was explained on the basis of Fourier-transform infrared measurements.

  9. On the spectral behavior of an ionic styryl dye: effect of micelle-polyethylene-block-polyethylene glycol diblock copolymer assembly.

    PubMed

    Sahoo, Dibakar; Bhattacharya, Prosenjit; Chakravorti, Sankar

    2009-10-15

    The interaction of anionic micelle sodium dodecyl sulfate (SDS) and amphiphilic block copolymers polyethylene-b-polyethylene glycol (PE-b-PEG) and the sharp change of excited-state charge-transfer complex photophysics of 2-(4-(dimethylamino)styryl)-1-methylpyridinium iodide (DASPMI) inside of the supramolecular assembly have been addressed in the paper. The dramatic enhancement of emission intensity of DASPMI incorporated inside of the nanostructure formed by micellar and polymeric chains indicates a completely different environment compared to that in the water and micellar system. A huge increase in the rotational relaxation time obtained from time-resolved anisotropy decay and the value of the order parameter is indicative of a very restrictive regime in the self-assembly system. The wobbling and translational motion of the probe is also restricted inside of the micelle-polymer aggregate due to the presence of polymer chains. The translational diffusion coefficient is drastically reduced due to the aggregation. PMID:19761273

  10. Fermentative degradation of polyethylene glycol by a strictly anaerobic, gram-negative, nonsporeforming bacterium, Pelobacter venetianus sp. nov.

    PubMed Central

    Schink, B; Stieb, M

    1983-01-01

    The synthetic polyether polyethylene glycol (PEG) with a molecular weight of 20,000 was anaerobically degraded in enrichment cultures inoculated with mud of limnic and marine origins. Three strains (Gra PEG 1, Gra PEG 2, and Ko PEG 2) of rod-shaped, gram-negative, nonsporeforming, strictly anaerobic bacteria were isolated in mineral medium with PEG as the sole source of carbon and energy. All strains degraded dimers, oligomers, and polymers of PEG up to a molecular weight of 20,000 completely by fermentation to nearly equal amounts of acetate and ethanol. The monomer ethylene glycol was not degraded. An ethylene glycol-fermenting anaerobe (strain Gra EG 12) isolated from the same enrichments was identified as Acetobacterium woodii. The PEG-fermenting strains did not excrete extracellular depolymerizing enzymes and were inhibited by ethylene glycol, probably owing to a blocking of the cellular uptake system. PEG, some PEG-containing nonionic detergents, 1,2-propanediol, 1,2-butanediol, glycerol, and acetoin were the only growth substrates utilized of a broad variety of sugars, organic acids, and alcohols. The isolates did not reduce sulfate, sulfur, thiosulfate, or nitrate and were independent of growth factors. In coculture with A. woodii or Methanospirillum hungatei, PEGs and ethanol were completely fermented to acetate (and methane). A marine isolate is described as the type strain of a new species, Pelobacter venetianus sp. nov. Its physiology and ecological significance, as well as the importance and possible mechanism of anaerobic polyether degradation, are discussed. Images PMID:6881964

  11. Fermentative degradation of polyethylene glycol by a strictly anaerobic, gram-negative, nonsporeforming bacterium, Pelobacter venetianus sp. nov.

    PubMed

    Schink, B; Stieb, M

    1983-06-01

    The synthetic polyether polyethylene glycol (PEG) with a molecular weight of 20,000 was anaerobically degraded in enrichment cultures inoculated with mud of limnic and marine origins. Three strains (Gra PEG 1, Gra PEG 2, and Ko PEG 2) of rod-shaped, gram-negative, nonsporeforming, strictly anaerobic bacteria were isolated in mineral medium with PEG as the sole source of carbon and energy. All strains degraded dimers, oligomers, and polymers of PEG up to a molecular weight of 20,000 completely by fermentation to nearly equal amounts of acetate and ethanol. The monomer ethylene glycol was not degraded. An ethylene glycol-fermenting anaerobe (strain Gra EG 12) isolated from the same enrichments was identified as Acetobacterium woodii. The PEG-fermenting strains did not excrete extracellular depolymerizing enzymes and were inhibited by ethylene glycol, probably owing to a blocking of the cellular uptake system. PEG, some PEG-containing nonionic detergents, 1,2-propanediol, 1,2-butanediol, glycerol, and acetoin were the only growth substrates utilized of a broad variety of sugars, organic acids, and alcohols. The isolates did not reduce sulfate, sulfur, thiosulfate, or nitrate and were independent of growth factors. In coculture with A. woodii or Methanospirillum hungatei, PEGs and ethanol were completely fermented to acetate (and methane). A marine isolate is described as the type strain of a new species, Pelobacter venetianus sp. nov. Its physiology and ecological significance, as well as the importance and possible mechanism of anaerobic polyether degradation, are discussed. PMID:6881964

  12. Basic Physicochemical Properties of Polyethylene Glycol Coated Gold Nanoparticles that Determine Their Interaction with Cells.

    PubMed

    Del Pino, Pablo; Yang, Fang; Pelaz, Beatriz; Zhang, Qian; Kantner, Karsten; Hartmann, Raimo; Martinez de Baroja, Natalia; Gallego, Marta; Möller, Marco; Manshian, Bella B; Soenen, Stefaan J; Riedel, René; Hampp, Norbert; Parak, Wolfgang J

    2016-04-25

    A homologous nanoparticle library was synthesized in which gold nanoparticles were coated with polyethylene glycol, whereby the diameter of the gold cores, as well as the thickness of the shell of polyethylene glycol, was varied. Basic physicochemical parameters of this two-dimensional nanoparticle library, such as size, ζ-potential, hydrophilicity, elasticity, and catalytic activity ,were determined. Cell uptake of selected nanoparticles with equal size yet varying thickness of the polymer shell and their effect on basic structural and functional cell parameters was determined. Data indicates that thinner, more hydrophilic coatings, combined with the partial functionalization with quaternary ammonium cations, result in a more efficient uptake, which relates to significant effects on structural and functional cell parameters. PMID:27028669

  13. Methoxy poly(ethylene glycol) conjugated doxorubicin micelles for effective killing of cancer cells.

    PubMed

    Zhang, Liming; Xia, Kai; Deng, Yan; Li, Song; Zhang, Chuanxiang; Lu, Zhuoxuan; He, Nongyue

    2014-08-01

    Methoxy poly(ethylene glycol) conjugated doxorubicin (mPEG-DOX) micelles are prepared for delivering drug effectively. The core of the unimolecular micelle is a DOX (doxorubicin) which is an anti-cancer chemotherapy drug, while the outer hydrophilic shell is composed of poly(ethylene glycol) (PEG) segments. Dynamic light scattering (DLS) analysis shows that the unimolecular micelles are uniform with a mean hydrodynamic diameter around 250 nm. The mPEG-DOX micelles can be internalized by the cancer cells and exhibit good cell uptake by the fluorescence microscopy. Obvious cytotoxicity is also observed when the concentration (count on DOX) is over 1 μg/mL. These findings indicate that these unique unimolecular micelles may offer a very promising approach for targeted cancer therapy. PMID:25936136

  14. Poly(ethylene glycol)-or silicone-modified hyaluronan for contact lens wetting agent applications.

    PubMed

    Paterson, Stefan M; Liu, Lina; Brook, Michael A; Sheardown, Heather

    2015-08-01

    Hyaluronan (HA) is a hydrophilic biopolymer that has been explored as a wetting agent in contact lens applications. In this study, HA was modified with siloxy or polyethylene glycol moieties using click chemistry to make it more soluble in monomer solutions used to synthesize model contact lens materials; unmodified HA was not soluble in the same monomer solutions. The water contents of the silicone hydrogels were not increased by the presence of modified HA, nor was there a decrease in the surface contact angle. However, modified HA did lead to a reduction in lysozyme adsorption in some cases. The leaching rate of HA modified with polyethylene glycol from a 78:22 DMA:TRIS(OH) hydrogel was significantly slower than for unmodified HA. PMID:25504586

  15. Conformational characteristics of polyethylene glycol macromolecules in aqueous solutions according to refractometry data

    NASA Astrophysics Data System (ADS)

    Abbasov, H. F.

    2014-06-01

    The aqueous solutions of polyethylene glycols with molecular masses of 600, 1000, 1500, 3000, 6000, and 20000 were studied by refractometry. The conformational polarizabilities, mean-square distances between the ends of the macromolecular chain, segment lengths, and the number of Kuhn segments in a macromolecule were determined using the Lorentz-Lorentz equation. The polarizability of a hydrated macro-molecule was represented as the sum of polarizabilities of the nonhydrated macromolecule with retained conformation and polarizabilities of the water molecules involved in hydration of macromolecules. The size of macromolecules stabilized starting from a certain concentration. It was concluded that the initial concentration of stabilization shifts toward low concentrations as the molecular mass of polyethylene glycol increases. The dependence of the mean-square distance between the ends of the macromolecular chain on the number of Kuhn segments was expressed as the exponential function with index 0.3.

  16. Crosslinked polymer gel electrolytes based on polyethylene glycol methacrylate and ionic liquid for lithium battery applications

    SciTech Connect

    Liao, Chen; Sun, Xiao-Guang; Dai, Sheng

    2013-01-01

    Gel polymer electrolytes were synthesized by copolymerization polyethylene glycol methyl ether methacrylate with polyethylene glycol dimethacrylate in the presence of a room temperature ionic liquid, methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY TFSI). The physical properties of gel polymer electrolytes were characterized by thermal analysis, impedance spectroscopy, and electrochemical tests. The ionic conductivities of the gel polymer electrolytes increased linearly with the amount of MPPY TFSI and were mainly attributed to the increased ion mobility as evidenced by the decreased glass transition temperatures. Li||LiFePO4 cells were assembled using the gel polymer electrolytes containing 80 wt% MPPY TFSI via an in situ polymerization method. A reversible cell capacity of 90 mAh g 1 was maintained under the current density of C/10 at room temperature, which was increased to 130 mAh g 1 by using a thinner membrane and cycling at 50 C.

  17. Interaction of Hyaluronan Binding Peptides with Glycosaminoglycans in Poly(ethylene glycol) Hydrogels

    PubMed Central

    2015-01-01

    This study investigates the incorporation of hyaluronan (HA) binding peptides into poly(ethylene glycol) (PEG) hydrogels as a mechanism to bind and retain hyaluronan for applications in tissue engineering. The specificity of the peptide sequence (native RYPISRPRKRC vs non-native RPSRPRIRYKC), the role of basic amino acids, and specificity to hyaluronan over other GAGs in contributing to the peptide–hyaluronan interaction were probed through experiments and simulations. Hydrogels containing the native or non-native peptide retained hyaluronan in a dose-dependent manner. Ionic interactions were the dominating mechanism. In diH2O the peptides interacted strongly with HA and chondroitin sulfate, but in phosphate buffered saline the peptides interacted more strongly with HA. For cartilage tissue engineering, chondrocyte-laden PEG hydrogels containing increasing amounts of HA binding peptide and exogenous HA had increased retention and decreased loss of cell-secreted proteoglycans in and from the hydrogel at 28 days. This new matrix-interactive hydrogel platform holds promise for tissue regeneration. PMID:24597474

  18. Steric stabilization of "charge-free" cellulose nanowhiskers by grafting of poly(ethylene glycol).

    PubMed

    Araki, Jun; Mishima, Shiho

    2015-01-01

    A sterically stabilized aqueous suspension of "charge-free" cellulose nanowhiskers was prepared by hydrochloric acid hydrolysis of cotton powders and subsequent surface grafting of monomethoxy poly(ethylene glycol) (mPEG). The preparation scheme included carboxylation of the terminal hydroxyl groups in mPEG via oxidation with silica gel particles carrying 2,2,6,6-tetramethyl-1-pyperidinyloxyl (TEMPO) moieties and subsequent esterification between terminal carboxyls in mPEG and surface hydroxyl groups of cellulose nanowhiskers, mediated by 1,1'-carbonyldiimidazole (CDI) in dimethyl sulfoxide or dimethylacetamide. Some of the prepared PEG-grafted samples showed remarkable flow birefringence and enhanced stability after 24 h, even in 0.1 M NaCl, suggesting successful steric stabilization by efficient mPEG grafting. Actual PEG grafting via ester linkages was confirmed by attenuated total reflectance-Fourier transform infrared spectrometry. In a typical example, the amount of grafted mPEG was estimated as ca. 0.3 g/g cellulose by two measurements, i.e., weight increase after grafting and weight loss after alkali cleavage of ester linkages. Transmission electron microscopy indicated unchanged nanowhisker morphology after mPEG grafting. PMID:25547722

  19. Biodistribution and pharmacokinetics of uniform magnetite nanoparticles chemically modified with polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Ruiz, A.; Hernández, Y.; Cabal, C.; González, E.; Veintemillas-Verdaguer, S.; Martínez, E.; Morales, M. P.

    2013-11-01

    The influence of polyethylene glycol (PEG) grafting on the pharmacokinetics, biodistribution and elimination of iron oxide nanoparticles is studied in this work. Magnetite nanoparticles (12 nm) were obtained via thermal decomposition of an iron coordination complex as a precursor. Particles were coated with meso-2,3-dimercaptosuccinic acid (DMSA) and conjugated to PEG-derived molecules by 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide (EDC) chemistry. Using a rat model, we explored the nanoparticle biodistribution pattern in blood and in different organs (liver, spleen and lungs) after intravenous administration of the product. The time of residence in blood was measured from the evolution of water proton relaxivities with time and Fe analysis in blood samples. The results showed that the residence time was doubled for PEG coated nanoparticles and consequently particle accumulation in liver and spleen was reduced. Post-mortem histological analyses showed no alterations in the liver and confirm heterogeneous distribution of NPs in the organ, in agreement with magnetic measurements and iron analysis. Finally, by successive magnetic resonance images we studied the evolution of contrast in the liver and measured the absorption, time of residence and excretion of nanoparticles in the liver during a one month period. On the basis of these results we propose different metabolic routes that determine the fate of magnetic nanoparticles.

  20. Interaction of hyaluronan binding peptides with glycosaminoglycans in poly(ethylene glycol) hydrogels.

    PubMed

    Roberts, Justine J; Elder, Robert M; Neumann, Alexander J; Jayaraman, Arthi; Bryant, Stephanie J

    2014-04-14

    This study investigates the incorporation of hyaluronan (HA) binding peptides into poly(ethylene glycol) (PEG) hydrogels as a mechanism to bind and retain hyaluronan for applications in tissue engineering. The specificity of the peptide sequence (native RYPISRPRKRC vs non-native RPSRPRIRYKC), the role of basic amino acids, and specificity to hyaluronan over other GAGs in contributing to the peptide-hyaluronan interaction were probed through experiments and simulations. Hydrogels containing the native or non-native peptide retained hyaluronan in a dose-dependent manner. Ionic interactions were the dominating mechanism. In diH2O the peptides interacted strongly with HA and chondroitin sulfate, but in phosphate buffered saline the peptides interacted more strongly with HA. For cartilage tissue engineering, chondrocyte-laden PEG hydrogels containing increasing amounts of HA binding peptide and exogenous HA had increased retention and decreased loss of cell-secreted proteoglycans in and from the hydrogel at 28 days. This new matrix-interactive hydrogel platform holds promise for tissue regeneration. PMID:24597474

  1. Immune cell impact of three differently coated lipid nanocapsules: pluronic, chitosan and polyethylene glycol

    PubMed Central

    Farace, Cristiano; Sánchez-Moreno, Paola; Orecchioni, Marco; Manetti, Roberto; Sgarrella, Francesco; Asara, Yolande; Peula-García, José M.; Marchal, Juan A.; Madeddu, Roberto; Delogu, Lucia G.

    2016-01-01

    Lipid nanocapsules (NCs) represent promising tools in clinical practice for diagnosis and therapy applications. However, the NC appropriate functionalization is essential to guarantee high biocompatibility and molecule loading ability. In any medical application, the immune system-impact of differently functionalized NCs still remains to be fully understood. A comprehensive study on the action exerted on human peripheral blood mononuclear cells (PBMCs) and major immune subpopulations by three different NC coatings: pluronic, chitosan and polyethylene glycol-polylactic acid (PEG) is reported. After a deep particle characterization, the uptake was assessed by flow-cytometry and confocal microscopy, focusing then on apoptosis, necrosis and proliferation impact in T cells and monocytes. Cell functionality by cell diameter variations, different activation marker analysis and cytokine assays were performed. We demonstrated that the NCs impact on the immune cell response is strongly correlated to their coating. Pluronic-NCs were able to induce immunomodulation of innate immunity inducing monocyte activations. Immunomodulation was observed in monocytes and T lymphocytes treated with Chitosan-NCs. Conversely, PEG-NCs were completely inert. These findings are of particular value towards a pre-selection of specific NC coatings depending on biomedical purposes for pre-clinical investigations; i.e. the immune-specific action of particular NC coating can be excellent for immunotherapy applications. PMID:26728491

  2. Immune cell impact of three differently coated lipid nanocapsules: pluronic, chitosan and polyethylene glycol.

    PubMed

    Farace, Cristiano; Sánchez-Moreno, Paola; Orecchioni, Marco; Manetti, Roberto; Sgarrella, Francesco; Asara, Yolande; Peula-García, José M; Marchal, Juan A; Madeddu, Roberto; Delogu, Lucia G

    2016-01-01

    Lipid nanocapsules (NCs) represent promising tools in clinical practice for diagnosis and therapy applications. However, the NC appropriate functionalization is essential to guarantee high biocompatibility and molecule loading ability. In any medical application, the immune system-impact of differently functionalized NCs still remains to be fully understood. A comprehensive study on the action exerted on human peripheral blood mononuclear cells (PBMCs) and major immune subpopulations by three different NC coatings: pluronic, chitosan and polyethylene glycol-polylactic acid (PEG) is reported. After a deep particle characterization, the uptake was assessed by flow-cytometry and confocal microscopy, focusing then on apoptosis, necrosis and proliferation impact in T cells and monocytes. Cell functionality by cell diameter variations, different activation marker analysis and cytokine assays were performed. We demonstrated that the NCs impact on the immune cell response is strongly correlated to their coating. Pluronic-NCs were able to induce immunomodulation of innate immunity inducing monocyte activations. Immunomodulation was observed in monocytes and T lymphocytes treated with Chitosan-NCs. Conversely, PEG-NCs were completely inert. These findings are of particular value towards a pre-selection of specific NC coatings depending on biomedical purposes for pre-clinical investigations; i.e. the immune-specific action of particular NC coating can be excellent for immunotherapy applications. PMID:26728491

  3. Complete Genome Sequence of Sphingopyxis terrae Strain 203-1 (NBRC 111660), a Polyethylene Glycol Degrader.

    PubMed

    Ohtsubo, Yoshiyuki; Nonoyama, Shouta; Nagata, Yuji; Numata, Mitsuru; Tsuchikane, Keiko; Hosoyama, Akira; Yamazoe, Atsushi; Tsuda, Masataka; Fujita, Nobuyuki; Kawai, Fusako

    2016-01-01

    The complete genome sequence of Sphingopyxis terrae strain 203-1, which is capable of growing on polyethylene glycol, was determined. The genome consisted of a chromosome with a size of 3.98 Mb and a plasmid with a size of 4,328 bp. The strain was deposited to the National Institute of Technology and Evaluation (Tokyo, Japan) under the number NBRC 111660. PMID:27284143

  4. Liquid-liquid distribution of B group vitamins in polyethylene glycol-based systems

    NASA Astrophysics Data System (ADS)

    Korenman, Ya. I.; Zykov, A. V.; Mokshina, N. Ya.

    2011-05-01

    General regularities of the liquid-liquid distribution of B1, B2, B6, and B12 vitamins in aqueous polyethylene glycol (PEG-2000, PEG-5000) solution-aqueous salt solution systems are studied. The influence of the salting-out agent, the concentration of the polymer, and its molecular weight on the distribution coefficients and recovery factors of the vitamins are considered. Equations relating the distribution coefficients (log D) to the polymer concentration are derived.

  5. Complete Genome Sequence of Sphingopyxis terrae Strain 203-1 (NBRC 111660), a Polyethylene Glycol Degrader

    PubMed Central

    Nonoyama, Shouta; Nagata, Yuji; Numata, Mitsuru; Tsuchikane, Keiko; Hosoyama, Akira; Yamazoe, Atsushi; Tsuda, Masataka; Fujita, Nobuyuki; Kawai, Fusako

    2016-01-01

    The complete genome sequence of Sphingopyxis terrae strain 203-1, which is capable of growing on polyethylene glycol, was determined. The genome consisted of a chromosome with a size of 3.98 Mb and a plasmid with a size of 4,328 bp. The strain was deposited to the National Institute of Technology and Evaluation (Tokyo, Japan) under the number NBRC 111660. PMID:27284143

  6. Protection of cellulose synthesis in detached cotton fibers by polyethylene glycol

    SciTech Connect

    Carpita, N.C.; Delmer, D.P.

    1980-11-01

    Detachment of the cotton fiber cell from the ovule results in loss of over 90% of the in vivo capacity for synthesis of (/sup 14/C)cellulose from (/sup 14/C)glucose. However, over 50% of the capacity for cellulose synthesis in the detached fiber population is protected when polyethylene glycol 4000 is present during detachment and incubation. Radioautography shows that approximately full capacity is restored in about half the fibers, whereas the other half of the population are incapable of cellulose synthesis from supplied glucose. The rate of cellulose synthesis in such fibers has a pH optimum of 6 and the optimum polyethylene glycol 4000 concentration is 0.06 molal (-9 bars). Cellulose synthesis in such detached fibers is synergistically stimulated by Ca/sup 2 +/ and Mg/sup 2 +/ and inhibited by K/sup +/. Evidence is presented which indicates that the protection by polyethylene glycol 4000 is due to its ability to promote membrane resealing, which seems to be required for protecting cellulose synthesis in the detached fiber; however, the requirement for membrane integrity is not exclusively involved in the maintenance of an energy generating system for the synthesis. The possibility that a membrane potential may be required for maintaining an active cellulose synthesizing system is discussed.

  7. Complete free energy landscape and statistical thermodynamics of single poly(ethylene glycol) molecules

    NASA Astrophysics Data System (ADS)

    Staple, Douglas; Hanke, Felix; Kreuzer, Hans Jürgen

    2007-03-01

    In this paper, we revisit the statistical mechanics of poly(ethylene glycol) with the intention to check ad hoc approximations made in previous works, namely to keep all C O bonds along the chain in the trans configuration. The theory developed here includes all the bonds on an equal footing. Starting with density functional theory calculations for the ethylene glycol monomer, dimer and trimer one can determine all the energetic and geometric parameters needed for a rotationally isomeric state model with interactions between nearest neighbour monomers included. The properties of short molecules are presented in detail, including the force-extension curves, end-to-end distributions, and also a discussion of the local helix properties. Finally, we use the transfer matrix method for long chains of 200 ethylene glycol monomers, i.e. 600 bonds. The agreement with the experimental force-extension curve is excellent.

  8. Preparation of poly(ethylene glycol)/polylactide hybrid fibrous scaffolds for bone tissue engineering

    PubMed Central

    Ni, PeiYan; Fu, ShaoZhi; Fan, Min; Guo, Gang; Shi, Shuai; Peng, JinRong; Luo, Feng; Qian, ZhiYong

    2011-01-01

    Polylactide (PLA) electrospun fibers have been reported as a scaffold for bone tissue engineering application, however, the great hydrophobicity limits its broad application. In this study, the hybrid amphiphilic poly(ethylene glycol) (PEG)/hydrophobic PLA fibrous scaffolds exhibited improved morphology with regular and continuous fibers compared to corresponding blank PLA fiber mats. The prepared PEG/PLA fibrous scaffolds favored mesenchymal stem cell (MSC) attachment and proliferation by providing an interconnected porous extracellular environment. Meanwhile, MSCs can penetrate into the fibrous scaffold through the interstitial pores and integrate well with the surrounding fibers, which is very important for favorable application in tissue engineering. More importantly, the electrospun hybrid PEG/PLA fibrous scaffolds can enhance MSCs to differentiate into bone-associated cells by comprehensively evaluating the representative markers of the osteogenic procedure with messenger ribonucleic acid quantitation and protein analysis. MSCs on the PEG/PLA fibrous scaffolds presented better differentiation potential with higher messenger ribonucleic acid expression of the earliest osteogenic marker Cbfa-1 and mid-stage osteogenic marker Col I. The significantly higher alkaline phosphatase activity of the PEG/PLA fibrous scaffolds indicated that these can enhance the differentiation of MSCs into osteoblast-like cells. Furthermore, the higher messenger ribonucleic acid level of the late osteogenic differentiation markers OCN (osteocalcin) and OPN (osteopontin), accompanied by the positive Alizarin red S staining, showed better maturation of osteogenic induction on the PEG/PLA fibrous scaffolds at the mineralization stage of differentiation. After transplantation into the thigh muscle pouches of rats, and evaluating the inflammatory cells surrounding the scaffolds and the physiological characteristics of the surrounding tissues, the PEG/PLA scaffolds presented good

  9. Mechanical, rheological, and bioactivity properties of ultra high-molecular-weight polyethylene bioactive composites containing polyethylene glycol and hydroxyapatite.

    PubMed

    Ahmad, Mazatusziha; Uzir Wahit, Mat; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

    2012-01-01

    Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

  10. Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite

    PubMed Central

    Ahmad, Mazatusziha; Wahit, Mat Uzir; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

    2012-01-01

    Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

  11. 40 CFR 721.4040 - Glycols, polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetra-methylbutyl)phenyl ether, sodium...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Glycols, polyethylene-, 3-sulfo-2... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4040 Glycols, polyethylene..., polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetramethyl butyl)phenyl ether, sodium salt (P-90-1565)...

  12. 40 CFR 721.4040 - Glycols, polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetra-methylbutyl)phenyl ether, sodium...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Glycols, polyethylene-, 3-sulfo-2... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4040 Glycols, polyethylene..., polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetramethyl butyl)phenyl ether, sodium salt (P-90-1565)...

  13. 40 CFR 721.4040 - Glycols, polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetra-methylbutyl)phenyl ether, sodium...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Glycols, polyethylene-, 3-sulfo-2... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4040 Glycols, polyethylene..., polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetramethyl butyl)phenyl ether, sodium salt (P-90-1565)...

  14. Polyethylene glycol versus dual sugar assay for gastrointestinal permeability analysis: is it time to choose?

    PubMed Central

    van Wijck, Kim; Bessems, Babs AFM; van Eijk, Hans MH; Buurman, Wim A; Dejong, Cornelis HC; Lenaerts, Kaatje

    2012-01-01

    Background Increased intestinal permeability is an important measure of disease activity and prognosis. Currently, many permeability tests are available and no consensus has been reached as to which test is most suitable. The aim of this study was to compare urinary probe excretion and accuracy of a polyethylene glycol (PEG) assay and dual sugar assay in a double-blinded crossover study to evaluate probe excretion and the accuracy of both tests. Methods Gastrointestinal permeability was measured in nine volunteers using PEG 400, PEG 1500, and PEG 3350 or lactulose-rhamnose. On 4 separate days, permeability was analyzed after oral intake of placebo or indomethacin, a drug known to increase intestinal permeability. Plasma intestinal fatty acid binding protein and calprotectin levels were determined to verify compromised intestinal integrity after indomethacin consumption. Urinary samples were collected at baseline, hourly up to 5 hours after probe intake, and between 5 and 24 hours. Urinary excretion of PEG and sugars was determined using high-pressure liquid chromatography-evaporative light scattering detection and liquid chromatography-mass spectrometry, respectively. Results Intake of indomethacin increased plasma intestinal fatty acid-binding protein and calprotectin levels, reflecting loss of intestinal integrity and inflammation. In this state of indomethacin-induced gastrointestinal compromise, urinary excretion of the three PEG probes and lactulose increased compared with placebo. Urinary PEG 400 excretion, the PEG 3350/PEG 400 ratio, and the lactulose/rhamnose ratio could accurately detect indomethacin-induced increases in gastrointestinal permeability, especially within 2 hours of probe intake. Conclusion Hourly urinary excretion and diagnostic accuracy of PEG and sugar probes show high concordance for detection of indomethacin-induced increases in gastrointestinal permeability. This comparative study improves our knowledge of permeability analysis in man

  15. Preparation of Microstructure Molds of Montmorillonite/Polyethylene Glycol Diacrylate and Multi-Walled Carbon Nanotube/Polyethylene Glycol Diacrylate Nanocomposites for Miniaturized Device Applications.

    PubMed

    Kim, Young Ho; Sohn, Jeong-Woo; Woo, Youngjae; Hong, Joo-Hyun; Kim, Gyu Man; Kang, Bong Keun; Park, Juyoung

    2015-10-01

    Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices. PMID:26726429

  16. Characterization of nephritogenic IgA immune complexes separated by polyethylene glycol

    SciTech Connect

    Imai, H.; Rifai, A.

    1986-03-05

    The size of IgA immune complexes (IgA-IC) plays an important role in the pathogenesis of experimental IgA nephropathy. The ability of different concentrations (3.5%, 5% and 7% w/v) of polyethylene glycol (PEG) to selectively precipitate IgA-IC with defined size, was examined using convalently cross-linked /sup 125/I-radiolabelled IgA-IC. These complexes were prepared with purified IgA anti-dinitrophenyl (DNP) antibodies and bis-DNP-pimelic acid ester. Size analysis of IgA-IC by gradient polyacrylamide gel electrophoresis (GPAGE) revealed a composition of 33% large-size (> 2 x 10/sup 6/ mw), 39% intermediate-size (4-20 x 10/sup 5/ mw), and 28% mixture of dimer and monomer IgA. The standard 3.5% PEG precipitated less than 7% of large- and intermediate-size IgA-IC. In contrast, 5% and 7% PEG precipitated 40% and 100% of large-size complexes, respectively. The 7% PEG was also effective in precipitating (40%) of the intermediate-size complexes. The correlation between PEG concentration and size of the precipitated IgA-IC was further confirmed by GPAGE and quantitative autoradiography of resolubilized PEG precipitates of discrete size IgA-IC obtained by gel filtration. They conclude the standard 3.5% PEG is inappropriate for precipitation of IgA-IC and recommend the use of 7% PEG for the detection of intermediate- and large-size IgA-IC.

  17. Liposomal Cu-64 labeling method using bifunctional chelators: polyethylene glycol spacer and chelator effects

    PubMed Central

    Seo, Jai Woong; Mahakian, Lisa M.; Kheirolomoom, Azadeh; Zhang, Hua; Meares, Claude F.; Ferdani, Riccardo; Anderson, Carolyn J.; Ferrara, Katherine W.

    2010-01-01

    Two bifunctional Cu-64 chelators (BFCs), (6-(6-(3-(2-pyridyldithio)propionamido)hexanamido)benzyl)-1,4,8,11-tetraazacyclotetradecane- 1,4,8,11-tetraacetic acid (TETA-PDP) and 4-(2-(2-pyridyldithioethyl)ethanamido)-11-carboxymethyl-1,4,8,11-tetraazabicyclo(6.6.2)hexadecane (CB-TE2A-PDEA), were synthesized and conjugated to long circulating liposomes (LCLs) via attachment to a maleimide lipid. An in vitro stability assay of 64Cu-TETA, 64Cu-TETA-PEG2k, and 64Cu-CB-TE2A-PEG2k liposomes showed that more than 86% of the radioactivity remains associated with the liposomal fraction after 48 hours of incubation with mouse serum. The in vivo time activity curves (TAC) for the three liposomal formulations showed that ~50% of the radioactivity cleared from the blood pool in 16 - 18 hours. As expected, the in vivo biodistribution and TAC data obtained at 48 hours demonstrate that the clearance of radioactivity from the liver slows with the incorporation of a polyethylene glycol-2k (PEG2k) brush. Our data suggest that 64Cu-TETA and 64Cu-CB-TE2A are similarly stable in the blood pool and accumulation of radioactivity in the liver and spleen is not related to the stability of Cu-64 chelator complex; however clearance of Cu-64 from the liver and spleen are faster when injected as 64Cu-TETA-chelated liposomes rather than 64Cu-CB-TE2A-chelated liposomes. PMID:20568726

  18. Online Aerosol Mass Spectrometry of Single Micrometer-Sized Particles Containing Poly(ethylene glycol)

    SciTech Connect

    Bogan, M J; Patton, E; Srivastava, A; Martin, S; Fergenson, D; Steele, P; Tobias, H; Gard, E; Frank, M

    2006-10-25

    Analysis of poly(ethylene glycol)(PEG)-containing particles by online single particle aerosol mass spectrometers equipped with laser desorption ionization (LDI) is reported. We demonstrate that PEG-containing particles are useful in the development of aerosol mass spectrometers because of their ease of preparation, low cost, and inherently recognizable mass spectra. Solutions containing millimolar quantities of PEGs were nebulized and, after drying, the resultant micrometer-sized PEG containing particles were sampled. LDI (266 nm) of particles containing NaCl and PEG molecules of average molecular weight <500 generated mass spectra reminiscent of mass spectra of PEG collected by other MS schemes including the characteristic distribution of positive ions (Na{sup +} adducts) separated by the 44 Da of the ethylene oxide units separating each degree of polymerization. PEGs of average molecular weight >500 were detected from particles that also contained t the tripeptide tyrosine-tyrosine-tyrosine or 2,5-dihydroxybenzoic acid, which were added to nebulized solutions to act as matrices to assist LDI using pulsed 266 nm and 355 nm lasers, respectively. Experiments were performed on two aerosol mass spectrometers, one reflectron and one linear, that each utilize two time-of-flight mass analyzers to detect positive and negative ions created from a single particle. PEG-containing particles are currently being employed in the optimization of our bioaerosol mass spectrometers for the application of measurements of complex biological samples, including human effluents, and we recommend that the same strategies will be of great utility to the development of any online aerosol LDI mass spectrometer platform.

  19. Bioprinting vessel-like constructs using hyaluronan hydrogels crosslinked with tetrahedral polyethylene glycol tetracrylates.

    PubMed

    Skardal, Aleksander; Zhang, Jianxing; Prestwich, Glenn D

    2010-08-01

    Bioprinting enables deposition of cells and biomaterials into spatial orientations and complexities that mirror physiologically relevant geometries. To facilitate the development of bioartificial vessel-like grafts, two four-armed polyethylene glycol (PEG) derivatives with different PEG chain lengths, TetraPEG8 and TetraPEG13, were synthesized from tetrahedral pentaerythritol derivatives. The TetraPEGs are unique multi-armed PEGs with a compact and symmetrical core. The TetraPEGs were converted to tetra-acrylate derivatives (TetraPAcs) which were used in turn to co-crosslink thiolated hyaluronic acid and gelatin derivatives into extrudable hydrogels for printing tissue constructs. First, the hydrogels produced by TetraPAc crosslinking showed significantly higher shear storage moduli when compared to PEG diacrylate (PEGDA)-crosslinked synthetic extracellular matrices (sECMs) of similar composition. These stiffer hydrogels have rheological properties more suited to bioprinting high-density cell suspensions. Second, TetraPAc-crosslinked sECMs were equivalent or superior to PEGDA-crosslinked gels in supporting cell growth and proliferation. Third, the TetraPac sECMs were employed in a proof-of-concept experiment by encapsulation of NIH 3T3 cells in sausage-like hydrogel macrofilaments. These macrofilaments were then printed into tubular tissue constructs by layer-by-layer deposition using the Fab@Home printing system. LIVE/DEAD viability/cytotoxicity-stained cross-sectional images showed the bioprinted cell structures to be viable in culture for up to 4 weeks with little evidence of cell death. Thus, biofabrication of cell suspensions in TetraPAc sECMs demonstrates the feasibility of building bioartificial blood vessel-like constructs for research and potentially clinical uses. PMID:20546891

  20. Physiological Investigation and Transcriptome Analysis of Polyethylene Glycol (PEG)-Induced Dehydration Stress in Cassava

    PubMed Central

    Fu, Lili; Ding, Zehong; Han, Bingying; Hu, Wei; Li, Yajun; Zhang, Jiaming

    2016-01-01

    Cassava is an important tropical and sub-tropical root crop that is adapted to drought environment. However, severe drought stress significantly influences biomass accumulation and starchy root production. The mechanism underlying drought-tolerance remains obscure in cassava. In this study, changes of physiological characters and gene transcriptome profiles were investigated under dehydration stress simulated by polyethylene glycol (PEG) treatments. Five traits, including peroxidase (POD) activity, proline content, malondialdehyde (MDA), soluble sugar and soluble protein, were all dramatically induced in response to PEG treatment. RNA-seq analysis revealed a gradient decrease of differentially expressed (DE) gene number in tissues from bottom to top of a plant, suggesting that cassava root has a quicker response and more induced/depressed DE genes than leaves in response to drought. Overall, dynamic changes of gene expression profiles in cassava root and leaves were uncovered: genes related to glycolysis, abscisic acid and ethylene biosynthesis, lipid metabolism, protein degradation, and second metabolism of flavonoids were significantly induced, while genes associated with cell cycle/organization, cell wall synthesis and degradation, DNA synthesis and chromatin structure, protein synthesis, light reaction of photosynthesis, gibberelin pathways and abiotic stress were greatly depressed. Finally, novel pathways in ABA-dependent and ABA-independent regulatory networks underlying PEG-induced dehydration response in cassava were detected, and the RNA-Seq results of a subset of fifteen genes were confirmed by real-time PCR. The findings will improve our understanding of the mechanism related to dehydration stress-tolerance in cassava and will provide useful candidate genes for breeding of cassava varieties better adapted to drought environment. PMID:26927071

  1. Physiological Investigation and Transcriptome Analysis of Polyethylene Glycol (PEG)-Induced Dehydration Stress in Cassava.

    PubMed

    Fu, Lili; Ding, Zehong; Han, Bingying; Hu, Wei; Li, Yajun; Zhang, Jiaming

    2016-01-01

    Cassava is an important tropical and sub-tropical root crop that is adapted to drought environment. However, severe drought stress significantly influences biomass accumulation and starchy root production. The mechanism underlying drought-tolerance remains obscure in cassava. In this study, changes of physiological characters and gene transcriptome profiles were investigated under dehydration stress simulated by polyethylene glycol (PEG) treatments. Five traits, including peroxidase (POD) activity, proline content, malondialdehyde (MDA), soluble sugar and soluble protein, were all dramatically induced in response to PEG treatment. RNA-seq analysis revealed a gradient decrease of differentially expressed (DE) gene number in tissues from bottom to top of a plant, suggesting that cassava root has a quicker response and more induced/depressed DE genes than leaves in response to drought. Overall, dynamic changes of gene expression profiles in cassava root and leaves were uncovered: genes related to glycolysis, abscisic acid and ethylene biosynthesis, lipid metabolism, protein degradation, and second metabolism of flavonoids were significantly induced, while genes associated with cell cycle/organization, cell wall synthesis and degradation, DNA synthesis and chromatin structure, protein synthesis, light reaction of photosynthesis, gibberelin pathways and abiotic stress were greatly depressed. Finally, novel pathways in ABA-dependent and ABA-independent regulatory networks underlying PEG-induced dehydration response in cassava were detected, and the RNA-Seq results of a subset of fifteen genes were confirmed by real-time PCR. The findings will improve our understanding of the mechanism related to dehydration stress-tolerance in cassava and will provide useful candidate genes for breeding of cassava varieties better adapted to drought environment. PMID:26927071

  2. Design and synthesis of multifunctional poly(ethylene glycol)s using enzymatic catalysis for multivalent cancer drug delivery

    NASA Astrophysics Data System (ADS)

    Seo, Kwang Su

    The objective of this research was to design and synthesize multifunctional poly(ethylene glycol)s (PEG)s using enzyme-catalyzed reactions for multivalent targeted drug delivery. Based on computer simulation for optimum folate binding, a four-arm PEG star topology with Mn = 1000 g/mol was proposed. First, a four-functional core based on tetraethylene glycol (TEG) was designed and synthesized using transesterification and Michael addition reactions in the presence of Candida antarctica lipase B (CALB) as a biocatalyst. The four-functional core (HO)2-TEG-(OH)2 core was successfully prepared by the CALB-catalyzed transesterification of vinyl acrylate (VA) with TEG and then Michael addition of diethanolamine to the resulting TEG diacrylate with/without the use of solvent. The functional PEG arms with fluorescein isothiocyanate (FITC) and folic acid (FA) were prepared using both traditional organic chemistry and enzyme-catalyzed reactions. FITC was reacted with the amine group of H2N-PEG-OH in the presence of triethylamine via nucleophilic addition onto the isothiocyanate group. Then, divinyl adipate (DVA) was transesterified with the FITC-PEG-OH product in the presence of CALB to produce the FITC-PEG vinyl ester that will be attached to the four-functional core via CALC-catalyzed transesterification. For the synthesis of FA-PEG vinyl ester arm, DVA was first reacted with PEG-monobenzyl ether (BzPEG-OH) in bulk in the presence of CALB. The BzPEG vinyl ester was then transesterified with 12-bromo-1-dodecanol in the presence of CALB. Finally, BzPEG-Br was attached to FA exclusively in the gamma position using a new method. The thesis also discusses fundamental studies that were carried out in order to get better understanding of enzyme catalyzed transesterification and Michael addition reactions. First, in an effort to investigate the effects of reagent and enzyme concentrations in transesterification, vinyl methacrylate (VMA) was reacted with 2-(hydroxyethyl) acrylate (2

  3. Transport and metabolism of glycolic acid by Chlamydomonas reinhardtii

    SciTech Connect

    Wilson, B.J.

    1987-01-01

    In order to understand the excretion of glycolate from Chlamydomonas reinhardtii, the conditions affecting glycolate synthesis and metabolism were investigated. Although glycolate is synthesized only in the light, the metabolism occurs in the light and dark with greater metabolism in the light due to refixation of photorespiratory CO/sub 2/. The amount of internal glycolate will affect the metabolism of externally added glycolate. When glycolate synthesis exceeds the metabolic capacity, glycolate is excreted from the cell. The transport of glycolate into the cells occurs very rapidly. Equilibrium is achieved at 4/sup 0/C within the time cells are pelleted by the silicone oil centrifugation technique through a layer of (/sup 14/C) glycolate. Glycolate uptake does not show the same time, temperature and pH dependencies as diffusion of benzoate. Uptake can be inhibited by treatment of cells with N-ethylmaleimide and stimulated in the presence of valino-mycin/KCl. Acetate and lactate are taken up as quickly as glycolate. The hypothesis was made that glycolate is transported by a protein carrier that transports monocarboxylic acids. The equilibrium concentration of glycolate is dependent on the cell density, implying that there may be a large number of transporter sites and that uptake is limited by substrate availability.

  4. Impedance Spectroscopy Study of Composite Thin Films of Hydrated Polyethylene Glycol

    SciTech Connect

    Al-Hamarneh, Ibrahim F.; Pedrow, Patrick D.; Goheen, Steven C.; Hartenstine, M. J.

    2007-10-01

    A polyethylene glycol (PEG) polymer was synthesized using a dip coating procedure on 316L stainless steel (SS) substrate pre-coated with a primer that consisted of radio frequency RF inductively coupled plasma-polymerized di (ethylene glycol) vinyl ether (EO2V). The primer and PEG composite film was studied with profilometer, optical microscope, scanning electron microscope (SEM), and a tape test to evaluate thickness, coverage, morphology, and adhesion, respectively. Response of the PEG composite film to an applied AC voltage was studied as a function of hydration state using impedance spectroscopy (IS). A resistor/capacitor network was used to interpret the impedance spectra. Electrical capacitance of the PEG film decreased with an exponentially decaying term as dehydration progressed. PEG film capacitance decay was consistent with a model describing water molecules diffusing through the PEG film.

  5. Complete Genome Sequence of Sphingopyxis macrogoltabida Strain 203N (NBRC 111659), a Polyethylene Glycol Degrader.

    PubMed

    Ohtsubo, Yoshiyuki; Nonoyama, Shouta; Nagata, Yuji; Numata, Mitsuru; Tsuchikane, Keiko; Hosoyama, Akira; Yamazoe, Atsushi; Tsuda, Masataka; Fujita, Nobuyuki; Kawai, Fusako

    2016-01-01

    We determined the complete genome sequence of Sphingopyxis macrogoltabida strain 203N, a polyethylene glycol degrader. Because the PacBio assembly (285× coverage) seemed to be full of nucleotide-level mismatches, the Newbler assembly of MiSeq mate-pair and paired-end data was used for finishing and the PacBio assembly was used as a reference. The PacBio assembly carried 414 nucleotide mismatches over 5,953,153 bases of the 203N genome. PMID:27284142

  6. Ionic conductivity and dielectric permittivity of polymer electrolyte plasticized with polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Das, S.; Ghosh, A.

    2016-05-01

    We have studied ionic conductivity and dielectric permittivity of PEO-LiClO4 solid polymer electrolyte plasticized with polyethylene glycol (PEG). The temperature dependence of the ionic conductivity has been well interpreted using Vogel-Tamman-Fulcher equation. The maximum dielectric constant is observed for 30 wt. % of PEG content. To get further insights into the ion dynamics, the complex dielectric permittivity has been studied with Havriliak-Negami function. The variation of relaxation time with inverse temperature obtained from HN formalism follows VTF nature.

  7. Polyethylene glycol-directed SnO2nanowires for enhanced gas-sensing properties

    NASA Astrophysics Data System (ADS)

    Yin, Ya-Xia; Jiang, Ling-Yan; Wan, Li-Jun; Li, Cong-Ju; Guo, Yu-Guo

    2011-04-01

    SnO2nanowires with lengths in the tens of micrometres range have been synthesized on a large scale via a facile polyethylene glycol-directed method at ambient temperature followed by a suitable thermal treatment of the precursor nanowires. The morphology of the precursor of the SnO2nanowires is tunable by changing the concentration of either SnCl2 or polyethylene glycol. After calcination, the resulting SnO2nanowires retain a similar shape to the precursor, but with hierarchical architecture, which can be considered as one-dimensional nanowires assembled by interconnected SnO2nanoparticles with a high surface-to-volume ratio. The SnO2nanowires are investigated with XRD, SEM, TEM, and gas sensing tests for detecting CO and H2. It is found that the present SnO2nanowires exhibit a remarkable sensitivity and low detection limit (10 ppm for H2), as well as good reproducibility and short response/recovery times, which benefit from the unique hierarchical structure with a high surface-to-volume ratio and the 3D network formed by the nanowires.SnO2nanowires with lengths in the tens of micrometres range have been synthesized on a large scale via a facile polyethylene glycol-directed method at ambient temperature followed by a suitable thermal treatment of the precursor nanowires. The morphology of the precursor of the SnO2nanowires is tunable by changing the concentration of either SnCl2 or polyethylene glycol. After calcination, the resulting SnO2nanowires retain a similar shape to the precursor, but with hierarchical architecture, which can be considered as one-dimensional nanowires assembled by interconnected SnO2nanoparticles with a high surface-to-volume ratio. The SnO2nanowires are investigated with XRD, SEM, TEM, and gas sensing tests for detecting CO and H2. It is found that the present SnO2nanowires exhibit a remarkable sensitivity and low detection limit (10 ppm for H2), as well as good reproducibility and short response/recovery times, which benefit from the

  8. Study on Biodegradation Process of Polyethylene Glycol with Exponential Glowth of Microbial Population

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaji; Kawai, Fusako

    Biodegradation of polyethylene glycol is studied mathematically. A mathematical model for depolymerization process of exogenous type is described. When a degradation rate is a product of a time factor and a molecular factor, a time dependent model can be transformed into a time independent model, and techniques developed in previous studies can be applied to the time independent model to determine the molecular factor. The time factor can be determined assuming the exponential growth of the microbial population. Those techniques are described, and numerical results are presented. A comparison between a numerical result and an experimental result shows that the mathematical method is appropriate for practical applications.

  9. Impact compressibility of a poly(ethylene glycol)-based nanocomposite fluid

    NASA Astrophysics Data System (ADS)

    Bragov, A. M.; Igumnov, L. A.; Konstantinov, A. Yu.; Lomunov, A. K.; Antonov, F. K.; Mossakovskii, P. A.

    2014-10-01

    The behavior of a poly(ethylene glycol)-based nanocomposite shear thickening fluid (STF) under impact loading conditions has been experimentally studied using the Kolsky method and related techniques. The dependence of the pressure in the STF on the volume strain magnitude has been determined. It is established that the radial and axial components of the stress tensor almost coincide, which shows that the material behaves like an incompressible liquid. The character of the stress-strain curves (hysteresis) indicates that the STF is characterized by some energy dissipation in the load-unload cycle.

  10. Cutaneous toxicity studies with methoxy polyethylene glycol-350 (MPEG-350) in rats and rabbits.

    PubMed

    Hermansky, S J; Leung, H W

    1997-01-01

    The methoxy polyethylene glycols (MPEGs), also referred to as polyethylene glycol methyl ethers, are high molecular weight polymers similar in structure and nomenclature to the polyethylene glycols. Because of the potential for repeated cutaneous exposure of humans to MPEG-350 and the known toxicity of lower alkylene glycol ethers such as ethylene glycol monomethyl ether (EGME), studies were conducted to evaluate the potential toxicity and irritation of MPEG-350 following repeated, cutaneous treatment. New Zealand White rabbits were cutaneously treated with 1.0 ml of either undiluted MPEG-350 or a 50% solution of MPEG-350 in 0.1% methyl cellulose in distilled water for 9 or 90 days. CD(SD)BR rats were cutaneously treated with up to 5 g/kg/day of undiluted MPEG-350 for 14 or 28 days. The treatment area was not occluded but animals were fitted with Elizabethan collars during treatment. Rabbits were treated 6 hr/day 5 days/wk. Rats were treated for at least 19 hr/day (at weekends, the exposure time was approximately 70 hr). None of the animals died. Slight decreases in mean absolute body weight of all dose groups of male rats as compared with the concurrent control group may have been related to minimal toxicity of the test substance but was probably secondary to the dosing procedures. Signs of slight cutaneous irritation were observed in many treated animals of both species but only a few rabbits had confirmatory microscopic diagnoses while none of the rats had microscopic changes in the skin. Slight decreases in the mean absolute weight of the testes, spleen and thymus were observed in rats treated with 5 g undiluted MPEG-350/kg/day for 14 days. Similar changes were not observed in rats following 28 days of treatment. There were no microscopic changes in any of these organs except for one rat that had moderate to high aspermatogenesis and multinucleated spermatids. There were no microscopic changes observed in the testes of any other animals (including rats treated

  11. The influence of poly(ethylene glycol) ether tetrasuccinimidyl glutarate on the structural, physical, and biological properties of collagen fibers.

    PubMed

    Sanami, Mohammad; Sweeney, India; Shtein, Zvi; Meirovich, Sigal; Sorushanova, Anna; Mullen, Anne Maria; Miraftab, Mohsen; Shoseyov, Oded; O'Dowd, Colm; Pandit, Abhay; Zeugolis, Dimitrios I

    2016-07-01

    Various chemical, natural, or synthetic in origin, crosslinking methods have been proposed over the years to stabilise collagen fibers. However, an optimal method has yet to be identified. Herein, we ventured to assess the potential of 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate, as opposed to glutaraldehyde (GTA), genipin and carbodiimide, on the structural, physical and biological properties of collagen fibers. The 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate induced an intermedium surface smoothness, denaturation temperature and swelling. The 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate fibers had significantly higher stress at break values than the carbodiimide fibers, but significantly lower than the GTA and genipin fibers. With respect to strain at break, no significant difference was observed among the crosslinking treatments. The 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate fibers exhibited significantly higher cell metabolic activity and DNA concentration that all other crosslinking treatments, promoted consistently cellular elongation along the longitudinal fiber axis and by day 7 they were completely covered by cells. Collectively, this work clearly demonstrates the potential of 4-star poly(ethylene glycol) ether tetrasuccinimidyl glutarate as collagen crosslinker. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 914-922, 2016. PMID:25952265

  12. Safety assessment on polyethylene glycols (PEGs) and their derivatives as used in cosmetic products.

    PubMed

    Fruijtier-Pölloth, Claudia

    2005-10-15

    This assessment focusses on polyethylene glycols (PEGs) and on anionic or nonionic PEG derivatives, which are currently used in cosmetics in Europe. These compounds are used in a great variety of cosmetic applications because of their solubility and viscosity properties, and because of their low toxicity. The PEGs, their ethers, and their fatty acid esters produce little or no ocular or dermal irritation and have extremely low acute and chronic toxicities. They do not readily penetrate intact skin, and in view of the wide use of preparations containing PEG and PEG derivatives, only few case reports on sensitisation reactions have been published, mainly involving patients with exposure to PEGs in medicines or following exposure to injured or chronically inflamed skin. On healthy skin, the sensitising potential of these compounds appears to be negligible. For some representative substances of this class, information was available on reproductive and developmental toxicity, on genotoxicty and carcinogenic properties. Taking into consideration all available information from related compounds, as well as the mode and mechanism of action, no safety concern with regard to these endpoints could be identified. Based on the available data it is therefore concluded that PEGs of a wide molecular weight range (200 to over 10,000), their ethers (laureths. ceteths, ceteareths, steareths, and oleths), and fatty acid esters (laurates, dilaurates, stearates, distearates) are safe for use in cosmetics. Limited data were available for PEG sorbitan/sorbitol fatty acid esters, PEG sorbitan beeswax and PEG soy sterols. Taking into account all the information available for closely related compounds, it can be assumed that these compounds as presently used in cosmetic preparations will not present a risk for human health. PEG castor oils and PEG hydrogenated castor oils have caused anaphylactic reactions when used in intravenous medicinal products. Their topical use in cosmetics is

  13. Studies of miscibility and specific interactions of antitumor-active anhydride copolymer and poly(ethylene glycol) blends.

    PubMed

    Can, Hatice Kaplan; Parvizikhosroshahi, Shahed; Uluışık, Erdem C

    2016-01-01

    The blending of polymers is of great interest, since the modification gives rise to diverse physical properties with the functionality of a polymer, without synthesis. Water-soluble antitumor-active poly(maleic anhydride-alt-acrylic acid) poly(MA-alt-AA) and poly(ethylene glycol) (PEG) blends were prepared by casting, and compatible properties were investigated by dilute solution viscometry. Viscosity measurements were made on ternary systems of polymer (1)/polymer (2)/solvent (H2O) and p-dioxane, at different concentrations of PEG and poly(MA-alt-AA). The interaction parameters Δβ, μ, Δk, Δb, β and α, which have been proposed, have been obtained using the viscosity data, to probe the miscibility of the polymer blends. The solid blends prepared were characterized with ATR-FTIR, (1)H-NMR, DTA and TGA. PMID:25406735

  14. Polyethylene glycol (PEG)-dendron phospholipids as innovative constructs for the preparation of super stealth liposomes for anticancer therapy.

    PubMed

    Pasut, Gianfranco; Paolino, Donatella; Celia, Christian; Mero, Anna; Joseph, Adrian Steve; Wolfram, Joy; Cosco, Donato; Schiavon, Oddone; Shen, Haifa; Fresta, Massimo

    2015-02-10

    Pegylation of nanoparticles has been widely implemented in the field of drug delivery to prevent macrophage clearance and increase drug accumulation at a target site. However, the shielding effect of polyethylene glycol (PEG) is usually incomplete and transient, due to loss of nanoparticle integrity upon systemic injection. Here, we have synthesized unique PEG-dendron-phospholipid constructs that form super stealth liposomes (SSLs). A β-glutamic acid dendron anchor was used to attach a PEG chain to several distearoyl phosphoethanolamine lipids, thereby differing from conventional stealth liposomes where a PEG chain is attached to a single phospholipid. This composition was shown to increase liposomal stability, prolong the circulation half-life, improve the biodistribution profile and enhance the anticancer potency of a drug payload (doxorubicin hydrochloride). PMID:25499917

  15. Millimetre wave rotational spectrum of glycolic acid

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Pszczółkowski, Lech; Białkowska-Jaworska, Ewa; Charnley, Steven B.

    2016-03-01

    The pure rotational spectrum of glycolic acid, CH2OHCOOH, was studied in the region 115-318 GHz. For the most stable SSC conformer, transitions in all vibrational states up to 400 cm-1 have been measured and their analysis is reported. The data sets for the ground state, v21 = 1 , and v21 = 2 have been considerably extended. Immediately higher in vibrational energy are two triads of interacting vibrational states and their rotational transitions have been assigned and successfully fitted with coupled Hamiltonians accounting for Fermi and Coriolis resonances. The derived energy level spacings establish that the vibrational frequency of the ν21 mode is close to 100 cm-1. The existence of the less stable AAT conformer in the near 50 °C sample used in our experiment was also confirmed and additional transitions have been measured.

  16. Surface modification of polydimethylsiloxane with photo-grafted poly(ethylene glycol) for micropatterned protein adsorption and cell adhesion.

    PubMed

    Sugiura, Shinji; Edahiro, Jun-ichi; Sumaru, Kimio; Kanamori, Toshiyuki

    2008-06-01

    In this study, we applied photo-induced graft polymerization to micropatterned surface modification of polydimethylsiloxane (PDMS) with poly(ethylene glycol). Two types of monomers, polyethylene glycol monoacrylate (PEGMA) and polyethylene glycol diacrylate (PEGDA), were tested for surface modification of PDMS. Changes in the surface hydrophilicity and surface element composition were characterized by contact angle measurement and electron spectroscopy for chemical analysis. The PEGMA-grafted PDMS surfaces gradually lost their hydrophilicity within two weeks. In contrast, the PEGDA-grafted PDMS surface maintained stable hydrophilic characteristics for more than two months. Micropatterned protein adsorption and micropatterned cell adhesion were successfully demonstrated using PEGDA-micropatterned PDMS surfaces, which were prepared by photo-induced graft polymerization using photomasks. The PEGDA-grafted PDMS exhibited useful characteristics for microfluidic devices (e.g. hydrophilicity, low protein adsorption, and low cell attachment). The technique presented in this study will be useful for surface modification of various research tools and devices. PMID:18242961

  17. Polyethylene glycol inhibits intestinal neoplasia and induces epithelial apoptosis in Apc(min) mice.

    PubMed

    Roy, Hemant K; Gulizia, James; DiBaise, John K; Karolski, William J; Ansari, Sajid; Madugula, Madhavi; Hart, John; Bissonnette, Marc; Wali, Ramesh K

    2004-11-01

    Efficacy of a safe and clinically utilized polyethylene glycol formulation (PEG-3350) to suppress intestinal tumors was investigated in the Apc(min) mouse-model of experimental carcinogenesis. Furthermore, based on our previous finding on the induction of apoptosis in HT-29 cells by PEG, we evaluated its ability to stimulate epithelial cell apoptosis in both Apc(min) mouse as well as AOM-treated rat as a potential molecular mechanism of chemoprevention. Twenty-two Apc(min) mice were randomized equally to PEG or vehicle (control) supplementation. Tumors were scored and uninvolved intestinal mucosal apoptosis was assayed using a modified terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) assay and by immunohistochemical detection of cleaved caspase-3. Supplementation of Apc(min) mice with 10% PEG 3350 (in drinking water) resulted in a 48% (P<0.05) reduction in intestinal tumor burden and induced 2-3 fold increase in mucosal apoptosis. Dietary supplementation of polyethylene glycol (5%) also stimulated colonic mucosal apoptosis 4-5 fold in AOM-treated rats, the regimen that we previously reported to reduce tumor burden by 76% (P<0.05). In summary, we demonstrate, for the first time, that PEG does protect against Apc(min) mouse tumorigenesis. The correlation between pro-apoptotic actions and chemopreventive efficacy of PEG in these models strongly implicates induction of apoptosis as one of the impending mechanisms of chemoprevention. PMID:15374630

  18. Acoustic, Thermal and Molecular Interactions of Polyethylene Glycol (2000, 3000, 6000)

    NASA Astrophysics Data System (ADS)

    Venkatramanan, K.; Padmanaban, R.; Arumugam, V.

    Polyethylene Glycol (PEG) is a condensation polymer of ethylene oxide and water. PEG find its application as emulsifying agents, detergents, soaps, plasticizers, ointments, etc. Though the chemical and physical properties of PEG are known, still because of their uses in day to day life, it becomes necessary to study few physical properties like ultrasonic velocity, viscosity and hence adiabatic compressibility, free length, etc. In the present study, an attempt has been made to compute the activation energy and hence to analyse the molecular interactions of aqueous solutions of Polyethylene Glycol of molar mass 2000, 3000 and 6000 at different concentrations (2%, 4%, 6%, 8% and 10%) at different temperatures (303K, 308K, 313K, 318K) by determining relative viscosity, ultrasonic velocity and density. Various parameters like adiabatic compressibility, viscous relaxation time, inter molecular free length, free volume, internal pressure, etc are calculated at 303K and the results are discussed in the light of polymer-solvent interaction. This study helps to understand the behavior of macro-molecules with respect to changing concentration and temperature. Furthermore, viscosity and activation energy results are correlated to understand the increased entanglement of the polymer chains due to the increase in the concentration of a polymer solution that leads to an increase in viscosity and an increase in the activation energy of viscous flow.

  19. Self-sterilized composite membranes of cellulose acetate/polyethylene glycol for water desalination.

    PubMed

    Ahmad, Adnan; Jamshed, Fahad; Riaz, Tabinda; Gul, Sabad-E-; Waheed, Sidra; Sabir, Aneela; AlAnezi, Adnan Alhathal; Adrees, Muhammad; Jamil, Tahir

    2016-09-20

    Cellulose acetate/Polyethylene glycol-600 composite membranes were fabricated by two step phase inversion procedure and modified by in-situ reduction of silver nitrate. FTIR spectra demonstrated the existence of functional groups for bonding of silver with oxygen at 370cm(-1), 535cm(-1). The XRD diffractogram indicates characteristic peaks at 2θ values of 38.10°, 44.30°, 64.40°, and 77.30° which confirm the successful incorporation of silver within matrix of composite membranes. The morphology of composite membranes with appearances of spongy voids was exemplified from the scanning electron microscope. The atomic force microscopy was used to determine the increase in the surface roughness of the membranes. The increase in hydrophilicity, measured through contact angle, is rendered to the embedment of silver. The modification of membranes increased the flux from 0.80 to 0.95L/hr.m(2). The resulting membranes have outstanding ability to fight against gram negative Escherichia Coli and Bacillus Sabtilus. The novel cellulose acetate/polyethylene glycol membranes customized with silver have paved the path for evolution of axenic membranes. PMID:27261744

  20. Utilization of Triton X-100 and polyethylene glycols during surfactant-mediated biodegradation of diesel fuel.

    PubMed

    Wyrwas, Bogdan; Chrzanowski, Łukasz; Ławniczak, Łukasz; Szulc, Alicja; Cyplik, Paweł; Białas, Wojciech; Szymański, Andrzej; Hołderna-Odachowska, Aleksandra

    2011-12-15

    The hypothesis regarding preferential biodegradation of surfactants applied for enhancement of microbial hydrocarbons degradation was studied. At first the microbial degradation of sole Triton X-100 by soil isolated hydrocarbon degrading bacterial consortium was confirmed under both full and limited aeration with nitrate as an electron acceptor. Triton X-100 (600 mg/l) was utilized twice as fast for aerobic conditions (t(1/2)=10.3h), compared to anaerobic conditions (t(1/2)=21.8h). HPLC/ESI-MS analysis revealed the preferential biodegradation trends in both components classes of commercial Triton X-100 (alkylphenol ethoxylates) as well as polyethylene glycols. The obtained results suggest that the observed changes in the degree of ethoxylation for polyethylene glycol homologues occurred as a consequence of the 'central fission' mechanism during Triton X-100 biodegradation. Subsequent experiments with Triton X-100 at approx. CMC concentration (150 mg/l) and diesel oil supported our initial hypothesis that the surfactant would become the preferred carbon source even for hydrocarbon degrading bacteria. Regardless of aeration regimes Triton X-100 was utilized within 48-72 h. Efficiency of diesel oil degradation was decreased in the presence of surfactant for aerobic conditions by approx. 25% reaching 60 instead of 80% noted for experiments without surfactant. No surfactant influence was observed for anaerobic conditions. PMID:21996621

  1. Characterization of indomethacin release from polyethylene glycol tablet fabricated with mold technique.

    PubMed

    Mesnukul, A; Yodkhum, K; Mahadlek, J; Phaechamud, T

    2010-01-01

    The purpose of this study was to use polyethylene glycol as a carrier to improve the solubility of an aqueous insoluble drug by melting and molding method. The release of dissolved drug was designed to be subsequently sustained with an addition of xanthan gum. The release of indomethacin from the developed system into phosphate buffer pH 6.2 was conducted using the dissolution apparatus. This carrier system could effectively enhance the solubility of indomethacin and an addition of xanthan gum could sustain the drug release. Eudragit L100 film coating could protect the carrier not to be disturbed with HCl buffer pH 1.2 and could dissolve in phosphate buffer pH 6.2, therefore, the drug release from coated tablet was initially very low but subsequently gradually released and prolonged in phosphate buffer pH 6.2. Differential scanning calorimetry study indicated the amorphous state of drug in polyethylene glycol carrier. Scanning electron microscopy photomicrograph indicated the drug diffusion outward through the porous network of matrix tablets into the dissolution fluid and curve fitting signified that the drug release kinetic was Fickian diffusion. PMID:20582196

  2. Polyethylene glycol-induced heteroassociation of malate dehydrogenase and citrate synthase

    SciTech Connect

    Merz, J.M.; Webster, T.A.; Appleman, J.R.; Manley, E.R.; Yu, H.A.; Datta, A.; Ackerson, B.J.; Spivey, H.O.

    1987-10-01

    Studies by dynamic and total intensity light scattering, ultracentrifugation, electron microscopy, and chemical crosslinking on solutions of the pig heart mitochondrial enzymes, malate dehydrogenase and citrate synthase (separately and together) demonstrate that polyethylene glycol induces very large homoassociations of each enzyme, and still larger heteroenzyme complexes between these two enzymes in the solution phase. Specificity of this heteroassociation is indicated by the facts that heteroassociations with bovine serum albumin were not observed for either the mitochondrial dehydrogenase or the synthase or between cytosolic malate dehydrogenase and citrate synthase. The weight fraction of the enzymes in the mitochondrial dehydrogenase-synthase associated particles in the solution phase was less than 0.03% with the dilute conditions used in the dynamic light scattering measurements. Neither palmitoyl-CoA nor other solution conditions tested significantly increased this weight fraction of associated enzymes in the solution phase. Because of the extremely low solubility of the associated species, however, the majority of the enzymes can be precipitated as the heteroenzyme complex. This precipitation is a classical first-order transition in spite of the large particle sizes and broad size distribution. Ionic effects on the solubility of the heteroenzyme complex appear to be of general electrostatic nature. Polyethylene glycol was found to be more potent in precipitating this complex than dextrans, polyvinylpyrrolidones, ficoll, and beta-lactoglobulin.

  3. Chemical Modification of Recombinant Interleukin 2 by Polyethylene Glycol Increases Its Potency in the Murine Meth A Sarcoma Model

    NASA Astrophysics Data System (ADS)

    Katre, Nandini V.; Knauf, Michael J.; Laird, Walter J.

    1987-03-01

    Recombinant human interleukin 2 purified from Escherichia coli has limited solubility at neutral pH and a short circulatory half-life. This recombinant interleukin 2 was chemically modified by an active ester of polyethylene glycol. The modified interleukin 2 was purified by hydrophobic interaction chromatography and characterized by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and isoelectric focusing. This conjugate was compared to unmodified recombinant interleukin 2 in vitro and in vivo. Covalent attachment of the hydrophilic polymer polyethylene glycol enhanced the solubility of interleukin 2, decreased its plasma clearance, and increased its antitumor potency in the Meth A murine sarcoma model.

  4. Interrelationship between partition behavior of organic compounds and proteins in aqueous dextran-polyethylene glycol and polyethylene glycol-sodium sulfate two-phase systems.

    PubMed

    Ferreira, Luisa A; da Silva, Nuno R; Wlodarczyk, Samarina R; Loureiro, Joana A; Madeira, Pedro P; Teixeira, José A; Uversky, Vladimir N; Zaslavsky, Boris Y

    2016-04-22

    Partition behavior of adenosine and guanine mononucleotides was examined in aqueous dextran-polyethylene glycol (PEG) and PEG-sodium sulfate two-phase systems. The partition coefficients for each series of mononucleotides were analyzed as a functions of the number of phosphate groups and found to be dependent on the nature of nucleic base and on the type of ATPS utilized. It was concluded that an average contribution of a phosphate group into logarithm of partition coefficient of a mononucleotide cannot be used to estimate the difference between the electrostatic properties of the coexisting phases of ATPS. The data obtained in this study were considered together with those for other organic compounds and proteins reported previously, and the linear interrelationship between logarithms of partition coefficients in dextran-PEG, PEG-Na2SO4 and PEG-Na2SO4-0.215M NaCl (all in 0.01M Na- or K/Na-phosphate buffer, pH 7.4 or 6.8) was established. Similar relationship was found for the previously reported data for proteins in Dex-PEG, PEG-600-Na2SO4, and PEG-8000-Na2SO4 ATPS. It is suggested that the linear relationships of the kind established in ATPS may be observed for biological properties of compounds as well. PMID:27016118

  5. Effect of Polyethylene Glycol on Properties and Drug Encapsulation-Release Performance of Biodegradable/Cytocompatible Agarose-Polyethylene Glycol-Polycaprolactone Amphiphilic Co-Network Gels.

    PubMed

    Chandel, Arvind K Singh; Kumar, Chinta Uday; Jewrajka, Suresh K

    2016-02-10

    We synthesized agarose-polycaprolactone (Agr-PCL) bicomponent and Agr-polyethylene glycol-PCL (Agr-PEG-PCL) tricomponent amphiphilic co-network (APCN) gels by the sequential nucleophilic substitution reaction between amine-functionalized Agr and activated halide terminated PCL or PCL-b-PEG-b-PCL copolymer for the sustained and localized delivery of hydrophilic and hydrophobic drugs. The biodegradability of the APCNs was confirmed using lipase and by hydrolytic degradation. These APCN gels displayed good cytocompatibility and blood compatibility. Importantly, these APCN gels exhibited remarkably high drug loading capacity coupled with sustained and triggered release of both hydrophilic and hydrophobic drugs. PEG in the APCNs lowered the degree of phase separation and enhanced the mechanical property of the APCN gels. The drug loading capacity and the release kinetics were also strongly influenced by the presence of PEG, the nature of release medium, and the nature of the drug. Particularly, PEG in the APCN gels significantly enhanced the 5-fluorouracil loading capacity and lowered its release rate and burst release. Release kinetics of highly water-soluble gemcitabine hydrochloride and hydrophobic prednisolone acetate depended on the extent of water swelling of the APCN gels. Cytocompatibility/blood compatibility and pH and enzyme-triggered degradation together with sustained release of drugs show great promise for the use of these APCN gels in localized drug delivery and tissue engineering applications. PMID:26760672

  6. Effects of hydrophobic drug polyesteric core interactions on drug loading and release properties of poly(ethylene glycol) polyester poly(ethylene glycol) triblock core shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Khoee, Sepideh; Hassanzadeh, Salman; Goliaie, Bahram

    2007-05-01

    BAB amphiphilic triblock copolymers consisting of poly(ethylene glycol) (B) (PEG) as the hydrophilic segment and different polyesters (A) as the hydrophobic block were prepared by a polycondensation reaction as efficient model core-shell nanoparticles to assay the effect of interactions between the hydrophobic drug and the polyesteric core in terms of drug loading content and release profile. PEG-poly(hexylene adipate)-PEG (PEG-PHA-PEG) and PEG-poly(butylene adipate)-PEG (PEG-PBA-PEG) to PEG-poly(ethylene adipate)-PEG (PEG-PEA-PEG) core-shell type nanoparticles entrapping quercetin (an anticarcinogenic, allergy inhibitor and antibacterial agent), were prepared by a nanoprecipitation method and characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and x-ray diffraction (XRD) techniques. It was found that the obtained nanoparticles showed a smooth surface and spherical shape with controllable sizes in the range of 64-74 nm, while drug loading varied from 7.24% to 19% depending on the copolymer composition and the preparation conditions. The in vitro release behaviour exhibited a sustained release and was affected by the polymer-drug interactions. UV studies revealed the presence of hydrogen bonding as the main existing interaction between quercetin and polyesters in the nanosphere cores.

  7. GLYCOLIC ACID PHYSICAL PROPERTIES, IMPURITIES, AND RADIATION EFFECTS ASSESSMENT

    SciTech Connect

    Pickenheim, B.; Bibler, N.

    2010-06-08

    The DWPF is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H{sub 2} and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O{sub 2} when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and pumping of the solution may be

  8. Polyethylene glycol coated CoFe{sub 2}O{sub 4} nanoparticles: A potential spinel ferrite for biomedical applications

    SciTech Connect

    Humbe, Ashok V.; Birajdar, Shankar D.; Jadhav, K. M.; Bhandari, J. M.; Waghule, N. N.; Bhagwat, V. R.

    2015-06-24

    The structural and magnetic properties of the polyethylene glycol (PEG) coated cobalt spinel ferrite (CoFe{sub 2}O{sub 4}) nanoparticles have been reported in the present study. CoFe{sub 2}O{sub 4} nanoparticles were prepared by sol-gel auto-combustion method using citric acid + ethylene glycol as a fuel. The prepared powder of cobalt ferrite nanoparticles was annealed at 600°C for 6h and used for further study. The structural characterization of CoFe{sub 2}O{sub 4} nanoparticles were carried out by X-ray diffraction technique. The X-ray analysis confirmed the formation of single phase cubic spinel structure. The crystallite size, Lattice constant and X-ray density of the PEG coated CoFe{sub 2}O{sub 4} nanoparticles were calculated by using XRD data. The presence of PEG on CoFe{sub 2}O{sub 4} nanoparticles and reduced agglomeration in the CoFe{sub 2}O{sub 4} nanoparticles were revealed by SEM studies. The magnetic properties were studied by pulse field hysteresis loop tracer technique at a room temperature. The magnetic parameters such as saturation magnetization, remanence magnetization, coercivity etc have been obtained. These magnetic parameters were get decreased by PEG coating.

  9. Polyethylene glycol-conjugated chondroitin sulfate A derivative nanoparticles for tumor-targeted delivery of anticancer drugs.

    PubMed

    Lee, Jae-Young; Park, Ju-Hwan; Lee, Jeong-Jun; Lee, Song Yi; Chung, Suk-Jae; Cho, Hyun-Jong; Kim, Dae-Duk

    2016-10-20

    Polyethylene glycol (PEG)-decorated chondroitin sulfate A-deoxycholic acid (CSD) nanoparticles (NPs) were fabricated for the selective delivery of doxorubicin (DOX) to ovarian cancer. CSD-PEG was synthesized via amide bond formation between the NH2 group of methoxypolyethylene glycol amine and the COOH group of CSD. CSD-PEG/DOX NPs with a 247nm mean diameter, negative zeta potential, and >90% drug encapsulation efficiency were prepared. Sustained and pH-dependent DOX release profiles from CSD-PEG NPs were observed in dissolution tests. Endocytosis of NPs by SKOV-3 cells (CD44 receptor-positive human ovarian cancer cells), based on the CSA-CD44 receptor interaction, was determined by flow cytometry and confocal laser scanning microscopy (CLSM) studies. PEGylation of NPs also resulted in reduced drug clearance (CL) in vivo and improved relative bioavailability, compared to non-PEGylated NPs, as determined by the pharmacokinetic study performed after intravenous administration in rats. Developed CSD-PEG NPs can be a promising delivery vehicle for the therapy of CD44 receptor-expressing ovarian cancers. PMID:27474544

  10. Photocurable surgical tissue adhesive glues composed of photoreactive gelatin and poly(ethylene glycol) diacrylate.

    PubMed

    Nakayama, Y; Matsuda, T

    1999-01-01

    This article presents a novel photochemically driven surgical tissue adhesive technology using photoreactive gelatins and a water-soluble difunctional macromer (poly(ethylene glycol) diacrylate: PEGDA).The gelatins were partially derivatized with photoreactive groups, such as ultraviolet light (UV)-reactive benzophenone and visible light-reactive xanthene dye (e.g., fluorescein sodium salt, eosin Y, and rose bengal). A series of the prepared photocurable tissue adhesive glues, consisting of the photoreactive gelatin, PEGDA, and a saline solution with or without ascorbic acid as a reducing agent, were viscous solutions under warming, and their effectiveness was evaluated as hemostasis- and anastomosis-aid in cardiovascular surgery. Regardless of the type of photoreactive groups, the irradiation of the photocurable tissue adhesive glues by UV or visible light within 1 min produced water-swollen gels, which had a high adhesive strength to wet collagen film. These were due to the synergistic action of photoreactive group-initiated photo-cross-linking and photograft polymerization. An increase in the irradiation time resulted in increased gel yield and reduced water swellability. A decrease in the molecular weight of PEGDA and an increase in concentration of both gelatin and PEGDA resulted in reduced water swellability and increased tensile and burst strengths of the resultant gels. In rats whose livers were injured with a trephine in laparotomy, the bleeding spots were coated with the photocurable adhesive glue and irradiated through an optical fiber. The coated solution was immediately converted to a swollen gel. The gel was tightly adhered to the liver tissue presumably by interpenetration, and concomitantly hemostasis was completed. The anastomosis treatment with the photocurable glue in the canine abdominal or thoracic aortas incised with a knife resulted in little bleeding under pulsatile flow after declamping. Histological examination showed that the glues

  11. 75 FR 50926 - 2-propenoic acid, 2-methyl-, C12-16-alkyl esters, telomers with 1-dodecanethiol, polyethylene...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of 2-propenoic acid, 2-methyl-, C12-16- alkyl esters, telomers with 1-dodecanethiol, polyethylene-polypropylene glycol ether with propylene glycol monomethacrylate (1:1), and styrene 2,2'-(1,2-diazenediyl)bis[2-methylbutanenitrile]-initiated, number average molecular weight (in AMU) 4000; when used as an......

  12. GLYCOLIC ACID PHYSICAL PROPERTIES, IMPURITIES, AND RADIATION EFFECTS ASSESSMENT

    SciTech Connect

    Lambert, D.; Pickenheim, B.; Hay, M.

    2011-06-20

    The Defense Waste Processing Facility (DWPF) is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H{sub 2} and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O{sub 2} when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and

  13. Effects of blending poly(D,L-lactide) with poly(ethylene glycol) on the higher-oder crystalline structures of poly(ethylene glycol) as revealed by small-angle X-ray scattering

    NASA Astrophysics Data System (ADS)

    Tien, N. D.; Hoa, T. P.; Kimura, G.; Yamashiro, Y.; Fujiwara, H.; Mochizuki, M.; Sasaki, S.; Sakurai, S.

    2011-01-01

    Effects of blending poly(lactic acid) (PLA) with poly(ethylene glycol) (PEG) on higher-order crystalline structures of PEG were examined using small-angle X-ray scattering (SAXS). For this purpose, the fact that two polymers are both crystalline makes situtation much complicated. To simplify, non-crystalline PLA is suitable. Thus, we used poly(D,L-lactic acid) (DLPLA), which is random copolymer comprising D- and L-lactic acid moieties. Multiple scattering peaks arising from the regular crystalline lamellar structure were observed for the PEG homopolymer and the blends. Surprisingly, the structure is much more regular for the blend DLPLA/PEG at composition of 20/80 wt.% than for the PEG homopolymer. Also for this blend sample as well as for a PEG homopolymer, very peculiar SAXS profiles were observed just 1°C below Tm of PEG. This is found to be a particle scattering of plate-like objects, which has never been reported for polymer blends or crystalline polymers. Futhermore, it was found that there was strong hysteresis of the higher-order structure formation.

  14. Complete Genome Sequence of Sphingopyxis macrogoltabida Type Strain NBRC 15033, Originally Isolated as a Polyethylene Glycol Degrader

    PubMed Central

    Nagata, Yuji; Numata, Mitsuru; Tsuchikane, Kieko; Hosoyama, Akira; Yamazoe, Atsushi; Tsuda, Masataka; Fujita, Nobuyuki; Kawai, Fusako

    2015-01-01

    Sphingopyxis macrogoltabida strain 203, the type strain of the species, grew on polyethylene glycol (PEG) and has been deposited to the stock culture at the Biological Resource Center, National Institute of Technology and Evaluation (NITE), under the number NBRC 15033. Here, we report the complete genome sequence of strain NBRC 15033. Unfortunately, genes for PEG degradation were missing. PMID:26659674

  15. Sizing the Bacillus anthracis PA63 Channel with Nonelectrolyte Poly(Ethylene Glycols)

    PubMed Central

    Nablo, Brian J.; Halverson, Kelly M.; Robertson, Joseph W. F.; Nguyen, Tam L.; Panchal, Rekha G.; Gussio, Rick; Bavari, Sina; Krasilnikov, Oleg V.; Kasianowicz, John J.

    2008-01-01

    Nonelectrolyte polymers of poly(ethylene glycol) (PEG) were used to estimate the diameter of the ion channel formed by the Bacillus anthracis protective antigen 63 (PA63). Based on the ability of different molecular weight PEGs to partition into the pore and reduce channel conductance, the pore appears to be narrower than the one formed by Staphylococcus aureus α-hemolysin. Numerical integration of the PEG sample mass spectra and the channel conductance data were used to refine the estimate of the pore's PEG molecular mass cutoff (∼1400 g/mol). The results suggest that the limiting diameter of the PA63 pore is <2 nm, which is consistent with an all-atom model of the PA63 channel and previous experiments using large ions. PMID:18645196

  16. Polyethylene glycol-based ultrasound-assisted extraction of magnolol and honokiol from Cortex Magnoliae Officinalis.

    PubMed

    He, Lei; Fan, Tao; Hu, Jianguo; Zhang, Lijin

    2015-01-01

    In this study, a kind of green solvent named polyethylene glycol (PEG) was developed for the ultrasound-assisted extraction (UAE) of magnolol and honokiol from Cortex Magnoliae Officinalis. The effects of PEG molecular weight, PEG concentration, sample size, pH, ultrasonic power and extraction time on the extraction of magnolol and honokiol were investigated to optimise the extraction conditions. Under the optimal extraction conditions, the PEG-based UAE supplied higher extraction efficiencies of magnolol and honokiol than the ethanol-based UAE and traditional ethanol-reflux extraction. Furthermore, the correlation coefficient (R(2)), repeatability (relative standard deviation, n = 6) and recovery confirmed the validation of the proposed extraction method, which were 0.9993-0.9996, 3.1-4.6% and 92.3-106.8%, respectively. PMID:25204856

  17. Modification of macroporous silica gel with polyethylene glycol by exposure to radiation

    SciTech Connect

    Garkavenko, L.G.; Kiselev, A.V.; Nikitin, Yu.S.; Topchieva, I.N.

    1986-11-01

    Samples of KSK-1 macroporous silica gel with a surface modified by different amounts of polyethylene glycol (PEG) have been prepared by exposure to radiation. The influence of the method of coating with 20,000 PEG, the nature of the solvent used, and the radiation dose on its content in the modified samples after prolonged washing with water has been studied. The modified samples have been used to investigate the adsorption of serum albumin from aqueous solutions. The adsorption of albumin on silica gel coated with 1.2-1.5 mg/m/sup 2/ of polymer is significantly reduced in comparison with the untreated silica gel; no adsorption of protein occurs at PEG contents of > 1.6 mg/m/sup 2/.

  18. Structure of phospholipid monolayers containing poly(ethylene glycol) lipids at the air-water interface

    SciTech Connect

    Majewski, J.; Smith, G.S.; Kuhl, T.L.; Israelachvili, J.N.; Gerstenberg, M.C.

    1997-04-17

    The density distribution of a lipid monolayer at the air-water interface mixed with varying amounts of lipid with poly(ethylene glycol)polymer headgroups (polymer-lipid or PEG-lipid) was measured using neutron reflectometry. The structure of the monolayer at the interface was greatly perturbed by the presence of the bulky polymer-lipid headgroups resulting in a large increase in the thickness of the headgroup region normal to the interface and a systematic roughening of the interface with increasing polymer-lipid content. These results show how bulky hydrophilic moieties cause significant deformations and out-of-place protrusions of phospholipid monolayers and presumably bilayers, vesicles and biological membranes. In terms of polymer physics, very short polymer chains tethered to the air-water interface follow scaling behavior with a mushroom to brush transition with increasing polymer grafting density. 34 refs., 9 figs., 1 tab.

  19. Polyethylene glycol and divalent salt-induced DNA reentrant condensation revealed by single molecule measurements.

    PubMed

    Cheng, Chao; Jia, Jun-Li; Ran, Shi-Yong

    2015-05-21

    In this study, we investigated the DNA condensation induced by polyethylene glycol (PEG) with different molecular weights (PEG 600 and PEG 6000) in the presence of NaCl or MgCl2 by using magnetic tweezers (MT) and atomic force microscopy (AFM). The MT measurements show that with increasing NaCl concentration, the critical condensation force in the PEG 600-DNA or PEG 6000-DNA system increased approximately linearly. PEG 6000 solution has a larger critical force than PEG 600 solution at a given NaCl concentration. In comparison, a parabolic trend of the critical condensation force was observed with increasing MgCl2 concentration, indicating that DNA undergoes a reentrant condensation. The AFM results show that the morphologies of the compacted DNA-PEG complexes depended on the salt concentration and were consistent with the MT results. PMID:25871460

  20. Influence of polyethylene glycol on the size of Schizosaccharomyces pombe electropores

    SciTech Connect

    Hood, M.T.; Stachow, C. )

    1992-04-01

    The role of polyethylene glycol (PEG) in the transformation of Schizosaccharomyces pombe by electroporation is investigated by fluorescein isothiocyanate-dextran uptake and transformation studies. It is shown that when S. pombe cells are electroporated in the presence of PEG, the permeability state created is sustained until removal of PEG. In addition, the permeability of electroporated S. pombe envelopes is further increased with longer incubation times in PEG. The increased permeability is apparently a result of enlarged pores (electropores) due to the presence of PEG. Comparison of a heat pulse transformation protocol with electroporation suggests a second role for PEG in the uptake of macromolecules. Since pores are not thought to be created during a heat pulse, the PEG may be facilitating the uptake of plasmid DNA. This facilitation of uptake would also be expected to affect DNA uptake by electroporated cells.

  1. Rapid detection of polyethylene glycol sonolysis upon functionalization of carbon nanomaterials.

    PubMed

    Murali, Vasanth S; Wang, Ruhung; Mikoryak, Carole A; Pantano, Paul; Draper, Rockford

    2015-09-01

    Polyethylene glycol (PEG) and related polymers are often used in the functionalization of carbon nanomaterials in procedures that involve sonication. However, PEG is very sensitive to sonolytic degradation and PEG degradation products can be toxic to mammalian cells. Thus, it is imperative to assess potential PEG degradation to ensure that the final material does not contain undocumented contaminants that can introduce artifacts into experimental results. Described here is a simple and inexpensive polyacrylamide gel electrophoresis method to detect the sonolytic degradation of PEG. The method was used to monitor the integrity of PEG phospholipid constructs and branched chain PEGs after different sonication times. This approach not only helps detect degraded PEG, but should also facilitate rapid screening of sonication parameters to find optimal conditions that minimize PEG damage. PMID:25662826

  2. Preparation and characterization of polyethylene glycol diacrylate microgels using electron beam radiation

    SciTech Connect

    Hamzah, Mohd Yusof; Isa, Naurah Mat; Napia, Liyana M. Ali

    2014-02-12

    The use of microemulsion in the development of nanosized gels based on polyethylene glycol diacrylate (PEGDA) is demonstrated. PEGDA was solubilized in n-heptane with use of sodium docusate (AOT) at 0.15M concentration to form reverse micelles. These micelles were than irradiated at 5, 10, 15, 20 and 25 kGy using electron beam (EB) to crosslink the entrapped polymer in the micelles. Ionizing radiation was imparted to the emulsions to generate crosslinking reaction in the micelles formed. The nanosized gels were evaluated in terms of particle diameter using dynamic light scattering (DLS) and the images of the nanosized gels were studied using transmission electron microscopy (TEM). Results show that the size and shape of the particles are influenced by concentration of PEGDA and radiation dose. This study showed that this method can be utilized to produce nanosized gels.

  3. High-frequency fusion of Streptomyces parvulus or Streptomyces antibioticus protoplasts induced by polyethylene glycol.

    PubMed Central

    Ochi, K; Hitchcock, M J; Katz, E

    1979-01-01

    Conditions were established for the regeneration of protoplasts of Streptomyces parvulus and Streptomyces antibioticus to the mycelial form. Regeneration was accomplished with a hypertonic medium that contained sucrose, CaCl2, MgCl2, and low levels of phosphate. High-frequency fusion of protoplasts derived from auxotrophic strains of S. parvulus or S. antibioticus was induced by polyethylene glycol 4,000 (42%, wt/vol). The frequency of genetic transfer by the fusogenic procedure varied with the auxotrophic strains examined. Fusion with auxotrophic strains of S. parvulus resulted in the formation of true prototrophic recombinants. Similar studies with S. antibioticus revealed that both stable prototrophic recombinants and heterokaryons were formed. PMID:479112

  4. Evaluation of liquid chromatography column retentivity using macromolecular probes. IV. Poly(ethylene glycol) bonded phase.

    PubMed

    Berek, Dusan; Mendichi, Raniero

    2004-02-01

    Interaction properties of the novel HPLC silica gel-poly(ethylene glycol) (PEG) bonded phase were evaluated applying polymeric test substances, viz. polystyrenes, poly(methyl methacrylate)s, poly(ethylene oxide)s and poly(2-vinyl pyridine)s, and eluents of different polarities. Silanols on the silica gel surface are well shielded by the PEG phase, and silanophilic adsorption of macromolecules is suppressed in comparison with most silica C(18) bonded phases. The adsorption of solutes on the -OH groups of the PEG phase seems to be low as well. The partition of macromolecules in favor of the PEG phase is inferior to that observed in case of the silica C(18) phases. The volume of the PEG bonded phase is small and it is supposed that the PEG chains assume flat conformation on the silica gel surface. PMID:14698238

  5. Poly(ethylene glycol)-Prodrug Conjugates: Concept, Design, and Applications

    PubMed Central

    Banerjee, Shashwat S.; Aher, Naval; Patil, Rajesh; Khandare, Jayant

    2012-01-01

    Poly(ethylene glycol) (PEG) is the most widely used polymer in delivering anticancer drugs clinically. PEGylation (i.e., the covalent attachment of PEG) of peptides proteins, drugs, and bioactives is known to enhance the aqueous solubility of hydrophobic drugs, prolong circulation time, minimize nonspecific uptake, and achieve specific tumor targetability through the enhanced permeability and retention effect. Numerous PEG-based therapeutics have been developed, and several have received market approval. A vast amount of clinical experience has been gained which has helped to design PEG prodrug conjugates with improved therapeutic efficacy and reduced systemic toxicity. However, more efforts in designing PEG-based prodrug conjugates are anticipated. In light of this, the current paper highlights the synthetic advances in PEG prodrug conjugation methodologies with varied bioactive components of clinical relevance. In addition, this paper discusses FDA-approved PEGylated delivery systems, their intended clinical applications, and formulations under clinical trials. PMID:22645686

  6. Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants

    PubMed Central

    Thompson, Susan; Stukel, Jessica; AlNiemi, Abrar; Willits, Rebecca Kuntz

    2013-01-01

    This work describes the formation of poly(ethylene glycol) (PEG) microgels via a photopolymerized precipitation reaction. Precipitation reactions offer several advantages over traditional microsphere fabrication techniques. Contrary to emulsion, suspension, and dispersion techniques, microgels formed by precipitation are of uniform shape and size, i.e. low polydispersity index, without the use of organic solvents or stabilizers. The mild conditions of the precipitation reaction, customizable properties of the microgels, and low viscosity for injections make them applicable for in vivo purposes. Unlike other fabrication techniques, microgel characteristics can be modified by changing the starting polymer molecular weight. Increasing the starting PEG molecular weight increased microgel diameter and swelling ratio. Further modifications are suggested such as encapsulating molecules during microgel crosslinking. Simple adaptations to the PEG microgel building blocks are explored for future applications of microgels as drug delivery vehicles and tissue engineering scaffolds. PMID:24378988

  7. Hydrophilicity improvement in polyphenylsulfone nanofibrous filtration membranes through addition of polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Kiani, Shirin; Mousavi, Seyed Mahmoud; Shahtahmassebi, Nasser; Saljoughi, Ehsan

    2015-12-01

    Novel hydrophilic polyphenylsulfone (PPSU) nanofibrous membrane was prepared by electrospinning of the PPSU solution blended with polyethylene glycol 400 (PEG 400). The influence of the PEG concentration on the membrane characteristics was studied using scanning electron microscopy (SEM), water contact angle measurement, and tensile test. Filtration performance of the membranes was investigated by measurement of pure water flux (PWF) and determination of the rejection values of the pollution indices during treatment of canned beans production wastewater. According to the results, blending the PPSU solution with 10 wt.% PEG 400 resulted in formation of a nanofibrous membrane with high porosity and increased mechanical strength which exhibited a low water contact angle of 8.9° and high water flux of 7920 L/m2h. Flux recovery of the mentioned membrane which was assessed by filtration of a solution containing bovine serum albumin (BSA) was 83% indicating a noticeable antifouling property.

  8. Rapid detection of polyethylene glycol sonolysis upon functionalization of carbon nanomaterials

    PubMed Central

    Murali, Vasanth S.; Wang, Ruhung; Mikoryak, Carole A.; Pantano, Paul; Draper, Rockford

    2015-01-01

    Polyethylene glycol (PEG) and related polymers are often used in the functionalization of carbon nanomaterials in procedures that involve sonication. However, PEG is very sensitive to sonolytic degradation and PEG degradation products can be toxic to mammalian cells. Thus, it is imperative to assess potential PEG degradation to ensure that the final material does not contain undocumented contaminants that can introduce artifacts into experimental results. Described here is a simple and inexpensive polyacrylamide gel electrophoresis method to detect the sonolytic degradation of PEG. The method was used to monitor the integrity of PEG phospholipid constructs and branched chain PEGs after different sonication times. This approach not only helps detect degraded PEG, but should also facilitate rapid screening of sonication parameters to find optimal conditions that minimize PEG damage. PMID:25662826

  9. Investigation of the suppression effect of polyethylene glycol on copper electroplating by electrochemical impedance spectroscopy

    SciTech Connect

    Hung, C.-C.; Lee, W.-H.; Wang, Y.-L.; Chan, D.-Y.; Hwang, G.-J.

    2008-09-15

    Polyethylene glycol (PEG) is an additive that is commonly used as a suppressor in the semiconductor copper (Cu)-electroplating process. In this study, electrochemical impedance spectroscopy (EIS) was used to analyze the electrochemical behavior of PEG in the Cu-electroplating process. Polarization analysis, cyclic-voltammetry stripping, and cell voltage versus plating time were examined to clarify the suppression behavior of PEG. The equivalent circuit simulated from the EIS data shows that PEG inhibited the Cu-electroplating rate by increasing the charge-transfer resistance as well as the resistance of the adsorption layer. The presence of a large inductance demonstrated the strong adsorption of cuprous-PEG-chloride complexes on the Cu surface during the Cu-electroplating process. Increasing the PEG concentration appears to increase the resistances of charge transfer, the adsorption layer, and the inductance of the electroplating system.

  10. Poly(ethylene glycol) diacrylate-supported ionogels with consistent capacitive behavior and tunable elastic response.

    PubMed

    Visentin, Adam F; Panzer, Matthew J

    2012-06-27

    Harnessing the many favorable properties of ionic liquids in a solid electrolyte thin film form is desirable for a host of electrical energy storage applications, including electrochemical double layer capacitors. Using a cross-linked polymer matrix to provide structural support, freestanding ionogel materials can be achieved with a wide range of polymer weight fractions. Compression testing and impedance spectroscopy have been used to characterize the mechanical and electrical responses of ionogels containing between 4.9 and 44.7 wt % poly(ethylene glycol) diacrylate. Although the elastic modulus of these solid electrolyte materials is observed to vary by more than 4 orders of magnitude within the composition range studied, concomitant changes in gel ionic conductivity and double layer capacitance were much less dramatic. PMID:22583832

  11. Physiologically based pharmacokinetic modeling of polyethylene glycol-coated polyacrylamide nanoparticles in rats.

    PubMed

    Li, Dingsheng; Johanson, Gunnar; Emond, Claude; Carlander, Ulrika; Philbert, Martin; Jolliet, Olivier

    2014-08-01

    Nanoparticles' health risks depend on their biodistribution in the body. Phagocytosis may greatly affect this distribution but has not yet explicitly accounted for in whole body pharmacokinetic models. Here, we present a physiologically based pharmacokinetic model that includes phagocytosis of nanoparticles to explore the biodistribution of intravenously injected polyethylene glycol-coated polyacrylamide nanoparticles in rats. The model explains 97% of the observed variation in nanoparticles amounts across organs. According to the model, phagocytizing cells quickly capture nanoparticles until their saturation and thereby constitute a major reservoir in richly perfused organs (spleen, liver, bone marrow, lungs, heart and kidneys), storing 83% of the nanoparticles found in these organs 120 h after injection. Key determinants of the nanoparticles biodistribution are the uptake capacities of phagocytizing cells in organs, the partitioning between tissue and blood, and the permeability between capillary blood and tissues. This framework can be extended to other types of nanoparticles by adapting these determinants. PMID:24392664

  12. Mixture of cholesterol end-capped polyethylene glycol with DSPC liposomal

    NASA Astrophysics Data System (ADS)

    Sharifi, Soheil

    2015-07-01

    The dynamic of network of self-assembled liposome by end-capped polymer was investigated using dynamic light scattering. The liposome network, physically cross-linked by mixed liposome solutions with three different length scale of cholesterol end-capped polyethylene glycol. The network of liposome is dependent on both the polymer concentration and length scale. In the pure liposome, one motion at low time scale is observed by DLS. In the higher concentration of polymer in liposome, several motion is observed that the fast motion is alpha relaxation and other two slow motion are beta and gamma relaxations. The distance between diffusion coefficient of fast and slow relaxation is increased with increase of length scale of endcapped polymers. The SAXS data is fitted with a Percus-Yevick hard sphere model and it shows that the size of liposome increasing with increase of polymer length scale in the mixture system.

  13. Accumulation of magnetic iron oxide nanoparticles coated with variably sized polyethylene glycol in murine tumors.

    PubMed

    Larsen, Esben Kjær Unmack; Nielsen, Thomas; Wittenborn, Thomas; Rydtoft, Louise Munk; Lokanathan, Arcot R; Hansen, Line; Østergaard, Leif; Kingshott, Peter; Howard, Kenneth A; Besenbacher, Flemming; Nielsen, Niels Chr; Kjems, Jørgen

    2012-04-01

    Iron oxide nanoparticles have found widespread applications in different areas including cell separation, drug delivery and as contrast agents. Due to water insolubility and stability issues, nanoparticles utilized for biological applications require coatings such as the commonly employed polyethylene glycol (PEG). Despite its frequent use, the influence of PEG coatings on the physicochemical and biological properties of iron nanoparticles has hitherto not been studied in detail. To address this, we studied the effect of 333-20,000 Da PEG coatings that resulted in larger hydrodynamic size, lower surface charge, longer circulation half-life, and lower uptake in macrophage cells when the particles were coated with high molecular weight (M(w)) PEG molecules. By use of magnetic resonance imaging, we show coating-dependent in vivo uptake in murine tumors with an optimal coating M(w) of 10,000 Da. PMID:22395568

  14. Aspiration Pneumonitis Caused by Polyethylene Glycol-Electrolyte Solution Treated with Conservative Management

    PubMed Central

    Mosquera, Ricardo A.; McDonald, Mark; Samuels, Cheryl

    2014-01-01

    Polyethylene glycol (PEG) electrolyte solution, Golytely, is an osmotic laxative commonly used in preoperative bowel cleansing. In this case report, a 9-year-old boy developed aspiration pneumonitis following accidental infusion of PEG solution into his right lung following migration of his nasogastric tube (NGT). Hypoxemia and tachypnea without respiratory failure were observed after infusion. Because PEG is a nonabsorbable toxic material, previous case reports have advocated for the performance of bronchoalveolar lavage (BAL) in the treatment of PEG pneumonitis. With close monitoring, our patient was able to be successfully treated without the need for invasive interventions including BAL or intubation. Generalizations about PEG absorption in the lung based on its permeability in the gastrointestinal tract should not deter the use of more conservative treatment in the appropriate patient. PMID:24955273

  15. Bioactivity of some chemotherapeutic agents in selected polyethylene glycol ointment bases.

    PubMed

    Farouk, A; Béla, S; Géza, R; Mohamed, S; Abdei Hadi, I

    1989-03-01

    Six different chemotherapeutic agents were individually incorporated in each of fourteen selected polyethylene glycol ointment bases, and their bioactivities were assessed using different diffusion techniques. The prepared medicated ointments were evaluated for drug release using the standard microbiological agar cup diffusion, the long period method and the short period method, as well as dialysis through artificial kidney membrane. On the basis of consistency, stability and diffusion results, formulation 11 was the most suitable base for ampicillin, formulation 14 for oxytetracycline HCl, formulation 10 and 9 for neomycin sulphate, and preparation 10 for chloramphenicol. On the basis of the results of drug release, it was evident that formulation 3 was the best for ampicillin and chloramphenicol, formulation 2 for erythromycin, formulation 4 for neomycin sulphate, formulation 12 for sulphadimidine, and formulation 14 for oxytetracycline HCl. PMID:2735193

  16. Effects of pH and ionic strength on precipitation of phytopathogenic viruses by polyethylene glycol.

    PubMed

    Pastorek, J; Marcinka, K

    1989-01-01

    The effects of ionic strength of the solution (changed by varying NaCl concentrations or buffer molarity) on the precipitation with polyethylene glycol (PEG) 6000 were studied on phytopathogenic viruses of different morphology: the isometric red clover mottle virus (RCMV), rod-shaped tobacco mosaic virus, flexuous potato virus X (PVX) and bacilliform alfalfa mosaic virus. With increasing NaCl concentration or buffer molarity up to a certain level (0.1 mol/l), the efficiency of PEG precipitation increased. This relationship did not apply to PVX. The effects of pH on PEG precipitation were studied on RCMV. The efficiency of precipitation increased with decreasing difference between pH of the solution and pI of the virus. PMID:2565676

  17. Protein partitioning in poly(ethylene glycol)/sodium polyacrylate aqueous two-phase systems.

    PubMed

    Johansson, Hans-Olof; Magaldi, Flavio Musa; Feitosa, Eloi; Pessoa, Adalberto

    2008-01-18

    The partition of hemoglobin, lysozyme and glucose-6-phosphate dehydrogenase (G6PDH) in a novel inexpensive aqueous two-phase system (ATPS) composed by poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) has been studied. The effect of NaCl and Na(2)SO(4), pH and PEG molecular size on the partitioning has been studied. At high pH (above 9), hemoglobin partitions strongly to the PEG-phase. Although some precipitation of hemoglobin occurs, high recovery values are obtained particularly for lysozyme and G6PDH. The partitioning forces are dominated by the hydrophobic and electrochemical (salt) effects, since the positively charged lysozyme and negatively charged G6PDH partitions to the non-charged PEG and the strongly negatively charged polyacrylate enriched phase, respectively. PMID:18078945

  18. Poly(ethylene glycol) conjugated enzyme with enhanced hydrophobic compatibility for self-cleaning coatings.

    PubMed

    Zhang, Liting; Wu, Songtao; Buthe, Andreas; Zhao, Xueyan; Jia, Hongfei; Zhang, Songping; Wang, Ping

    2012-11-01

    Enzyme-based smart materials constitute a rapidly growing group of functional materials. Often the natively evolved enzymes are not compatible with hydrophobic synthetic materials, thus significantly limiting the performance of enzymes. This work investigates the use of a polyethylene glycol (PEG)-conjugated detergent enzyme for self-cleaning coatings. As a result, PEG conjugated α-amylase demonstrated a much more homogeneous distribution in polyurethane coatings than the parent native enzyme as detected by both fluorescent microscopy and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (SEM-EDX). Additionally, the conjugated enzyme showed enhanced retention in the coating and much improved thermal stability with a halflife of 20 days detected at 80 °C and over 350 days under room temperature. Such coating-incorporated enzyme afforded interesting self-cleaning functionality against starch-based stains as examined through a slipping drop test. PMID:23067105

  19. Solubility of Naproxen in Polyethylene Glycol 200 + Water Mixtures at Various Temperatures

    PubMed Central

    Panahi-Azar, Vahid; Soltanpour, Shahla; Martinez, Fleming; Jouyban, Abolghasem

    2015-01-01

    The solubility of naproxen in binary mixtures of polyethylene glycol 200 (PEG 200) + water at the temperature range from 298.0 K to 318.0 K were reported. The combinations of Jouyban-Acree model + van’t Hoff and Jouyban-Acree model + partial solubility parameters were used to predict the solubility of naproxen in PEG 200 + water mixtures at different temperatures. Combination of Jouyban-Acree model with van’t Hoff equation can be used to predict solubility in PEG 200 + water with only four solubility data in mono-solvents. The obtained solubility calculation errors vary from ~ 17 % up to 35 % depend on the number of required input data. Non-linear enthalpy-entropy compensation was found for naproxen in the investigated solvent system and the Jouyban−Acree model provides reasonably accurate mathematical descriptions of the thermodynamic data of naproxen in the investigated binary solvent systems. PMID:26664370

  20. Optimizing the surface density of polyethylene glycol chains by grafting from binary solvent mixtures

    NASA Astrophysics Data System (ADS)

    Arcot, Lokanathan; Ogaki, Ryosuke; Zhang, Shuai; Meyer, Rikke L.; Kingshott, Peter

    2015-06-01

    Polyethylene glycol (PEG) brushes are very effective at controlling non-specific deposition of biological material onto surfaces, which is of paramount importance to obtaining successful outcomes in biomaterials, tissue engineered scaffolds, biosensors, filtration membranes and drug delivery devices. We report on a simple 'grafting to' approach involving binary solvent mixtures that are chosen based on Hansen's solubility parameters to optimize the solubility of PEG thereby enabling control over the graft density. The PEG thiol-gold model system enabled a thorough characterization of PEG films formed, while studies on a PEG silane-silicon system examined the versatility to be applied to any substrate-head group system by choosing an appropriate solvent pair. The ability of PEG films to resist non-specific adsorption of proteins was quantitatively assessed by full serum exposure studies and the binary solvent strategy was found to produce PEG films with optimal graft density to efficiently resist protein adsorption.

  1. Polyethylene glycol modification decreases the cardiac toxicity of carbonaceous dots in mouse and zebrafish models

    PubMed Central

    Chen, Jian-tao; Sun, Hua-qin; Wang, Wei-liang; Xu, Wen-ming; He, Qin; Shen, Shun; Qian, Jun; Gao, Hui-le

    2015-01-01

    Aim: Carbonaceous dots (CDs), which have been used for diagnosis, drug delivery and gene delivery, are accumulated in heart at high concentrations. To improve their biocompatibility, polyethylene glycol-modified CDs (PEG-CDs) were prepared. In this study we compared the cardiac toxicity of CDs and PEG-CDs in mouse and zebrafish models. Methods: Mice were intravenously treated with CDs (size: 4.9 nm, 5 mg·kg−1·d−1) or PEG-CDs (size: 8.3 nm, 5 mg·kg−1·d−1) for 21 d. Their blood biochemistry indices, ECG, and histological examination were examined for evaluation of cardiac toxicity. CDs or PEG-CDs was added in incubator of cmlc2 transgenic Zebrafish embryos at 6 hpf, and the shape and size of embryos' hearts were observed at 48 hpf using a fluorescent microscope. Furthermore, whole-mount in situ hybridization was used to examine the expression of early cardiac marker gene (clml2) at 48 hpf. Results: Administration of CDs or PEG-CDs in mice caused mild, but statistically insignificant reduction in serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels detected at 7 d, which were returned to the respective control levels at 21 d. Neither CDs nor PEG-CDs caused significant changes in the morphology of heart cells. Administration of CDs, but not PEG-CDs, in mice caused marked increase of heart rate. Both CDs and PEG-CDs did not affect other ECG parameters. In the zebrafish embryos, addition of CDs (20 μg/mL) caused heart development delay, whereas addition of CDs (80 μg/mL) led to heart malformation. In contrast, PEG-CDs caused considerably small changes in heart development, which was consistent with the results from the in situ hybridization experiments. Conclusion: CDs causes greater cardiac toxicity, especially regarding heart development. Polyethylene glycol modification can attenuate the cardiac toxicity of CDs. PMID:26456589

  2. Efficacy and complications of polyethylene glycols for treatment of constipation in children: a meta-analysis.

    PubMed

    Chen, Si-Le; Cai, Shi-Rong; Deng, Liang; Zhang, Xin-Hua; Luo, Te-Dong; Peng, Jian-Jun; Xu, Jian-Bo; Li, Wen-Feng; Chen, Chuang-Qi; Ma, Jin-Ping; He, Yu-Long

    2014-10-01

    Constipation is a common childhood complaint. In 90% to 95% of children, constipation is functional, which means that there is no objective evidence of an underlying pathological condition. Polyethylene glycol (PEG or macrogol) solution is an osmotic laxative agent that is absorbed in only trace amounts from the gastrointestinal tract and routinely used to treat chronic constipation in adults. Here, we report the results of a meta-analysis of PEG-based laxatives compared with lactulose, milk of magnesia (magnesium hydroxide), oral liquid paraffin (mineral oil), or acacia fiber, psyllium fiber, and fructose in children. This meta-analysis was conducted in accordance with PRISMA guidelines and involved searches of MEDLINE, Cochrane, EMBASE, and Google Scholar databases up to February 10, 2014, using the keywords (Constipation OR Functional Constipation OR Fecal Impaction) AND (Children) AND (Polyethylene Glycol OR Laxative). Primary efficacy outcomes included a number of stool passages/wk and percentage of patients who reported satisfactory stool consistency. Secondary safety outcomes included diarrhea, abdominal pain, nausea or vomiting, pain or straining at defecation, bloating or flatulence, hard stool consistency, poor palatability, and rectal bleeding. We identified 231 articles, 27 of which were suitable for full-text review and 10 of which were used in the meta-analysis. Patients who were treated with PEG experienced more successful disimpaction compared with those treated with non-PEG laxatives. Treatment-related adverse events were acceptable and generally well tolerated. PEG-based laxatives are effective and safe for chronic constipation and for resolving fecal impaction in children. Children's acceptance of PEG-based laxatives appears to be better than non-PEG laxatives. Optimal dosages, routes of administration, and PEG regimens should be determined in future randomized controlled studies and meta-analyses. PMID:25310742

  3. Polyethylene glycol versus sodium picosulfalte bowel preparation in the setting of a colorectal cancer screening program

    PubMed Central

    Kherad, Omar; Restellini, Sophie; Martel, Myriam; Barkun, Alan N

    2015-01-01

    BACKGROUND: Adequate bowel preparation for colonoscopy is an important predictor of colonoscopy quality. OBJECTIVE: To determine the difference in terms of effectiveness between different existing colon cleansing products in the setting of a colorectal cancer screening program. METHODS: The records of consecutive patients who underwent colonoscopy at the Montreal General Hospital (Montreal, Quebec) between April 2013 and April 2014 were retrospectively extracted from a dedicated electronic digestive endoscopic institutional database. RESULTS: Overall, 2867 charts of patients undergoing colonoscopy were assessed, of which 1130 colonoscopies were performed in a screening setting; patients had adequate bowel preparation in 90%. Quality of preparation was documented in only 61%. Bowel preparation was worse in patients receiving sodium picosulfate (PICO) alone compared with polyethylene glycol, in a screening setting (OR 0.3 [95% CI 0.2 to 0.6]). Regardless of the preparation type, the odds of achieving adequate quality cleansing was 6.6 for patients receiving a split-dose regimen (OR 6.6 [95% CI 2.1 to 21.1]). In multivariable analyses, clinical variables associated with inadequate bowel preparation in combined population were use of PICO, a nonsplit regimen and inpatient status. The polyp detection rate was very high (45.6%) and was correlated with withdrawal time. CONCLUSION: Preparation quality needs to be more consistently included in the colonoscopy report. Split-dose regimens increased the quality of colon cleansing across all types of preparations and should be the preferred method of administration. Polyethylene glycol alone provided better bowel cleansing efficacy than PICO in a screening setting but PICO remains an alternative in association with an adjuvant. PMID:26301330

  4. Synthesis and photophysicochemical studies of poly(ethylene glycol) conjugated symmetrical and asymmetrical zinc phthalocyanines

    NASA Astrophysics Data System (ADS)

    Dinçer, Hatice; Mert, Humeyra; Çalışkan, Emel; Atmaca, Göknur Yaşa; Erdoğmuş, Ali

    2015-12-01

    Synthesis and characterization of poly(ethylene glycol) conjugated symmetrical and asymmetrical zinc phthalocyanines (ZnPcs) is described. Copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) click reaction between azide functional methoxypoly(ethylene glycol) (mPEG-N3) and tetra terminal alkynyl substituted ZnPc yields star polymer with ZnPc core. Furthermore, CuAAC click reaction between asymmetrically terminal alkynyl substituted zinc phthalocyanine (aZnPc) and mPEG-N3 yields aZnPc end functionalized PEG. Spectral, photophysical (fluorescence quantum yield), photochemical (singlet oxygen (ΦΔ), and photodegradation quantum yield (Φd) properties of the symmetrically, and asymmetrically PEGylated ZnPcs are investigated to be used as sensitizers in photodynamic therapy (PDT). The quantum yield values of fluorescence (ΦF) and singlet oxygen generation (ΦΔ) for water soluble symmetrically PEGylated ZnPc in aqueous solution are calculated as 0.01 and 0.14 respectively, suggesting its potential as photosensitizer in PDT treatment.

  5. Mechanics of semiflexible chains formed by poly(ethylene glycol)-linked paramagnetic particles.

    PubMed

    Biswal, Sibani Lisa; Gast, Alice P

    2003-08-01

    Magnetorheological particles, permanently linked into chains, provide a magnetically actuated means to manipulate microscopic fluid flow. Paramagnetic colloidal particles form reversible chains by acquiring dipole moments in the presence of an external magnetic field. By chemically connecting paramagnetic colloidal particles, flexible magnetoresponsive chains can be created. We link the paramagnetic microspheres using streptavidin-biotin binding. Streptavidin coated microspheres are placed in a flow cell and a magnetic field is applied, causing the particles to form chains. Then a solution of polymeric linkers of bis-biotin-poly(ethylene glycol) molecules is added in the presence of the field. These linked chains remain responsive to a magnetic field; however, in the absence of an external magnetic field these chains bend and flex due to thermal motion. The chain flexibility is determined by the length of the spacer molecule between particles and is quantified by the flexural rigidity or bending stiffness. To understand the mechanical properties of the chains, we use a variety of optical trapping experiments to measure the flexural rigidity. Increasing the length of the poly(ethylene glycol) chain in the linker increases the flexibility of the chains. PMID:14524968

  6. The characterization of dendronized poly(ethylene glycol)s and poly(ethylene glycol) multi-arm stars using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Myers, Brittany K; Zhang, Boyu; Lapucha, Joanna E; Grayson, Scott M

    2014-01-15

    The synthesis of branched poly(ethylene glycol) (PEG) derivatives, namely star PEG and dendronized PEG, can be challenging and their purity can be difficult to ascertain using traditional techniques, such as NMR and GPC. Herein, the detailed characterization of these branched PEGs using MALDI-ToF MS was investigated in order to confirm their structural purity. In this light, mass spectrometry offers a number of advantages for polymer characterization, including the ability to get detailed structural data, such as end group masses, from microgram-scale samples. In addition, the ability to rapidly acquire data from crude reaction aliquots makes MALDI-ToF MS ideal for monitoring end group transformations. PMID:24370103

  7. Material compatibility evaluation for DWPF nitric-glycolic acid-literature review

    SciTech Connect

    Mickalonis, J.; Skidmore, E.

    2013-06-01

    Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid.

  8. Triggered release of siRNA from poly(ethylene glycol)-protected, pH-dependent liposomes

    PubMed Central

    Auguste, Debra T.; Furman, Kay; Wong, Andrew; Fuller, Jason; Armes, Steven P.; Deming, Timothy J.; Langer, Robert

    2008-01-01

    The ability of small interfering RNA (siRNA) to regulate gene expression has potential therapeutic applications, but its use is limited by inefficient delivery. Triggered release of adsorbed poly(ethylene glycol) (PEG)-b-polycation polymers from pH-dependent (PD) liposomes enables protection from immune recognition during circulation (pH 7.4) and subsequent intracellular delivery of siRNA within the endosome (pH ~5.5). Polycationic blocks, based on either poly[2-(dimethylamino)ethyl methacrylate] (31 or 62 DMA repeat units) or polylysine (21 K repeat units), act as anchors for a PEG (113 ethylene glycol repeat units) protective block. Incorporation of 1,2-dioleoyl-3-dimethylammonium-propane (DAP), a titratable lipid, increases the liposome’s net cationic character within acidic environments, resulting in polymer desorption and membrane fusion. Liposomes encapsulating siRNA demonstrate green fluorescent protein (GFP) silencing in genetically-modified, GFP-expressing HeLa cells and glyceraldehyde-3-phosphate dehydrogenase (GAPD) knockdown in human umbilical vein endothelial cells (HUVEC). Bare and PD liposomes coated with PEG113-DMA31 exhibit a 0.16±0.2 and 0.32±0.3 fraction of GFP knockdown, respectively. In contrast, direct siRNA administration and Oligofectamine complexed siRNA reduce GFP expression by 0.06±0.02 and 0.14±0.02 fractions, respectively. Our in vitro data indicates that polymer desorption from PD liposomes enhances siRNA-mediated gene knockdown. PMID:18601962

  9. Polyvinyl alcohol-graft-polyethylene glycol hydrogels improve utility and biofunctionality of injectable collagen biomaterials.

    PubMed

    Hartwell, Ryan; Chan, Ben; Elliott, Keenan; Alnojeidi, Hatem; Ghahary, Aziz

    2016-01-01

    Collagen-based materials have become a staple in both research and the clinic. In wound care, collagen-based materials comprise a core gamut of biological dressings and therapeutic strategies. In research, collagen-based materials are employed in everything from 3D cultures to bioprinting. Soluble collagen is well characterized to undergo fibrillation at neutral pH and 37 °C. To remain stable, a neutralized collagen solution must be maintained at 4 °C. These physical characteristics of collagen impose limitations on its utility. In our previous work, we identified that the incorporation of a simple polyvinyl alcohol:borate hydrogel could improve the rate of collagen gel fibrillation. In this work we sought to further investigate the interactions of polyvinyl alcohol blend variants, as surfactant-like polymers, in comparison with known non-polymer surfactants. To conduct our investigations scaffold variants were created using increasing concentrations of polyvinyl alcohol, differing combinations of polymers, and non-polymer surfactants Tweens 20 and 80, and TritonX-100. Activation energy for collagen fibrillation was found to significantly decrease in the presence of polyvinyl alcohols (p  <  0.01) at and above 0.4%w/v concentration. Further, addition of polyvinyl alcohol-graft-polyethylene glycol had the greatest enhancement (2.02 fold) on the fibrillation kinetics (p  <  0.01), wetting properties and the stability of the collagen scaffolds post-freeze drying. Our results demonstrated that the addition of polyvinyl alcohol hydrogels to a collagen solution could stabilize collagen solution such that the solution could easily be lyophilized (at pH 7) and then reconstituted with water. Cells cultured in polyvinyl alcohol scaffolds also exhibited more organized F-actin, as well as a reduced abundance of pro-collagen and α-smooth actin. In conclusion, our results demonstrate for the first time that polyvinyl alcohol, preferably polyvinyl alcohol-graft-polyethylene

  10. Transdermal thiol-acrylate polyethylene glycol hydrogel synthesis using near infrared light

    NASA Astrophysics Data System (ADS)

    Chung, Solchan; Lee, Hwangjae; Kim, Hyung-Seok; Kim, Min-Gon; Lee, Luke P.; Lee, Jae Young

    2016-07-01

    Light-induced polymerization has been widely applied for hydrogel synthesis, which conventionally involves the use of ultraviolet or visible light to activate a photoinitiator for polymerization. However, with these light sources, transdermal gelation is not efficient and feasible due to their substantial interactions with biological systems, and thus a high power is required. In this study, we used biocompatible and tissue-penetrating near infrared (NIR) light to remotely trigger a thiol-acrylate reaction for efficient in vivo gelation with good controllability. Our gelation system includes gold nanorods as a photothermal agent, a thermal initiator, diacrylate polyethylene glycol (PEG), and thiolated PEG. Irradiation with a low-power NIR laser (0.3 W cm-2) could induce gelation via a mixed-mode reaction with a small increase in temperature (~5 °C) under the optimized conditions. We also achieved successful transdermal gelation via the NIR-assisted photothermal thiol-acryl reactions. This new type of NIR-assisted thiol-acrylate polymerization provides new opportunities for in situ hydrogel formation for injectable hydrogels and delivery of drugs/cells for various biomedical applications.Light-induced polymerization has been widely applied for hydrogel synthesis, which conventionally involves the use of ultraviolet or visible light to activate a photoinitiator for polymerization. However, with these light sources, transdermal gelation is not efficient and feasible due to their substantial interactions with biological systems, and thus a high power is required. In this study, we used biocompatible and tissue-penetrating near infrared (NIR) light to remotely trigger a thiol-acrylate reaction for efficient in vivo gelation with good controllability. Our gelation system includes gold nanorods as a photothermal agent, a thermal initiator, diacrylate polyethylene glycol (PEG), and thiolated PEG. Irradiation with a low-power NIR laser (0.3 W cm-2) could induce gelation

  11. Leveling effects of ammonium salts on thermal stabilities of polyethylene glycols.

    PubMed

    Xia, Juan; Song, Le Xin; Liu, Wei; Teng, Yue

    2013-10-28

    In this work, the thermal stabilities of a series of polyethylene glycols (PEG 4000, 6000 and 10000) were investigated after compositing with different kinds of inorganic salts, such as ammonium molybdate tetrahydrate (AMT), NH4VO3, (NH4)2SO4, NH4NO3, Na2SO4, Na2MoO4. It was first observed that all the ammonium salts exerted leveling effects for the thermal stabilities of the PEGs. In other words, the presence of the ammonium salts caused the occurrence of the maximum decomposition rates of the PEGs with the same repeat sequence but different chain lengths at almost the same temperatures. Leveling effects were defined by three parameters: leveling spans, leveling degrees and dispersion degrees of leveling. Further experiments revealed that leveling effects also occur in similar types of polymers: polypropylene glycols (PPG 2000, 3000 and 4000). A series of independent experiments including Fourier transformation infrared spectroscopy, Raman spectroscopy, differential scanning calorimetry, time-of-flight mass spectrometry, conductivity and field-emission scanning electron microscopy were performed to explore the origin of leveling effects. We consider that the interaction between inorganic ions and polymer molecules and the Hofmeister effect of ions in solution are two important factors affecting the stability of salt–polymer composites, because they can contribute to decrease the interaction between the polymer chains, leading to changes in the conformation and pyrolysis mode of polymers. We believe that the finding of leveling effects would be significant for both basic and applied research of soft matter. PMID:26029781

  12. Synthesis, characterization and cytotoxicity of poly(ethylene glycol)-graft-trimethyl chitosan block copolymers.

    PubMed

    Mao, Shirui; Shuai, Xintao; Unger, Florian; Wittmar, Matthias; Xie, Xiulan; Kissel, Thomas

    2005-11-01

    PEGylated trimethyl chitosan (TMC) copolymers were synthesized in an attempt to both increase the solubility of chitosan in water, and improve the biocompatibility of TMC. A series of copolymers with different degrees of substitution were obtained by grafting activated poly(ethylene glycol)s (PEG) of different MW onto TMC via primary amino groups. Structure of the copolymers was characterized using 1H, 13C NMR spectroscopy and GPC. Solubility experiments demonstrated that PEG-g-TMC copolymers were completely water-soluble over the entire pH range of 1-14 regardless of the PEG MW, even when the graft density was as low as 10%. Using the methyl tetrazolium (MTT) assay, the effect of TMC molecular weight, PEGylation ratio, PEG and TMC molecular weight in the copolymers, and complexation with insulin on the cytotoxicity of TMC was examined, and IC50 values were calculated with L929 cell line. All polymers exhibited a time- and dose-dependent cytotoxic response that increased with molecular weight. PEGylation can decrease the cytotoxicity of TMC to a great extent in the case of low molecular weight TMCs. According to the cytotoxicity results, PEG 5 kDa is superior for PEGylation when compared to PEG 550 Da at similar graft ratios. Complexation with insulin further increased cell viability. In addition, Lactate dehydrogenase (LDH) assays were performed to quantify the membrane-damaging effects of the copolymers, which is in line with the conclusion drawn from MTT assay. Moreover, the safety of the copolymers was corroborated by observing the morphological change of the cells with inverted phase contrast microscopy. Based upon these results PEG-g-TMC merits further investigations as a drug delivery vehicle. PMID:15913769

  13. Polyethylene glycol, unique among laxatives, suppresses aberrant crypt foci, by elimination of cells

    PubMed Central

    Taché, Sylviane; Parnaud, Géraldine; Van Beek, Erik; Corpet, Denis E.

    2006-01-01

    Background Polyethylene glycol (PEG), an osmotic laxative, is a very potent inhibitor of colon cancer in rats. In a search for mechanisms, we tested the hypothesis that fecal bulking and moisture decreases colon carcinogenesis. We also looked for PEG effects on crypt cells in vivo. Methods Fischer 344 rats (N=272) were given an injection of the colon carcinogen azoxymethane. They were then randomized to a standard AIN76 diet containing one of 19 laxative agents (5% w/w in most cases): PEG 8000 and other PEG-like compounds, carboxymethylcellulose, polyvinylpyrrolidone, sodium polyacrylate, calcium polycarbophil, karaya gum, psyllium, mannitol, sorbitol, lactulose, propylene glycol, magnesium hydroxide, sodium phosphate, bisacodyl, docusate, and paraffin oil. Aberrant crypt foci (ACF) and fecal values were measured blindly after a 30-day treatment. Proliferation, apoptosis, and the removal of cells from crypts were studied in control and PEG-fed rats by various methods, including TUNEL and fluorescein dextran labeling. Results PEG 8000 reduced nine-fold the number of ACF in rats (p<0.001). The other PEGs and magnesium-hydroxide modestly suppressed ACF, but not the other laxatives. ACF number did not correlate with fecal weight or moisture. PEG doubled the apoptotic bodies per crypt (p<0.05), increased proliferation by 25–50% (p<0.05) and strikingly increased (>40-fold) a fecal marker of epitheliolysis in the gut (p<0.001). PEG normalized the percentage of fluorescein dextran labeled cells on the top of ACF (p<0.001). Conclusions Among laxatives, only PEG afforded potent chemoprevention. PEG protection was not due to increased fecal bulking, but likely to the elimination of cells from precancerous lesions. PMID:16716974

  14. GLYCOLIC-FORMIC ACID FLOWSHEET FINAL REPORT FOR DOWNSELECTION DECISION

    SciTech Connect

    Lambert, D.; Pickenheim, B.; Stone, M.; Newell, J.; Best, D.

    2011-03-10

    Flowsheet testing was performed to develop the nitric-glycolic-formic acid flowsheet (referred to as the glycolic-formic flowsheet throughout the rest of the report) as an alternative to the nitric/formic flowsheet currently being processed at the DWPF. This new flowsheet has shown that mercury can be removed in the Sludge Receipt and Adjustment Tank (SRAT) with minimal hydrogen generation. All processing objectives were also met, including greatly reducing the Slurry Mix Evaporator (SME) product yield stress as compared to the baseline nitric/formic flowsheet. Forty-six runs were performed in total, including the baseline run and the melter feed preparation runs. Significant results are summarized. The baseline nitric/formic flowsheet run, using the SB6 simulant produced by Harrell was extremely difficult to process successfully under existing DWPF acceptance criteria with this simulant at the HM levels of noble metals. While nitrite was destroyed and mercury was removed to near the DWPF limit, the rheology of the SRAT and SME products were well above design basis and hydrogen generation far exceeded the DWPF SRAT limit. In addition, mixing during the SME cycle was very poor. In this sense, the nitric/glycolic/formic acid flowsheet represents a significant upgrade over the current flowsheet. Mercury was successfully removed with almost no hydrogen generation and the SRAT and SME products yield stresses were within process limits or previously processed ranges. The glycolic-formic flowsheet has a very wide processing window. Testing was completed from 100% to 200% of acid stoichiometry and using a glycolic-formic mixture from 40% to 100% glycolic acid. The testing met all processing requirements throughout these processing windows. This should allow processing at an acid stoichiometry of 100% and a glycolic-formic mixture of 80% glycolic acid with minimal hydrogen generation. It should also allow processing endpoints in the SRAT and SME at significantly higher

  15. Volume and dielectric properties of cesium perchlorate and its solubility in aqueous solutions of polyethylene glycol-600

    NASA Astrophysics Data System (ADS)

    Yukhno, G. D.; Krasnoperova, A. P.

    2013-12-01

    The dependences of density and static dielectric permeability of water solutions of polyethylene glycol-600 on temperature and polyglycol concentration are studied. It is found that the maximum in the dependences of dielectric permeability on solvent composition is due to intermolecular interactions between water and polyglycol, resulting in the formation of oxonium compounds. The solubility of cesium perchlorate CsClO4 in a water-polyethylene glycol-600 system is investigated using radioactive indicators with 137Cs isotopes over the range of concentrations of mixed solvents at temperatures ranging from 278.15 to 318.15 K. Thermodynamic characteristics of CsClO4 dissolution in mixed solvents are also calculated and analyzed.

  16. Extraction of americium in different oxidation states in a two-phase aqueous system based on poly(ethylene glycol)

    SciTech Connect

    Molochnikova, N.P.; Frenkel', B.F.; Myasoedov, B.F.; Shkinev, V.M.; Spivakov, B.Ya.; Zolotov, Yu.A.

    1987-09-01

    The extraction of americium in different states of oxidation was studied in a two-phase aqueous system based on poly(ethylene glycol). Conditions were found for the quantitative extraction of americium (III) and americium (V) from solutions of ammonium sulfate in the pH range of 3-5 and in the presence of arsenazo III. The composition of the complexes of americium with the reagent was determined; americium (III) reacts with arsenazo III in solutions of ammonium sulfate to form complexes with the composition of MeR and Me/sub 2/R. Characteristics of the absorption spectra of complexes of americium (III) and (V) with arsenazo III in ammonium sulfate solutions and in extracts based on aqueous solutions of poly(ethylene glycol) were found. The molar extinction coefficients of complexes of americium with arsenazo III were determined in these solutions.

  17. Molecular structure of a water-polyethylene glycol-KOH system, according to densitometry and viscometry data

    NASA Astrophysics Data System (ADS)

    Masimov, E. A.; Pashayev, B. G.; Hasanov, H. Sh.; Musayeva, S. I.

    2013-12-01

    The dynamic viscosity and density of a water-polyethylene glycol-KOH system are measured at temperatures of 293.15 to 323.15 K in concentrations ranging from 0.00001 and 0.001 (mole fractions). The activation parameters of viscous flow (Δ G {η/≠}, Δ H {η/≠}, and Δ S {η/≠}), structural temperature ( T 0), the partial molar volume of polyethylene glycol (PEG) in solution , intrinsic viscosity([η]), and the Huggins constant ( K H), are calculated. It is found that PEG has a structuring effect on water in water-PEG and water-PEG-KOH systems, with the PEG structuring effect in the latter being somewhat attenuated by the destructuring influence of KOH.

  18. Bilayered biodegradable poly(ethylene glycol)/poly(butylene terephthalate) copolymer (Polyactive) as substrate for human fibroblasts and keratinocytes.

    PubMed

    van Dorp, A G; Verhoeven, M C; Koerten, H K; van Blitterswijk, C A; Ponec, M

    1999-12-01

    The purpose of this study was to find an optimal polymer matrix and to optimize the culture conditions for human keratinocytes and fibroblasts for the development of a human skin substitute. For this purpose porous, dense bilayers made of a block copolymer of poly(ethylene glycol terephthalate) (PEGT) and poly(butylene terephthalate) (PBT; Polyactivetrade mark) with a PEGT/PBT weight ratio of 55/45 and a PEG molecular weight (MW) of 300, 600, 1000, or 4000 Da were used. The best performance was achieved with PEGT/PBT copolymer with MW of PEG 300 D (300PEG55PBT45). When fibroblasts were seeded into the porous underlayer and cultured for 3 weeks in medium supplemented with 100 microg/mL ascorbic acid, all pores were filled with fibroblasts and with extracellular matrix, which was judged from the presence of collagen types I, III, and IV, and laminin. When seeded onto the dense top layer of the bilayered (cell free or fibroblast populated) copolymer matrix, human keratinocytes grew out into confluent sheets. After subsequent lifting to the air-liquid interface, a multilayered epithelium with a morphology corresponding to that of the native epidermis was formed. Some differences could still be observed: the expression and localization of some differentiation specific proteins was different and close to that seen in hyperproliferative epidermis; a basal lamina and anchoring zone were absent. PMID:10487879

  19. Immobilization of Quantum Dots in the Photo-Cross-Linked Poly(ethylene glycol)-Based Hydrogel

    SciTech Connect

    Gattas-Asfura, Kerim M.; Zheng, Yujun; Micic, Miodrag ); Snedaker, Michael J.; Ji, Xiaojun; Sui, Guodong; Orbulescu, Jhony; Andreopoulos, Fotios M.; Pham, Si M.; Wang, Chong M. )

    2003-09-25

    An inorganic/organic composite hybrid nano-system has been successfully synthesized in which nanocrystalline quantum dots (QDs) were effectively immobilized within a photo-cross-linked poly(ethylene glycol) hydrogel. Organometallic synthesis of CdTe and CdSe QDs was accomplished with a trioctylphosphine oxide (TOPO) cap. Replacing the TOPO cap with mercaptoacetic acid groups further yielded modified water-soluble nanocrystals. The immobilization of these functionalized CdTe and CdSe QDs within PEG hydrogel network has been shown to be effective through utilization of physical trapping. The CdTe and CdSe QDs had a particle diameter of 4.5 and 2.5-6.0 nm, respectively. The most efficiently trapped QDs had a size of 4.5 nm or larger. Particle size determination was derived from spectroscopic (absorption and photoluminescence) and high-resolution transmission electron microscopic techniques. These QD-immobilized gel systems demonstrated photoluminescence characteristics unique to semiconductor QD nanocrystals. The authors have envisioned the utilization of the unique photophysical properties of this material as a convenient signal transducer for in vivo biosensing. The most promising application of the described QD/PEG-NC hybrid system is in the fields of in vivo fluorescence microscopy and as a monitoring system for drug delivery and wound healing.

  20. The effects of poly(zwitterions)s versus poly(ethylene glycol) surface coatings on the biodistribution of protein nanoparticles.

    PubMed

    Wang, Jing; Yuan, Shanmei; Zhang, Yajun; Wu, Wei; Hu, Yong; Jiang, Xiqun

    2016-08-16

    Zwitterionic poly(carboxybetaine) (PCB), poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and non-ionic poly(ethylene glycol) (PEG), which have similar degrees of polymerization, were grafted to branched polyethyleneimine (PEI) to generate PCB-grafted PEI (PEI-PCB), PMPC-grafted PEI (PEI-PMPC) and PEG-grafted PEI (PEI-PEG) copolymers, respectively. These grafted PEI copolymers with almost the same grafting number were coated on the surface of 110 nm bovine serum albumin-poly(N-3-acrylamidophenylboronic acid) (BSA-PAPBA) nanoparticles to make a comparison of the surface decoration effect on the biodistribution of nanoparticles. Compared to the nanoparticles without surface decoration, surface decoration with the copolymers significantly prolonged the circulation time of BSA-PAPBA nanoparticles, leading to remarkable enhancement of tumor uptake of the nanoparticles. The drug accumulation at the tumor site reached more than 10% injected dose per gram of tumor. Among them, the PEI-PMPC-decorated nanoparticles exhibited the best performance in tumor accumulation and anticancer ability. Thus, these surface-decorated nanoparticles may serve as a strong candidate for high tumor accumulation of drug delivery systems. PMID:27426309

  1. Crystalline polyoxometalate (POM)-polyethylene glycol (PEG) composites aimed as non-humidified intermediate-temperature proton conductors

    NASA Astrophysics Data System (ADS)

    Tsuboi, Masaki; Hibino, Mitsuhiro; Mizuno, Noritaka; Uchida, Sayaka

    2016-02-01

    Crystalline polyoxometalate (POM)-polyethylene glycol (PEG) composites aimed as non-humidified intermediate-temperature proton conductors were synthesized and characterized by single crystal and powder XRD, solid state MASNMR, and TG-DTA measurements. Among the POM-PEG composites, Cs2.7H0.3[PW12O40]·1.2PEG1000 (CsHPW-PEG1000) possessed one-dimensional channels with diameters of ca. 6 and 8 Å, where PEG probably resided, and showed the best performance as a proton conductor (1.2×10-5 S cm-1 at 443 K). Proton conductivities of POM-PEG composites decreased by the increase in molecular weights of PEG (CsHPW-PEG12,000) or anion charges (CsHSiW-PEG1000). Variable contact time 13C-CP (cross polarization) MASNMR revealed that local mobility (i.e., segmental motion) of PEG is related to the trends in proton conductivities. These results show that amount of acidic protons (H+) is not the primary factor in proton conduction and that segmental motion of PEG assists the proton hopping among POMs in the crystal lattice of POM-PEG composites.

  2. The first step in polyethylene glycol degradation by sphingomonads proceeds via a flavoprotein alcohol dehydrogenase containing flavin adenine dinucleotide.

    PubMed

    Sugimoto, M; Tanabe, M; Hataya, M; Enokibara, S; Duine, J A; Kawai, F

    2001-11-01

    Several Sphingomonas spp. utilize polyethylene glycols (PEGs) as a sole carbon and energy source, oxidative PEG degradation being initiated by a dye-linked dehydrogenase (PEG-DH) that oxidizes the terminal alcohol groups of the polymer chain. Purification and characterization of PEG-DH from Sphingomonas terrae revealed that the enzyme is membrane bound. The gene encoding this enzyme (pegA) was cloned, sequenced, and expressed in Escherichia coli. The purified recombinant enzyme was vulnerable to aggregation and inactivation, but this could be prevented by addition of detergent. It is as a homodimeric protein with a subunit molecular mass of 58.8 kDa, each subunit containing 1 noncovalently bound flavin adenine dinucleotide but not Fe or Zn. PEG-DH recognizes a broad variety of primary aliphatic and aromatic alcohols as substrates. Comparison with known sequences revealed that PEG-DH belongs to the group of glucose-methanol-choline (GMC) flavoprotein oxidoreductases and that it is a novel type of flavoprotein alcohol dehydrogenase related (percent identical amino acids) to other, so far uncharacterized bacterial, membrane-bound, dye-linked dehydrogenases: alcohol dehydrogenase from Pseudomonas oleovorans (46%); choline dehydrogenase from E. coli (40%); L-sorbose dehydrogenase from Gluconobacter oxydans (38%); and 4-nitrobenzyl alcohol dehydrogenase from a Pseudomonas species (35%). PMID:11673442

  3. pH-Responsive Poly(ethylene glycol)/Poly(L-lactide) Supramolecular Micelles Based on Host-Guest Interaction.

    PubMed

    Zhang, Zhe; Lv, Qiang; Gao, Xiaoye; Chen, Li; Cao, Yue; Yu, Shuangjiang; He, Chaoliang; Chen, Xuesi

    2015-04-29

    pH-responsive supramolecular amphiphilic micelles based on benzimidazole-terminated poly(ethylene glycol) (PEG-BM) and β-cyclodextrin-modified poly(L-lactide) (CD-PLLA) were developed by exploiting the host-guest interaction between benzimidazole (BM) and β-cyclodextrin (β-CD). The dissociation of the supramolecular micelles was triggered in acidic environments. An antineoplastic drug, doxorubicin (DOX), was loaded into the supramolecular micelles as a model drug. The release of DOX from the supramolecular micelles was clearly accelerated as the pH was reduced from 7.4 to 5.5. The DOX-loaded PEG-BM/CD-PLLA supramolecular micelles displayed an enhanced intracellular drug-release rate in HepG2 cells compared to the pH-insensitive DOX-loaded PEG-b-PLLA counterpart. After intravenous injection into nude mice bearing HepG2 xenografts by the tail vein, the DOX-loaded supramolecular micelles exhibited significantly higher tumor inhibition efficacy and reduced systemic toxicity compared to free DOX. Furthermore, the DOX-loaded supramolecular micelles showed a blood clearance rate markedly lower than that of free DOX and comparable to that of the DOX-loaded PEG-b-PLLA micelles after intravenous injection into rats. Therefore, the pH-responsive PEG-BM/CD-PLLA supramolecular micelles hold potential as a smart nanocarrier for anticancer drug delivery. PMID:25856564

  4. Development and in vitro assessment of enzymatically-responsive poly(ethylene glycol) hydrogels for the delivery of therapeutic peptides

    PubMed Central

    Van Hove, Amy H.; Beltejar, Michael-John; Benoit, Danielle S. W.

    2015-01-01

    Despite the recent expansion of peptide drugs, delivery remains a challenge due to poor localization and rapid clearance. Therefore, a hydrogel-based platform technology was developed to control and sustain peptide drug release via matrix metalloproteinase (MMP) activity. Specifically, hydrogels were composed of poly(ethylene glycol) and peptide drugs flanked by MMP substrates and terminal cysteine residues as crosslinkers. First, peptide drug bioactivity was investigated in expected released forms (e.g., with MMP substrate residues) in vitro prior to incorporation into hydrogels. Three peptides (Qk (from Vascular Endothelial Growth Factor), SPARC113, and SPARC118 (from Secreted Protein Acidic and Rich in Cysteine)) retained bioactivity and were used as hydrogel crosslinkers in full MMP degradable forms. Upon treatment with MMP2, hydrogels containing Qk, SPARC113, and SPARC118 degraded in 6.7, 6 and 1 days, and released 5, 8 and, 19% of peptide, respectively. Further investigation revealed peptide drug size controlled hydrogel swelling and degradation rate, while hydrophobicity impacted peptide release. Additionally, degraded Qk, SPARC113, and SPARC118 releasing hydrogels increased endothelial cell tube formation 3.1, 1.7, and 2.8-fold, respectively. While pro-angiogenic peptides were the focus of this study, the design parameters detailed allow for adaptation of hydrogels to control peptide release for a variety of therapeutic applications. PMID:25178558

  5. Fabrication of tethered carbon nanotubes in cellulose acetate/polyethylene glycol-400 composite membranes for reverse osmosis.

    PubMed

    Sabir, Aneela; Shafiq, Muhammad; Islam, Atif; Sarwar, Afsheen; Dilshad, Muhammad Rizwan; Shafeeq, Amir; Zahid Butt, Muhammad Taqi; Jamil, Tahir

    2015-11-01

    In this study pristine multi-walled carbon nanotubes (MWCNTs) were surface engineered (SE) in strong acidic medium by oxidation purification method to form SE-MWCNT. Five different amount of SE-MWCNT ranging from 0.1 to 0.5 wt% were thoroughly and uniformly dispersed in cellulose acetate/polyethylene glycol (CA/PEG400) polymer matrix during synthesis of membrane by dissolution casting method. The structural analysis, surface morphology and roughness was carried out by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively, which showed that the dispersed SE-MWCNT was substantially tethered in CA/PEG400 polymer matrix membrane. The thermogravimetric analysis (TGA) of membranes also suggested some improvement in thermal properties with the addition of SE-MWCNT. Finally, the performance of these membranes was assessed for suitability in drinking water treatment. The permeation flux and salt rejection were determined by using indigenously fabricated reverse osmosis pilot plant with 1000 ppm NaCl feed solution. The results showed that the tethered SE-MWCNT/CA/PEG400 polymer matrix membrane, with strong SE-MWCNTs/polymer matrix interaction, improved the salt rejection performance of the membrane with the salt rejection of 99.8% for the highest content of SE-MWCNT. PMID:26256386

  6. Proteomic and phosphoproteomic analysis of polyethylene glycol-induced osmotic stress in root tips of common bean (Phaseolus vulgaris L.)

    PubMed Central

    Horst, Walter Johannes

    2013-01-01

    Previous studies have shown that polyethylene glycol (PEG)-induced osmotic stress (OS) reduces cell-wall (CW) porosity and limits aluminium (Al) uptake by root tips of common bean (Phaseolus vulgaris L.). A subsequent transcriptomic study suggested that genes related to CW processes are involved in adjustment to OS. In this study, a proteomic and phosphoproteomic approach was applied to identify OS-induced protein regulation to further improve our understanding of how OS affects Al accumulation. Analysis of total soluble proteins in root tips indicated that, in total, 22 proteins were differentially regulated by OS; these proteins were functionally categorized. Seventy-seven per- cent of the total expressed proteins were involved in metabolic pathways, particularly of carbohydrate and amino acid metabolism. An analysis of the apoplastic proteome revealed that OS reduced the level of five proteins and increased that of seven proteins. Investigation of the total soluble phosphoproteome suggested that dehydrin responded to OS with an enhanced phosphorylation state without a change in abundance. A cellular immunolocalization analysis indicated that dehydrin was localized mainly in the CW. This suggests that dehydrin may play a major protective role in the OS-induced physical breakdown of the CW structure and thus maintenance of the reversibility of CW extensibility during recovery from OS. The proteomic and phosphoproteomic analyses provided novel insights into the complex mechanisms of OS-induced reduction of Al accumulation in the root tips of common bean and highlight a key role for modification of CW structure. PMID:24123251

  7. A poly(ethylene glycol)-based surfactant for formulation of drug-loaded mucus penetrating particles.

    PubMed

    Mert, Olcay; Lai, Samuel K; Ensign, Laura; Yang, Ming; Wang, Ying-Ying; Wood, Joseph; Hanes, Justin

    2012-02-10

    Mucosal surfaces are protected by a highly viscoelastic and adhesive mucus layer that traps most foreign particles, including conventional drug and gene carriers. Trapped particles are eliminated on the order of seconds to hours by mucus clearance mechanisms, precluding sustained and targeted drug and nucleic acid delivery to mucosal tissues. We have previously shown that polymeric coatings that minimize adhesive interactions with mucus constituents lead to particles that rapidly penetrate human mucus secretions. Nevertheless, a particular challenge in formulating drug-loaded mucus penetrating particles (MPP) is that many commonly used surfactants are either mucoadhesive, or do not facilitate efficient drug encapsulation. We tested a novel surfactant molecule for particle formulation composed of Vitamin E conjugated to 5 kDa poly(ethylene glycol) (VP5k). We show that VP5k-coated poly(lactide-co-glycolide) (PLGA) nanoparticles rapidly penetrate human cervicovaginal mucus, whereas PLGA nanoparticles coated with polyvinyl alcohol or Vitamin E conjugated to 1 kDa PEG were trapped. Importantly, VP5k facilitated high loading of paclitaxel, a frontline chemo drug, into PLGA MPP, with controlled release for at least 4 days and negligible burst release. Our results offer a promising new method for engineering biodegradable, drug-loaded MPP for sustained and targeted delivery of therapeutics at mucosal surfaces. PMID:21911015

  8. Enzymatically-responsive pro-angiogenic peptide-releasing poly(ethylene glycol) hydrogels promote vascularization in vivo.

    PubMed

    Van Hove, Amy H; Burke, Kathleen; Antonienko, Erin; Brown, Edward; Benoit, Danielle S W

    2015-11-10

    Therapeutic angiogenesis holds great potential for a myriad of tissue engineering and regenerative medicine approaches. While a number of peptides have been identified with pro-angiogenic behaviors, therapeutic efficacy is limited by poor tissue localization and persistence. Therefore, poly(ethylene glycol) hydrogels providing sustained, enzymatically-responsive peptide release were exploited for peptide delivery. Two pro-angiogenic peptide drugs, SPARC113 and SPARC118, from the Secreted Protein Acidic and Rich in Cysteine, were incorporated into hydrogels as crosslinking peptides flanked by matrix metalloproteinase (MMP) degradable substrates. In vitro testing confirmed peptide drug bioactivity requires sustained delivery. Furthermore, peptides retain bioactivity with residual MMP substrates present after hydrogel release. Incorporation into hydrogels achieved enzymatically-responsive bulk degradation, with peptide release in close agreement with hydrogel mass loss and released peptides retaining bioactivity. Interestingly, SPARC113 and SPARC118-releasing hydrogels had significantly different degradation time constants in vitro (1.16 and 8.77×10(-2) h(-1), respectively), despite identical MMP degradable substrates. However, upon subcutaneous implantation, both SPARC113 and SPARC118 hydrogels exhibited similar degradation constants of ~1.45×10(-2) h(-1), and resulted in significant ~1.65-fold increases in angiogenesis in vivo compared to controls. Thus, these hydrogels represent a promising pro-angiogenic approach for applications such as tissue engineering and ischemic tissue disorders. PMID:26365781

  9. Cytocompatible Poly(ethylene glycol)-co-polycarbonate Hydrogels Crosslinked by Copper-free, Strain-promoted “Click” Chemistry

    PubMed Central

    Xu, Jianwen; Filion, Tera M.; Prifti, Fioleda

    2013-01-01

    Strategies to encapsulate cells in cytocompatible 3-dimensional hydrogels with tunable mechanical properties and degradability without harmful gelling conditions are highly desired for regenerative medicine applications. Here we reported a method for preparing poly(ethylene glycol)-co-polycarbonate hydrogels through copper-free, strain-promoted azide-alkyne cycloaddition (SPAAC) “Click” chemistry. Hydrogels with varying mechanical properties were formed by “clicking” azido-functionalized poly(ethylene glycol)-co-polycarbonate macromers with dibenzocyclooctyne functionalized poly(ethylene glycol) under physiological conditions within minutes. Bone marrow stromal cells encapsulated in these gels exhibited higher cellular viability than those encapsulated in photo-crosslinked poly(ethylene glycol) dimethacrylate. The precise control over the macromer compositions, the cytocompatible SPAAC crosslinking, and the degradability of the polycarbonate segments combined make these hydrogels promising candidates for scaffold- and stem cell-assisted tissue repair and regeneration. PMID:21954076

  10. A new synthesis of lamellar-mesostructured silica by using poly(ethylene glycol) distearate as template

    SciTech Connect

    Zhang Huanzhi; Jin Zhengwei; Wang Xiaodong

    2008-11-03

    A lamellar-mesostructured silica has been synthesized by using poly(ethylene glycol) distearate as template in ethanol solution. Highly ordered lamellar mesostructure was confirmed by X-ray diffraction pattern, transmission electronic microscopy, and nitrogen adsorption-desorption isotherm. The material obtained in this work has a large interlayer distance, and good thermal and mechanical stabilities, which can favor the preparation of the in situ polymerized nanocomposites based on intercalation of polymers in the lamellar-mesostructured silica.

  11. Heteromerous interactions among glycolytic enzymes and of glycolytic enzymes with F-actin: effects of poly(ethylene glycol).

    PubMed

    Walsh, J L; Knull, H R

    1988-01-01

    Interactions of glucose-6-phosphate isomerase (D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9), aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate lyase, EC 4.1.2.13), glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12), triose-phosphate isomerase (D-glyceraldehyde-3-phosphate ketol-isomerase, EC 5.3.1.1), phosphoglycerate mutase (D-phosphoglycerate 2,3-phosphomutase, EC 5.4.2.1), phosphoglycerate kinase (ATP:3-phospho-D-glycerate 1-phosphotransferase, EC 2.7.3), enolase (2-phospho-D-glycerate hydro-lyase, EC 4.2.1.11), pyruvate kinase (ATP:Pyruvate O2-phosphotransferase, EC 2.7.1.40) and lactate dehydrogenase [S)-lactate:NAD+ oxidoreductase, EC 1.1.1.27) with F-actin, among the glycolytic enzymes listed above, and with phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) were studied in the presence of poly(ethylene glycol). Both purified rabbit muscle enzymes and rabbit muscle myogen, a high-speed supernatant fraction containing the glycolytic enzymes, were used to study enzyme-F-actin interactions. Following ultracentrifugation, F-actin and poly(ethylene glycol) tended to increase and KCl to decrease the pelleting of enzymes. In general, the greater part of the pelleting occurred in the presence of both F-actin and poly(ethylene glycol) and the absence of KCl. Enzymes that pelleted more in myogen preparations than as individual purified enzymes in the presence of poly(ethylene glycol) and the absence of F-actin were tested for specific enzyme-enzyme associations, several of which were observed. Such interactions support the view that the internal cell structure is composed of proteins that interact with one another to form the microtrabecular lattice. PMID:3334856

  12. Physical and rheological characterisation of polyethylene glycol-cashew-nut tree gum aqueous two-phase systems.

    PubMed

    Oliveira, L A; Sarubbo, L A; Porto, A L F; Lima-Filho, J L; Campos-Takaki, G M; Tambourgi, E B

    2002-01-01

    The characterisation of the polyethylene glycol-cashew-nut tree gum aqueous two-phase system is described. Factors which affect the phase diagram including polymer molecular mass, pH and temperature were analysed. The physico-chemical properties of the system such as density, viscosity, volume ratio and phase separation times were also described. The characteristics of the system studied indicate it to be very attractive as a separation technique. PMID:11824395

  13. Aqueous Biphasic Systems Based on Salting-Out Polyethylene Glycol or Ionic Solutions: Strategies for Actinide or Fission Product Separations

    SciTech Connect

    Rogers, Robin D.; Gutowski, Keith E.; Griffin, Scott T.; Holbrey, John D.

    2004-03-29

    Aqueous biphasic systems can be formed by salting-out (with kosmotropic, waterstructuring salts) water soluble polymers (e.g., polyethylene glycol) or aqueous solutions of a wide range of hydrophilic ionic liquids based on imidazolium, pyridinium, phosphonium and ammonium cations. The use of these novel liquid/liquid biphases for separation of actinides or other fission products associated with nuclear wastes (e.g., pertechnetate salts) has been demonstrated and will be described in this presentation.

  14. Poly(ethylene glycol)-grafted copolymers as synthetic equivalents of benzyltriethylammonium chloride for triphase catalytic alkylation

    SciTech Connect

    Kimura, Y.; Kirszensztejn, P.; Regan, S.L.

    1983-02-11

    Synthetic results are reported, which show that simple poly(ethylene glycols) grafted to cross-linked polystyrene are remarkably active and stable triphase catalysts for the alkylation of nitriles, ketones, and alcohols. Resins were prepared from commercial chloromethylated polystyrene by using standard grafting procedures. For comparison of their efficacies for promoting alkylation, the conversion of phenylacetonitrile to 2-phenylhexane-nitrile was chosen as a standard reaction.

  15. Biomechanical Performances of Networked Polyethylene Glycol Diacrylate: Effect of Photoinitiator Concentration, Temperature, and Incubation Time

    PubMed Central

    Khandaker, Morshed; Orock, Albert; Tarantini, Stefano; White, Jeremiah; Yasar, Ozlem

    2016-01-01

    Nutrient conduit networks can be introduced within the Polyethylene Glycol Diacrylate (PEGDA) tissue construct to enable cells to survive in the scaffold. Nutrient conduit networks can be created on PEGDA by macrochannel to nanochannel fabrication techniques. Such networks can influence the mechanical and cell activities of PEGDA scaffold. There is no study conducted to evaluate the effect of nutrient conduit networks on the maximum tensile stress and cell activities of the tissue scaffold. The study aimed to explore the influence of the network architecture on the maximum tensile stress of PEGDA scaffold and compared with the nonnetworked PEGDA scaffold. Our study found that there are 1.78 and 2.23 times decrease of maximum tensile stress due to the introduction of nutrient conduit networks to the PEGDA scaffold at 23°C and 37°C temperature conditions, respectively. This study also found statistically significant effect of network architecture, PI concentration, temperature, and wait time on the maximum failure stress of PEGDA samples (P value < 0.05). Cell viability results demonstrated that networked PEGDA hydrogels possessed increased viability compared to nonnetworked and decreased viability with increased photoinitiator concentrations. The results of this study can be used for the design of PEGDA scaffold with macrosize nutrient conduit network channels. PMID:26925104

  16. Subunit Stabilization and Polyethylene Glycolation of Cocaine Esterase Improves In Vivo Residence Time

    SciTech Connect

    Narasimhan, Diwahar; Collins, Gregory T.; Nance, Mark R.; Nichols, Joseph; Edwald, Elin; Chan, Jimmy; Ko, Mei-Chuan; Woods, James H.; Tesmer, John J.G.; Sunahara, Roger K.

    2012-03-15

    No small-molecule therapeutic is available to treat cocaine addiction, but enzyme-based therapy to accelerate cocaine hydrolysis in serum has gained momentum. Bacterial cocaine esterase (CocE) is the fastest known native enzyme that hydrolyzes cocaine. However, its lability at 37 C has limited its therapeutic potential. Cross-linking subunits through disulfide bridging is commonly used to stabilize multimeric enzymes. Herein we use structural methods to guide the introduction of two cysteine residues within dimer interface of CocE to facilitate intermolecular disulfide bond formation. The disulfide-crosslinked enzyme displays improved thermostability, particularly when combined with previously described mutations that enhance stability (T172R-G173Q). The newly modified enzyme yielded an extremely stable form of CocE (CCRQ-CocE) that retained greater than 90% of its activity after 41 days at 37 C, representing an improvement of more than 4700-fold over the wild-type enzyme. CCRQ-CocE could also be modified by polyethylene glycol (PEG) polymers, which improved its in vivo residence time from 24 to 72 h, as measured by a cocaine lethality assay, by self-administration in rodents, and by measurement of inhibition of cocaine-induced cardiovascular effects in rhesus monkeys. PEG-CCRQ elicited negligible immune response in rodents. Subunit stabilization and PEGylation has thus produced a potential protein therapeutic with markedly higher stability both in vitro and in vivo.

  17. Entrapping quercetin in silica/polyethylene glycol hybrid materials: Chemical characterization and biocompatibility.

    PubMed

    Catauro, Michelina; Bollino, Flavia; Nocera, Paola; Piccolella, Simona; Pacifico, Severina

    2016-11-01

    Sol-gel synthesis was exploited to entrap quercetin, a natural occurring antioxidant polyphenol, in silica-based hybrid materials, which differed in their polyethylene glycol (PEG) content (6, 12, 24 and 50wt%). The materials obtained, whose nano-composite nature was ascertained by Scanning Electron Microscopy (SEM), were chemically characterized by Fourier Transform InfraRed (FT-IR) and UV-Vis spectroscopies. The results prove that a reaction between the polymer and the drug occurred. Bioactivity tests showed their ability to induce hydroxyapatite nucleation on the sample surfaces. The direct contact method was applied to screen the cytotoxicity of the synthetized materials towards fibroblast NIH 3T3 cells, commonly used for in vitro biocompatibility studies, and three nervous system cell lines (neuroblastoma SH-SY5Y, glioma U251, and pheochromocytoma PC12 cell lines), adopted as models in oxidative stress related studies. Using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay NIH 3T3 proliferation was assessed and the morphology was not compromised by direct exposure to the materials. Analogously, PC-12, and U-251 cell lines were not affected by new materials. SH-SY5Y appeared to be the most sensitive cell line with cytotoxic effects of 20-35%. PMID:27524014

  18. Polyethylene glycols in oral and parenteral formulations--A critical review.

    PubMed

    Gullapalli, Rampurna P; Mazzitelli, Carolyn L

    2015-12-30

    Polyethylene glycols (PEGs) are frequently employed as vehicles in oral and parenteral dosage forms. PEGs have low toxicity, are miscible with aqueous fluids in all proportions, and dissolve many poorly aqueous soluble compounds. Compounds with poor aqueous solubility and resulting poor bioavailability and considerable individual variability in the absorption were shown to provide exceptionally high bioavailability and reduced inter-subject variability in plasma concentrations when dosed as solutions or suspensions in PEGs. The advantages offered by PEGs, however, are not without potential challenges that must also be considered and which are the focus of this review. First, PEGs often may have high solubilizing power for some poorly aqueous soluble compounds, the high affinity of these vehicles for water can potentially lead to precipitation of the dissolved compounds when the formulations encounter an aqueous environment in vitro or in vivo, resulting in reduced bioavailability of the compounds. Second, PEGs, due to the presence of hydroxyl groups in their structures, are reactive with compounds dissolved within, resulting in the formation of degradation products. Third, PEGs, due to the presence of recurring ether groups in their polymer chains, are also inherently susceptible to autooxidative reactions, resulting in the formation of highly reactive products, which degrade several compounds formulated with PEGs. The objective is to review the applications and limitations of PEGs in pharmaceutical dosage forms and discuss solutions to mitigate challenges that may potentially arise from their use. PMID:26581774

  19. Anhydric maleic functionalization and polyethylene glycol grafting of lactide-co-trimethylene carbonate copolymers.

    PubMed

    Díaz, A; Del Valle, L; Franco, L; Sarasua, J R; Estrany, F; Puiggalí, J

    2014-09-01

    Lactide and trimethylene carbonate copolymers were successfully grafted with polyethylene glycol via previous functionalization with maleic anhydride and using N,N'-diisopropylcarbodiimide as condensing agent. Maleinization led to moderate polymer degradation. Specifically, the weight average molecular weight decreased from 36,200 to 30,200 g/mol for the copolymer having 20 mol% of trimethylene carbonate units. Copolymers were characterized by differential scanning calorimetry, thermogravimetry and X-ray diffraction. Morphology of spherulites and lamellar crystals was evaluated with optical and atomic force microscopies, respectively. The studied copolymers were able to crystallize despite the randomness caused by the trimethylene carbonate units and the lateral groups. Contact angle measurements indicated that PEG grafted copolymers were more hydrophilic than parent copolymers. This feature justified that enzymatic degradation in lipase medium and proliferation of both epithelial-like and fibroblast-like cells were enhanced. Grafted copolymers were appropriate to prepare regular drug loaded microspheres by the oil-in-water emulsion method. Triclosan release from loaded microspheres was evaluated in two media. PMID:25063149

  20. Hydrophilic and amphiphilic polyethylene glycol-based hydrogels with tunable degradability prepared by "click" chemistry.

    PubMed

    Truong, Vinh; Blakey, Idriss; Whittaker, Andrew K

    2012-12-10

    Hydrogels with tunable degradability have potential uses in a range of applications including drug delivery and tissue scaffolds. A series of poly(ethylene glycol) (PEG) hydrogels and amphiphilic PEG-poly(trimethylene carbonate ) (PTMC) hydrogels were prepared using copper-catalyzed Huisgen's 1,3-dipolar cycloaddition, or "click" chemistry as the coupling chemistry. The fidelity of the coupling chemistry was confirmed using Fourier transform infrared (FTIR) and 1H magic angle spinning (MAS) NMR spectroscopy while thorough swelling and degradation studies of the hydrogels were performed to relate network structure to the physical properties. The cross-linking efficiency calculated using the Flory-Rehner equation varied from 0.90 to 0.99, which indicates that the networks are close to "ideal" at a molecular level. However, at the microscopic level cryogenic scanning electron microscopy (cryo-SEM) indicated that some degree of phase separation was occurring during cross-linking. At 37 °C and pH 7.4, the degradation rate of the hydrogels increased with decreasing cross-link density in the network. Introduction of PTMC as the cross-linker produced an amphiphilic gel with higher cross-link density and a longer degradation time. The degradability of the resultant hydrogels could thus be tuned through control of molecular weight and structure of the precursors. PMID:23134321

  1. Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform

    NASA Astrophysics Data System (ADS)

    Markelov, Denis A.; Matveev, Vladimir V.; Ingman, Petri; Nikolaeva, Marianna N.; Penkova, Anastasia V.; Lahderanta, Erkki; Boiko, Natalia I.; Chizhik, Vladimir I.

    2016-04-01

    We have studied copolymer dendrimer structure: carbosilane dendrimers with terminal phenylbenzoate mesogenic groups attached by poly(ethylene) glycol (PEG) spacers. In this system PEG spacers are additional tuning to usual copolymer structure: dendrimer with terminal mesogenic groups. The dendrimer macromolecules were investigated in a dilute chloroform solution by 1H NMR methods (spectra and relaxations). It was found that the PEG layer in G = 5 generations dendrimer is “frozen” at high temperatures (above 260 K), but it unexpectedly becomes “unfrozen” at temperatures below 250 K (i.e., melting when cooling). The transition between these two states occurs within a small temperature range (~10 K). Such a behavior is not observed for smaller dendrimer generations (G = 1 and 3). This effect is likely related to the low critical solution temperature (LCST) of PEG and is caused by dendrimer conformations, in which the PEG group concentration in the layer increases with growing G. We suppose that the unusual behavior of PEG fragments in dendrimers will be interesting for practical applications such as nanocontainers or nanoreactors.

  2. Injectable Dopamine-Modified Poly(ethylene glycol) Nanocomposite Hydrogel with Enhanced Adhesive Property and Bioactivity

    PubMed Central

    2015-01-01

    A synthetic mimic of mussel adhesive protein, dopamine-modified four-armed poly(ethylene glycol) (PEG-D4), was combined with a synthetic nanosilicate, Laponite (Na0.7+(Mg5.5Li0.3Si8)O20(OH)4)0.7–), to form an injectable naoncomposite tissue adhesive hydrogel. Incorporation of up to 2 wt % Laponite significantly reduced the cure time while enhancing the bulk mechanical and adhesive properties of the adhesive due to strong interfacial binding between dopamine and Laponite. The addition of Laponite did not alter the degradation rate and cytocompatibility of PEG-D4 adhesive. On the basis of subcutaneous implantation in rat, PEG-D4 nanocomposite hydrogels elicited minimal inflammatory response and exhibited an enhanced level of cellular infiltration as compared to Laponite-free samples. The addition of Laponite is potentially a simple and effective method for promoting bioactivity in a bioinert, synthetic PEG-based adhesive while simultaneously enhancing its mechanical and adhesive properties. PMID:25222290

  3. Polyethylene Glycol-Fused Allografts Produce Rapid Behavioral Recovery After Ablation of Sciatic Nerve Segments

    PubMed Central

    Riley, D.C.; Bittner, G.D.; Mikesh, M.A.; Cardwell, N.L.; Pollins, A.C.; Ghergherehchi, C.L.; Sunkesula, S.R. Bhupanapadu; Ha, T.N.; Hall, B.T.D.; Poon, A.D.; Pyarali, M.; Boyer, R.B.; Mazal, A.T.; Munoz, N.; Trevino, R.C.; Schallert, T.; Thayer, W.P.

    2014-01-01

    Restoration of neuronal functions by outgrowths regenerating at ~1mm/d from the proximal stumps of severed peripheral nerves takes many weeks or months, if it occurs at all, especially after ablation of nerve segments. Distal segments of severed axons typically degenerate in 1–3 days. The purpose of this study was to show that Wallerian degeneration could be prevented or retarded and lost behavioral function restored following ablation of 0.5 – 1 cm segments of rat sciatic nerves in host animals. This is achieved using 0.8 – 1.1cm microsutured donor allografts treated with bioengineered solutions varying in ionic and polyethylene glycol (PEG) concentrations (modified PEG-fusion procedure), being careful not to stretch any portion of donor or host sciatic nerves. Our data show that PEG-fusion permanently restores axonal continuity within minutes as initially assessed by action potential conduction and intracellular diffusion of dye. Behavioral functions mediated by the sciatic nerve are largely restored within 2 – 4 wk as measured by the Sciatic Functional Index (SFI). Increased restoration of sciatic behavioral functions after ablating 0.5 – 1 cm segments is associated with greater numbers of viable myelinated axons within, and distal to, PEG-fused allografts. Many such viable myelinated axons are almost-certainly spared from Wallerian degeneration by PEG-fusion. PEG-fusion of donor allografts may produce a paradigm-shift in the treatment of peripheral nerve injuries. PMID:25425242

  4. Case of inappropriate ADH syndrome: hyponatremia due to polyethylene glycol bowel preparation.

    PubMed

    Ko, Sun-Hye; Lim, Chul-Hyun; Kim, Jae-Young; Kang, Seung Hun; Baeg, Myong Ki; Oh, Hyun Jin

    2014-09-14

    Colonoscopic screening has been reported to reduce deaths from colorectal cancer. Adequate bowel preparation is essential for this and safety is an important issue in choosing the methods. Polyethylene glycol (PEG) is regarded as a safe method for cleansing, especially compared with oral sodium phosphate. Here, we present a case of hyponatremia caused by the syndrome of inappropriate antidiuretic hormone (ADH) syndrome after PEG precolonoscopic cleansing resulting in generalized tonic-clonic seizures. A 62-year-old women had ingested PEG for precolonoscopic bowel cleansing. While waiting for the colonoscopy, she developed a stuporous mentality and generalized tonic-clonic seizures, which did not correlate with brain magnetic resonance imaging. Her serum sodium level was 113 mEq per liter and laboratory analyses were consistent with inappropriate ADH syndrome. Her thyroid and adrenal functions were normal. There were no malignancies, infections, respiratory disorders or central nervous disorders and she had no history of taking either diuretics or other medications, which might have caused inappropriate ADH syndrome. She was treated with 3% hypertonic saline and showed a complete neurological recovery as her sodium levels recovered. Follow-up visits showed the patient to have a normal sodium level without neurologic deficits. This case shows that inappropriate ADH syndrome can be caused by PEG preparation, which implies that physicians have to be aware of the possible side effects of this colonic cleansing approach and mindful of the possible ensuing symptoms. PMID:25232272

  5. Binding characteristics between poly(ethylene glycol) and hydrophilic modified ibuprofen in aqueous solution.

    PubMed

    Wei, Duo; Ge, Lingling; Guo, Rong

    2010-03-18

    The solubility of ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), is enhanced by synthesizing ibuprofen ester with a water-soluble polymer, poly(ethylene glycol) (PEG), and the product obtained functions as a nonionic surfactant (IBF-PEG800, IP800). The morphology and aggregation behavior of IP800 micelles and IP800/PEG complexes in aqueous solution are investigated by (1)H NMR technology, dynamic light scattering (DLS), isothermal titration calorimetry (ITC), and fluorescence resonance energy transfer (FRET). The microstructure of IP800 micelles is strongly related to the concentration of IP800. IP800 monomers can form looser micelles at relatively low concentrations and much tighter micelles at high concentrations. And the binding model of PEG with looser IP800 micelles dramatically depends on the molecular weight and concentration of PEG: PEG with lower molecular weight (MW < or = 2000 Da) inserts to the interface of the hydrophilic corona and hydrophobic core of IP800 micelles; PEG with higher molecular weight (MW > 2000 Da) binds to the surface of IP800 micelles, and one long PEG chain (6000 < MW < or = 20000 Da) wraps several IP800 micelles. Besides, the ratio of short chain PEG400 to IP800 micelles of the IP800/PEG complex is about 15:1 at a fixed concentration of IP800 (0.05 mM), and for the long chain PEG20000 it is 1:3-1:4. PMID:20178332

  6. ExtraPEG: A Polyethylene Glycol-Based Method for Enrichment of Extracellular Vesicles

    PubMed Central

    Rider, Mark A.; Hurwitz, Stephanie N.; Meckes, David G.

    2016-01-01

    Initially thought to be a means for cells to eliminate waste, secreted extracellular vesicles, known as exosomes, are now understood to mediate numerous healthy and pathological processes. Though abundant in biological fluids, purifying exosomes has been challenging because their biophysical properties overlap with other secreted cell products. Easy-to-use commercial kits for harvesting exosomes are now widely used, but the relative low-purity and high-cost of the preparations restricts their utility. Here we describe a method for purifying exosomes and other extracellular vesicles by adapting methods for isolating viruses using polyethylene glycol. This technique, called ExtraPEG, enriches exosomes from large volumes of media rapidly and inexpensively using low-speed centrifugation, followed by a single small-volume ultracentrifugation purification step. Total protein and RNA harvested from vesicles is sufficient in quantity and quality for proteomics and sequencing analyses, demonstrating the utility of this method for biomarker discovery and diagnostics. Additionally, confocal microscopy studies suggest that the biological activity of vesicles is not impaired. The ExtraPEG method can be easily adapted to enrich for different vesicle populations, or as an efficient precursor to subsequent purification techniques, providing a means to harvest exosomes from many different biological fluids and for a wide variety of purposes. PMID:27068479

  7. Polyethylene glycol (PEG)-Poly(N-isopropylacrylamide) (PNIPAAm) based thermosensitive injectable hydrogels for biomedical applications.

    PubMed

    Alexander, Amit; Ajazuddin; Khan, Junaid; Saraf, Swarnlata; Saraf, Shailendra

    2014-11-01

    Protein and peptide delivery by the use of stimuli triggered polymers remains to be the area of interest among the scientist and innovators. In-situ forming gel for the parenteral route in the form of hydrogel and implants are being utilized for various biomedical applications. The formulation of gel depends upon factors such as temperature modulation, pH changes, the presence of ions and ultra-violet irradiation, from which drug is released in a sustained and controlled manner. Among various stimuli triggered factors, thermoresponsive is the most potential one for the delivery of protein and peptides. Poly(ethylene glycol) (PEG) based copolymers play a crucial role as a biomedical material for biomedical applications, because of its biocompatibility, biodegradability, thermosensitivity and easy controlled characters. This review, stresses on the physicochemical property, stability and compositions prospects of smart thermoresponsive polymer specifically, PEG/Poly(N-isopropylacrylamide) (PNIPAAm) based thermoresponsive injectable hydrogels, recently utilized for biomedical applications. PEG-PNIPAAm based hydrogel exhibits good gelling mechanical strength and minimizes the initial burst effect of the drug. In addition, upon changing the composition and proportion of the copolymer molecular weight and ratio, the gelling time can be reduced to a great extent providing better sol-gel transition. The hydrogel formed by the same is able to release the drug over a long duration of time, meanwhile is also biocompatible and biodegradable. Manuscript will give the new researchers an idea about the potential and benefits of PNIPAAm based thermoresponsive hydrogels for the biomedical application. PMID:25092423

  8. Polyethylene glycol dimethyl ether (PEGDME)-based electrolyte for lithium metal battery

    NASA Astrophysics Data System (ADS)

    Carbone, Lorenzo; Gobet, Mallory; Peng, Jing; Devany, Matthew; Scrosati, Bruno; Greenbaum, Steve; Hassoun, Jusef

    2015-12-01

    We propose in this work a polyethylene glycol dimethyl ether (MW 500) dissolving lithium trifluoromethansulfonate (LiCF3SO3) salt as suitable electrolyte media for a safe and efficient use of the lithium metal anode in battery. Voltammetry and galvanostatic tests reveal significant enhancement of the electrolyte characteristics, in terms of cycling life and chemical stability, by the addition of lithium nitrate (LiNO3) to the solution. Furthermore, PFG NMR measurements suggest the applicability of the electrolyte in battery in terms of ionic conductivity, lithium transference number, ionic-association degree and self-diffusion coefficient. Accordingly, the electrolyte is employed in a lithium battery using lithium iron phosphate as the selected cathode. The battery delivers a stable capacity of 150 mAh g-1 and flat working voltage of 3.5 V, thus leading to a theoretical energy density referred to the cathode of 520 Wh kg-1. This battery is considered a suitable energy storage system for advanced applications requiring both high safety and high energy density.

  9. Ultrafiltration – an alternative method to polyethylene glycol precipitation for macroprolactin detection

    PubMed Central

    Beda-Maluga, Karolina; Pisarek, Hanna; Romanowska, Irena; Komorowski, Jan; Świętosławski, Jacek

    2015-01-01

    Introduction The aim of the study was to evaluate two methods of macroprolactin (MaPRL) detection – precipitation with polyethylene glycol (PEG) and ultrafiltration and to compare these techniques with “gold standard” – gel filtration chromatography (GFC). Material and methods The study was conducted on 245 patients – 45 with organic and 200 with functional hyperprolactinaemia. In all the subjects MaPRL was detected by precipitation with PEG and ultrafiltration. Additionally, gel filtration chromatography was performed in some of the serum samples. Results Macroprolactinaemia was detected in 27 patients – 8 with prolactinoma and 19 with functional hyperprolactinaemia. Assessing positive and negative results for MaPRL, we observed high diagnostic agreement (95.9%) and positive correlation (r = 0.506, p < 0.001) between the methods. The results of precipitation and ultrafiltration positive for MaPRL were concordant in 63%. The dominance of MaPRL detected with precipitation and/or ultrafiltration was confirmed by GFC in 76% of cases (all patients with functional hyperprolactinaemia). Among 6 examined patients with prolactinoma, GFC showed four false-positive results – 1 case of precipitation and 3 cases of ultrafiltration. Conclusions Efficacy of MaPRL detection with precipitation and ultrafiltration is comparable especially in cases of functional hyperprolactinaemia. In patients with prolactinoma, precipitation seems to be a more efficient separation method. PMID:26528343

  10. Dense Poly(ethylene glycol) Brushes Reduce Adsorption and Stabilize the Unfolded Conformation of Fibronectin.

    PubMed

    Faulón Marruecos, David; Kastantin, Mark; Schwartz, Daniel K; Kaar, Joel L

    2016-03-14

    Polymer brushes, in which polymers are end-tethered densely to a grafting surface, are commonly proposed for use as stealth coatings for various biomaterials. However, although their use has received considerable attention, a mechanistic understanding of the impact of brush properties on protein adsorption and unfolding remains elusive. We investigated the effect of the grafting density of poly(ethylene glycol) (PEG) brushes on the interactions of the brush with fibronectin (FN) using high-throughput single-molecule tracking methods, which directly measure protein adsorption and unfolding within the brush. We observed that, as grafting density increased, the rate of FN adsorption decreased; however, surface-adsorbed FN unfolded more readily, and unfolded molecules were retained on the surface for longer residence times relative to those of folded molecules. These results, which are critical for the rational design of PEG brushes, suggest that there is a critical balance between protein adsorption and conformation that underlies the utility of such brushes in physiological environments. PMID:26866385

  11. Evaluation of the polyethylene glycol-indirect antiglobulin test for routine compatibility testing.

    PubMed

    Slater, J L; Griswold, D J; Wojtyniak, L S; Reisling, M J

    1989-10-01

    All specimens received in the blood bank over a 5-month period for crossmatch or group and screen requests were tested in parallel by a polyethylene glycol-indirect antiglobulin test (PEG-IAT) and a low-ionic-strength saline (LISS)-IAT. The sera of 41 of 1471 patients had reactions, with 50 antibodies being detected. Ten antibodies reacted only on the PEG-IAT and 14 only by the LISS-IAT; the remaining 26 antibodies were detected by both methods. Of the antibodies that reacted only by the LISS-IAT, one (anti-Jka) was considered clinically significant, whereas five of the antibodies that reacted only by the PEG-IAT (1 anti-c, 2-Fya, 1-Jkb, and 1-S) were considered significant. Two antibodies of questionable clinical significance were detected only by the PEG-IAT. In 97 percent of the sera tested, no reaction was detected by either method. The PEG-IAT is an acceptable technique for routine compatibility testing. PMID:2799893

  12. Lipid-polyethylene glycol based nano-ocular formulation of ketoconazole.

    PubMed

    Kakkar, Shilpa; Karuppayil, Sankunny Mohan; Raut, Jayant S; Giansanti, Fabrizio; Papucci, Laura; Schiavone, Nicola; Kaur, Indu Pal

    2015-11-10

    Ophthalmic mycoses including corneal keratitis or endophthalmitis affects 6-million persons/year and can cause blindness. Its management requires antifungals to penetrate the ocular tissue. Oral use of Ketoconazole (KTZ), the first broad-spectrum antifungal to be marketed, is now restricted to life-threatening infections due to severe adverse effects and drug-interactions. Local use of KTZ loaded nanocarrier system can address its toxicity, poor solubility, photodegradation, permeation and bioavailability issues. Solid lipid nanoparticles (SLNs) comprising Compritol(®) 888 ATO and PEG 600 matrix, were presently prepared using hot high-pressure homogenization. Employing extensive characterization: TEM, NMR, DSC, XRD and FTIR, it is proposed that SLNs comprise of a polyethylene glycol (PEG) core into which KTZ is dissolved. PEG endows the lipid matrix with amorphousness and imperfections; rigidity; and, stability to aggregation, on storage and autoclaving. PEG is a simple, cost-effective and safe polymer with superior solubilizing and surfactant-supporting properties. Without its inclusion KTZ could not be loaded into SLNs. It ensured high incorporation efficiency (70%) of KTZ; small size (126 nm); and, better permeation into the eye. Pharmacokinetic studies indicated 2.5 and 1.6 fold higher bioavailability (AUC) in aqueous and vitreous humor, respectively. Biocompatibility and in vitro (both in corneal and retinal cell lines) and in vivo (in rabbits) ocular safety is the other highlight of developed formulation. PMID:26325312

  13. Polyethylene Glycol Preconditioning: An Effective Strategy to Prevent Liver Ischemia Reperfusion Injury

    PubMed Central

    Pantazi, Eirini; Calvo, Maria; Folch-Puy, Emma; Serafín, Anna; Panisello, Arnau; Adam, René; Roselló-Catafau, Joan

    2016-01-01

    Hepatic ischemia reperfusion injury (IRI) is an inevitable clinical problem for liver surgery. Polyethylene glycols (PEGs) are water soluble nontoxic polymers that have proven their effectiveness in various in vivo and in vitro models of tissue injury. The present study aims to investigate whether the intravenous administration of a high molecular weight PEG of 35 kDa (PEG 35) could be an effective strategy for rat liver preconditioning against IRI. PEG 35 was intravenously administered at 2 and 10 mg/kg to male Sprague Dawley rats. Then, rats were subjected to one hour of partial ischemia (70%) followed by two hours of reperfusion. The results demonstrated that PEG 35 injected intravenously at 10 mg/kg protected efficiently rat liver against the deleterious effects of IRI. This was evidenced by the significant decrease in transaminases levels and the better preservation of mitochondrial membrane polarization. Also, PEG 35 preserved hepatocyte morphology as reflected by an increased F-actin/G-actin ratio and confocal microscopy findings. In addition, PEG 35 protective mechanisms were correlated with the activation of the prosurvival kinase Akt and the cytoprotective factor AMPK and the inhibition of apoptosis. Thus, PEG may become a suitable agent to attempt pharmacological preconditioning against hepatic IRI. PMID:26981166

  14. Effect of Polyethylene Glycol on the Formation of Magnetic Nanoparticles Synthesized by Magnetospirillum magnetotacticum MS-1.

    PubMed

    Shimoshige, Hirokazu; Kobayashi, Hideki; Mizuki, Toru; Nagaoka, Yutaka; Inoue, Akira; Maekawa, Toru

    2015-01-01

    Magnetotactic bacteria (MTB) synthesize intracellular magnetic nanocrystals called magnetosomes, which are composed of either magnetite (Fe3O4) or greigite (Fe3S4) and covered with lipid membranes. The production of magnetosomes is achieved by the biomineralization process with strict control over the formation of magnetosome membrane vesicles, uptake and transport of iron ions, and synthesis of mature crystals. These magnetosomes have high potential for both biotechnological and nanotechnological applications, but it is still extremely difficult to grow MTB and produce a large amount of magnetosomes under the conventional cultural conditions. Here, we investigate as a first attempt the effect of polyethylene glycol (PEG) added to the culture medium on the increase in the yield of magnetosomes formed in Magnetospirillum magnetotacticum MS-1. We find that the yield of the formation of magnetosomes can be increased up to approximately 130 % by adding PEG200 to the culture medium. We also measure the magnetization of the magnetosomes and find that the magnetosomes possess soft ferromagnetic characteristics and the saturation mass magnetization is increased by 7 %. PMID:25993286

  15. Effect of Polyethylene Glycol on the Formation of Magnetic Nanoparticles Synthesized by Magnetospirillum magnetotacticum MS-1

    PubMed Central

    Shimoshige, Hirokazu; Kobayashi, Hideki; Mizuki, Toru; Nagaoka, Yutaka; Inoue, Akira; Maekawa, Toru

    2015-01-01

    Magnetotactic bacteria (MTB) synthesize intracellular magnetic nanocrystals called magnetosomes, which are composed of either magnetite (Fe3O4) or greigite (Fe3S4) and covered with lipid membranes. The production of magnetosomes is achieved by the biomineralization process with strict control over the formation of magnetosome membrane vesicles, uptake and transport of iron ions, and synthesis of mature crystals. These magnetosomes have high potential for both biotechnological and nanotechnological applications, but it is still extremely difficult to grow MTB and produce a large amount of magnetosomes under the conventional cultural conditions. Here, we investigate as a first attempt the effect of polyethylene glycol (PEG) added to the culture medium on the increase in the yield of magnetosomes formed in Magnetospirillum magnetotacticum MS-1. We find that the yield of the formation of magnetosomes can be increased up to approximately 130 % by adding PEG200 to the culture medium. We also measure the magnetization of the magnetosomes and find that the magnetosomes possess soft ferromagnetic characteristics and the saturation mass magnetization is increased by 7 %. PMID:25993286

  16. Volumetric properties and spectroscopic studies of pyridine or nicotine solutions in liquid polyethylene glycols.

    PubMed

    Visak, Zoran P; Ilharco, Laura M; Garcia, Ana Rosa; Najdanovic-Visak, Vesna; Fareleira, João M N A; Caetano, Fernando J P; Kijevcanin, Mirjana L; Serbanovic, Slobodan P

    2011-07-01

    Densities and molar excess volumes of the solutions of pyridine or nicotine in liquid polyethylene glycol, PEG200 and PEG400, have been determined at several temperatures. The experimental molar excess volumes are negative, thus indicating strong attractive interactions between the components, as could be expected considering their highly polar nature and good hydrogen bond abilities. For the pyridine systems, this negativity is slightly increased as the temperature rises, while the opposite tendency is observed for the nicotine mixtures. When pyridine and nicotine solutions are compared, the former-particularly those with PEG400-exhibit substantially more negative molar excess volumes than the latter. The effect of the polymer chain length on the results for the nicotine solutions is almost negligible. However, this is not the case when pyridine is one of the components: a longer chain induced considerably higher compression on mixing. The Fourier-transform infrared analysis allowed interpretation of the negative experimental molar excess volumes in terms of specific inter- and intramolecular interactions. PMID:21604799

  17. Absorption of polyethylene glycol (PEG) polymers: the effect of PEG size on permeability.

    PubMed

    Gursahani, Hema; Riggs-Sauthier, Jennifer; Pfeiffer, Juergen; Lechuga-Ballesteros, David; Fishburn, C Simone

    2009-08-01

    Polyethylene glycol (PEG) polymers are large amphiphilic molecules that are highly hydrated in solution. To explore the permeability properties of different sized PEG polymers across epithelial membranes in vivo, we examined the absorption of fluorescently labeled PEG conjugates sized 0.55-20 kDa from the lung, since this system provides a reservoir that limits rapid diffusion of molecules away from the site of delivery and enables permeability over longer times to be examined. Following intratracheal delivery in rats, the PEG polymers underwent absorption with first-order kinetics described by single exponential decay curves. PEG size produced a marked influence on the rate of uptake from the lung, with half-lives ranging from 2.4 to 13 h, although above a size of 5 kDa, no further change in rate was observed. PEG size likewise affected retention in alveolar macrophages and in lung tissue; whereas smaller PEG sizes (<2 kDa) were effectively cleared within 48 h, larger PEG sizes (>5 kDa) remained in lung cells and tissue for up to 7 days. These data demonstrate that PEG polymers can be absorbed across epithelial membranes and that PEG size plays a dominant role in controlling the rate and mechanism of absorption. PMID:19408293

  18. Superoxide dismutase and catalase conjugated to polyethylene glycol increases endothelial enzyme activity and oxidant resistance

    SciTech Connect

    Beckman, J.S.; Minor, R.L. Jr.; White, C.W.; Repine, J.E.; Rosen, G.M.; Freeman, B.A.

    1988-05-15

    Covalent conjugation of superoxide dismutase and catalase with polyethylene glycol (PEG) increases the circulatory half-lives of these enzymes from <10 min to 40 h, reduced immunogenicity, and decreases sensitivity to proteolysis. Because PEG has surface active properties and can induce cell fusion, the authors hypothesized that PEG conjugation could enhance cell binding and association of normally membrane-impermeable enzymes. Incubation of cultured porcine aortic endothelial cells with /sup 125/I-PEG-catalase or /sup 125/I-PEG-superoxide dismutase produced a linear, concentration-dependent increase in cellular enzyme activity and radioactivity. Fluorescently labeled PEG-superoxide dismutase incubated with endothelial cells showed a vesicular localization. Mechanical injury to cell monolayers, which is known to stimulate endocytosis, further increased the uptake of fluorescent PEG-superoxide dismutase. Addition of PEG and PEG-conjugated enzymes perturbed the spin-label binding environment, indicative of producing an increase in plasma membrane fluidity. Thus, PEG conjugation to superoxide dismutase and catalase enhances cell association of these enzymes in a manner which increases cellular enzyme activities and provides prolonged protection from partially reduced oxygen species.

  19. Anaerobic degradation of alcohol ethoxylates and polyethylene glycols in marine sediments.

    PubMed

    Traverso-Soto, Juan M; Rojas-Ojeda, Patricia; Sanz, José Luis; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2016-02-15

    This research is focused on alcohol polyethoxylates (AEOs), nonionic surfactants used in a wide variety of products such as household cleaners and detergents. Our main objective in this work was to study the anaerobic degradation of these compounds and their main aerobic degradation products and precursors (polyethylene glycols, PEGs, which are also used for many other applications) in marine sediments, providing the first data available on this topic. First, we observed that average AEO sediment-water partition coefficients (Kd) increased towards those homologs having longer alkyl chains (from 257 L/kg for C12 to 5772 L/kg for C18),which were less susceptible to undergo biodegradation. Overall, AEO and PEG removal percentages reached up to 99.7 and 93%, respectively, after 169 days of incubation using anaerobic conditions in sediments ([O2] = 0 ppm, Eh = -170 to -380 mV and T = 30 °C). Average half-life was estimated to be in a range from 10 to 15 days for AEO homologs (C12AEO8-C18AEO8), and 18 days for PEGEO8.Methanogenic activity proved to be intense during the experiment, confirming the occurrence of anaerobic conditions. This is the first study showing that AEOs and PEGs can be degraded in absence of oxygen in marine sediments, so this new information should be taken into account for future environmental risk assessments on these chemicals. PMID:26657255

  20. Biodegradation of various molecular weights of linear polyethylene glycol (PEG) in activated sludge

    SciTech Connect

    Hansmann, M.A.; Bookland, E.A.; Keough, T.W.; Larson, R.J.

    1995-12-31

    Linear polyethylene glycols (PEG) of various average molecular weights (PEG 1000, PEG 3400, PEG 8000, PEG 20000) were tested in a semi-continuous activated sludge test (SCAS), followed by a CO{sub 2} production test to determine which MWs are inherently biodegradable. Complete biodegradation was confirmed analytically using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI TOF MS). The SCAS test estimates the removal of the test substance during wastewater treatment in activated sludge. SCAS removal, as measured by soluble organic carbon (SOC) was > 90% for the PEG 1000, PEG 3400, and PEG 8000, while PEG 20000 showed a SCAS removal of 28%. These results indicate that SCAS removal was largely due to degradation. The CO{sub 2} production test measures the mineralization of the test substance using activated sludge from the SCAS units as the inoculum. The CO{sub 2} test results show that PEG 1000, PEG 3400, and PEG 8000 are inherently biodegradable, with an average %TC02 > 80% by day 50 and remaining SOC < 10% as measured at day 50. Complete loss of material was confirmed by MALDI TOF MS. The PEG 20000 showed 40% TCO2 by day 50, with 50% SOC remaining. MALDI TOF MS confirmed the presence of parent material. Based on these results, PEGs of MW 8000 and less appear to be biodegradable.

  1. Validation of polyethylene glycol 3350 as a poorly absorbable marker for intestinal perfusion studies.

    PubMed

    Schiller, L R; Santa Ana, C A; Porter, J; Fordtran, J S

    1997-01-01

    Polyethylene glycol (PEG) has been used as a poorly absorbable marker in intestinal perfusion studies, but there is controversy about the absorbability of PEG, particularly when glucose-sodium cotransport is occurring. Total intestinal perfusion studies were done in five normal humans using three solutions containing 1 g/liter PEG 3350 and designed to produce low rates of water absorption, high rates of water absorption, or high rates of glucose-sodium cotransport. Water absorption rates were calculated by traditional nonabsorbable marker equations and by a novel balance technique in which absorption was taken as the difference between the volumes of solution infused and recovered during steady-state conditions. Effluent PEG recovery was 99 +/- 4%, 109 +/- 2%, and 104 +/- 6% of the amount infused with each solution. Water absorption rates measured by use of PEG concentrations were similar to those calculated by the balance technique (r = 0.99). The complete recovery of PEG confirms the poor absorbability of PEG 3350, and the excellent agreement between techniques validates PEG as a poorly absorbed marker, even when glucose-sodium cotransport is occurring. PMID:9009108

  2. Highly effective poly(ethylene glycol) architectures for specific inhibition of immune receptor activation.

    PubMed

    Baird, Emily J; Holowka, David; Coates, Geoffrey W; Baird, Barbara

    2003-11-11

    Architectural features of synthetic ligands were systematically varied to optimize inhibition of mast cell degranulation initiated by multivalent crossing of IgE-receptor complexes. A series of ligands were generated by end-capping poly(ethylene glycol) (PEG) polymers and amine-based dendrimers with the hapten 2,4-dinitrophenyl (DNP). These were used to explore the influence of polymeric backbone length, valency, and hapten presentation on binding to anti-DNP IgE and inhibition of stimulated activation of RBL cells. Monovalent MPEG(5000)-DNP (IC(50) = 50 nM), bivalent DNP-PEG(3350)-DNP (IC(50) = 8 nM), bismonovalent MPEG(5000)-DNP(2) (IC(50) = 20 nM), bisbivalent DNP(2)-PEG(3350)-DNP(2) (IC(50) = 3nM) and DNP(4)-dendrimer ligands (IC(50) = 50 nM) all effectively inhibit cellular activation caused by multivalent antigen, DNP-bovine serum albumin. For different DNP ligands, we provide evidence for more effective inhibition due to (i) preferential formation of intra-IgE cross-links by bivalent ligands of sufficient length, (ii) self-association of monovalent ligands with longer tails, and (iii) higher probability of binding for bisvalent ligands. We also show that larger DNP(16)-dendrimers of higher valency trigger degranulation by cross-linking IgE-receptor complexes, whereas smaller DNP-dendrimers are inhibitory. Thus, features of synthetic ligands can be manipulated to control receptor occupation, aggregation, and inhibition of the cellular response. PMID:14596588

  3. Subunit Stabilization and Polyethylene Glycolation of Cocaine Esterase Improves In Vivo Residence TimeS⃞

    PubMed Central

    Narasimhan, Diwahar; Collins, Gregory T.; Nance, Mark R.; Nichols, Joseph; Edwald, Elin; Chan, Jimmy; Ko, Mei-Chuan; Woods, James H.; Tesmer, John J. G.

    2011-01-01

    No small-molecule therapeutic is available to treat cocaine addiction, but enzyme-based therapy to accelerate cocaine hydrolysis in serum has gained momentum. Bacterial cocaine esterase (CocE) is the fastest known native enzyme that hydrolyzes cocaine. However, its lability at 37°C has limited its therapeutic potential. Cross-linking subunits through disulfide bridging is commonly used to stabilize multimeric enzymes. Herein we use structural methods to guide the introduction of two cysteine residues within dimer interface of CocE to facilitate intermolecular disulfide bond formation. The disulfide-crosslinked enzyme displays improved thermostability, particularly when combined with previously described mutations that enhance stability (T172R-G173Q). The newly modified enzyme yielded an extremely stable form of CocE (CCRQ-CocE) that retained greater than 90% of its activity after 41 days at 37°C, representing an improvement of more than 4700-fold over the wild-type enzyme. CCRQ-CocE could also be modified by polyethylene glycol (PEG) polymers, which improved its in vivo residence time from 24 to 72 h, as measured by a cocaine lethality assay, by self-administration in rodents, and by measurement of inhibition of cocaine-induced cardiovascular effects in rhesus monkeys. PEG-CCRQ elicited negligible immune response in rodents. Subunit stabilization and PEGylation has thus produced a potential protein therapeutic with markedly higher stability both in vitro and in vivo. PMID:21890748

  4. A pilot study on ethanol-polyethylene glycol-formalin fixation of farm animal cadavers.

    PubMed

    Janczyk, Pawel; Weigner, Janet; Luebke-Becker, Antina; Richardson, Kenneth C; Plendl, Johanna

    2011-01-01

    Most embalming of cadavers for anatomical dissection in veterinary medicine has used 6-10% formaldehyde resulting in discoloured and rigid specimens. This project produced teaching specimens of sheep, horse and calf cadavers having their musculoskeletal and visceral structures with a natural appearance using a fixation solution with lowered concentrations of formaldehyde (2% and 3%) together with ethanol and polyethylene glycols. Fixation parameters (palpable consistency, flexibility, colour, tissue hydration and odour) were assessed qualitatively by twice weekly dissections over two months for sheep and three months for horses and calf. Formaldehyde levels, measured in the breathing zone, were below the maximum allowable concentration in all specimens except for a 300 kg horse cadaver. To evaluate the effectiveness of the fixation solution in microbial inhibition, tissue samples were taken and analyzed for the presence of culturable aerobic and anaerobic bacteria, yeasts and moulds. Single colonies of Pseudomonas oryzihabitans, Chryseobacterium sp., Acinetobacter sp. were isolated from lungs, and Micrococcus sp. and Bacillus sp. were isolated from one muscle sample. PMID:22059293

  5. Anaphylaxis to Polyethylene Glycol (Colyte®) in a Patient with Diverticulitis.

    PubMed

    Lee, So Hee; Hwang, Sun Hyuk; Park, Jin Soo; Park, Hae Sim; Shin, Yoo Seob

    2016-10-01

    Polyethylene glycols (PEGs) are believed to be chemically inert agents, but larger PEG polymers could have immunogenicity. A 39-year-old man was referred to emergency room for loss of consciousness and dyspnea after taking of PEG-3350 (Colyte®). In laboratory findings, the initial serum tryptase level was increased to 91.9 mg/L (normal range: 0.00-11.40 mg/L) without any other laboratory abnormalities. The intradermal test with 10 mg/mL Colyte® showed a 5 × 5 mm wheal, but basophil activation and histamine releasability tests were negative. PEG-3350 is widely used as an osmotic laxative due to its lack of absorption from the gastrointestinal tract. However, the loss of mucosal integrity at gastrointestinal membrane such as diverticulitis may be a predisposing factor for anaphylaxis to Colyte®. We report a case of anaphylaxis induced by the ingestion of PEG-3350 in a patient with diverticulitis which might be a risk factor of anaphylaxis. PMID:27550498

  6. Patterned Array of Poly(ethylene glycol) Silane Monolayer for Label-Free Detection of Dengue.

    PubMed

    Rosly, Nor Zida; Ahmad, Shahrul Ainliah Alang; Abdullah, Jaafar; Yusof, Nor Azah

    2016-01-01

    In the present study, the construction of arrays on silicon for naked-eye detection of DNA dengue was demonstrated. The array was created by exposing a polyethylene glycol (PEG) silane monolayer to 254 nm ultraviolet (UV) light through a photomask. Formation of the PEG silane monolayer and photomodifed surface properties was thoroughly characterized by using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The results of XPS confirmed that irradiation of ultraviolet (UV) light generates an aldehyde functional group that offers conjugation sites of amino DNA probe for detection of a specific dengue virus target DNA. Employing a gold enhancement process after inducing the electrostatic interaction between positively charged gold nanoparticles and the negatively charged target DNA hybridized to the DNA capture probe allowed to visualize the array with naked eye. The developed arrays demonstrated excellent performance in diagnosis of dengue with a detection limit as low as 10 pM. The selectivity of DNA arrays was also examined using a single base mismatch and noncomplementary target DNA. PMID:27571080

  7. Synthesis and Characterization of Tunable Poly(Ethylene Glycol): Gelatin Methacrylate Composite Hydrogels

    PubMed Central

    Hutson, Che B.; Nichol, Jason W.; Aubin, Hug; Bae, Hojae; Yamanlar, Seda; Al-Haque, Shahed; Koshy, Sandeep T.

    2011-01-01

    Poly(ethylene glycol) (PEG) hydrogels are popular for cell culture and tissue-engineering applications because they are nontoxic and exhibit favorable hydration and nutrient transport properties. However, cells cannot adhere to, remodel, proliferate within, or degrade PEG hydrogels. Methacrylated gelatin (GelMA), derived from denatured collagen, yields an enzymatically degradable, photocrosslinkable hydrogel that cells can degrade, adhere to and spread within. To combine the desirable features of each of these materials we synthesized PEG-GelMA composite hydrogels, hypothesizing that copolymerization would enable adjustable cell binding, mechanical, and degradation properties. The addition of GelMA to PEG resulted in a composite hydrogel that exhibited tunable mechanical and biological profiles. Adding GelMA (5%–15% w/v) to PEG (5% and 10% w/v) proportionally increased fibroblast surface binding and spreading as compared to PEG hydrogels (p<0.05). Encapsulated fibroblasts were also able to form 3D cellular networks 7 days after photoencapsulation only within composite hydrogels as compared to PEG alone. Additionally, PEG-GelMA hydrogels displayed tunable enzymatic degradation and stiffness profiles. PEG-GelMA composite hydrogels show great promise as tunable, cell-responsive hydrogels for 3D cell culture and regenerative medicine applications. PMID:21306293

  8. Synthesis and characterization of tunable poly(ethylene glycol): gelatin methacrylate composite hydrogels.

    PubMed

    Hutson, Che B; Nichol, Jason W; Aubin, Hug; Bae, Hojae; Yamanlar, Seda; Al-Haque, Shahed; Koshy, Sandeep T; Khademhosseini, Ali

    2011-07-01

    Poly(ethylene glycol) (PEG) hydrogels are popular for cell culture and tissue-engineering applications because they are nontoxic and exhibit favorable hydration and nutrient transport properties. However, cells cannot adhere to, remodel, proliferate within, or degrade PEG hydrogels. Methacrylated gelatin (GelMA), derived from denatured collagen, yields an enzymatically degradable, photocrosslinkable hydrogel that cells can degrade, adhere to and spread within. To combine the desirable features of each of these materials we synthesized PEG-GelMA composite hydrogels, hypothesizing that copolymerization would enable adjustable cell binding, mechanical, and degradation properties. The addition of GelMA to PEG resulted in a composite hydrogel that exhibited tunable mechanical and biological profiles. Adding GelMA (5%-15% w/v) to PEG (5% and 10% w/v) proportionally increased fibroblast surface binding and spreading as compared to PEG hydrogels (p<0.05). Encapsulated fibroblasts were also able to form 3D cellular networks 7 days after photoencapsulation only within composite hydrogels as compared to PEG alone. Additionally, PEG-GelMA hydrogels displayed tunable enzymatic degradation and stiffness profiles. PEG-GelMA composite hydrogels show great promise as tunable, cell-responsive hydrogels for 3D cell culture and regenerative medicine applications. PMID:21306293

  9. Grafting of poly(ethylene glycol) on click chemistry modified Si(100) surfaces.

    PubMed

    Flavel, Benjamin S; Jasieniak, Marek; Velleman, Leonora; Ciampi, Simone; Luais, Erwann; Peterson, Joshua R; Griesser, Hans J; Shapter, Joe G; Gooding, J Justin

    2013-07-01

    Poly(ethylene glycol) (PEG) is one of the most extensively studied antifouling coatings due to its ability to reduce protein adsorption and improve biocompatibility. Although the use of PEG for antifouling coatings is well established, the stability and density of PEG layers are often inadequate to provide optimum antifouling properties. To improve on these shortcomings, we employed the stepwise construction of PEG layers onto a silicon surface. Acetylene-terminated alkyl monolayers were attached to nonoxidized crystalline silicon surfaces via a one-step hydrosilylation procedure with 1,8-nonadiyne. The acetylene-terminated surfaces were functionalized via a copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of the surface-bound alkynes with an azide to produce an amine terminated layer. The amine terminated layer was then further conjugated with PEG to produce an antifouling surface. The antifouling surface properties were investigated by testing adsorption of human serum albumin (HSA) and lysozyme (Lys) onto PEG layers from phosphate buffer solutions. Detailed characterization of protein fouling was carried out with X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) combined with principal component analysis (PCA). The results revealed no fouling of albumin onto PEG coatings whereas the smaller protein lysozyme adsorbed to a very low extent. PMID:23790067

  10. Poly(ethylene glycol)-containing hydrogel surfaces for antifouling applications in marine and freshwater environments.

    PubMed

    Ekblad, Tobias; Bergström, Gunnar; Ederth, Thomas; Conlan, Sheelagh L; Mutton, Robert; Clare, Anthony S; Wang, Su; Liu, Yunli; Zhao, Qi; D'Souza, Fraddry; Donnelly, Glen T; Willemsen, Peter R; Pettitt, Michala E; Callow, Maureen E; Callow, James A; Liedberg, Bo

    2008-10-01

    This work describes the fabrication, characterization, and biological evaluation of a thin protein-resistant poly(ethylene glycol) (PEG)-based hydrogel coating for antifouling applications. The coating was fabricated by free-radical polymerization on silanized glass and silicon and on polystyrene-covered silicon and gold. The physicochemical properties of the coating were characterized by infrared spectroscopy, ellipsometry, and contact angle measurements. In particular, the chemical stability of the coating in artificial seawater was evaluated over a six-month period. These measurements indicated that the degradation process was slow under the test conditions chosen, with the coating thickness and composition changing only marginally over the period. The settlement behavior of a broad and diverse group of marine and freshwater fouling organisms was evaluated. The tested organisms were barnacle larvae (Balanus amphitrite), algal zoospores (Ulva linza), diatoms (Navicula perminuta), and three bacteria species (Cobetia marina, Marinobacter hydrocarbonoclasticus, and Pseudomonas fluorescens). The biological results showed that the hydrogel coating exhibited excellent antifouling properties with respect to settlement and removal. PMID:18759475

  11. Direct force measurement of the stability of poly(ethylene glycol)-polyethylenimine graft films.

    PubMed

    Nnebe, Ijeoma M; Tilton, Robert D; Schneider, James W

    2004-08-15

    The stability and passivity of poly(ethylene glycol)-polyethylenimine (PEG-PEI) graft films are important for their use as antifouling coatings in a variety of biotechnology applications. We have used AFM colloidal-probe force measurements combined with optical reflectometry to characterize the surface properties and stability of PEI and dense PEG-PEI graft films on silica. Initial contact between bare silica probes and PEI-modified surfaces yields force curves that exhibit a long-range electrostatic repulsion and short-range attraction between the surfaces, indicating spontaneous desorption of PEI in the aqueous medium. Further transfer of PEI molecules to the probe occurs with subsequent application of forces between FR = 300 and 500 microN/m. The presence of PEG reduces the adhesive properties of the PEI surface and prevents transfer of PEI molecules to the probe with continuous contact, though an initial desorption of PEI still occurs. Glutaraldehyde crosslinking of the graft films prevents both the initial desorption and subsequent transfer of the PEI, resulting in sustained attractive interaction forces of electrostatic origin between the negatively charged probe and the positively charged copolymer graft films. PMID:15271557

  12. Nanostructured antifouling poly(ethylene glycol) films for silicon-based microsystems.

    PubMed

    Sharma, Sadhana; Desai, Tejal A

    2005-02-01

    The creation of antifouling surfaces is one of the major prerequisites for silicon-based micro-electrical-mechanical systems for biomedical and analytical applications (known as BioMEMS). Poly(ethylene glycol) (PEG), a water-soluble, nontoxic, and nonimmunogenic polymer has the unique ability to reduce nonspecific protein adsorption and cell adhesion and, therefore, is generally coupled with a wide variety of surfaces to improve their biocompatibility. To this end, we have analyzed PEG thin films of various grafting densities (i.e., number of PEG chains per unit area) coupled to silicon using a single-step PEG-silane coupling reaction scheme using variable-angle ellipsometry. Initial PEG concentration and coupling time were varied to attain different grafting densities. These data were theoretically analyzed to understand the phenomenon of PEG film formation. Furthermore, all the PEG films were evaluated for their ability to control biofouling using albumin and fibrinogen as the model proteins. PEG thin films formed by using higher PEG concentrations ( > or = 10 mM PEG) or coupling time ( > or = 1 h) demonstrated enhanced protein fouling resistance behavior. This analysis is expected to be useful to form PEG films of desired grafting density on silicon substrates for appropriate application. PMID:15853141

  13. Using poly(ethylene glycol) silane to prevent protein adsorption in microfabricated silicon channels

    NASA Astrophysics Data System (ADS)

    Bell, Darrel J.; Brody, James P.; Yager, Paul

    1998-03-01

    Microfluidic devices fabricated in silicon are quickly finding use in many areas of technology. Exploration of new applications of this technology has shown both advantages and disadvantages to extreme miniaturization of chemical assays. While accuracy, efficiency and smaller sample volumes are among the advantages, interactions between the walls of the micro-channels and the fluid or particles it contains are among the disadvantages. Our group is applying this technology to chemical and biological warfare (CBW) agent purification and detection. We present preliminary result towards achieving a long-term antifouling surface in our detection system. A microfluidic device was anisotropically etched in a (100) silicon wafer and attached to a Pyrex glass slip to create an enclosed channel. Poly(ethylene glycol) (PEG) silane was covalently bonded to the hydroxyls of an oxide layer on the silicon device and the Pyrex cover slip. Fluorescently labeled ovalbumin, a CBW simulant, was in contact with an unmodified and PEG-modified channel. The extent of adsorption was determined using fluorescence microscopy.

  14. The effect of polyethylene glycol on the stability of pores in polyvinyl alcohol hydrogels during annealing.

    PubMed

    Bodugoz-Senturk, Hatice; Choi, Jeeyoung; Oral, Ebru; Kung, Jean H; Macias, Celia E; Braithwaite, Gavin; Muratoglu, Orhun K

    2008-01-01

    Poly(vinyl alcohol) (PVA) hydrogels are candidate biomaterials for cartilage resurfacing or interpositional arthroplasty devices requiring high-creep resistance and high water content to maintain lubricity. Annealing of PVA improves creep resistance but also reduces the water content. We hypothesized that maintaining poly(ethylene glycol) (PEG) within PVA during annealing would prevent the collapse of the pores and thus would result in high equilibrium water content (EWC). Our hypothesis tested positive. The PVA hydrogels containing PEG maintained their opacity through annealing and exhibited large pores under confocal imaging while hydrogels not containing PEG turned translucent and no pores were visible after annealing. The EWC of gels annealed with PEG (83 +/- 1.0%) was higher than that of the gels processed without PEG (55 +/- 4.8). The crystallinity of the former was 8.0 +/- 1.7% and the latter was 27.5 +/- 8.7%. The hydrogels processed in the presence of PEG exhibited a significantly higher total creep strain (69 +/- 3.4%) when compared to the PEG-free hydrogels (17 +/- 3.7) under an initial contact stress of 0.45 MPa. EWC appeared to be strongly related to the creep resistance of annealed PVA theta-gels. PMID:17950839

  15. An Improved Cryosection Method for Polyethylene Glycol Hydrogels Used in Tissue Engineering

    PubMed Central

    Ruan, Jia-Ling; Tulloch, Nathaniel L.; Muskheli, Veronica; Genova, E. Erin; Mariner, Peter D.; Anseth, Kristi S.

    2013-01-01

    The high water content of hydrogels allows these materials to closely mimic the native biological extracellular conditions, but it also makes difficult the histological preparation of hydrogel-based bioengineered tissue. Paraffin-embedding techniques require dehydration of hydrogels, resulting in substantial collapse and deformation, whereas cryosectioning is hampered by the formation of ice crystals within the hydrogel material. Here, we sought to develop a method to obtain good-quality cryosections for the microscopic evaluation of hydrogel-based tissue-engineered constructs, using polyethylene glycol (PEG) as a test hydrogel. Conventional sucrose solutions, which dehydrate cells while leaving extracellular water in place, produce a hydrogel block that is brittle and difficult to section. We therefore replaced sucrose with multiple protein-based and nonprotein-based solutions as cryoprotectants. Our analysis demonstrated that overnight incubation in bovine serum albumin (BSA), fetal bovine serum (FBS), polyvinyl alcohol (PVA), optimum cutting temperature (OCT®) compound, and Fisher HistoPrep frozen tissue-embedding media work well to improve the cryosectioning of hydrogels. The protein-based solutions give background staining with routine hematoxylin and eosin, but the use of nonprotein-based solutions PVA and OCT reduces this background by 50%. These methods preserve the tissue architecture and cellular details with both in vitro PEG constructs and in constructs that have been implanted in vivo. This simple hydrogel cryosectioning technique improves the methodology for creation of good-quality histological sections from hydrogels in multiple applications. PMID:23448137

  16. Docetaxel and curcumin-containing poly(ethylene glycol)-block-poly(ɛ-caprolactone) polymer micelles

    NASA Astrophysics Data System (ADS)

    Thuy Duong Le, Thi; Huyen La, Thi; Phuc Le, Thi Minh; Phuc Pham, Van; Huyen Nguyen, Thi Minh; Huan Le, Quang

    2013-06-01

    Polymeric nanoparticles (NPs) prepared from poly(ethylene glycol)-block-poly (ɛ-caprolactone) (PEG-PCL) were fabricated by the modified nanoprecipitation method with and without sonication to entrap docetaxel (Doc) and curcumin (Cur). NPs were characterized in terms of morphology, size distribution, zeta potential, encapsulation efficiency and cytotoxicity. The particles have a ˜45-80 nm mean diameter with a spherical shape. The cellular uptake of the NPs was observed after 2 and 4 h of incubation by fluorescence of curcumin loaded with docetaxel. The cell viability was evaluated by an [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay on the Hela cell line. Doc and Doc-Cur NPs had higher cytotoxicity and a much lower IC50 value compared with free Doc or Cur after 24 and 48 h of incubation. Doc and Cur incorporated into the PEG-PCL NPs had the highest cytotoxicity in comparison with all other NPs and may be considered as an attractive and promising drug delivery system for cancer treatment.

  17. Synthesis and Characterization of a Poly(ethylene glycol)-Poly(simvastatin) Diblock Copolymer

    PubMed Central

    Asafo-Adjei, Theodora A.; Dziubla, Thomas D.; Puleo, David A.

    2014-01-01

    Biodegradable polyesters are commonly used as drug delivery vehicles, but their role is typically passive, and encapsulation approaches have limited drug payload. An alternative drug delivery method is to polymerize the active agent or its precursor into a degradable polymer. The prodrug simvastatin contains a lactone ring that lends itself to ring-opening polymerization (ROP). Consequently, simvastatin polymerization was initiated with 5 kDa monomethyl ether poly(ethylene glycol) (mPEG) and catalyzed via stannous octoate. Melt condensation reactions produced a 9.5 kDa copolymer with a polydispersity index of 1.1 at 150 °C up to a 75 kDa copolymer with an index of 6.9 at 250 °C. Kinetic analysis revealed first-order propagation rates. Infrared spectroscopy of the copolymer showed carboxylic and methyl ether stretches unique to simvastatin and mPEG, respectively. Slow degradation was demonstrated in neutral and alkaline conditions. Lastly, simvastatin, simvastatin-incorporated molecules, and mPEG were identified as the degradation products released. The present results show the potential of using ROP to polymerize lactone-containing drugs such as simvastatin. PMID:25431653

  18. Protein adsorption to polyethylene glycol modified liposomes from fibrinogen solution and from plasma.

    PubMed

    Price, M E; Cornelius, R M; Brash, J L

    2001-06-01

    Unmodified and polyethylene glycol (PEG) modified neutral and negatively charged liposomes were prepared by freeze-thaw and extrusion followed by chromatographic purification. The effects of PEG molecular weight (PEG 550, 2000, 5000), PEG loading (0-15 mol%), and liposome surface charge on fibrinogen adsorption were quantified using radiolabeling techniques. All adsorption isotherms increased monotonically over the concentration range 0-3 mg/ml and adsorption levels were low. Negatively charged liposomes adsorbed significantly more fibrinogen than neutral liposomes. PEG modification had no effect on fibrinogen adsorption to neutral liposomes. An inverse relationship was found between PEG loading of negatively charged liposomes and fibrinogen adsorption. PEGs of all three molecular weights at a loading of 5 mol% reduced fibrinogen adsorption to negatively charged liposomes. Protein adsorption from diluted plasma (10% normal strength) to four different liposome types (neutral, PEG-neutral, negatively charged, and PEG-negatively charged) was investigated using gel electrophoresis and immunoblotting. The profiles of adsorbed proteins were similar on all four liposome types, but distinctly different from the profile of plasma itself, indicating a partitioning effect of the lipid surfaces. alpha2-macroglobulin and fibronectin were significantly enriched on the liposomes whereas albumin, transferrin, and fibrinogen were depleted compared to plasma. Apolipoprotein AI was a major component of the adsorbed protein layers. The blot of complement protein C3 adsorbed on the liposomes suggested that the complement system was activated. PMID:11406096

  19. Mass spectrometric behaviour of carboxylated polyethylene glycols and carboxylated octylphenol ethoxylates.

    PubMed

    Frańska, Magdalena; Zgoła, Agnieszka; Rychłowska, Joanna; Szymański, Andrzej; Łukaszewski, Zenon; Frański, Rafał

    2003-01-01

    Mass spectrometric behaviour of mono- and di-carboxylated polyethylene glycols (PEGCs and CPEGCs) and carboxylated octylphenol ethoxylates (OPECs) are discussed. The tendency for ionisation (deprotonation, protonation and cationisation by alkali metal cations) of carboxylated PEGs was compared with that of non-carboxylated correspondents by using both secondary ion mass spectrometry (SIMS) and electrospray ionisation (ESI). The fragmentation of the PEGCs and CPEGCs is discussed and also compared with their neutral correspondents, PEGs. The B/E mass spectra were recorded, using secondary ion mass spectrometry as a method for generation, for deprotonated and protonated molecules and molecules cationised by alkali metal cations. The fragmentation behaviour of PEGs is found to be different from that of CPEGCs, The presence of carboxylic groups may be confirmed not only by the determination of molecular weights of the ethoxylates studied, but also on the basis of the fragment ions formed. The metastable decomposition of the [OPEC-H](-) ions proceed through the cleavage of the bond between the octylphenol moiety and the ethoxylene chain leading to the octylphenoxy anions. It permits determination of the mass of the hydrophobic moiety of the studied carboxylated alkylphenol ethoxylate. ESI mass spectra recorded in the negative ion mode were found to be more suitable for the determination of the average molecular weight of carboxylated ethoxylates than SI mass spectra. PMID:12939494

  20. Prevention of peritendinous adhesions with electrospun polyethylene glycol/polycaprolactone nanofibrous membranes.

    PubMed

    Chen, Chih-Hao; Chen, Shih-Hsien; Shalumon, K T; Chen, Jyh-Ping

    2015-09-01

    Postoperative adhesion formation is the major complication that could occur after acute tendon surgery. The application of an anti-adhesive membrane at the post-surgical site is deemed as a potential way to solve this problem by preventing adhesive fibrotic tissue development. In this study, we fabricated electrospun composite poly(ethylene glycol) (PEG)/poly(caprolactone) (PCL) nanofibrous membrane (NFM) to prevent peritendinous adhesions, which could act as a barrier between the tendon and surrounding tissues, without interrupting mass transfer and normal tendon gliding. PCL/PEG NFMs of 0% PEG (PCL), 25% PEG (25PECL), 50% PEG (50PECL) and 75% PEG (75PECL) were prepared and characterized for physico-chemical properties. The PCL NFM shows the lowest protein permeability while 25PECL NFM exhibited the largest fiber diameter, smallest pore size and the largest ultimate stress and strain. The 75PECL NFM had the lowest water contact angle and the highest Young's modulus. In vitro cell adhesion and migration experiments with fibroblasts indicate that all NFMs could prevent cell penetration, with 75PECL NFM having the least cell attachment. In vivo application of 75PECL NFM on the repaired site of rabbit flexor tendon rupture model demonstrated improved efficacy compared with the PCL NFM and a commercial anti-adhesion barrier (Seprafilm™), from gross observation, histological analysis and functional assays. We concluded that 75PECL NFM could function as an effective anti-adhesion membrane after tendon surgery in a clinical setting. PMID:26115533

  1. Hydrophilicity improvement of mercerized bacterial cellulose films by polyethylene glycol graft.

    PubMed

    da Silva, Renata; Sierakowski, Maria R; Bassani, Helen P; Zawadzki, Sônia F; Pirich, Cleverton L; Ono, Lucy; de Freitas, Rilton A

    2016-05-01

    In this work, polyethylene glycol (PEG), of tree distinct molar masses (200, 300 and 400 g mol(-1)), was grafted onto mercerized bacterial nanocellulose (BNCm) and applied to produce nanofilms (BNCm-PEG). The products BNCm-PEG were characterized by NMR and thermal analysis. Solid-state NMR and X-ray diffraction analyses exhibited no significant differences in index of BNCm-PEG derivatives compared to BNCm, indicating that grafting reaction did not modify the BNCm crystalline structure. The apparent contact angle of the films showed that BNCm-PEG films exhibited a pronounced increase in the polar components (BNCm: 8.1 mN m(-1) vs BNCm-PEG400: 29.4 mN m(-1)), and a decrease in dispersive components (BNCm: 41.7 mN m(-1) vs BNCm-PEG400: 35.2 mN m(-1)) of the surface free energy. The BNCm-PEG films were more hydrophilic than BNCm and retained the biocompatibility with L929 fibroblast cells culture. PMID:26845482

  2. Controlling Affinity Binding with Peptide-Functionalized Poly(ethylene glycol) Hydrogels**

    PubMed Central

    Lin, Chien-Chi; Anseth, Kristi S.

    2009-01-01

    Poly(ethylene glycol) (PEG) hydrogels functionalized with peptide moieties have been widely used in regenerative medicine applications. While many studies have suggested the importance of affinity binding within PEG hydrogels, the relationships between the structures of the peptide motifs and their binding to protein therapeutics remain largely unexplored, especially in the recently developed thiol-acrylate photopolymerization systems. Herein, we employ Förster resonance energy transfer (FRET) and thiol-acrylate photopolymerizations to investigate how the architectures of affinity peptides in crosslinked hydrogels affect their binding to diffusible proteins. The binding between diffusible streptavidin and biotinylated peptide immobilized to PEG hydrogel network was used as a model system to reveal the interplay between affinity binding and peptide sequences/architectures. In addition, we design peptides with different structures to enhance affinity binding within PEG hydrogels and to provide tunable affinity-based controlled delivery of basic fibroblast growth factor (bFGF). This study demonstrates the importance of affinity binding in controlling the availability of hydrogel-encapsulated proteins and provides strategies for enhancing affinity binding of protein therapeutics to bound peptide moieties in thiol-acrylate photopolymerized PEG hydrogels. The results presented herein should find useful on the design and fabrication of hydrogels to retain and sustained release of growth factors for promoting tissue regeneration. PMID:20148198

  3. Poly(propylene fumarate)/Polyethylene Glycol-Modified Graphene Oxide Nanocomposites for Tissue Engineering.

    PubMed

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2016-07-20

    Poly(propylene fumarate) (PPF)-based nanocomposites incorporating different amounts of polyethylene glycol-functionalized graphene oxide (PEG-GO) have been prepared via sonication and thermal curing, and their surface morphology, structure, thermal stability, hydrophilicity, water absorption, biodegradation, cytotoxicity, mechanical, viscoelastic and antibacterial properties have been investigated. SEM and TEM images corroborated that the noncovalent functionalization with PEG caused the exfoliation of GO into thinner flakes. IR spectra suggested the presence of strong hydrogen-bonding interactions between the nanocomposite components. A gradual rise in the level of hydrophilicity, water uptake, biodegradation rate, surface roughness, protein absorption capability and thermal stability was found upon increasing GO concentration in the composites. Tensile tests revealed improved stiffness, strength and toughness for the composites compared to unfilled PPF, ascribed to a homogeneous GO dispersion within the matrix along with a strong PPF/PEG-GO interfacial adhesion via polar and hydrogen bonding interactions. Further, the nanocomposites retained enough stiffness and strength under a biological state to provide effective support for bone tissue formation. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus and Staphylococcus epidermidis as well as Gram-negative Pseudomonas aeruginosa and Escherichia coli microorganisms, and it rose sharply upon increasing GO concentration; systematically, the biocide effect was stronger versus Gram-positive bacteria. Cell viability data demonstrated that PPF/PEG-GO composites do not induce toxicity over human dermal fibroblasts. These novel materials show great potential to be applied in the bone tissue engineering field. PMID:27383639

  4. Properties of polyethylene glycol/cyclodextrin hydrogels revealed by spin probes and spin labelling methods.

    PubMed

    Ionita, Gabriela; Ariciu, Ana Maria; Turcu, Ioana Maria; Chechik, Victor

    2014-03-21

    The properties of a gel consisting of a covalent network formed by the reaction of isocyanate end-capped polyethylene glycol (PEG) with β-cyclodextrin, were investigated by EPR spectroscopy. Spin-labelled cyclodextrin was incorporated into the cross-link points of the gel and at the chain ends. The dynamics of the gel fibres as reported by the spin label, was found to be sensitive to the H-bonding ability of the solvent, density of cross-links and temperature. Addition of spin probes (e.g., TEMPO and adamantane-TEMPO) to the unlabelled gel made it possible to characterise the solvent pools in the gel. While TEMPO was uniformly distributed throughout the solvent pools, the adamantane derivative was located at the gel fibre-solvent pool interface; these two probes thus reported on the different locations in the solvent pools. At low temperature, the gels were shown to prevent ice crystallisation in the solvent pools resulting in the formation of supercooled water. Both probes showed that the water froze at ca. 250 K, thus suggesting that the properties of the supercooled water are uniform across the solvent pools. PMID:24651650

  5. Protective Effect of Intravenous High Molecular Weight Polyethylene Glycol on Fatty Liver Preservation

    PubMed Central

    Bejaoui, Mohamed; Pantazi, Eirini; Folch-Puy, Emma; Panisello, Arnau; Calvo, María; Pasut, Gianfranco; Rimola, Antoni; Navasa, Miquel; Adam, René; Roselló-Catafau, Joan

    2015-01-01

    Ischemia reperfusion injury (IRI) leads to significant tissue damage in liver surgery. Polyethylene glycols (PEGs) are water soluble nontoxic polymers that have proved their effectiveness against IRI. The objective of our study was to investigate the potential protective effects of intravenous administration of a high molecular weight PEG of 35 kDa (PEG 35) in steatotic livers subjected to cold ischemia reperfusion. In this study, we used isolated perfused rat liver model to assess the effects of PEG 35 intravenous administration after prolonged cold ischemia (24 h, 4°C) and after reperfusion (2 h, 37°C). Liver injury was measured by transaminases levels and mitochondrial damage was determined by confocal microscopy assessing mitochondrial polarization (after cold storage) and by measuring glutamate dehydrogenase activity (after reperfusion). Also, cell signaling pathways involved in the physiopathology of IRI were assessed by western blot technique. Our results show that intravenous administration of PEG 35 at 10 mg/kg ameliorated liver injury and protected the mitochondria. Moreover, PEG 35 administration induced a significant phosphorylation of prosurvival protein kinase B (Akt) and activation of cytoprotective factors e-NOS and AMPK. In conclusion, intravenous PEG 35 efficiently protects steatotic livers exposed to cold IRI. PMID:26543868

  6. Hybrid Atomistic and Coarse-Grained Molecular Dynamics Simulations of Polyethylene Glycol (PEG) in Explicit Water.

    PubMed

    Stanzione, Francesca; Jayaraman, Arthi

    2016-05-01

    In-silico design of polymeric biomaterials requires molecular dynamics (MD) simulations that retain essential atomistic/molecular details (e.g., explicit water around the biofunctional macromolecule) while simultaneously achieving large length and time scales pertinent to macroscale function. Such large-scale atomistically detailed macromolecular MD simulations with explicit solvent representation are computationally expensive. One way to overcome this limitation is to use an adaptive resolution scheme (AdResS) in which the explicit solvent molecules dynamically adopt either atomistic or coarse-grained resolution depending on their location (e.g., near or far from the macromolecule) in the system. In this study we present the feasibility and the limitations of AdResS methodology for studying polyethylene glycol (PEG) in adaptive resolution water, for varying PEG length and architecture. We first validate the AdResS methodology for such systems, by comparing PEG and solvent structure with that from all-atom simulations. We elucidate the role of the atomistic zone size and the need for calculating thermodynamic force correction within this AdResS approach to correctly reproduce the structure of PEG and water. Lastly, by varying the PEG length and architecture, we study the hydration of PEG, and the effect of PEG architectures on the structural properties of water. Changing the architecture of PEG from linear to multiarm star, we observe reduction in the solvent accessible surface area of the PEG, and an increase in the order of water molecules in the hydration shells. PMID:27108869

  7. Bistable random laser that uses a phase transition of polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Saito, Mitsunori; Nishimura, Yoshihiro

    2016-03-01

    Polyethylene glycol (PEG) is transparent in the liquid phase and turns to a translucent solid through a phase transition at around room temperature. A PEG solution of rhodamine 6G was excited by a laser pulse (527 nm wavelength, 10 ns duration, 190 μJ) to measure fluorescence spectra during the phase transition process. Whereas the fluorescence peak was weak and broad at 60 °C (spontaneous emission), a strong, narrow peak appeared in the temperature range below 50 °C, since a stimulated emission (amplified spontaneous emission) took place due to the scattering in the solid PEG. This laser emission control was repeatable by reversing an electric voltage (-12 or +12 V) that drove a Peltier element. Interestingly, the sample exhibited a strong stimulated emission at 52 °C during the heating process, although no strong emission was visible at the same temperature during the cooling process (bistability). The fluorescence peak wavelength was tunable between 566 and 572 nm by changing the cooling rate.

  8. PEG and Thickeners: A Critical Interaction Between Polyethylene Glycol Laxative and Starch-Based Thickeners.

    PubMed

    Carlisle, Brian J; Craft, Garrett; Harmon, Julie P; Ilkevitch, Alina; Nicoghosian, Jenik; Sheyner, Inna; Stewart, Jonathan T

    2016-09-01

    Clinicians commonly encounter dysphagia and constipation in a skilled nursing population. Increasing the viscosity of liquids, usually with a starch- or xanthan gum-based thickener, serves as a key intervention for patients with dysphagia. We report a newly identified and potentially dangerous interaction between polyethylene glycol 3350 laxative (PEG) and starch-thickened liquids. A patient requiring nectar-thickened liquids became constipated, and medical staff prescribed PEG for constipation. His nurse observed that the thickened apple juice immediately thinned to near-water consistency when PEG was added. She obtained the same results with thickened water and coffee. We quantified this phenomenon by isothermal rotational rheology. Results confirmed a precipitous loss of thickening when PEG was added to starch-based thickeners but not with xanthan gum-based thickeners. Clinicians and front-line staff should be aware of this potentially critical interaction between PEG- and starch-based thickeners. Although confirmatory studies are needed, our preliminary data suggest that PEG may be compatible with xanthan gum-- based thickeners. PMID:27569713

  9. Surface activity and flocculation behavior of polyethylene glycol-functionalized silica nanoparticles.

    PubMed

    Björkegren, Sanna Maria Sofi; Nordstierna, Lars; Törncrona, Anders; Persson, Michael E; Palmqvist, Anders E C

    2015-08-15

    Colloidal silica nanoparticles have been functionalized with methyl polyethylene glycol silane (mPEG silane) and the PEGylated particles have been characterized with focus on exploring their surface chemical properties. The degree of surface functionalization was quantified using NMR diffusometry, and the measurements showed that the silane binds covalently to the silica surface. Samples with surface coverages ranging from 0.068 to 0.315 μmol silane/m(2) have been analyzed. The functionalized particles proved to be surface active and showed a significant reduction in surface charge and zeta potential with increasing degree of PEG functionalization. All samples showed colloidal stability at neutral pH and above within the range studied. At lower pH, the samples with low surface coverage displayed a reversible flocculation behavior, while samples with a high surface coverage and samples without functionalization remained stable. This suggests that steric stabilization is effective at low pH when the surface coverage is high enough; electrostatic stabilization is effective for samples without functionalization; and that inter-particle PEG-silica interactions cause flocculation of particles with too low degrees of PEG functionalization. PMID:25957235

  10. In vivo degradation of polyurethane foam with 55 wt % polyethylene glycol.

    PubMed

    Broekema, Ferdinand I; Van Leeuwen, M Barbara M; Van Minnen, Baucke; Bos, Rudolf R M

    2015-11-01

    Most topical hemostatic agents are based on animal-derived products like collagen and gelatin. They carry the potential risk of pathogen transmission while adjustments in the production process of these materials are limited. A synthetic hemostatic agent based on polyurethane (PU) and polyethylene glycol (PEG) was developed to overcome these disadvantages. The goal of this study was to compare the degradation process of this biomaterial to collagen and gelatin hemostatic agents. Samples of the test materials were implanted subcutaneously in both rats and rabbits. The animals were sacrificed at certain time intervals up to three years and the explanted samples were microscopically assessed. The histological examination showed a comparable pattern of degradation for the different test materials. Remnants of gelatin and collagen were seen up to 26 and 39 weeks, respectively. For PU, it took up to three years before micro-particles of the material were no longer detected. All biomaterials showed a good biocompatibility and no severe foreign body reactions occurred. The good biocompatibility and predictable pattern of resorption indicate that PU can be used as a topical hemostatic agent. However, a degradation time comparable to collagen and gelatin would be favorable. PMID:25904301

  11. Polyethylene Glycol Formulations Show Different Soft Tissue Remodeling and Angiogenesis Features

    PubMed Central

    Oteri, Giacomo; Pizzino, Gabriele; Pisano, Michele; Peditto, Matteo; Squadrito, Francesco

    2015-01-01

    Background: Soft tissue regeneration and remodeling is fundamental in periodontal surgery, thus we investigated the angiogenic response elicited in the subcutaneous tissue of rats by a proprietary, polyethylene glycol hydrogel formulation (PEG) alone or conjugated with specific amelogenins (EMD) or nanobioglass particles (NBG). Methods: Discs with three different formulations (PEG, PEG-EMD, and PEG-NBG) were inserted into four unconnected subcutaneous pouches, produced on the back of Sprague-Dawley rats (n=56, divided into three groups), and used for blood flow evaluation by Laser Doppler analysis at 1, 2, 4, 8, and 16 weeks or for histological and immunohistochemical analysis at 1, 2, 4, 8, and 16 weeks. Results: All formulations showed tissue integration, absence of inflammatory reaction (as revealed by myeloperoxidase staining), and increased vascularization (by counting microvascular density following CD31 staining). Laser Doppler analysis revealed a statistically significant increase in blood flow after 1 week for PEG-EMD and after 2 weeks for PEG-NBG. The angiogenic response was significantly increased at 1, 2, and 8 weeks for PEG-EMD, but only at 4 weeks for PEG-NBG. Conclusions: The studied biomaterials revealed equal biocompatibility and tissue integration properties. PEG-EMD showed the most pronounced and consistent angiogenic response in the early phases of wound healing, while the PEG-NBG formulation provided a slower and delayed, but relevant, response. PMID:25275669

  12. Chemical dechlorination of hexachlorobenzene with polyethylene glycol and hydroxide: Dominant effect of temperature and ionic potential

    PubMed Central

    Xiao, Ye; Jiang, Jianguo; Huang, Hai

    2014-01-01

    Persistent organic pollutants (POPs) originating from POP waste are playing an increasingly important role in the elevation of regional POP levels. In this study we realized the complete dechlorination of high concentration hexachlorobenzene (HCB) waste in the presence of polyethylene glycol and hydroxide, rather than using conventional high temperature incineration. Here, we demonstrate the dominant effect of temperature and hydroxide on HCB dechlorination in this process. Complete dechlorination of HCB was only observed at temperature about 200°C or above within 4 h reaction, and the apparent activation energy of this process was 43.1 kJ/mol. The alkalinity of hydroxides had notable effects on HCB dechlorination, and there was a considerable linear relationship between the natural logarithm of the HCB dechlorination rate constant and square root of the ionic potential of metal cation (R2 = 0.9997, p = 0.0081, n = 3). This study highlights a promising technology to realize complete dechlorination of POP waste, especially at high concentrations, in the presence of PEG in conjunction with hydroxide. PMID:25200551

  13. Polyethylene glycol-fused allografts produce rapid behavioral recovery after ablation of sciatic nerve segments.

    PubMed

    Riley, D C; Bittner, G D; Mikesh, M; Cardwell, N L; Pollins, A C; Ghergherehchi, C L; Bhupanapadu Sunkesula, S R; Ha, T N; Hall, B T D; Poon, A D; Pyarali, M; Boyer, R B; Mazal, A T; Munoz, N; Trevino, R C; Schallert, T; Thayer, W P

    2015-04-01

    Restoration of neuronal functions by outgrowths regenerating at ∼1 mm/day from the proximal stumps of severed peripheral nerves takes many weeks or months, if it occurs at all, especially after ablation of nerve segments. Distal segments of severed axons typically degenerate in 1-3 days. This study shows that Wallerian degeneration can be prevented or retarded, and lost behavioral function can be restored, following ablation of 0.5-1-cm segments of rat sciatic nerves in host animals. This is achieved by using 0.8-1.1-cm microsutured donor allografts treated with bioengineered solutions varying in ionic and polyethylene glycol (PEG) concentrations (modified PEG-fusion procedure), being careful not to stretch any portion of donor or host sciatic nerves. The data show that PEG fusion permanently restores axonal continuity within minutes, as initially assessed by action potential conduction and intracellular diffusion of dye. Behavioral functions mediated by the sciatic nerve are largely restored within 2-4 weeks, as measured by the sciatic functional index. Increased restoration of sciatic behavioral functions after ablating 0.5-1-cm segments is associated with greater numbers of viable myelinated axons within and distal to PEG-fused allografts. Many such viable myelinated axons are almost certainly spared from Wallerian degeneration by PEG fusion. PEG fusion of donor allografts may produce a paradigm shift in the treatment of peripheral nerve injuries. PMID:25425242

  14. Highly efficient SO₂ absorption and its subsequent utilization by weak base/polyethylene glycol binary system.

    PubMed

    Yang, Zhen-Zhen; He, Liang-Nian; Zhao, Ya-Nan; Yu, Bing

    2013-02-01

    A binary system consisting of polyethylene glycol (PEG, proton donor)/PEG-functionalized base with suitable basicity was developed for efficient gas desulfurization (GDS) and can be regarded as an alternative approach to circumvent the energy penalty problem in the GDS process. High capacity for SO(2) capture up to 4.88 mol of SO(2)/mol of base was achieved even under low partial pressure of SO(2). Furthermore, SO(2) desorption runs smoothly under mild conditions (N(2), 25 °C) and no significant drop in SO(2) absorption was observed after five-successive absorption-desorption cycles. On the other hand, the absorbed SO(2) by PEG(150)MeIm/PEG(150), being considered as the activated form of SO(2), can be directly transformed into value-added chemicals under mild conditions, thus eliminating the energy penalty for SO(2) desorption and simultaneously realizing recycle of the absorbents. Thus, this SO(2) capture and utilization (SCU) process offers an alternative way for GDS and potentially enables the SO(2) conversion from flue gas to useful chemicals as a value-added process. PMID:23323771

  15. Efficiency of SPIONs functionalized with polyethylene glycol bis(amine) for heavy metal removal

    NASA Astrophysics Data System (ADS)

    Wanna, Yongyuth; Chindaduang, Anon; Tumcharern, Gamolwan; Phromyothin, Darinee; Porntheerapat, Supanit; Nukeaw, Jiti; Hofmann, Heirich; Pratontep, Sirapat

    2016-09-01

    Hybrid magnetic nanoparticles based on poly(methylmethacrylate) (PMMA) and super-paramagnetic iron oxide nanopaticles (SPIONs) with selective surface modification has been developed for heavy metal removal by applying external magnetic fields. The nanoparticles were prepared by the emulsion polymerization technique in an aqueous suspension of SPIONs. The hydrolysis of carboxyl functional group was then applied for grafting polyethylene glycol bis(amine)(PEG-bis(amine)) onto the PMMA-coated SPIONs. The morphology, the chemical structure and the magnetic properties of the grafted nanoparticles were investigated. The efficiency of the hybrid nanoparticles for heavy metal removal were conducted on Pb(II), Hg(II), Cu(II) and Co(II) in aqueous solutions.The metal concentration in the solutions after separation by the hybrid nanoparticles was determined by inductively coupled plasma optical emission spectrometer (ICP-OES). The results show the heavy metal uptake ratios of 0.08, 0.04, 0.03, and 0.01 mM per gramme of the grafted SPIONs for Pb(II), Hg(II), Cu(II), and Co(II), respectively. A competitive removal of Cu(II), Pb(II), Co(II) and Hg(II) ions in mixed metal salt solutions has also been studied.The heavy metal removal efficiency of the hybrid nanoparitcles was found to depend on the cation radius, in accordance with capture of metal ions by the amine group.

  16. Adsorption efficiency of poly(ethylene glycol)/chitosan/CNT blends for maltene fraction separation.

    PubMed

    Abdeen, Z

    2016-06-01

    Poly(ethylene glycol)/chitosan (PEG/CH) hydrogel and its composite containing carbon nanotubes (PEG/CH/CNTs) were prepared using a simple blending method. The effect of the PEG/CH ratio on the water uptake was studied and optimized. And the prepared hydrogels were characterized by XRD, SEM, and FTIR. Also, the ability of each of the prepared hydrogels to adsorb and separate maltene fractions was compared using saturates, aromatics, resins, and asphaltenes (SARA) method. From the results, it was noticed that the adsorption capacity and separation ability of PEG/CH/CNT are better than that of PEG/CH. But the released amount of alkane fractions using these hydrogels is higher than that in the reference (without using hydrogel). This may be attributed to degradation of maltene residue to alkanes and that degradation is better by using PEG/CH adsorbent than PEG/CH/CNT. Although, from a practical point of view, where PEG/CH/CNT hydrogel may be favorable, it has an acceptable ability to adsorb and separate the maltene fractions. PMID:26922460

  17. Polyethylene glycol acrylate-grafted polysulphone membrane for artificial lungs: plasma modification and haemocompatibility improvement.

    PubMed

    Wang, Weiping; Huang, Xin; Yin, Haiyan; Fan, Wenling; Zhang, Tao; Li, Lei; Mao, Chun

    2015-12-01

    In this study, polyethylene glycol acrylate (PEGA) was introduced onto the surface of polysulphone (PSF) membrane to prepare PSF-PEGA membranes through low-temperature plasma technology for haemocompatibility improvement of artificial lungs. The effects of plasma power, PEGA solution concentration and dipcoating temperature on surface modification were systematically investigated. Results of Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and PEGA grafting degree confirmed that PEGA was successfully grafted onto the PSF membranes. Contact angle values showed that the hydrophilicity of the PSF-PEGA membrane surface increased by 21.5%. The results of the protein adsorption, platelet adhesion and coagulation tests further showed the excellent haemocompatibility of the modified membrane. Gas exchange tests also revealed that at a porcine blood flow rate of 5 l min(-1), O2 and CO2 exchange rates through the PSF-PEGA membrane were 198.6 and 170.9 ml min(-1), respectively; approximately this is the gas exchange capacity of commercial respiratory assistance devices. PMID:26658212

  18. Subunit stabilization and polyethylene glycolation of cocaine esterase improves in vivo residence time.

    PubMed

    Narasimhan, Diwahar; Collins, Gregory T; Nance, Mark R; Nichols, Joseph; Edwald, Elin; Chan, Jimmy; Ko, Mei-Chuan; Woods, James H; Tesmer, John J G; Sunahara, Roger K

    2011-12-01

    No small-molecule therapeutic is available to treat cocaine addiction, but enzyme-based therapy to accelerate cocaine hydrolysis in serum has gained momentum. Bacterial cocaine esterase (CocE) is the fastest known native enzyme that hydrolyzes cocaine. However, its lability at 37°C has limited its therapeutic potential. Cross-linking subunits through disulfide bridging is commonly used to stabilize multimeric enzymes. Herein we use structural methods to guide the introduction of two cysteine residues within dimer interface of CocE to facilitate intermolecular disulfide bond formation. The disulfide-crosslinked enzyme displays improved thermostability, particularly when combined with previously described mutations that enhance stability (T172R-G173Q). The newly modified enzyme yielded an extremely stable form of CocE (CCRQ-CocE) that retained greater than 90% of its activity after 41 days at 37°C, representing an improvement of more than 4700-fold over the wild-type enzyme. CCRQ-CocE could also be modified by polyethylene glycol (PEG) polymers, which improved its in vivo residence time from 24 to 72 h, as measured by a cocaine lethality assay, by self-administration in rodents, and by measurement of inhibition of cocaine-induced cardiovascular effects in rhesus monkeys. PEG-CCRQ elicited negligible immune response in rodents. Subunit stabilization and PEGylation has thus produced a potential protein therapeutic with markedly higher stability both in vitro and in vivo. PMID:21890748

  19. Effects of salinity, temperature, and polyethylene glycol on the seed germination of sunflower (Helianthus annuus L.).

    PubMed

    Luan, Zhihui; Xiao, Moxin; Zhou, Daowei; Zhang, Hongxiang; Tian, Yu; Wu, Yi; Guan, Bo; Song, Yantao

    2014-01-01

    Salinization has severe influences on agriculture in the whole world. The main aims of this work were to evaluate osmotic effect and ion effect of NaCl on seed germination of three sunflower (Helianthus annuus L.) cultivars interacting with three alternating temperature regimes and to select the most salt tolerant cultivars to plant in the saline region. Seeds were germinated in the isotonic NaCl and polyethylene glycol (PEG) solutions of -0.45, -0.90, -1.34, -1.79, and -2.24 MPa at 10:20, 15:25, and 20:30 °C temperature regimes. Both NaCl and PEG inhibited germination, but the effects of NaCl were less as compared to that of PEG, which means that adverse effects of PEG on germination were due to osmotic effect rather than specific ion accumulation. For the three cultivars, higher germination occurred at 10:20 °C in NaCl treatments and at 20:30 °C in the isotonic PEG treatments. Among the three cultivars, Sandaomei (SDM) is the most tolerant to salt and PEG stress. PMID:25610896

  20. Effects of Salinity, Temperature, and Polyethylene Glycol on the Seed Germination of Sunflower (Helianthus annuus L.)

    PubMed Central

    Luan, Zhihui; Xiao, Moxin; Zhou, Daowei; Tian, Yu; Wu, Yi; Guan, Bo; Song, Yantao

    2014-01-01

    Salinization has severe influences on agriculture in the whole world. The main aims of this work were to evaluate osmotic effect and ion effect of NaCl on seed germination of three sunflower (Helianthus annuus L.) cultivars interacting with three alternating temperature regimes and to select the most salt tolerant cultivars to plant in the saline region. Seeds were germinated in the isotonic NaCl and polyethylene glycol (PEG) solutions of −0.45, −0.90, −1.34, −1.79, and −2.24 MPa at 10 : 20, 15 : 25, and 20 : 30°C temperature regimes. Both NaCl and PEG inhibited germination, but the effects of NaCl were less as compared to that of PEG, which means that adverse effects of PEG on germination were due to osmotic effect rather than specific ion accumulation. For the three cultivars, higher germination occurred at 10 : 20°C in NaCl treatments and at 20 : 30°C in the isotonic PEG treatments. Among the three cultivars, Sandaomei (SDM) is the most tolerant to salt and PEG stress. PMID:25610896

  1. Bioactive Modification of Poly(ethylene glycol) Hydrogels for Tissue Engineering

    PubMed Central

    Zhu, Junmin

    2010-01-01

    In this review, we explore different approaches for introducing bioactivity into poly(ethylene glycol) (PEG) hydrogels. Hydrogels are excellent scaffolding materials for repairing and regenerating a variety of tissues because they can provide a highly swollen three-dimensional (3D) environment similar to soft tissues. Synthetic hydrogels like PEG-based hydrogels have advantages over natural hydrogels, such as the ability for photopolymerization, adjustable mechanical properties, and easy control of scaffold architecture and chemical compositions. However, PEG hydrogels alone cannot provide an ideal environment to support cell adhesion and tissue formation due to their bio-inert nature. The natural extracellular matrix (ECM) has been an attractive model for the design and fabrication of bioactive scaffolds for tissue engineering. ECM-mimetic modification of PEG hydrogels has emerged as an important strategy to modulate specific cellular responses. To tether ECM-derived bioactive molecules (BMs) to PEG hydrogels, various strategies have been developed for the incorporation of key ECM biofunctions, such as specific cell adhesion, proteolytic degradation, and signal molecule-binding. A number of cell types have been immobilized on bioactive PEG hydrogels to provide fundamental knowledge of cell/scaffold interactions. This review addresses the recent progress in material designs and fabrication approaches leading to the development of bioactive hydrogels as tissue engineering scaffolds. PMID:20303169

  2. Adsorption of poly(ethylene glycol)-modified lysozyme to silica.

    PubMed

    Daly, Susan M; Przybycien, Todd M; Tilton, Robert D

    2005-02-15

    Covalent grafting of poly(ethylene glycol) (PEG) to pharmaceutical proteins, "PEGylation", is becoming more commonplace due to improved therapeutic efficacy. As these conjugates encounter interfaces in manufacture, purification, and end use and adsorption to these interfaces may alter achievable production yields and in vivo efficacies, it is important to understand how PEGylation affects protein adsorption mechanisms. To this end, we have studied the adsorption of unmodified and PEGylated chicken egg lysozyme to silica, using optical reflectometry, total internal reflection fluorescence (TIRF) spectroscopy, and atomic force microscopy (AFM) under varying conditions of ionic strength and extent of PEG modification. PEGylation of lysozyme changes the shape of the adsorption isotherm and alters the preferred orientation of lysozyme on the surface. There is an abrupt transition in the isotherm from low to high surface excess concentrations that correlates with a change in orientation of mono-PEGylated conjugates lying with the long axis parallel to the silica surface to an orientation with the long axis oriented perpendicular to the surface. No sharp transition is observed in the adsorption isotherm for di-PEGylated lysozyme within the range of concentrations examined. The net effect of PEGylation is to decrease the number of protein molecules per unit area relative to the adsorption of unmodified lysozyme, even under conditions where the surface is densely packed with conjugates. This is due to the area sterically excluded by the PEG grafts. The other major effect of PEGylation is to make conjugate adsorption significantly less irreversible than unmodified lysozyme adsorption. PMID:15697278

  3. The effect of an increase in chain length on the mechanical properties of polyethylene glycols.

    PubMed

    Al-Nasassrah, M A; Podczeck, F; Newton, J M

    1998-07-01

    The mechanical properties of different molecular weights of polyethylene glycol (PEG) have been determined by formation of compacted tablets and beams, which were subjected to diametral compression and 3-point bending, respectively. From diametral compression, the tensile strength for the different grades of PEG was determined. Flat beams made from powder by compaction were used to determine Young's modulus of elasticity. Beams into which a notch had been introduced after formation allowed the fracture mechanical parameters of critical stress intensity factor, K(IC), and fracture toughness, R, to be determined. Evaluation of these parameters as a function of compact porosity allowed extrapolation to values at zero porosity, providing an estimate of the material properties. The increase in chain length of the PEG was found to have a non-linear effect on tensile strength and Young's modulus. The ductility of the polymer increased proportionally to the increase in chain length, reflected by the linear relationship between K(IC) and the molecular weight. Young's modulus and critical stress intensity factor allowed the estimation of the strain energy release rate, G(IC), which is the driving force in crack propagation. Consequently, the tensile strength at zero porosity was found to be predictable from the values of G(IC) and the molecular weight of the different grades of PEG. PMID:9700020

  4. Capillary electrophoretic separation of poly(ethylene glycol)-modified granulocyte-colony stimulating factor.

    PubMed

    Lee, Kyung Soo; Na, Dong Hee

    2010-03-01

    We evaluated the utility of capillary electrophoretic methods for analyzing poly(ethylene glycol) (PEG)-modified granulocyte-colony stimulating factor (G-CSF), a long-acting form of GCSF for the treatment of cancer therapy-induced neutropenia. Low- and high-molecularweight PEG-G-CSF conjugates prepared with aldehyde-activated PEG-5K and PEG-20K were separated by high-performance size-exclusion chromatography (HP-SEC), capillary zone electrophoresis (CZE), and sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE). HPSEC showed low resolution for separating mono- and di-PEG-G-CSFs. SDS-CGE had higher resolution, but required a long analysis and had low peak efficiency. CZE could successfully separate both PEG-5K- and PEG-20K-conjugated G-CSFs with a running time of 20 min and high peak efficiency. In conclusion, CZE was better than SDS-CGE for separating PEG-G-CSF conjugates and will be useful for PEGylation studies, such as reaction monitoring for optimization of the PEGylation reaction, and purity and stability tests of PEG-G-CSF. PMID:20361316

  5. Tabletability assessment of conventional formulations containing Vitamin E tocopheryl polyethylene glycol succinate.

    PubMed

    Jin, Feiyan; Tatavarti, Aditya

    2010-04-15

    Vitamin E tocopheryl polyethylene glycol succinate (TPGS) is known to enhance the bioavailability of poorly water-soluble drugs via solubility and permeability enhancement. Few studies have evaluated feasibility of formulating TPGS in conventional solid dosage forms such as tablets due to processing challenges resulting from its waxy nature and low melting point (approximately 37 degrees C). The objective of this study is to systematically investigate the tabletability of conventional high shear wet granulation (WG) formulations incorporated with Vitamin E TPGS. Impact of critical formulation variables such as levels of TPGS, hydroxypropyl cellulose (binder) and Prosolv (extragranular filler) on product quality attributes was studied using a full factorial experimental design. The potential influence of temperature elevation during processing was assessed through a heated die fitted onto a compaction simulator. Bilayer tabletability of the TPGS formulation was also assessed in combination with a secondary non-TPGS formulation. TPGS levels significantly impacted tensile strength (TS), disintegration time and dissolution. Heat sensitivity studies indicated that TS reduction upon exposure to heat was minimized by higher levels of extragranular fillers. Acceptable interfacial strength of bilayer tablets was achieved and tablets could be coated without the need for hydroalcoholic solutions. The study demonstrates preliminary feasibility to develop monolithic and bilayer coated tablet formulations containing up to 10% (w/w) TPGS for the given compound and drug load. Further studies are required to validate these findings at larger scales. PMID:20083178

  6. Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform.

    PubMed

    Markelov, Denis A; Matveev, Vladimir V; Ingman, Petri; Nikolaeva, Marianna N; Penkova, Anastasia V; Lahderanta, Erkki; Boiko, Natalia I; Chizhik, Vladimir I

    2016-01-01

    We have studied copolymer dendrimer structure: carbosilane dendrimers with terminal phenylbenzoate mesogenic groups attached by poly(ethylene) glycol (PEG) spacers. In this system PEG spacers are additional tuning to usual copolymer structure: dendrimer with terminal mesogenic groups. The dendrimer macromolecules were investigated in a dilute chloroform solution by (1)H NMR methods (spectra and relaxations). It was found that the PEG layer in G = 5 generations dendrimer is "frozen" at high temperatures (above 260 K), but it unexpectedly becomes "unfrozen" at temperatures below 250 K (i.e., melting when cooling). The transition between these two states occurs within a small temperature range (~10 K). Such a behavior is not observed for smaller dendrimer generations (G = 1 and 3). This effect is likely related to the low critical solution temperature (LCST) of PEG and is caused by dendrimer conformations, in which the PEG group concentration in the layer increases with growing G. We suppose that the unusual behavior of PEG fragments in dendrimers will be interesting for practical applications such as nanocontainers or nanoreactors. PMID:27052599

  7. Transparent, elastomeric and tough hydrogels from poly(ethylene glycol) and silicate nanoparticles.

    PubMed

    Gaharwar, Akhilesh K; Rivera, Christian P; Wu, Chia-Jung; Schmidt, Gudrun

    2011-12-01

    The structures and mechanical properties of both physically and covalently cross-linked nanocomposite hydrogels made from poly(ethylene glycol) (PEG) and silicate nanoparticles (Laponite RD) are investigated. Injectable nanocomposite precursor solutions can be covalently cross-linked via photopolymerization. The resulting hydrogels are transparent and have interconnected pores, high elongation and toughness. These properties depend on the hydrogel composition, polymer-nanoparticle interactions and degree of cross-linking (both physical and covalent). Covalent cross-linking of polymer chains leads to the formation of an elastic network, whereas physical cross-linking between nanoparticles and polymer chains induces viscoelastic properties. At high deformations covalent bonds may be broken but physical bonds rebuild and to some extent self-heal the overall network structure. Addition of silicate also enhances the bioactivity and adhesiveness of the hydrogel as these materials stick to soft tissue as well as to hard surfaces. In addition, MC3T3-E1 mouse preosteoblast cells readily adhere and spread on nanocomposite hydrogel surfaces. Collectively, the combinations of properties such as elasticity, stiffness, interconnected network, adhesiveness to surfaces and bio-adhesion to cells provide inspiration and opportunities to engineer mechanically strong and elastic tissue matrixes for orthopedic, craniofacial and dental applications. PMID:21839864

  8. Transdermal thiol-acrylate polyethylene glycol hydrogel synthesis using near infrared light.

    PubMed

    Chung, Solchan; Lee, Hwangjae; Kim, Hyung-Seok; Kim, Min-Gon; Lee, Luke P; Lee, Jae Young

    2016-08-01

    Light-induced polymerization has been widely applied for hydrogel synthesis, which conventionally involves the use of ultraviolet or visible light to activate a photoinitiator for polymerization. However, with these light sources, transdermal gelation is not efficient and feasible due to their substantial interactions with biological systems, and thus a high power is required. In this study, we used biocompatible and tissue-penetrating near infrared (NIR) light to remotely trigger a thiol-acrylate reaction for efficient in vivo gelation with good controllability. Our gelation system includes gold nanorods as a photothermal agent, a thermal initiator, diacrylate polyethylene glycol (PEG), and thiolated PEG. Irradiation with a low-power NIR laser (0.3 W cm(-2)) could induce gelation via a mixed-mode reaction with a small increase in temperature (∼5 °C) under the optimized conditions. We also achieved successful transdermal gelation via the NIR-assisted photothermal thiol-acryl reactions. This new type of NIR-assisted thiol-acrylate polymerization provides new opportunities for in situ hydrogel formation for injectable hydrogels and delivery of drugs/cells for various biomedical applications. PMID:27389611

  9. Injectable dopamine-modified poly(ethylene glycol) nanocomposite hydrogel with enhanced adhesive property and bioactivity.

    PubMed

    Liu, Yuan; Meng, Hao; Konst, Shari; Sarmiento, Ryan; Rajachar, Rupak; Lee, Bruce P

    2014-10-01

    A synthetic mimic of mussel adhesive protein, dopamine-modified four-armed poly(ethylene glycol) (PEG-D4), was combined with a synthetic nanosilicate, Laponite (Na(0.7+)(Mg5.5Li0.3Si8)O20(OH)4)(0.7-)), to form an injectable naoncomposite tissue adhesive hydrogel. Incorporation of up to 2 wt % Laponite significantly reduced the cure time while enhancing the bulk mechanical and adhesive properties of the adhesive due to strong interfacial binding between dopamine and Laponite. The addition of Laponite did not alter the degradation rate and cytocompatibility of PEG-D4 adhesive. On the basis of subcutaneous implantation in rat, PEG-D4 nanocomposite hydrogels elicited minimal inflammatory response and exhibited an enhanced level of cellular infiltration as compared to Laponite-free samples. The addition of Laponite is potentially a simple and effective method for promoting bioactivity in a bioinert, synthetic PEG-based adhesive while simultaneously enhancing its mechanical and adhesive properties. PMID:25222290

  10. Synthesis and Biological Evaluation of Novel Water-Soluble Poly-(ethylene glycol)-10-hydroxycamptothecin Conjugates.

    PubMed

    Guo, Na; Jiang, Du; Wang, Luyao; You, Xing; Teng, Yu-Ou; Yu, Peng

    2015-01-01

    In order to improve the antitumor activity and water solubility of 10-hydroxycamptothecin (HCPT), a series of novel HCPT conjugates were designed and synthesized by conjugating polyethylene glycol (PEG) to the 10-hydroxyl group of HCPT via a valine spacer. The in vitro stability of these synthesized compounds was determined in pH 7.4 buffer at 37 °C, and the results showed that they released HCPT at different rates. All the compounds demonstrated significant antitumor activity in vitro against K562, HepG2 and HT-29 cells. Among them, compounds, 4a, 4d, 4e and 4f, exhibited 2-5 times higher potency than HCPT. The stability and antitumor activity of these conjugates were found to be closely related to the length of PEG and the linker type, conjugates with a relatively short PEG chain and carbamate linkages (compounds 4a and 4f) exhibited controlled release of HCPT and excellent antitumor in vitro activity. PMID:26007190

  11. Polyethylene glycol-containing polyurethane hydrogel coatings for improving the biocompatibility of neural electrodes.

    PubMed

    Rao, Li; Zhou, Haihan; Li, Tao; Li, Chengyan; Duan, Yanwen Y

    2012-07-01

    The instability of the interface between chronically implanted neuroprosthetic devices and neural tissue is a major obstacle to the long-term use of such devices in clinical practice. In this study, we investigate the feasibility of polyethylene glycol (PEG)-containing polyurethane (PU) hydrogel as coatings for polydimethylsiloxane (PDMS)-based neural electrodes in order to achieve a stable neural interface. The influence of PU hydrogel coatings on electrode electrochemical behaviour was investigated. Importantly, the biocompatibility of PU hydrogel coatings was evaluated in vitro and in vivo. Changes in the electrochemical impedance of microelectrodes with PU coatings were negligible. The amount of protein adsorption on the PDMS substrate was reduced by 93% after coating. Rat pheochromocytoma (PC12) cells exhibited more and longer neurites on PU films than on PDMS substrates. Furthermore, PDMS implants with (n=10) and without (n=8) PU coatings were implanted into the cortex of rats and the tissue response to the implants was evaluated 6 weeks post-implantation. GFAP staining for astrocytes and NeuN staining for neurons revealed that PU coatings attenuated glial scarring and reduced the neuronal cell loss around the implants. All of these findings suggest that PU hydrogel coating is feasible and favourable for neural electrode applications. PMID:22406507

  12. Biodegradable DNA-enabled poly(ethylene glycol) hydrogels prepared by copper-free click chemistry.

    PubMed

    Barker, Karolyn; Rastogi, Shiva K; Dominguez, Jose; Cantu, Travis; Brittain, William; Irvin, Jennifer; Betancourt, Tania

    2016-01-01

    Significant research has focused on investigating the potential of hydrogels in various applications and, in particular, in medicine. Specifically, hydrogels that are biodegradable lend promise to many therapeutic and biosensing applications. Endonucleases are critical for mechanisms of DNA repair. However, they are also known to be overexpressed in cancer and to be present in wounds with bacterial contamination. In this work, we set out to demonstrate the preparation of DNA-enabled hydrogels that could be degraded by nucleases. Specifically, hydrogels were prepared through the reaction of dibenzocyclooctyne-functionalized multi-arm poly(ethylene glycol) with azide-functionalized single-stranded DNA in aqueous solutions via copper-free click chemistry. Through the use of this method, biodegradable hydrogels were formed at room temperature in buffered saline solutions that mimic physiological conditions, avoiding possible harmful effects associated with other polymerization techniques that can be detrimental to cells or other bioactive molecules. The degradation of these DNA-cross-linked hydrogels upon exposure to the model endonucleases Benzonase(®) and DNase I was studied. In addition, the ability of the hydrogels to act as depots for encapsulation and nuclease-controlled release of a model protein was demonstrated. This model has the potential to be tailored and expanded upon for use in a variety of applications where mild hydrogel preparation techniques and controlled material degradation are necessary including in drug delivery and wound healing systems. PMID:26541212

  13. FTIR spectroscopic study of poly(ethylene glycol)-nifedipine dispersion stability in different relative humidities.

    PubMed

    Iqbal, Waleed S; Chan, K L

    2015-01-01

    Solid dispersion has shown to be a promising formulation strategy to enhance dissolution for hydrophobic drugs. However, solid dispersions are often thermodynamically unstable, there is a continuous interest in studying their stabilities. In this study, attenuated total reflectance Fourier transform infrared (ATR-FTIR) was used to compare the amount of crystalline nifedipine formed in different formula of poly(ethylene glycol) (PEG)-nifedipine solid dispersions when exposed at various relative humidities (RHs) for 2 h at 40°C. The ratio of the crystalline nifedipine band and an internal reference band in the out of plane δ(C-H) region has been used to indicate the relative degree of drug crystallisation in a sample. A band ratio of ∼0.05 and 0.5 was respectively indicative of a fully amorphous or crystallised drug in the formula. Results show that increasing the RH generally increases the amount of crystalline nifedipine. Formulations with low (5%, w/w) nifedipine concentration in higher molecular weight PEG were found to be better at resisting crystallisation. Deliquescence of the 10% nifedipine in PEG 4000 was observed at 77% and 100% RH with a reduction in crystalline nifedipine. All 5% (w/w) nifedipine samples were stable at RH below 77%. Crystallisation of nifedipine occurred at all RH when drug loading was increased to 10% (w/w). PMID:25410816

  14. Poly(ethylene glycol) enhances the surface activity of a pulmonary surfactant.

    PubMed

    Yu, Laura M Y; Lu, James J; Chiu, Idy W Y; Leung, Kin Shun; Chan, Yawen W; Zhang, Ling; Policova, Zdenka; Hair, Michael L; Neumann, A Wilhelm

    2004-08-01

    The primary role of lung surfactant is to reduce surface tension at the air-liquid interface of alveoli during respiration. Axisymmetric drop shape analysis (ADSA) was used to study the effect of poly(ethylene glycol) (PEG) on the rate of surface film formation of a bovine lipid extract surfactant (BLES), a therapeutic lung surfactant preparation. PEG of molecular weights 3,350; 8,000; 10,000; 35,000; and 300,000 in combination with a BLES mixture of 0.5 mg/mL was studied. The adsorption rate of BLES alone at 0.5 mg/mL was much slower than that of a natural lung surfactant at the same concentration; more than 200 s are required to reach the equilibrium surface tension of 25 mJ/m(2). PEG, while not surface active itself, enhances the adsorption of BLES to an extent depending on its concentration and molecular weight. These findings suggest that depletion attraction induced by higher molecular weight PEG (in the range of 8,000 to 35,000) may be responsible for increasing the adsorption rate of BLES at low concentration. The results provide a basis for using PEG as an additive to BLES to reduce its required concentration in clinical treatment, thus reducing the cost for surfactant replacement therapy. PMID:15276633

  15. Macroporous interpenetrating network of polyethylene glycol (PEG) and gelatin for cartilage regeneration.

    PubMed

    Zhang, Jingjing; Wang, Justin; Zhang, Hui; Lin, Jianhao; Ge, Zigang; Zou, Xuenong

    2016-01-01

    Poor mechanical properties hinder the application of hydrogels in cartilage tissue engineering. In this study, macroporous interpenetrating network (IPN) hydrogels of gelatin and polyethylene glycol (PEG) were fabricated for use as a functional biomaterial to support chondrocyte culture. The IPN structure enhanced mechanical properties, while the macroporous structure facilitated cell-cell interactions. The hydrogels had pore sizes around 80 μm with favorable interconnectivity, reduced volume swelling ratios, and nearly unchanged weight swelling ratios with increasing gelatin ratios. More significantly, the Young's modulus increased with increasing gelatin ratio, reaching a 5.3-fold increase (p  <  0.01) in IPN-10% over that of the PEG group. Chondrocytes developed elongated and fibroblast morphologies with extensive cell-cell interaction throughout IPN hydrogels, compared with round, isolated aggregates in PEG hydrogels. The glycosaminoglycan (GAG) accumulation was significantly higher in IPN hydrogels than in PEG hydrogels at day 21 and day 28. Additionally, significantly higher gene expressions of collagen II (p  <  0.01) and sox-9 (p  <  0.01) were found in IPN-10% when compared with other groups. Overall, the macroporous IPN hydrogels showed strong tissue formation abilities and enhanced mechanical properties, demonstrating high potential as scaffolds for cartilage regeneration. PMID:27305040

  16. CO2 - and O2 -sensitive fluorophenyl end-capped poly(ethylene glycol).

    PubMed

    Choi, Jung Yoon; Kim, Jin Young; Moon, Hyo Jung; Park, Min Hee; Jeong, Byeongmoon

    2014-01-01

    Pentafluorophenyl end-capped poly(ethylene glycol) (PF-PEG-PF) aqueous solution shows a lower critical solution temperature (LCST), which is sensitive to the type of gases dissolved in the solution. LCST increases from 24.5 to 26 °C when dissolved carbon dioxide is replaced by oxygen. The transparent-to-turbid transition is reversibly observed when the dissolved carbon dioxide in the PF-PEG-PF aqueous solution is exchanged with oxygen, and vice versa, at 24.5 °C. (19) F NMR and (1) H NMR spectra of the PF-PEG-PF in D2 O suggest that 1) dehydration of PEG is the main reason of developing LCST of the PF-PEG-PF aqueous solution, 2) minute differences in the intermolecular interactions, as demonstrated by changes in the chemical shift of the PF-PEG-PF peaks, induce such a difference in LCST. This paper provides a new insight in designing a stimuli-responsive polymer in that fine tuning of a phase transition can be controlled by the type of dissolved gas. PMID:24272990

  17. Gelatin Microgel Incorporated Poly(ethylene glycol)-Based Bioadhesive with Enhanced Adhesive Property and Bioactivity.

    PubMed

    Li, Yuting; Meng, Hao; Liu, Yuan; Narkar, Ameya; Lee, Bruce P

    2016-05-18

    Up to 7.5 wt % of chemically cross-linked gelatin microgel was incorporated into dopamine-modified poly(ethylene glycol) (PEGDM) adhesive to simultaneously improve the material property and bioactivity of the PEG-based bioadhesive. Incorporation of gelatin microgel reduced cure time while it increased the elastic modulus and cross-linking density of the adhesive network. Most notably, the loss modulus values for microgel-containing adhesive were an order of magnitude higher when compared to microgel-free control. This drastic increase in the viscous dissipation ability of the adhesive is attributed to the introduction of reversible physical bonds into the adhesive network with the incorporation of the gelatin microgel. Additionally, incorporation of the microgel increased the adhesive properties of PEGDM by 1.5- to 2-fold. From in vitro cell culture studies, the composite adhesive is noncytotoxic and the incorporation of microgels provided binding site for promoting fibroblast attachment and viability. The subcutaneous implantation study indicated that the microgel-containing PEGDM adhesive is biocompatible and the incorporated microgels provided pockets for rapid cellular infiltration. Gelatin microgel incorporation was demonstrated to be a facile method to simultaneously enhance the adhesive property and the bioactivity of PEG-based adhesive. PMID:27111631

  18. Polyethylene glycol rinse solution: An effective way to prevent ischemia-reperfusion injury

    PubMed Central

    Zaouali, Mohamed Amine; Bejaoui, Mohamed; Calvo, Maria; Folch-Puy, Emma; Pantazi, Eirini; Pasut, Gianfranco; Rimola, Antoni; Ben Abdennebi, Hassen; Adam, René; Roselló-Catafau, Joan

    2014-01-01

    AIM: To test whether a new rinse solution containing polyethylene glycol 35 (PEG-35) could prevent ischemia-reperfusion injury (IRI) in liver grafts. METHODS: Sprague-Dawley rat livers were stored in University of Wisconsin preservation solution and then washed with different rinse solutions (Ringer’s lactate solution and a new rinse solution enriched with PEG-35 at either 1 or 5 g/L) before ex vivo perfusion with Krebs-Heinseleit buffer solution. We assessed the following: liver injury (transaminase levels), mitochondrial damage (glutamate dehydrogenase activity), liver function (bile output and vascular resistance), oxidative stress (malondialdehyde), nitric oxide, liver autophagy (Beclin-1 and LCB3) and cytoskeleton integrity (filament and globular actin fraction); as well as levels of metalloproteinases (MMP2 and MMP9), adenosine monophosphate-activated protein kinase (AMPK), heat shock protein 70 (HSP70) and heme oxygenase 1 (HO-1). RESULTS: When we used the PEG-35 rinse solution, reduced hepatic injury and improved liver function were noted after reperfusion. The PEG-35 rinse solution prevented oxidative stress, mitochondrial damage, and liver autophagy. Further, it increased the expression of cytoprotective heat shock proteins such as HO-1 and HSP70, activated AMPK, and contributed to the restoration of cytoskeleton integrity after IRI. CONCLUSION: Using the rinse solution containing PEG-35 was effective for decreasing liver graft vulnerability to IRI. PMID:25473175

  19. Monodisperse polyethylene glycol diacrylate hydrogel microsphere formation by oxygen-controlled photopolymerization in a microfluidic device.

    PubMed

    Krutkramelis, K; Xia, B; Oakey, J

    2016-04-12

    PEG-based hydrogels have become widely used as drug delivery and tissue scaffolding materials. Common among PEG hydrogel-forming polymers are photopolymerizable acrylates such as polyethylene glycol diacrylate (PEGDA). Microfluidics and microfabrication technologies have recently enabled the miniaturization of PEGDA structures, thus enabling many possible applications for nano- and micro- structured hydrogels. The presence of oxygen, however, dramatically inhibits the photopolymerization of PEGDA, which in turn frustrates hydrogel formation in environments of persistently high oxygen concentration. Using PEGDA that has been emulsified in fluorocarbon oil via microfluidic flow focusing within polydimethylsiloxane (PDMS) devices, we show that polymerization is completely inhibited below critical droplet diameters. By developing an integrated model incorporating reaction kinetics and oxygen diffusion, we demonstrate that the critical droplet diameter is largely determined by the oxygen transport rate, which is dictated by the oxygen saturation concentration of the continuous oil phase. To overcome this fundamental limitation, we present a nitrogen micro-jacketed microfluidic device to reduce oxygen within the droplet, enabling the continuous on-chip photopolymerization of microscale PEGDA particles. PMID:26987384

  20. Polyethylene glycol-polyvinyl alcohol grafted copolymer: study of the bioavailability after oral administration to rats.

    PubMed

    Heuschmid, Franziska F; Schuster, Paul; Lauer, Birthe; Fabian, Eric; Leibold, Edgar; van Ravenzwaay, Bennard

    2013-07-01

    The absorption, urinary excretion, and the biliary excretion of a single oral dose of 10 or 1000 mg/kg bw of (14)C-polyethylene glycol-polyvinyl alcohol (PEG-PVA) grafted copolymer were studied in adult male and female rats. In a balance/excretion experiment, the total excretion of ingested radioactivity was determined over a period of 168 h and residual radioactivity was detected in selected tissues and the carcass. In a biliary excretion experiment, excretion of radioactivity via the bile duct was determined over a period of 48 h after administration of the substance to cannulated rats. Most, if not all, of the radioactivity (>100%) was excreted within 48 h via the feces regardless of sex or dose. Urinary excretion was very limited: 0.45-0.50% of dose at the low dose and 0.22-0.27% of dose at the high dose. At both dose levels, residual radioactivity in the carcass and all organs and tissues after 168 h was ≤ 0.02% of dose. Biliary excretion was 0.01-0.02% of dose. Based on these findings, the bioavailability of PEG-PVA grafted copolymer was determined to be <1% demonstrating that absorption was virtually negligible following a single oral administration to male and female rats. PMID:23321424

  1. Intraspinal Delivery of Polyethylene Glycol-coated Gold Nanoparticles Promotes Functional Recovery After Spinal Cord Injury

    PubMed Central

    Papastefanaki, Florentia; Jakovcevski, Igor; Poulia, Nafsika; Djogo, Nevena; Schulz, Florian; Martinovic, Tamara; Ciric, Darko; Loers, Gabrielle; Vossmeyer, Tobias; Weller, Horst; Schachner, Melitta; Matsas, Rebecca

    2015-01-01

    Failure of the mammalian central nervous system (CNS) to regenerate effectively after injury leads to mostly irreversible functional impairment. Gold nanoparticles (AuNPs) are promising candidates for drug delivery in combination with tissue-compatible reagents, such as polyethylene glycol (PEG). PEG administration in CNS injury models has received interest for potential therapy, but toxicity and low bioavailability prevents clinical application. Here we show that intraspinal delivery of PEG-functionalized 40-nm-AuNPs at early stages after mouse spinal cord injury is beneficial for recovery. Positive outcome of hind limb motor function was accompanied by attenuated inflammatory response, enhanced motor neuron survival, and increased myelination of spared or regrown/sprouted axons. No adverse effects, such as body weight loss, ill health, or increased mortality were observed. We propose that PEG-AuNPs represent a favorable drug-delivery platform with therapeutic potential that could be further enhanced if PEG-AuNPs are used as carriers of regeneration-promoting molecules. PMID:25807288

  2. Rationalization of Membrane Protein Crystallization with Polyethylene Glycol Using a Simple Depletion Model

    PubMed Central

    Tanaka, Shinpei; Ataka, Mitsuo; Onuma, Kazuo; Kubota, Tomomi

    2003-01-01

    Based on the importance of crystallizing membrane proteins in a rational way, cytochrome bc1 complex (BC1) was crystallized using polyethylene glycol (PEG) as a sole crystallization agent. Interaction between protein-detergent complexes of BC1 was estimated by dynamic light scattering, and was compared with the numerical calculation using the Derjaguin-Landau-Verwey-Overbeek potential plus a depletion potential, without considering specific surface properties of the protein-detergent complexes. The experiments and calculation were found to be consistent and we obtained a relation between PEG molecular weight M and the range of depletion zone δ as δ ∼ M0.48±0.02. The stability of liquid phase of BC1 solutions was controlled by a ratio of (the range of depletion zone)/(the radius of a BC1 particle), which was consistent with recent theoretical predictions. The crystallization was most successful under a condition where the stability of the liquid phase changed from stable to unstable. The PEG molecular weight that fulfilled this condition coincided with the one used empirically to crystallize BC1 in the past by a number of groups. These results are compared to the fact that membrane proteins were often successfully crystallized close to the detergent cloud point. PMID:12719259

  3. Polyethylene glycol fusion repair prevents reinnervation accuracy in rat peripheral nerve.

    PubMed

    Robinson, Grant A; Madison, Roger D

    2016-07-01

    Functional recovery following a peripheral nerve injury is made easier when regenerating axons correctly reinnervate their original targets. Polyethylene glycol (PEG) has recently been used in attempts to fuse severed peripheral axons during suture-based repair, but an analysis of target selectivity following such repair has not been undertaken. The rat femoral nerve (in which muscle and cutaneous pathways comingle proximally but segregate distally into separate terminal nerve branches) is a convenient in vivo model for assessing motor neuron regeneration accuracy. The present study uses retrograde labeling of motor neurons to compare reinnervation accuracy after suture-based nerve repair with and without PEG fusion. The results show that adding PEG to the suture repair site blocked the preference of motor neurons to reinnervate correctly the distal terminal nerve branch to muscle that was seen with suture repair. Retrograde transport and diffusion studies also determined that PEG fusion allowed passage of probes across the repair site, as has previously been seen, but did not result in motor neuron labeling in the spinal cord. The results suggest that PEG fusion disrupts the beneficial trophic influence of muscle on motor neuron reinnervation accuracy normally seen after suture repair and that such fusion-based approaches may be best suited to nerve injuries in which accurate target reinnervation at the terminal nerve branch level is not a priority. © 2016 Wiley Periodicals, Inc. PMID:26994857

  4. Fibrin-Loaded Porous Poly(Ethylene Glycol) Hydrogels as Scaffold Materials for Vascularized Tissue Formation

    PubMed Central

    Jiang, Bin; Waller, Thomas M.; Larson, Jeffery C.; Appel, Alyssa A.

    2013-01-01

    Vascular network formation within biomaterial scaffolds is essential for the generation of properly functioning engineered tissues. In this study, a method is described for generating composite hydrogels in which porous poly(ethylene glycol) (PEG) hydrogels serve as scaffolds for mechanical and structural support, and fibrin is loaded within the pores to induce vascularized tissue formation. Porous PEG hydrogels were generated by a salt leaching technique with 100–150-μm pore size and thrombin (Tb) preloaded within the scaffold. Fibrinogen (Fg) was loaded into pores with varying concentrations and polymerized into fibrin due to the presence of Tb, with loading efficiencies ranging from 79.9% to 82.4%. Fibrin was distributed throughout the entire porous hydrogels, lasted for greater than 20 days, and increased hydrogel mechanical stiffness. A rodent subcutaneous implant model was used to evaluate the influence of fibrin loading on in vivo response. At weeks 1, 2, and 3, all hydrogels had significant tissue invasion, but no difference in the depth of invasion was found with the Fg concentration. Hydrogels with fibrin loading induced more vascularization, with a significantly higher vascular density at 20 mg/mL (week 1) and 40 mg/mL (weeks 2 and 3) Fg concentration compared to hydrogels without fibrin. In conclusion, we have developed a composite hydrogel that supports rapid vascularized tissue ingrowth, and thus holds great potential for tissue engineering applications. PMID:23003671

  5. Polyethylene-Glycol-Modified Single-Walled Carbon Nanotubes for Intra-Articular Delivery to Chondrocytes

    PubMed Central

    Sacchetti, Cristiano; Liu-Bryan, Ru; Magrini, Andrea; Rosato, Nicola; Bottini, Nunzio; Bottini, Massimo

    2015-01-01

    Osteoarthritis (OA) is a common and debilitating degenerative disease of articular joints for which no disease-modifying medical therapy is currently available. Inefficient delivery of pharmacologic agents into cartilage-resident chondrocytes after systemic administration has been a limitation to the development of anti-OA medications. Direct intra-articular injection enables delivery of high concentrations of agents in close proximity to chondrocytes; however, the efficacy of this approach is limited by the fast clearance of small molecules and biomacromolecules after injection into the synovial cavity. Coupling of pharmacologic agents with drug delivery systems able to enhance their residence time and cartilage penetration can enhance the effectiveness of intra-articularly injected anti-OA medications. Herein we describe an efficient intra-articular delivery nanosystem based on single-walled carbon nanotubes (SWCNTs) modified with polyethylene glycol (PEG) chains (PEG-SWCNTs). We show that PEG-SWCNTs are capable to persist in the joint cavity for a prolonged time, enter the cartilage matrix, and deliver gene inhibitors into chondrocytes of both healthy and OA mice. PEG-SWCNT nanoparticles did not elicit systemic or local side effects. Our data suggest that PEG-SWCNTs represent a biocompatible and effective nanocarrier for intra-articular delivery of agents to chondrocytes. PMID:25415768

  6. Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform

    PubMed Central

    Markelov, Denis A.; Matveev, Vladimir V.; Ingman, Petri; Nikolaeva, Marianna N.; Penkova, Anastasia V.; Lahderanta, Erkki; Boiko, Natalia I.; Chizhik, Vladimir I.

    2016-01-01

    We have studied copolymer dendrimer structure: carbosilane dendrimers with terminal phenylbenzoate mesogenic groups attached by poly(ethylene) glycol (PEG) spacers. In this system PEG spacers are additional tuning to usual copolymer structure: dendrimer with terminal mesogenic groups. The dendrimer macromolecules were investigated in a dilute chloroform solution by 1H NMR methods (spectra and relaxations). It was found that the PEG layer in G = 5 generations dendrimer is “frozen” at high temperatures (above 260 K), but it unexpectedly becomes “unfrozen” at temperatures below 250 K (i.e., melting when cooling). The transition between these two states occurs within a small temperature range (~10 K). Such a behavior is not observed for smaller dendrimer generations (G = 1 and 3). This effect is likely related to the low critical solution temperature (LCST) of PEG and is caused by dendrimer conformations, in which the PEG group concentration in the layer increases with growing G. We suppose that the unusual behavior of PEG fragments in dendrimers will be interesting for practical applications such as nanocontainers or nanoreactors. PMID:27052599

  7. Preparation and characterization of a microencapsulated polyethylene glycol cross-linked polyhemoglobin.

    PubMed

    Knirsch, Marcos C; Dell'Anno, Filippo; Chicoma, Dennis; Stephano, Marco Antonio; Bou-Chacra, Nádia A; Palombo, Domenico; Converti, Attilio; Polakiewicz, Bronislaw

    2015-11-01

    Many complications are associated to the therapeutic use of blood, among which are not only transfusion adverse events but also other issues such as lack of donors and high costs for collecting, testing, preserving, and distributing blood packages. Therefore, a clinically viable "blood substitute" is considered the holy grail of traumatology and may greatly benefit medicine. One of the most successful approaches to date is conjugating hemoglobin with polyethylene glycol (PEG). This conjugation aims mainly at overcoming free cell hemoglobin toxicity, which makes its use as oxygen carrier in pure form unfeasible. To improve PEG-hemoglobin conjugates feasibility, we propose applying dual functional PEG cross-linking hemoglobin molecules encapsulated by a protein carrier. The new oxygen carrier showed mean values of the hydrodynamic diameter, dispersity, and zeta potential of 1370 nm, 0.029 and -36 mV, respectively, evidencing the successful synthesis of PEG bis(N-succinimidyl succinate) and polyhemoglobin as well as the structuring of protein carrier. PMID:26314399

  8. Stabilization of Chromobacterium viscosum Lipase (CVL) Against Ultrasound Inactivation by the Pretreatment with Polyethylene Glycol (PEG).

    PubMed

    Talukder, Md Mahabubur Rahman; Shiong, Simon Choo Sze

    2015-12-01

    Although ultrasound has been used to accelerate many enzymatic reactions, the low stability of enzymes in such a system still remains a critical issue, limiting its industrial application. Here, we have reported that polyethylene glycol (PEG) pretreatment stabilized Chromobacterium viscosum lipase (CVL) in ultrasound-assisted water-isooctane emulsion. PEGs of different molecular weights and concentrations were used to pretreat CVL, and the pretreated lipase activities for olive oil hydrolysis were investigated at different ultrasonic powers. The best result was attained with PEG400 at 100 mg/ml for a lipase concentration of 0.02 mg/ml and an ultrasonic power of 106 W. The half-life time of PEG400-treated lipase at 106 W was 54 min, a 27-fold higher than that attained using untreated lipase. Circular dichroism (CD) spectra suggested that PEG increased the rigidity of CVL structure, which favored the lipase stability against ultrasound inactivation. These results have important implications for the exploitation of ultrasound in biocatalytic process. PMID:26373941

  9. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

    PubMed

    Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

    2016-01-01

    A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days. PMID:27367738

  10. Miscibility and degradability of poly(lactic acid)poly(ethylene oxide)/poly(ethylene glycol) blends

    SciTech Connect

    Yue, C.L.; Dave, V.; Gross, R.A.; McCarthy, S.P.

    1995-12-01

    Poly(lactic acid) [PLA] was melt blended with polyethylene(oxide) [PEG] and poly(ethylene glycol) [PEG] in different compositions to form blown films. It was determined that PLA was miscible with PEO in all compositions. Based on Gordon-Taylor equation, it was determined that the interactions between PLA and PEO is stronger than PEG. The addition of low molecular weight PEG improved the elongation and tear strength of the blends. Enzymatic degradation results shows that the weight loss of all the samples was more than 80% of the initial weight in 48 hours.

  11. Glycolic acid production in the engineered yeasts Saccharomyces cerevisiae and Kluyveromyces lactis

    PubMed Central

    2013-01-01

    Background Glycolic acid is a C2 hydroxy acid that is a widely used chemical compound. It can be polymerised to produce biodegradable polymers with excellent gas barrier properties. Currently, glycolic acid is produced in a chemical process using fossil resources and toxic chemicals. Biotechnological production of glycolic acid using renewable resources is a desirable alternative. Results The yeasts Saccharomyces cerevisiae and Kluyveromyces lactis are suitable organisms for glycolic acid production since they are acid tolerant and can grow in the presence of up to 50 g l-1 glycolic acid. We engineered S. cerevisiae and K. lactis for glycolic acid production using the reactions of the glyoxylate cycle to produce glyoxylic acid and then reducing it to glycolic acid. The expression of a high affinity glyoxylate reductase alone already led to glycolic acid production. The production was further improved by deleting genes encoding malate synthase and the cytosolic form of isocitrate dehydrogenase. The engineered S. cerevisiae strain produced up to about 1 g l-1 of glycolic acid in a medium containing d-xylose and ethanol. Similar modifications in K. lactis resulted in a much higher glycolic acid titer. In a bioreactor cultivation with d-xylose and ethanol up to 15 g l-1 of glycolic acid was obtained. Conclusions This is the first demonstration of engineering yeast to produce glycolic acid. Prior to this work glycolic acid production through the glyoxylate cycle has only been reported in bacteria. The benefit of a yeast host is the possibility for glycolic acid production also at low pH, which was demonstrated in flask cultivations. Production of glycolic acid was first shown in S. cerevisiae. To test whether a Crabtree negative yeast would be better suited for glycolic acid production we engineered K. lactis in the same way and demonstrated it to be a better host for glycolic acid production. PMID:24053654

  12. Determination of the surface density of polyethylene glycol on gold nanoparticles by use of microscale thermogravimetric analysis.

    PubMed

    Sebby, K B; Mansfield, E

    2015-04-01

    The widespread integration of nanoparticle technologies into biomedicine will depend on the ability to repeatedly create particles with well-defined properties and predictable behaviors. For this to happen, fast, reliable, inexpensive, and widely available techniques to characterize nanomaterials are needed. Characterization of the surface molecules is particularly important since the surface, including the surface molecule density, plays a dominant role in determining how nanoparticles interact with their surroundings. Here, 10 and 30 nm gold nanoparticle NIST Standard Reference Materials were functionalized with fluorescently labeled polyethylene glycol (PEG) with either thiolate or lipoic acid anchoring groups to evaluate analytical techniques for determining surface coverage. The coating of the nanoparticles was confirmed with dynamic light scattering, microscale thermogravimetric analysis (μ-TGA), and ultraviolet-visible (UV-vis) spectroscopy. A UV-vis method for determining gold nanoparticle concentrations that takes into account spectral broadening upon functionalization was developed. The amount of bound PEG was quantified with μ-TGA, a technique analogous to thermogravimetric analysis that uses quartz crystal microbalances, and fluorescence spectroscopy of displaced ligands. It is shown that μ-TGA is a convenient technique for the quantification of ligands bound to inorganic particles while sacrificing a minimal amount of sample, and the treatment of the functionalized nanoparticle dispersions with dithiothreitol may be insufficient to achieve complete displacement of the surface ligands for quantification by fluorescence measurements. The μ-TGA and fluorescence results were used to determine ligand footprint sizes-average areas occupied by each ligand on the particles' surface. The lipoic acid bound ligands had footprint sizes of 0.21 and 0.25 nm(2) on 10 and 30 nm particles, respectively while the thiolate ligands had footprint sizes of 0.085 and 0

  13. Cellular mechanisms of plasmalemmal sealing and axonal repair by polyethylene glycol and methylene blue.

    PubMed

    Spaeth, C S; Robison, T; Fan, J D; Bittner, G D

    2012-05-01

    Mammalian neurons and all other eukaryotic cells endogenously repair traumatic injury within minutes by a Ca²⁺-induced accumulation of vesicles that interact and fuse with each other and the plasmalemma to seal any openings. We have used uptake or exclusion of extracellular fluorescent dye to measure the ability of rat hippocampal B104 cells or rat sciatic nerves to repair (seal) transected neurites in vitro or transected axons ex vivo. We report that endogenous sealing in both preparations is enhanced by Ca²⁺-containing solutions and is decreased by Ca²⁺-free solutions containing antioxidants such as dithiothreitol (DTT), melatonin (MEL), methylene blue (MB), and various toxins that decrease vesicular interactions. In contrast, the fusogen polyethylene glycol (PEG) at 10-50 mM artificially seals the cut ends of B104 cells and rat sciatic axons within seconds and is not affected by Ca²⁺ or any of the substances that affect endogenous sealing. At higher concentrations, PEG decreases sealing of transected axons and disrupts the plasmalemma of intact cells. These PEG-sealing data are consistent with the hypothesis that lower concentrations of PEG directly seal a damaged plasmalemma. We have considered these and other data to devise a protocol using a well-specified series of solutions that vary in tonicity, Ca²⁺, MB, and PEG content. These protocols rapidly and consistently repair (PEG-fuse) rat sciatic axons in completely cut sciatic nerves in vivo rapidly and dramatically to restore long-lasting morphological continuity, action potential conduction, and behavioral functions. PMID:22302626

  14. Inner ear delivery of dexamethasone using injectable silk-polyethylene glycol (PEG) hydrogel.

    PubMed

    Yu, Dehong; Sun, Changling; Zheng, Zhaozhu; Wang, Xueling; Chen, Dongye; Wu, Hao; Wang, Xiaoqin; Shi, Fuxin

    2016-04-30

    Minimally invasive delivery and sustained release of therapeutics to the inner ear are of importance to the medical treatment of inner ear disease. In this study, the injectable silk fibroin-polyethylene glycol (Silk-PEG) hydrogel was investigated as a drug delivery carrier to deliver poorly soluble micronized dexamethasone (mDEX) to the inner ear of guinea pigs. Encapsulation of mDEX with a loading up to 5% (w/v) did not significantly change the silk gelation time, and mDEX were evenly distributed in the PEG-Silk hydrogel as visualized by SEM. The loading of mDEX in Silk-PEG hydrogel largely influenced in vitro drug release kinetics. The optimized Silk-PEG-mDEX hydrogel (2.5% w/v loading, in situ-forming,10μl) was administered directly onto the round window membrane of guinea pigs. The DEX concentration in perilymph maintained above 100ng/ml for at least 10 days for the Silk-PEG formulation while less than 12h for the control sample of free mDEX. Minimal systemic exposure was achieved with low DEX concentrations (<0.2μg/ml) in cerebrospinal fluid (CSF) and plasma in the first 2h after the local application of the Silk-PEG-mDEX hydrogel. A transient hearing threshold shift was found but then resolved after 14days as revealed by auditory brainstem response (ABR), showing minimal inflammatory responses on the round window membrane and scala taympani. The Silk-PEG hydrogel completely degraded in 21 days. Thus, the injectable PEG-Silk hydrogel is an effective and safe vehicle for inner ear delivery and sustained release of glucocorticoid. PMID:26972377

  15. Effect of polyethylene glycols on the trans-ungual delivery of terbinafine.

    PubMed

    Nair, Anroop B; Chakraborty, Bireswar; Murthy, S Narasimha

    2010-12-01

    Topical nail drug delivery could be improved by identifying potent chemical penetration enhancers. The purpose of this study was to assess the effect of polyethylene glycols (PEGs) on the trans-ungual delivery of terbinafine. In vitro permeation studies were carried out by passive and iontophoresis (0.5 mA/cm2) processes for a period of 1 h using gel formulations containing different molecular weight PEGs (30%w/w). The release of drug from the loaded nail plates and the possible mechanisms for the enhanced delivery was studied. Passive delivery using formulation with low molecular weight PEGs (200 and 400 MW) indicated moderate enhancement in the permeation and drug load in the nail plate, compared to the control formulation. However, the effect of low molecular weight PEGs was predominant during iontophoresis process with greater amount of terbinafine being permeated (≈35 µg/cm2) and loaded into the nail plate (≈2.7 µg/mg). However, little or no effect on drug delivery was observed with high molecular weight PEGs (1000- 3350 MW) in passive and iontophoresis processes. Release of drug from the nail plates loaded by iontophoresis using low molecular weight PEG (400 MW) exhibited sustain effect which continued over a period of 72 days. The enhancement in drug permeation by low molecular weight PEGs is likely due to their ability to lead to greater water uptake and swelling of nail. This study concluded that the low molecular weight PEGs are indeed a promising trans-ungual permeation enhancer. PMID:20955143

  16. Effect of solvent on the charging mechanisms of poly(ethylene glycol) in droplets.

    PubMed

    Soltani, Sepideh; Oh, Myong In; Consta, Styliani

    2015-03-21

    We examine the effect of solvent on the charging mechanisms of a macromolecule in a droplet by using molecular dynamics simulations. The droplet contains excess charge that is carried by sodium ions. To investigate the principles of the charging mechanisms of a macromolecule in a droplet, we simulate aqueous and methanol droplets that contain a poly(ethylene glycol) (PEG) molecule. We find that the solvent plays a critical role in the charging mechanism and in the manner that the sodiated PEG emerges from a droplet. In the aqueous droplets, the sodiated PEG is released from the droplet while it is being charged at a droplet charge state below the Rayleigh limit. The charging of PEG occurs on the surface of the droplet. In contrast to the aqueous droplets, in the methanol droplet, the sodiated PEG resides in the interior of the droplet and it may become charged at any location in the droplet, interior or surface. The sodiated PEG emerges from the droplet by drying-out of the solvent. Even though these two mechanisms appear to be phenomenologically similar to the widely accepted ion-evaporation and charge-residue mechanisms, they have fundamental differences from those. An integral part of the mechanism that the macromolecular ions emerge from droplets is the droplet morphology. Droplet morphologies give rise to different solvation interactions between the solvent and the macromolecule. In the water-sodiated PEG system, we find the extrusion of the PEG morphology, while in methanol-sodiated droplet, we find the "pearl-on-the-necklace" morphology and the extrusion of the sodiated PEG in the last stage of the desolvation process. These findings provide insight into the mechanisms that macromolecules acquire their charge in droplets produced in electrospray ionization experiments. PMID:25796249

  17. Surface forces and protein adsorption on dextran- and polyethylene glycol-modified polydimethylsiloxane.

    PubMed

    Farrell, Megan; Beaudoin, Stephen

    2010-12-01

    Dextran and polyethylene glycol (PEG) are often covalently bound to the surface of polydimethylsiloxane (PDMS) for the purpose of modifying its hydrophilicity and biocompatibility. In this work, the effects of the dextran and PEG on the morphology, wetting, and surface charge of the resulting surfaces were quantified and correlated with changes in the amount of fibrinogen and albumin adsorbed from aqueous solution. PDMS films were functionalized in a microwave oxygen plasma to create surface hydroxyl groups that were subsequently aminated by incubation in a (3-aminopropyl)trimethoxysilane (APTES) solution. Oxidized dextran and PEG-aldehyde were linked to the surface amines via reductive amination. This process resulted in low surface coverage of immobilized PEG in the end-on conformation and a more uniform and dense distribution of side-on immobilized dextran. The immobilized dextran reduced the contact angle of the PDMS film from 109° to 80° and neutralized the zeta potential over the pH range from 3 to 11. An atomic force microscope was used to measure the interaction force between the modified PDMS and a model hydrophobic surface (polystyrene latex) and a model hydrophilic surface (silica) in aqueous solution to show that van der Waals and hydrophobic attractive forces are the dominant forces for protein adsorption in this system. The PEG- and dextran-modified PDMS were exposed to BSA and fibrinogen to test their resistance to protein adsorption. The coatings were ineffective at reducing the adsorption of either molecule, and the dextran-modification of the PDMS caused more BSA to adsorb than in the case of the unmodified PDMS. PMID:20801620

  18. Quantifying the Coverage Density of Poly(ethylene glycol) Chains on the Surface of Gold Nanostructures

    PubMed Central

    Xia, Xiaohu; Yang, Miaoxin; Wang, Yucai; Zheng, Yiqun; Li, Qingge; Chen, Jingyi; Xia, Younan

    2011-01-01

    The coverage density of poly(ethylene glycol) (PEG) is a key parameter in determining the efficiency of PEGylation, a process pivotal to in vivo delivery and targeting of nanomaterials. Here we report four complementary methods for quantifying the coverage density of PEG chains on various types of Au nanostructures by using a model system based on HS-PEG-NH2 with different molecular weights. Specifically, the methods involve reactions with fluorescamine and ninhydrin, as well as labeling with fluorescein isothiocyanate (FITC) and Cu2+ ions. The first two methods use conventional amine assays to measure the number of unreacted HS-PEG-NH2 molecules left behind in the solution after incubation with the Au nanostructures. The other two methods involve coupling between the terminal –NH2 groups of adsorbed -S-PEG-NH2 chains and FITC or a ligand for Cu2+ ion, and thus pertain to the “active” –NH2 groups on the surface of a Au nanostructure. We found that the coverage density decreased as the length of PEG chains increased. A stronger binding affinity of the initial capping ligand to the Au surface tended to reduce the PEGylation efficiency by slowing down the ligand exchange process. For the Au nanostructures and capping ligands we have tested, the PEGylation efficiency decreased in the order of citrate-capped nanoparticles > PVP-capped nanocages ≈ CTAC-capped nanoparticles ≫ CTAB-capped nanorods, where PVP, CTAC, and CTAB stand for poly(vinyl pyrrolidone), cetyltrimethylammonium chloride, and cetyltrimethylammonium bromide, respectively. PMID:22148912

  19. Polyethylene Glycol-Mediated Synthesis of Cubic Iron Oxide Nanoparticles with High Heating Power.

    PubMed

    Iacovita, Cristian; Stiufiuc, Rares; Radu, Teodora; Florea, Adrian; Stiufiuc, Gabriela; Dutu, Alina; Mican, Sever; Tetean, Romulus; Lucaciu, Constantin M

    2015-12-01

    Iron oxide magnetic nanoparticles (IOMNPs) have been successfully synthesized by means of solvothermal reduction method employing polyethylene glycol (PEG200) as a solvent. The as-synthesized IOMNPs are poly-dispersed, highly crystalline, and exhibit a cubic shape. The size of IOMNPs is strongly dependent on the reaction time and the ration between the amount of magnetic precursor and PEG200 used in the synthesis method. At low magnetic precursor/PEG200 ratio, the cubic IOMNPs coexist with polyhedral IOMNPs. The structure and morphology of the IOMNPs were thoroughly investigated by using a wide range of techniques: TEM, XRD, XPS, FTIR, and RAMAN. XPS analysis showed that the IOMNPs comprise a crystalline magnetite core bearing on the outer surface functional groups from PEG200 and acetate. The presence of physisorbed PEG200 on the IOMNP surface is faintly detected through FT-IR spectroscopy. The surface of IOMNPs undergoes oxidation into maghemite as proven by RAMAN spectroscopy and the occurrence of satellite peaks in the Fe2p XP spectra. The magnetic studies performed on powder show that the blocking temperature (TB) of IOMNPs is around 300 K displaying a coercive field in between 160 and 170 Oe. Below the TB, the field-cooled (FC) curves turn concave and describe a plateau indicating that strong magnetic dipole-dipole interactions are manifested in between IOMNPs. The specific absorption rate (SAR) values increase with decreasing nanoparticle concentrations for the IOMNPs dispersed in water. The SAR dependence on the applied magnetic field, studied up to magnetic field amplitude of 60 kA/m, presents a sigmoid shape with saturation values up to 1700 W/g. By dispersing the IOMNPs in PEG600 (liquid) and PEG1000 (solid), it was found that the SAR values decrease by 50 or 75 %, indicating that the Brownian friction within the solvent was the main contributor to the heating power of IOMNPs. PMID:26446074

  20. Polyethylene Glycol-Mediated Synthesis of Cubic Iron Oxide Nanoparticles with High Heating Power

    NASA Astrophysics Data System (ADS)

    Iacovita, Cristian; Stiufiuc, Rares; Radu, Teodora; Florea, Adrian; Stiufiuc, Gabriela; Dutu, Alina; Mican, Sever; Tetean, Romulus; Lucaciu, Constantin M.

    2015-10-01

    Iron oxide magnetic nanoparticles (IOMNPs) have been successfully synthesized by means of solvothermal reduction method employing polyethylene glycol (PEG200) as a solvent. The as-synthesized IOMNPs are poly-dispersed, highly crystalline, and exhibit a cubic shape. The size of IOMNPs is strongly dependent on the reaction time and the ration between the amount of magnetic precursor and PEG200 used in the synthesis method. At low magnetic precursor/PEG200 ratio, the cubic IOMNPs coexist with polyhedral IOMNPs. The structure and morphology of the IOMNPs were thoroughly investigated by using a wide range of techniques: TEM, XRD, XPS, FTIR, and RAMAN. XPS analysis showed that the IOMNPs comprise a crystalline magnetite core bearing on the outer surface functional groups from PEG200 and acetate. The presence of physisorbed PEG200 on the IOMNP surface is faintly detected through FT-IR spectroscopy. The surface of IOMNPs undergoes oxidation into maghemite as proven by RAMAN spectroscopy and the occurrence of satellite peaks in the Fe2p XP spectra. The magnetic studies performed on powder show that the blocking temperature (TB) of IOMNPs is around 300 K displaying a coercive field in between 160 and 170 Oe. Below the TB, the field-cooled (FC) curves turn concave and describe a plateau indicating that strong magnetic dipole-dipole interactions are manifested in between IOMNPs. The specific absorption rate (SAR) values increase with decreasing nanoparticle concentrations for the IOMNPs dispersed in water. The SAR dependence on the applied magnetic field, studied up to magnetic field amplitude of 60 kA/m, presents a sigmoid shape with saturation values up to 1700 W/g. By dispersing the IOMNPs in PEG600 (liquid) and PEG1000 (solid), it was found that the SAR values decrease by 50 or 75 %, indicating that the Brownian friction within the solvent was the main contributor to the heating power of IOMNPs.

  1. New technetium-99m generator technologies utilizing polyethylene glycol-based aqueous biphasic systems

    SciTech Connect

    Rogers, R.D.; Bond, A.H.; Zhang, Jianhua; Horwitz, P.

    1995-12-31

    Two new schemes for TcO{sub 4}{sup {minus}}/MoO{sub 4}{sup 2{minus}} separations from OH{sup {minus}} and MoO{sub 4}{sup 2{minus}} media using polyethylene glycol (PEG)-based aqueous biphasic systems (ABS) have been developed. The two most important salt solutions in current {sup 99m}Tc-generator technologies, OH{sup {minus}} and MoO{sub 4}{sup 2{minus}}, also salt out PEG to form ABS. In liquid/liquid PEG- ABS, pertechnetate can be separated from molybdate with separation factors as high as 10,000. Stripping is accomplished by reduction of the TcO{sub 4}{sup {minus}} and back extraction into a salt solution. the strip solution can be the salt of an imaging agent (e.g., Na{sub 4}HEDPA) and thus may, under the appropriate conditions, be injected directly into the human body. {sup 99m}TcO{sub 4}{sup {minus}} can also be concentrated from a dilute load solution of {sup 99}MoO{sub 4}{sup 2{minus}} in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with K{sub 2}CO{sub 3} assures that all {sup 99}MoO{sub 4}{sup 2{minus}} is removed from the column and this is confirmed by a rapid drop in {sup 99}Mo activity by the fourth free column volume (fcv) of rinse. The {sup 99m}TcO{sub 4}{sup {minus}} is then eluted with water. This chromatographic separation affords 94% of the {sup 99m}TcO{sub 4}{sup {minus}} activity in 5 fcv, with the y spectrum showing less than 2 {times} 10{sup {minus}4} of the original {sup 99}Mo activity.

  2. Platelet adhesion and activation on polyethylene glycol modified polyurethane surfaces. Measurement of cytoplasmic calcium.

    PubMed

    Park, K D; Suzuki, K; Lee, W K; Lee, J E; Kim, Y H; Sakurai, Y; Okano, T

    1996-01-01

    Polyurethane (PU) surfaces were modified by coupling polyethylene glycol (PEG; molecular weight, 1,000) chains carrying different terminal groups (PU-PEG1K-OH, PU-PEG1K-NH2, PU-PEG1K-SO3) and longer PEG chains (MW, 3,350; PU-PEG3.4K-OH). The modified PU surfaces have the same PEG (1K) chain density. Surface induced platelet activation was evaluated by measuring cytoplasmic free calcium concentration in platelets contacting modified surfaces, and platelet adhesion onto modified surfaces was investigated in vitro. Cytoplasmic free calcium levels in platelets contacting PU-PEG-SO3 remained relatively constant, in contrast to the significant increase observed for PU-PEG-NH2, PU-PEG-OH, and control PU surfaces. The degree of platelet adhesion clearly demonstrates that all PEG graft surfaces prevented platelet adhesion. Among PEG1K surfaces, PU-PEG-SO3 shows the lowest platelet adhesion. In the case of relatively longer PEG grafted surfaces (PU-PEG3.4K-OH and PU-PEG3.4K-Hep), both surfaces were found to prevent the increase in both cytoplasmic free calcium and platelet adhesion. These results suggest that longer PEG chain grafting is more effective than shorter grafting in preventing platelet activation and adhesion because of the highly dynamic movement of hydrated PEG chains at the interface. In addition, in vitro platelet interaction is dependent upon terminal groups of PEG chains on PEG1K series surfaces. PMID:8945010

  3. Preferences for foods varying in macronutrients and tannins by lambs supplemented with polyethylene glycol.

    PubMed

    Titus, C H; Provenza, F D; Perevolotsky, A; Silanikove, N

    2000-06-01

    Supplemental polyethylene glycol (PEG) increases intake when animals eat foods high in tannins, but little is known about how PEG affects preference for foods that vary in concentrations of macronutrients and tannin. We investigated how varying macronutrients and tannins (commercially available extracts from quebracho trees) affected food intake, and we assessed the degree to which PEG (MW 3350) affected intake of tannin-rich foods by sheep. From 0715 to 1800 daily, lambs were offered diets that varied in concentrations of macronutrients: high energy/low protein (75% barley/25% alfalfa), medium energy/medium protein (35% barley/65% alfalfa), and low energy/high protein (100% alfalfa). Preference for these diets was determined in the absence of tannin, and then, in Trials 1 to 3, tannin was added in increasing concentrations (from 5 to 20%) to the diets with high and medium levels of energy. In Trial 4, tannin (10%) also was added to the low-energy diet. Lambs were supplemented with either 50 g of PEG mixed with 50 g of ground barley or 50 g of ground barley alone from 0700 to 1715 daily; lambs always consumed all of these supplements. In the absence of added tannins, all lambs preferred high energy/low protein > medium energy/medium protein > low energy/high protein. As tannin levels increased, preference for the high- and medium-energy foods decreased, and all lambs preferred foods that were lower in tannins and higher in protein. Lambs supplemented with PEG ate more macronutrients and tannins than unsupplemented lambs, and the effect became increasingly apparent as tannin levels increased from Trials 1 to 4. We conclude that the effectiveness of supplemental PEG may be low if alternative forages are equal or superior in nutritional quality and contain fewer metabolites with adverse effects. In such cases, animals would likely prefer alternatives to high-tannin foods. PMID:10875625

  4. Polyethylene glycol-mediated colorectal cancer chemoprevention: roles of epidermal growth factor receptor and Snail.

    PubMed

    Wali, Ramesh K; Kunte, Dhananjay P; Koetsier, Jennifer L; Bissonnette, Marc; Roy, Hemant K

    2008-09-01

    Polyethylene glycol (PEG) is a clinically widely used agent with profound chemopreventive properties in experimental colon carcinogenesis. We reported previously that Snail/beta-catenin signaling may mediate the suppression of epithelial proliferation by PEG, although the upstream events remain unclear. We report herein the role of epidermal growth factor receptor (EGFR), a known mediator of Snail and overexpressed in approximately 80% of human colorectal cancers, on PEG-mediated antiproliferative and hence antineoplastic effects in azoxymethane (AOM) rats and HT-29 colon cancer cells. AOM rats were randomized to either standard diet or one with 10% PEG-3350 and euthanized 8 weeks later. The colonic samples were subjected to immunohistochemical or Western blot analyses. PEG decreased mucosal EGFR by 60% (P < 0.001). Similar PEG effects were obtained in HT-29 cells. PEG suppressed EGFR protein via lysosmal degradation with no change in mRNA levels. To show that EGFR antagonism per se was responsible for the antiproliferative effect, we inhibited EGFR by either pretreating cells with gefitinib or stably transfecting with EGFR-short hairpin RNA and measured the effect of PEG on proliferation. In either case, PEG effect was blunted, suggesting a vital role of EGFR. Flow cytometric analysis revealed that EGFR-short hairpin RNA cells, besides having reduced membrane EGFR, also expressed low Snail levels (40%), corroborating a strong association. Furthermore, in EGFR silenced cells, PEG effect on EGFR or Snail was muted, similar to that on proliferation. In conclusion, we show that EGFR is the proximate membrane signaling molecule through which PEG initiates antiproliferative activity with Snail/beta-catenin pathway playing the central intermediary function. PMID:18790788

  5. A Dense Poly(ethylene glycol) Coating Improves Penetration of Large Polymeric Nanoparticles within Brain Tissue

    PubMed Central

    Nance, Elizabeth A.; Woodworth, Graeme F.; Sailor, Kurt A.; Shih, Ting-Yu; Xu, Qingguo; Swaminathan, Ganesh; Xiang, Dennis; Eberhart, Charles; Hanes, Justin

    2013-01-01

    Prevailing opinion suggests that only substances up to 64 nm in diameter can move at appreciable rates through the brain extracellular space (ECS). This size range is large enough to allow diffusion of signaling molecules, nutrients, and metabolic waste products, but too small to allow efficient penetration of most particulate drug delivery systems and viruses carrying therapeutic genes, thereby limiting effectiveness of many potential therapies. We analyzed the movements of nanoparticles of various diameters and surface coatings within fresh human and rat brain tissue ex vivo and mouse brain in vivo. Nanoparticles as large as 114-nm in diameter diffused within the human and rat brain, but only if they were densely coated with poly(ethylene glycol) (PEG). Using these minimally adhesive PEG-coated particles, we estimated that human brain tissue ECS has some pores larger than 200 nm, and that more than one-quarter of all pores are ≥100 nm. These findings were confirmed in vivo in mice, where 40- and 100-nm, but not 200-nm, nanoparticles, spread rapidly within brain tissue, only if densely coated with PEG. Similar results were observed in rat brain tissue with paclitaxel-loaded biodegradable nanoparticles of similar size (85 nm) and surface properties. The ability to achieve brain penetration with larger nanoparticles is expected to allow more uniform, longer-lasting, and effective delivery of drugs within the brain, and may find use in the treatment of brain tumors, stroke, neuroinflammation, and other brain diseases where the blood-brain barrier is compromised or where local delivery strategies are feasible. PMID:22932224

  6. Feasibility of poly(ethylene glycol) derivatives as diagnostic drug carriers for tumor imaging.

    PubMed

    Kanazaki, Kengo; Sano, Kohei; Makino, Akira; Yamauchi, Fumio; Takahashi, Atsushi; Homma, Tsutomu; Ono, Masahiro; Saji, Hideo

    2016-03-28

    Poly(ethylene glycol) (PEG) is an artificial but biocompatible hydrophilic polymer that has been widely used in clinical products. To evaluate the feasibility of using PEG derivative itself as a tumor imaging carrier via an enhanced permeability and retention (EPR) effect, we prepared indium-111-labeled PEG ((111)In-DTPA-PEG) and indocyanine green (ICG)-labeled PEG (ICG-PEG) with PEG molecular weights of 5-40kDa and investigated their in vivo biodistribution in colon26 tumor-bearing mice. Thereafter, single-photon emission computed tomography (SPECT) and photoacoustic (PA) imaging studies were performed. The in vivo biodistribution studies demonstrated increased tumor uptake and a prolongation of circulation half-life as the molecular weight of PEG increased. Although the observed differences in in vivo biodistribution were dependent on the labeling method ((111)In or ICG), the tumor-to-normal tissue ratios were comparable. Because PEG-based probes with a molecular weight of 20kDa (PEG20) showed a preferable biodistribution (highest accumulation among tissues excised and relatively high tumor-to-blood ratios), an imaging study using (111)In-DTPA-PEG20 and ICG-PEG20 was performed. Colon26 tumors inoculated in the right shoulder were clearly visualized by SPECT 24h after administration. Furthermore, PA imaging using ICG-PEG20 also detected tumor regions, and the detected PA signals increased in proportion with the injected dose. These results suggest that PEG derivatives (20kDa) serve as robust diagnostic drug carriers for tumor imaging. PMID:26869546

  7. Osteogenic potential of poly(ethylene glycol)-poly(dimethylsiloxane) hybrid hydrogels.

    PubMed

    Munoz-Pinto, Dany J; Jimenez-Vergara, Andrea Carolina; Hou, Yaping; Hayenga, Heather N; Rivas, Alejandra; Grunlan, Melissa; Hahn, Mariah S

    2012-08-01

    Growth factors have been shown to be potent mediators of osteogenesis. However, their use in tissue-engineered scaffolds not only can be costly but also can induce undesired responses in surrounding tissues. Thus, the ability to specifically induce osteogenic differentiation in the absence of exogenous growth factors through manipulation of scaffold material properties would be desirable for bone regeneration. Previous research indicates that addition of inorganic or hydrophobic components to organic, hydrophilic scaffolds can enhance multipotent stem cell (MSC) osteogenesis. However, the combined impact of scaffold inorganic content and hydrophobicity on MSC behavior has not been systematically explored, particularly in three-dimensional (3D) culture systems. The aim of the present study was therefore to examine the effects of simultaneous increases in scaffold hydrophobicity and inorganic content on MSC osteogenic fate decisions in a 3D culture environment toward the development of intrinsically osteoinductive scaffolds. Mouse 10T½ MSCs were encapsulated in a series of novel scaffolds composed of varying levels of hydrophobic, inorganic poly(dimethylsiloxane) (PDMS) and hydrophilic, organic poly(ethylene glycol) (PEG). After 21 days of culture, increased levels of osteoblast markers, runx2 and osteocalcin, were observed in scaffolds with increased PDMS content. Bone extracellular matrix (ECM) molecules, collagen I and calcium phosphate, were also elevated in formulations with higher PDMS:PEG ratios. Importantly, this osteogenic response appeared to be specific in that markers for chondrocytic, smooth muscle cell, and adipocytic lineages were not similarly affected by variations in scaffold PDMS content. As anticipated, the increase in scaffold hydrophobicity accompanying increasing PDMS levels was associated with elevated scaffold serum protein adsorption. Thus, scaffold inorganic content combined with alterations in adsorbed serum proteins may underlie the

  8. Osteogenic Potential of Poly(Ethylene Glycol)–Poly(Dimethylsiloxane) Hybrid Hydrogels

    PubMed Central

    Munoz-Pinto, Dany J.; Jimenez-Vergara, Andrea Carolina; Hou, Yaping; Hayenga, Heather N.; Rivas, Alejandra; Grunlan, Melissa

    2012-01-01

    Growth factors have been shown to be potent mediators of osteogenesis. However, their use in tissue-engineered scaffolds not only can be costly but also can induce undesired responses in surrounding tissues. Thus, the ability to specifically induce osteogenic differentiation in the absence of exogenous growth factors through manipulation of scaffold material properties would be desirable for bone regeneration. Previous research indicates that addition of inorganic or hydrophobic components to organic, hydrophilic scaffolds can enhance multipotent stem cell (MSC) osteogenesis. However, the combined impact of scaffold inorganic content and hydrophobicity on MSC behavior has not been systematically explored, particularly in three-dimensional (3D) culture systems. The aim of the present study was therefore to examine the effects of simultaneous increases in scaffold hydrophobicity and inorganic content on MSC osteogenic fate decisions in a 3D culture environment toward the development of intrinsically osteoinductive scaffolds. Mouse 10T½ MSCs were encapsulated in a series of novel scaffolds composed of varying levels of hydrophobic, inorganic poly(dimethylsiloxane) (PDMS) and hydrophilic, organic poly(ethylene glycol) (PEG). After 21 days of culture, increased levels of osteoblast markers, runx2 and osteocalcin, were observed in scaffolds with increased PDMS content. Bone extracellular matrix (ECM) molecules, collagen I and calcium phosphate, were also elevated in formulations with higher PDMS:PEG ratios. Importantly, this osteogenic response appeared to be specific in that markers for chondrocytic, smooth muscle cell, and adipocytic lineages were not similarly affected by variations in scaffold PDMS content. As anticipated, the increase in scaffold hydrophobicity accompanying increasing PDMS levels was associated with elevated scaffold serum protein adsorption. Thus, scaffold inorganic content combined with alterations in adsorbed serum proteins may underlie the

  9. Phosphate-Containing Polyethylene Glycol Polymers Prevent Lethal Sepsis by Multidrug-Resistant Pathogens

    PubMed Central

    Zaborin, Alexander; Defazio, Jennifer R.; Kade, Matthew; Kaiser, Brooke L. Deatherage; Belogortseva, Natalia; Camp, David G.; Smith, Richard D.; Adkins, Joshua N.; Kim, Sangman M.; Alverdy, Alexandria; Goldfeld, David; Firestone, Millicent A.; Collier, Joel H.; Jabri, Bana; Tirrell, Matthew

    2014-01-01

    Antibiotic resistance among highly pathogenic strains of bacteria and fungi is a growing concern in the face of the ability to sustain life during critical illness with advancing medical interventions. The longer patients remain critically ill, the more likely they are to become colonized by multidrug-resistant (MDR) pathogens. The human gastrointestinal tract is the primary site of colonization of many MDR pathogens and is a major source of life-threatening infections due to these microorganisms. Eradication measures to sterilize the gut are difficult if not impossible and carry the risk of further antibiotic resistance. Here, we present a strategy to contain rather than eliminate MDR pathogens by using an agent that interferes with the ability of colonizing pathogens to express virulence in response to host-derived and local environmental factors. The antivirulence agent is a phosphorylated triblock high-molecular-weight polymer (here termed Pi-PEG 15–20) that exploits the known properties of phosphate (Pi) and polyethylene glycol 15-20 (PEG 15-20) to suppress microbial virulence and protect the integrity of the intestinal epithelium. The compound is nonmicrobiocidal and appears to be highly effective when tested both in vitro and in vivo. Structure functional analyses suggest that the hydrophobic bis-aromatic moiety at the polymer center is of particular importance to the biological function of Pi-PEG 15-20, beyond its phosphate content. Animal studies demonstrate that Pi-PEG prevents mortality in mice inoculated with multiple highly virulent pathogenic organisms from hospitalized patients in association with preservation of the core microbiome. PMID:24277029

  10. Need and utility of a polyethylene glycol marker to ensure against urine falsification among heroin users

    PubMed Central

    Jones, Jermaine D.; Atchison, Jared J.; Madera, Gabriela; Metz, Verena E.; Comer, Sandra D.

    2015-01-01

    Background Deceptive methods of falsifying urine samples are of concern for anyone who relies on accurate urine toxicology results. A novel method to combat these efforts utilizes polyethylene glycol (PEG) markers administered orally prior to providing a urine sample. By using various PEG combinations to create a tracer capsule of unique composition, each urine sample can be matched to that individual. The goal of this study was to determine the effectiveness of using the PEG marker system among active heroin users screening for research studies. Methods Upon each screening visit, participants (N=55) were randomized to provide an unobserved urine sample, or the PEG tracer procedure was used. LCMS analysis was used to distinguish the PEG combinations, and allowed us to provide a unique qualitative analysis of patterns of drug use (N=168, total urine specimens). Results The unique composition of the tracer capsules was accurately detected in 83.5% of the urine specimens. Analyses of inconsistencies implicated a number of possible attempts at fraudulence (11.4%) and investigator/lab error (5.1%). Among this sample, the concurrent use of multiple classes of psychoactive drugs was more common than not, though concomitant drug use was often underreported. Conclusion Urine drug testing should be the minimum standard for obtaining information about drug use as self-report was unreliable even in a situation where there were no perceived adverse consequences for full disclosure. In cases where there are significant pressures for individuals to falsify these data, more protective collection methods such as the PEG marker system should be considered. PMID:26051158

  11. Efficacy of mosapride citrate with polyethylene glycol solution for colonoscopy preparation

    PubMed Central

    Tajika, Masahiro; Niwa, Yasumasa; Bhatia, Vikram; Kawai, Hiroki; Kondo, Shinya; Sawaki, Akira; Mizuno, Nobumasa; Hara, Kazuo; Hijioka, Susumu; Matsumoto, Kazuya; Kobayashi, Yuji; Saeki, Akira; Akabane, Asana; Komori, Koji; Yamao, Kenji

    2012-01-01

    AIM: To evaluate the efficacy and safety of adjunctive mosapride citrate for bowel preparation before colonoscopy. METHODS: We conducted a randomized, double-blind, placebo-controlled study with mosapride in addition to polyethylene glycol (PEG)-electrolyte solution. Of 250 patients undergoing colonoscopy, 124 were randomized to receive 2 L PEG plus 15 mg of mosapride citrate (mosapride group), and 126 received 2 L PEG plus placebo (placebo group). Patients completed a questionnaire reporting the acceptability and tolerability of the bowel preparation process. The efficacy of bowel preparation was assessed by colonoscopists using a 5-point scale based on Aronchick’s criteria. The primary end point was optimal bowel preparation rates (scores of excellent/good/fair vs poor/inadequate). RESULTS: A total of 249 patients were included in the analysis. In the mosapride group, optimal bowel preparation rates were significantly higher in the left colon compared with the placebo group (78.2% vs 65.6%, P < 0.05), but not in the right colon (76.5% vs 66.4%, P = 0.08). After excluding patients with severe constipation, there was a significant difference in bowel preparation in both the left and right colon (82.4% vs 66.7%, 80.8% vs 67.5%, P < 0.05, P < 0.01). The incidence of adverse events was similar in both groups. Among the subgroup who had previous colonoscopy experience, a significantly higher number of patients in the mosapride group felt that the current preparation was easier compared with patients in the placebo group (34/72 patients vs 24/74 patients, P < 0.05). CONCLUSION: Mosapride citrate may be an effective and safe adjunct to PEG-electrolyte solution that leads to improved quality of bowel preparation, especially in patients without severe constipation. PMID:22654449

  12. Intercalation behavior of poly(ethylene glycol) in organically modified montmorillonite

    NASA Astrophysics Data System (ADS)

    Zhu, Shipeng; Peng, Hongmei; Chen, Jinyao; Li, Huilin; Cao, Ya; Yang, Yunhua; Feng, Zhihai

    2013-07-01

    In this paper, two kinds of organically modified montmorillonite (OMMT) were prepared using alkylammonium surfactants with different alkyl chain numbers. XRD results showed the interlayer spacing of OMMT increased with low concentration surfactants. With further increasing the surfactants concentration, the interlayer spacing of OMMT was unchanged. Meanwhile, FTIR was used to characterize the local environments of surfactants in the interlayer space of OMMT. The results suggested that the double chain surfactant D-18 preferred to adopt highly ordered conformation compared with single chain surfactant S-18 in interlayer space of OMMT. It indicated that the surface property of the OMMT is affected by the concentration and configuration of the intercalated surfactants. Moreover, the effect of the OMMT type, or more particularly the chemical nature of the organic modifier in the interlayer spacing and the poly(ethylene glycol) (PEG) concentration onintercalation behavior of PEG chains in OMMT were investigated with XRD and DSC.The results indicated that PEG chains could not intercalate into Na-MMT when the surfactants were saturated in interlayer space of Na-MMT. PEG chains could intercalate into the interlayer space of SM when the S-18 concentration was lower than 2.00CEC, implying that the low surfactant concentration modified SM provided a better environment (presumably through the balanced hydrophobic and hydrophilic surfaces) for the PEG intercalation as well. However, PEG did not intercalate into the interlayer space of DM when the D-18 concentration was higher than 1.00CEC. It could be attributed to the hydrophobic double alkyl chains of DM increased with D-18. The increased hydrophobic properties in the interlayer space of 1.50DM hybrids can prevent the intercalation of hydrophilic PEG.

  13. Pharmacokinetic and thrombolytic properties of cysteine-linked polyethylene glycol derivatives of staphylokinase.

    PubMed

    Vanwetswinkel, S; Plaisance, S; Zhi-Yong, Z; Vanlinthout, I; Brepoels, K; Lasters, I; Collen, D; Jespers, L

    2000-02-01

    Recombinant staphylokinase (SakSTAR) variants obtained by site-directed substitution with cysteine, in the core (lysine 96 [Lys96], Lys102, Lys109, and/or Lys135) or the NH(2)-terminal region that is released during activation of SakSTAR (serine 2 [Ser2] and/or Ser3), were derivatized with thiol-specific (ortho-pyridyl-disulfide or maleimide) polyethylene glycol (PEG) molecules with molecular weights of 5,000 (P5), 10,000 (P10), or 20,000 (P20). The specific activities and thrombolytic potencies in human plasma were unaltered for most variants derivatized with PEG (PEGylates), but maleimide PEG derivatives had a better temperature stability profile. In hamsters, SakSTAR was cleared at 2.2 mL/min; variants with 1 P5 molecule were cleared 2-to 5-fold; variants with 2 P5 or 1 P10 molecules were cleared 10-to 30-fold; and variants with 1 P20 molecule were cleared 35-fold slower. A bolus injection induced dose-related lysis of a plasma clot, fibrin labeled with 125 iodine ((125)I-fibrin plasma clot), and injected into the jugular vein. A 50% clot lysis at 90 minutes required 110 microg/kg SakSTAR; 50 to 110 microg/kg of core-substitution derivatives with 1 P5; 25 microg/kg for NH(2)-terminal derivatives with 1 P5; 5 to 25 microg/kg with derivatives with 2 P5 or 1 P10; and 7 microg/kg with P20 derivatives. Core substitution with 1 or 2 P5 molecules did not significantly reduce the immunogenicity of SakSTAR in rabbits. Derivatization of staphylokinase with a single PEG molecule allows controllable reduction of the clearance while maintaining thrombolytic potency at a reduced dose. This indicates that mono-PEGylated staphylokinase variants may be used for single intravenous bolus injection. PMID:10648406

  14. A colorimetric method for the molecular weight determination of polyethylene glycol using gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ling, Kai; Jiang, Hongyan; Zhang, Qiqing

    2013-12-01

    A gold nanoparticle (AuNP)-based colorimetric method was developed for the molecular weight (MW) determination of polyethylene glycol (PEG), a commonly used hydrophilic polymer. Addition of a salt solution to PEG-coated AuNP solutions helps in screening the electrostatic repulsion between nanoparticles and generating a color change of the solutions from wine red to blue in 10 min in accordance with the MW of PEG, which illustrates the different stability degrees (SDs) of the AuNPs. The SDs are calculated by the absorbance ratios of the stable to the aggregated AuNPs in the solution. The root mean square end-to-end length (< h 2>1/2) of PEG molecules shows a linear fit to the SDs of the PEG-coated AuNPs in a range of 1.938 ± 0.156 to 10.151 ± 0.176 nm. According to the Derjaguin-Landau-Verwey-Overbeek theory, the reason for this linear relationship is that the thickness of the PEG adlayer is roughly equivalent to the < h 2>1/2 of the PEG molecules in solution, which determines the SDs of the AuNPs. Subsequently, the MW of the PEG can be obtained from its < h 2>1/2 using a mathematical relationship between < h 2>1/2 and MW of PEG molecule. Applying this approach, we determined the < h 2>1/2 and the MW of four PEG samples according to their absorbance values from the ordinary ultraviolet-visible spectrophotometric measurements. Therefore, the MW of PEG can be distinguished straightforwardly by visual inspection and determined by spectrophotometry. This novel approach is simple, rapid, and sensitive.

  15. Development of Poly(Ethylene Glycol) Hydrogels for Salivary Gland Tissue Engineering Applications

    PubMed Central

    Shubin, Andrew D.; Felong, Timothy J.; Graunke, Dean; Ovitt, Catherine E.

    2015-01-01

    More than 40,000 patients are diagnosed with head and neck cancers annually in the United States with the vast majority receiving radiation therapy. Salivary glands are irreparably damaged by radiation therapy resulting in xerostomia, which severely affects patient quality of life. Cell-based therapies have shown some promise in mouse models of radiation-induced xerostomia, but they suffer from insufficient and inconsistent gland regeneration and accompanying secretory function. To aid in the development of regenerative therapies, poly(ethylene glycol) hydrogels were investigated for the encapsulation of primary submandibular gland (SMG) cells for tissue engineering applications. Different methods of hydrogel formation and cell preparation were examined to identify cytocompatible encapsulation conditions for SMG cells. Cell viability was much higher after thiol-ene polymerizations compared with conventional methacrylate polymerizations due to reduced membrane peroxidation and intracellular reactive oxygen species formation. In addition, the formation of multicellular microspheres before encapsulation maximized cell–cell contacts and increased viability of SMG cells over 14-day culture periods. Thiol-ene hydrogel-encapsulated microspheres also promoted SMG proliferation. Lineage tracing was employed to determine the cellular composition of hydrogel-encapsulated microspheres using markers for acinar (Mist1) and duct (Keratin5) cells. Our findings indicate that both acinar and duct cell phenotypes are present throughout the 14 day culture period. However, the acinar:duct cell ratios are reduced over time, likely due to duct cell proliferation. Altogether, permissive encapsulation methods for primary SMG cells have been identified that promote cell viability, proliferation, and maintenance of differentiated salivary gland cell phenotypes, which allows for translation of this approach for salivary gland tissue engineering applications. PMID:25762214

  16. Anisotropic Poly(Ethylene Glycol)/Polycaprolactone Hydrogel–Fiber Composites for Heart Valve Tissue Engineering

    PubMed Central

    Tseng, Hubert; Puperi, Daniel S.; Kim, Eric J.; Ayoub, Salma; Shah, Jay V.; Cuchiara, Maude L.; West, Jennifer L.

    2014-01-01

    The recapitulation of the material properties and structure of the native aortic valve leaflet, specifically its anisotropy and laminate structure, is a major design goal for scaffolds for heart valve tissue engineering. Poly(ethylene glycol) (PEG) hydrogels are attractive scaffolds for this purpose as they are biocompatible, can be modified for their mechanical and biofunctional properties, and can be laminated. This study investigated augmenting PEG hydrogels with polycaprolactone (PCL) as an analog to the fibrosa to improve strength and introduce anisotropic mechanical behavior. However, due to its hydrophobicity, PCL must be modified prior to embedding within PEG hydrogels. In this study, PCL was electrospun (ePCL) and modified in three different ways, by protein adsorption (pPCL), alkali digestion (hPCL), and acrylation (aPCL). Modified PCL of all types maintained the anisotropic elastic moduli and yield strain of unmodified anisotropic ePCL. Composites of PEG and PCL (PPCs) maintained anisotropic elastic moduli, but aPCL and pPCL had isotropic yield strains. Overall, PPCs of all modifications had elastic moduli of 3.79±0.90 MPa and 0.46±0.21 MPa in the parallel and perpendicular directions, respectively. Valvular interstitial cells seeded atop anisotropic aPCL displayed an actin distribution aligned in the direction of the underlying fibers. The resulting scaffold combines the biocompatibility and tunable fabrication of PEG with the strength and anisotropy of ePCL to form a foundation for future engineered valve scaffolds. PMID:24712446

  17. Anisotropic poly(ethylene glycol)/polycaprolactone hydrogel-fiber composites for heart valve tissue engineering.

    PubMed

    Tseng, Hubert; Puperi, Daniel S; Kim, Eric J; Ayoub, Salma; Shah, Jay V; Cuchiara, Maude L; West, Jennifer L; Grande-Allen, K Jane

    2014-10-01

    The recapitulation of the material properties and structure of the native aortic valve leaflet, specifically its anisotropy and laminate structure, is a major design goal for scaffolds for heart valve tissue engineering. Poly(ethylene glycol) (PEG) hydrogels are attractive scaffolds for this purpose as they are biocompatible, can be modified for their mechanical and biofunctional properties, and can be laminated. This study investigated augmenting PEG hydrogels with polycaprolactone (PCL) as an analog to the fibrosa to improve strength and introduce anisotropic mechanical behavior. However, due to its hydrophobicity, PCL must be modified prior to embedding within PEG hydrogels. In this study, PCL was electrospun (ePCL) and modified in three different ways, by protein adsorption (pPCL), alkali digestion (hPCL), and acrylation (aPCL). Modified PCL of all types maintained the anisotropic elastic moduli and yield strain of unmodified anisotropic ePCL. Composites of PEG and PCL (PPCs) maintained anisotropic elastic moduli, but aPCL and pPCL had isotropic yield strains. Overall, PPCs of all modifications had elastic moduli of 3.79±0.90 MPa and 0.46±0.21 MPa in the parallel and perpendicular directions, respectively. Valvular interstitial cells seeded atop anisotropic aPCL displayed an actin distribution aligned in the direction of the underlying fibers. The resulting scaffold combines the biocompatibility and tunable fabrication of PEG with the strength and anisotropy of ePCL to form a foundation for future engineered valve scaffolds. PMID:24712446

  18. Fabrication of Off-the-Shelf Multilumen Poly(Ethylene Glycol) Nerve Guidance Conduits Using Stereolithography.

    PubMed

    Arcaute, Karina; Mann, Brenda K; Wicker, Ryan B

    2011-01-01

    A manufacturing process for fabricating off-the-shelf multilumen poly(ethylene glycol) (PEG)-based nerve guidance conduits (NGCs) was developed that included the use of stereolithography (SL). A rapid fabrication strategy for complex 3D scaffolds incorporated postprocessing with lyophilization and sterilization to preserve the scaffold, creating an implantable product with improved suturability. SL is easily adaptable to changes in scaffold design, is compatible with various materials and cells, and can be expanded for mass manufacture. The fabricated conduits were characterized using optical and scanning electron microscopy, and measurements of swelling ratio, dimensional swelling factor, resistance to compression, and coefficient of friction were performed. Water absorption curves showed that the conduits after lyophilization and sterilization return easily and rapidly to a swollen state when placed in an aqueous solution, successfully maintaining their original overall structure as required for implantation. Postprocessed conduits at the swollen state were less slippery and therefore easier to handle than those without postprocessing. Suture pullout experiments showed that NGCs fabricated with a higher concentration of PEG were better able to resist suture pullout. NGCs having a multilumen design demonstrated a better resistance to compression than a single-lumen design with an equivalent surface area, as well as a greater force required to collapse the design. Conduits fabricated with a higher PEG concentration were shown to have compressive resistances comparable to those of commercially available NGCs. The use of SL with PEG and the manufacturing process developed here shows promise for improving the current state of the art in peripheral nerve repair strategies. PMID:20673135

  19. Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

    PubMed Central

    Pasut, Gianfranco; Panisello, Arnau; Folch-Puy, Emma; Lopez, Alexandre; Castro-Benítez, Carlos; Calvo, Maria; Carbonell, Teresa; García-Gil, Agustín; Adam, René; Roselló-Catafau, Joan

    2016-01-01

    Liver ischemia-reperfusion injury (IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ (ischemia) is exacerbated following the return of oxygen delivery (reperfusion). IRI is a major cause of primary non-function after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions (antioxidants, anti-cytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols (PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI. PMID:27605884

  20. Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury.

    PubMed

    Pasut, Gianfranco; Panisello, Arnau; Folch-Puy, Emma; Lopez, Alexandre; Castro-Benítez, Carlos; Calvo, Maria; Carbonell, Teresa; García-Gil, Agustín; Adam, René; Roselló-Catafau, Joan

    2016-07-28

    Liver ischemia-reperfusion injury (IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ (ischemia) is exacerbated following the return of oxygen delivery (reperfusion). IRI is a major cause of primary non-function after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions (antioxidants, anti-cytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols (PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI. PMID:27605884

  1. The Use of Polyethylene Glycol in Mammalian Herbivore Diet Studies: What Are We Measuring?

    PubMed

    Windley, Hannah R; Wigley, Hannah J; Ruscoe, Wendy A; Foley, William J; Marsh, Karen J

    2016-06-01

    Polyethylene glycol (PEG) has been used to study the intake and digestion of tannin-rich plants by mammalian herbivores because it preferentially binds to tannins. However, it is not clear whether the responses of herbivores to dietary PEG is due to increased protein availability from the release of tannin-bound protein, amelioration of tannin effects, or whether PEG also may bind to other compounds and change their activity in the gut. We used three native New Zealand tree species to measure the effect of PEG on the amount of foliage eaten by invasive common brushtail possums (Trichosurus vulpecula) and on in vitro digestible nitrogen (available N). The addition of PEG increased the in vitro available N content of Weinmannia racemosa foliage, and possums ate significantly more PEG-treated foliage than untreated foliage. However, possums also ate more PEG-treated Fuchsia excorticata foliage, even though PEG did not increase in vitro available N in this species. Possums ate very little Melicytus ramiflorus, regardless of PEG treatment, even though M. ramiflorus contained the highest concentration of in vitro available N. These results prompted us to use PEG and a protein supplement, casein, to manipulate the available N concentration of diets containing ground eucalypt foliage, a well-studied food species for possums. Again, the response of possums to PEG was independent of changes in in vitro available N. In addition, altering the protein content of the diet via the addition of casein did not affect how much food the possums consumed. We conclude that the effects of PEG on dry matter intake by mammalian herbivores are not due solely to the release of tannin-bound protein. There is need for a better understanding of PEG-tannin interactions in order to ensure that the use of PEG in nutritional studies does not outstrip an understanding of its mechanisms of action. PMID:27256074

  2. Antioxidant response of Stevia rebaudiana B. to polyethylene glycol and paclobutrazol treatments under in vitro culture.

    PubMed

    Hajihashemi, Shokoofeh; Ehsanpour, Ali Akbar

    2014-04-01

    This investigation was carried out with the aim of determining the effect of paclobutrazol (PBZ) (0 and 2 mg l(-1)) and polyethylene glycol (PEG) (0, 2, 4 and 6 % w/v of PEG 6000) treatments on antioxidant system of Stevia rebaudiana Bertoni under in vitro condition. Analysis of data showed that PEG treatment significantly increased hydrogen peroxide (H2O2) and phenolic contents, while PBZ treatment limited the effect of PEG on them. Our data revealed that PEG treatment significantly increased total antioxidant capacity, catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO) and peroxidase (POD) activity, while it inversely decreased glutathione reductase (GR) activity. The superoxide dismutase (SOD) activity was not affected by PEG treatment. PBZ treatment induced significantly higher levels of CAT and GR activity and lower levels of SOD activity in PEG-treated plants. PBZ in combination with PEG resulted in no significant difference on APX activity with PEG treatment alone. PBZ treatment prevented the effect of PEG on the PPO activity. PEG (with or without PBZ) treatment increased the ascorbate pool, whereas total glutathione level was not affected by PEG. Our finding indicated that PBZ reduced the negative effect of PEG treatment by quenching H2O2 accumulation and increasing the CAT activity. Collectively, the antioxidant capacity of S. rebaudiana in PEG treatment condition was associated with active enzymatic and non-enzymatic defence systems which partly could be improved by the PBZ treatment. In addition, a higher accumulation of phenolic compounds leads to a more potent reactive oxygen species scavenging activity in S. rebaudiana. PMID:24604127

  3. Apc-driven colon carcinogenesis in Pirc rat is strongly reduced by polyethylene glycol.

    PubMed

    Femia, Angelo Pietro; Becherucci, Caterina; Crucitta, Stefania; Caderni, Giovanna

    2015-11-01

    Polyethylene glycol (PEG) is one of the most powerful agents in reducing chemically induced carcinogenesis in rat colon. However, contrasting results in Min mice dampened the enthusiasm on this potentially strong and virtually safe, cancer chemopreventing agent. Pirc (F344/NTac-Apc (am1137) ) rats carrying a germline heterozygous mutation in the Apc gene, spontaneously develop multiple tumours in the colon thus modelling both familial adenomatous polyposis (FAP) and sporadic colorectal cancer (CRC). Given this similarity, we thought that these rats could be appropriate to test the efficacy of PEG 8000 in reducing carcinogenesis. Pirc male rats aged one month were treated with 5% PEG in drinking water for 2 or 6 months. Precancerous lesions were dramatically reduced after 2 months of PEG treatment (Mucin depleted foci (MDF)/colon were 99 ± 17 and 12 ± 8 in Controls and PEG-treated rats, respectively; p < 0.001; mean ± SD). Similarly, colon tumors were significantly reduced after 6 months of treatment (tumors/rat were 8.1 ± 2.3 and 3.6 ± 2.2 in Controls and PEG-treated rats, respectively; p < 0.05; mean ± SD). Colon proliferation, a parameter correlated to cancer risk, was also significantly lower in PEG-treated rats than in Controls, while apoptosis was not significantly affected. In conclusion, PEG markedly reduces colon carcinogenesis in Pirc rats mutated in Apc; we thus suggest that PEG may be used as chemopreventive agent to reduce cancer risk in FAP and CRC patients. PMID:25912754

  4. Safety of polyethylene glycol 3350 solution in chronic constipation: randomized, placebo-controlled trial

    PubMed Central

    McGraw, Thomas

    2016-01-01

    Purpose To evaluate the safety and tolerability of aqueous solution concentrate (ASC) of polyethylene glycol (PEG) 3350 in patients with functional constipation. Patients and methods The patients who met Rome III diagnostic criteria for functional constipation were randomized in this multicenter, randomized, placebo-controlled, single-blind study to receive once daily dose of PEG 3350 (17 g) ASC or placebo solution for 14 days. The study comprised a screening period (visit 1), endoscopy procedure (visits 2 and 3), and followup telephone calls 30 days post-treatment. Safety end points included adverse events (AEs), clinical laboratory evaluations, vital signs, and others. The primary end points were the proportion of patients with abnormalities of the oral and esophageal mucosa, detected by visual and endoscopic examination of the oral cavity and esophagus, respectively, compared with placebo. A secondary objective was to compare the safety and tolerability of ASC by evaluating AEs or adverse drug reactions. Results A total of 65 patients were enrolled in this study, 31 were randomized to PEG 3350 ASC and 34 were randomized to placebo, of which 62 patients completed the study. No patients in either group showed abnormalities in inflammation of the oral mucosa during visit 2 (before treatment) or visit 3 (after treatment). Fewer abnormalities of the esophageal mucosa were observed in the PEG 3350 ASC group than in the placebo group on visit 3, with no significant difference in the proportion of abnormalities between the treatment groups. Overall, 40 treatment-emergent AEs were observed in 48.4% of patients treated with PEG 3350 ASC, and 41 treatment-emergent AEs were observed in 55.9% of patients treated with placebo – nonsignificant difference of −7.5% (95% CI: −21.3, 6.3) between treatment groups. No serious AEs or deaths were reported, and no patient discontinued because of an AE. Conclusion PEG 3350 ASC is safe and well tolerated in patients with functional

  5. The curious ability of polyethylene glycol fusion technologies to restore lost behaviors after nerve severance.

    PubMed

    Bittner, G D; Sengelaub, D R; Trevino, R C; Peduzzi, J D; Mikesh, M; Ghergherehchi, C L; Schallert, T; Thayer, W P

    2016-03-01

    Traumatic injuries to PNS and CNS axons are not uncommon. Restoration of lost behaviors following severance of mammalian peripheral nerve axons (PNAs) relies on regeneration by slow outgrowths and is typically poor or nonexistent when after ablation or injuries close to the soma. Behavioral recovery after severing spinal tract axons (STAs) is poor because STAs do not naturally regenerate. Current techniques to enhance PNA and/or STA regeneration have had limited success and do not prevent the onset of Wallerian degeneration of severed distal segments. This Review describes the use of a recently developed polyethylene glycol (PEG) fusion technology combining concepts from biochemical engineering, cell biology, and clinical microsurgery. Within minutes after microsuturing carefully trimmed cut ends and applying a well-specified sequence of solutions, PEG-fused axons exhibit morphological continuity (assessed by intra-axonal dye diffusion) and electrophysiological continuity (assessed by conduction of action potentials) across the lesion site. Wallerian degeneration of PEG-fused PNAs is greatly reduced as measured by counts of sensory and/or motor axons and maintenance of axonal diameters and neuromuscular synapses. After PEG-fusion repair, cut-severed, crush-severed, or ablated PNAs or crush-severed STAs rapidly (within days to weeks), more completely, and permanently restore PNA- or STA-mediated behaviors compared with nontreated or conventionally treated animals. PEG-fusion success is enhanced or decreased by applying antioxidants or oxidants, trimming cut ends or stretching axons, and exposure to Ca(2+) -free or Ca(2+) -containing solutions, respectively. PEG-fusion technology employs surgical techniques and chemicals already used by clinicians and has the potential to produce a paradigm shift in the treatment of traumatic injuries to PNAs and STAs. PMID:26525605

  6. Characterizing the modification of surface proteins with poly(ethylene glycol) to interrupt platelet adhesion

    PubMed Central

    Xu, Haiyan; Kaar, Joel L.; Russell, Alan J.; Wagner, William R.

    2010-01-01

    Surface protein modification with poly(ethylene glycol) (PEG) can inhibit acute thrombosis on damaged vascular and biomaterial surfaces by blocking surface protein–platelet interactions. However, the feasibility of employing protein reactive PEGs to limit intravascular and biomaterial thrombosis in vivo is contingent upon rapid and extensive surface protein modification. To characterize the factors controlling this potential therapeutic approach, the model protein bovine serum albumin was adsorbed onto polyurethane surfaces and modified with PEG-carboxymethyl succinimidyl ester (PEG-NHS), PEG-isocyanate (PEG-ISO), or PEG-diisocyanate (PEG-DISO) in aqueous buffer at varying concentrations and contact times. It was found that up to 5 PEGs could be attached per albumin molecule within one min and that adsorbed albumin PEGylation approached maximal levels by 6 min. The lability of reactive PEGs in aqueous buffer reduced total protein modification by 50% when the PEG solution was incubated for 7 min prior to application. For fibrinogen PEGylation (performed in the solution phase), PEG-NHS was more reactive than PEG-ISO or PEG-DISO. The γ peptide of fibrinogen, which contains several key platelet-binding motifs, was highly modified. A marked reduction in platelet adhesion was observed on fibrinogen-adsorbed polyurethane treated with PEG-NHS or PEG-DISO. Relative differences in platelet adhesion on PEG-NHS and PEG-DISO modified surfaces could be attributed to differences in reactivity towards fibrinogen and the size of the polymer backbone. Taken together, these findings provide insight and guidance for applying protein reactive PEGs for the interruption of acute thrombotic deposition. PMID:16457880

  7. Phase formation study of magnesium titanate nanomaterial with polyethylene glycol template

    NASA Astrophysics Data System (ADS)

    Hariyani, Y.; Pratapa, S.

    2014-09-01

    The formation of geikielite (MgTiO3, abbreviated as MT) nanomaterial with an addition of polyethylene glycol (PEG)-1000 during synthesis is reported. The synthesis of MT was carried out by means of the dissolved-metal mixing route with PEG-1000 as a template. Prior to the synthesis, Mg and Ti powders, as the raw materials, were independently dissolved in 37% HCl to form MgCl2 and TiCl4 solutions, respectively. Meanwhile, PEG gels with various weights, namely 0.5; 1.0; 1.5; 2.0; 2.5g, were prepared by heating at around 30-40 °C. The solutions and PEG gels were then mixed for 5 hours and dried to temperatures of about 105-110 °C to produce powders with five different PEG compositions. Each of the dried powder was calcined at 600 °C for 1 hour. A sample with no PEG was also prepared following a similar procedure for comparison. The calcined powder was characterized by XRD and to which the data was then quantitatively analyzed by appliying Rietveld method using Rietica software. Results showed that introducing PEG-1000 leads to the formation of MgTi2O5. Further quantitative analysis showed that in general addition of PEG increased the MT weight fraction. Addition of 2.5g PEG increased MT content by more than 12%. The role of PEG on the templation is discussed. TEM micrographs are presented to support the discussion.

  8. Effect of solvent on the charging mechanisms of poly(ethylene glycol) in droplets

    NASA Astrophysics Data System (ADS)

    Soltani, Sepideh; Oh, Myong In; Consta, Styliani

    2015-03-01

    We examine the effect of solvent on the charging mechanisms of a macromolecule in a droplet by using molecular dynamics simulations. The droplet contains excess charge that is carried by sodium ions. To investigate the principles of the charging mechanisms of a macromolecule in a droplet, we simulate aqueous and methanol droplets that contain a poly(ethylene glycol) (PEG) molecule. We find that the solvent plays a critical role in the charging mechanism and in the manner that the sodiated PEG emerges from a droplet. In the aqueous droplets, the sodiated PEG is released from the droplet while it is being charged at a droplet charge state below the Rayleigh limit. The charging of PEG occurs on the surface of the droplet. In contrast to the aqueous droplets, in the methanol droplet, the sodiated PEG resides in the interior of the droplet and it may become charged at any location in the droplet, interior or surface. The sodiated PEG emerges from the droplet by drying-out of the solvent. Even though these two mechanisms appear to be phenomenologically similar to the widely accepted ion-evaporation and charge-residue mechanisms, they have fundamental differences from those. An integral part of the mechanism that the macromolecular ions emerge from droplets is the droplet morphology. Droplet morphologies give rise to different solvation interactions between the solvent and the macromolecule. In the water-sodiated PEG system, we find the extrusion of the PEG morphology, while in methanol-sodiated droplet, we find the "pearl-on-the-necklace" morphology and the extrusion of the sodiated PEG in the last stage of the desolvation process. These findings provide insight into the mechanisms that macromolecules acquire their charge in droplets produced in electrospray ionization experiments.

  9. Surface Forces and Protein Adsorption on Dextran- and Polyethylene Glycol-Modified Polydimethylsiloxane

    PubMed Central

    Farrell, Megan; Beaudoin, Stephen

    2010-01-01

    Dextran and polyethylene glycol (PEG) are often covalently bound to the surface of polydimethylsiloxane (PDMS) for the purpose of modifying its hydrophilicity and biocompatibility. In this work, the effects of the dextran and PEG on the morphology, wetting, and surface charge of the resulting surfaces were quantified and correlated with changes in the amount of fibrinogen and albumin adsorbed from aqueous solution. PDMS films were functionalized in a microwave oxygen plasma to create surface hydroxyl groups that were subsequently aminated by incubation in a (3-aminopropyl)trimethoxysilane (APTES) solution. Oxidized dextran and PEG-aldehyde were linked to the surface amines via reductive amination. This process resulted in low surface coverage of immobilized PEG in the end-on conformation and a more uniform and dense distribution of side-on immobilized dextran. The immobilized dextran reduced the contact angle of the PDMS film from 109° to 80° and neutralized the zeta potential over the pH range from 3 to 11. An atomic force microscope was used to measure the interaction force between the modified PDMS and a model hydrophobic surface (polystyrene latex) and a model hydrophilic surface (silica) in both water and electrolyte solutions to show that van der Waals and hydrophobic attractive forces are the dominant forces for protein adsorption in this system. The PEG- and dextran-modified PDMS were exposed to BSA and fibrinogen to test their resistance to protein adsorption. The coatings were ineffective at reducing the adsorption of either molecule, and the dextran-modification of the PDMS caused more BSA to adsorb than in the case of the unmodified PDMS. PMID:20801620

  10. The In Vitro and In Vivo Response to MMP-Sensitive Poly(Ethylene Glycol) Hydrogels.

    PubMed

    Amer, Luke D; Bryant, Stephanie J

    2016-06-01

    Enzyme-sensitive hydrogels are a promising class of materials for cell encapsulation and tissue engineering because their ability to be degraded by cell-secreted factors. However, it is well known that nearly all synthetic biomaterials elicit a foreign body response (FBR) upon implantation. Therefore, this study aimed to evaluate the in vitro and in vivo response to an enzyme-sensitive hydrogel. Hydrogels were formed from poly(ethylene glycol) with the peptide crosslinker, C-VPLS↓LYSG-C, which is susceptible to matrix metalloproteinases 2 and 9. We evaluated the hydrogel by exogenously delivered enzymes, encapsulated mesenchymal stem cells as a tissue engineering relevant cell type, and by macrophage-secreted factors in vitro and for the FBR through macrophage attachment in vitro and in a subcutaneous mouse model. These hydrogels rapidly degraded upon exposure to exogenous MMP-2 and to lesser degree with MMP-9. Encapsulated mesenchymal stem cells were capable of degrading the hydrogels via matrix metalloproteinases. Inflammatory macrophages were confirmed to attach to the hydrogels, but were not capable of rapidly degrading the hydrogels. In vivo, these hydrogels remained intact after 4 weeks and exhibited a classic FBR with inflammatory cells at the hydrogel surface and a fibrous capsule. In summary, these findings suggest that while this MMP-2/9 sensitive hydrogel is readily degraded in vitro, it does not undergo rapid degradation by the FBR. Thus, the long term stability of these hydrogels in vivo coupled with the ability for encapsulated cells to degrade the hydrogel makes them promising materials for tissue engineering. PMID:27080375

  11. Enhanced detection of infectious hematopoietic necrosis virus by pretreatment of cell monolayers with polyethylene glycol

    USGS Publications Warehouse

    Batts, W.N.; Winton, J.R.

    1989-01-01

    To improve quantification of very low levels of infectious hematopoietic necrosis virus (IHNV) in samples of tissue, ovarian fluid, or natural water supplies, we tested the ability of polyethylene glycol (PEG) to enhance the sensitivity and speed of the plaque assay system. We compared 4, 7, and 10% solutions of PEG of molecular weight 6,000, 8,000, or 20,000 applied at selected volumes and for various durations. When cell monolayers of epithelioma papulosum cyprini (EPC), fathead minnow (FHM), chinook salmon embryo (CHSE-214), and bluegill fry (BF2) were pretreated with 7% PEG-20,000, they produced 4-17-fold increases in plaque assay titers of IHNV. The plaque assay titers of viral hemorrhagic septicemia virus, chum salmon reovirus, and chinook salmon paramyxovirus were also enhanced by exposure of CHSE-214 cells to PEG, but the titers of infectious pancreatic necrosis virus and Oncorhynchus masou virus were not substantially changed. Plaques formed by IHNV on PEG-treated EPC cells incubated at 15°C had a larger mean diameter at 6 d than those on control cells at 8 d; this suggests the assay could be shortened by use of PEG. Pretreatment of EPC cell monolayers with PEG enabled detection of IHNV in some samples that appeared negative with untreated cells. For example, when ovarian fluid samples from chinook salmon Oncorhynchus tshawytscha were inoculated onto untreated monolayers of EPC cells, IHNV was detected in only 11 of 51 samples; 17 of the samples were positive when PEG-treated EPC cells were used.PDF

  12. Polyethylene glycol influences selection of foraging location by sheep consuming quebracho tannin.

    PubMed

    Villalba, J J; Provenza, F D

    2002-07-01

    Tannins are a heterogeneous group of phenolic polymers that can induce detrimental effects when consumed by herbivores. Polyethylene glycol (PEG) binds to tannins and thus attenuates their negative effects. Our objective was to determine whether sheep actively seek PEG when fed tannins and thus modify their foraging location as a function of the spatial distribution of PEG. Lambs were first trained to recognize the beneficial effects of PEG by offering a meal high in quebracho tannin (QT), which presumably caused malaise, and then PEG (MW, 3,350), which presumably led to recovery from malaise. Animals were then tested in an experimental area where they could forage at two different locations that contained in Trial 1 1) PEG and QT in adjacent food boxes (PEG+QT) or 2) QT and in Trial 2 1) PEG or 2) QT. Preference for foraging locations was tested under three conditions: 1) no preload meal, 2) a meal high in quebracho tannin 1 h before testing, and 3) a basal diet high in quebracho tannin. Lambs spent more time (P = 0.012) and ate more tannin-containing food (P = 0.022) at locations where PEG was present (PEG+QT) than where it was absent (QT; Trial 1). Lambs responded to increased tannins in their bodies (Conditions 2 and 3) by reducing intake (P = 0.0001; Trial 2) at sites containing only QT and by increasing intake (P = 0.0001, Trial 1; P = 0.001, Trial 2) and foraging time (P = 0.072, Trial 1; P = 0.0001, Trial 2) at locations where PEG was available. Thus, PEG influenced foraging location by sheep consuming quebracho tannin. Accordingly, it may be possible to formulate range blocks that enable herbivores to ingest PEG in tannin-rich habitats. Strategic distribution of PEG in those habitats may attract animals to underutilized feeding sites. PMID:12162651

  13. Preference for polyethylene glycol by sheep fed a quebracho tannin diet.

    PubMed

    Villalba, J J; Provenza, F D

    2001-08-01

    Tannins decrease food intake by reducing digestion and by causing illness, whereas polyethylene glycol (PEG) attenuates the aversive effects of tannins. Our objective was to determine whether sheep recognize the benefits of ingesting substances such as PEG when consuming tannins. If so, then ingestion of PEG should be 1) PEG-specific, 2) a function of previous experience with recovery from tannin-toxicosis, and 3) dependent on the presence/absence of tannins. During conditioning, lambs in Group 1 (n = 10) were offered a meal of high-tannin food, which presumably caused malaise, and then offered PEG (molecular weight, 3,350), which presumably led to recovery from malaise. Subsequently, lambs ingested a control food (wheat straw) that did not have the "medicinal" effects of PEG in the absence of the tannin diet. In contrast, lambs in Group 2 (n = 10) ingested PEG in the absence of the tannin diet, and they ingested the tannin diet only in association with wheat straw. Ingestion of PEG and straw by both groups of lambs increased as a function of the presence of tannins in the diet (P < 0.05). However, when offered a choice among the tannin diet, PEG and straw, or when given the tannin diet and then offered a choice between PEG and straw, lambs trained to associate PEG with tannins ate more PEG than lambs that ingested PEG without tannins (P < 0.05). The responses were apparently PEG-specific; straw intake did not differ between groups of lambs during testing (P > 0.05), and differences in PEG intake disappeared in the absence of tannins (P > 0.05). In summary, our results suggest that lambs fed high-tannin diets discriminated the effects of PEG from those provided by a "nonmedicinal" food (straw). Thus, it may be possible to formulate PEG supplements that allow herbivores to self-regulate intake of PEG under extensive management conditions. PMID:11518214

  14. Flixweed vs. Polyethylene Glycol in the Treatment of Childhood Functional Constipation: A Randomized Clinical Trial

    PubMed Central

    Nimrouzi, Majid; Sadeghpour, Omid; Imanieh, Mohammad Hadi; Shams Ardekani, Mohammadreza; Salehi, Alireza; Minaei, Mohamad Bagher; Zarshenas, Mohammad M.

    2015-01-01

    Background: Polyethylene glycol (PEG) is often considered as the first-line treatment for functional constipation in children. Descurainia sophia (L.) Webb et Berth (D. sophia) is a safe recommended medicine in Iranian folk and Traditional Persian Medicine for the treatment of constipation. Objectives: To clinically compare D. sophia with PEG 4000 (without electrolyte) in pediatric constipation and to assess its efficacy and side effects. Patients and Methods: 120 patients aged 2 - 12 years with constipation for at least 3 months were included in an 8 weeks lasting randomized controlled trial within two parallel-groups. Children received either PEG, 0.4 g/kg/day, or D. sophia seeds, 2 grams (for children aged 2 - 4 years) and 3 grams (for those aged > 4 years) per day. Results: A total of 109 patients completed the study (56 in D. sophia and 53 in PEG group). At the end of the study, 36 (64.3%) patients in D. sophia group and 29 (54.7%) in PEG group were out of Rome III criteria (P = 0.205). Median weekly stool frequency in 0, 1, 2, 3 weeks of the treatment was found to be 2, 5, 5, 5 in D. sophia and 3, 4, 4, 5 in PEG group (P = 0.139, 0.076, 0.844, 0.294), respectively. The number of patients who suffered flatulence was less (5, 8.9%) in D. sophia group as compared to PEG group (6, 11.3%) at the end of the trial (P = 0.461). D. sophia taste was less tolerated. Conclusions: D. sophia is introduced as a cheap and available medication which can be applied as a safe alternative to conventional PEG in the management of pediatric chronic functional constipation. PMID:26196006

  15. Randomized controlled trial of sodium phosphate tablets vs polyethylene glycol solution for colonoscopy bowel cleansing

    PubMed Central

    Jung, Yoon Suk; Lee, Chang Kyun; Kim, Hyo Jong; Eun, Chang Soo; Han, Dong Soo; Park, Dong Il

    2014-01-01

    AIM: To compare efficacy, patient compliance, acceptability, satisfaction, safety, and adenoma detection rate of sodium phosphate tablets (NaP, CLICOLONTM) to a standard 4 L polyethylene glycol (PEG) solution for bowel cleansing for adults undergoing colonoscopy. METHODS: In this multicenter, randomized, prospective, investigator-blind study, the relatively young (19-60 years) healthy outpatients without comorbidity were randomly assigned to one of two arms. All colonoscopy were scheduled in the morning. The NaP group was asked to take 4 tablets, 5 times the evening before and 4 tablets, 3 times early on the morning of the colonoscopy. The PEG group was asked to ingest 2 L of solution the evening before and 2 L early in the morning of the procedure. Adequacy of bowel preparation was scored using the Boston bowel preparation scale. RESULTS: No significant differences were observed between the NaP group (n = 158) and PEG group (n = 162) in bowel cleansing quality (adequate preparation 93.0% vs 92.6%, P = 0.877), patient compliance (P = 0.228), overall adverse events (63.3% vs 69.1%, P = 0.269), or adenoma detection rate (34.8% vs 35.2%, P = 0.944). Patient acceptability, satisfaction, and patient rating of taste were higher in the NaP group than in the PEG group (P < 0.001). CONCLUSION: NaP tablets, compared with PEG solution, produced equivalent colon cleansing, did not cause more side effects, and had better patient acceptability and satisfaction in the relatively young (age < 60 years) healthy individuals without comorbidity. An oral tablet formulation could make bowel preparation less burdensome, resulting in greater patient participation in screening programs. PMID:25400471

  16. Behavioral recovery from traumatic brain injury after membrane reconstruction using polyethylene glycol

    PubMed Central

    Koob, Andrew O; Colby, Julia M; Borgens, Richard B

    2008-01-01

    Polyethylene glycol (PEG; 2000 MW, 30% by volume) has been shown to mechanically repair damaged cellular membranes and reduce secondary axotomy after traumatic brain and spinal cord injury (TBI and SCI respectively). This repair is achieved following spontaneous reassembly of cell membranes made possible by the action of targeted hydrophilic polymers which first seal the compromised portion of the plasmalemma, and secondarily, allow the lipidic core of the compromised membranes to resolve into each other. Here we compared PEG-treated to untreated rats using a computer-managed open-field behavioral test subsequent to a standardized brain injury. Animals were evaluated after a 2-, 4-, and 6-hour delay in treatment after TBI. Treated animals receive a single subcutaneous injection of PEG. When treated within 2 hours of the injury, injured PEG-treated rats showed statistically significant improvement in their exploratory behavior recorded in the activity box when compared to untreated but brain-injured controls. A delay of 4 hours reduced this level of achievement, but a statistically significant improvement due to PEG injection was still clearly evident in most outcome measures compared at the various evaluation times. A further delay of 2 more hours, however, eradicated the beneficial effects of PEG injection as revealed using this behavioral assessment. Thus, there appears to be a critical window of time in which PEG administration after TBI can provide neuroprotection resulting in an enhanced functional recovery. As is often seen in clinically applied acute treatments for trauma, the earlier the intervention can be applied, the better the outcome. PMID:18588669

  17. Bioavailability enhancement of a poorly water-soluble drug by solid dispersion in polyethylene glycol-polysorbate 80 mixture.

    PubMed

    Joshi, Hemant N; Tejwani, Ravindra W; Davidovich, Martha; Sahasrabudhe, Vaishali P; Jemal, Mohammed; Bathala, Mohinder S; Varia, Sailesh A; Serajuddin, Abu T M

    2004-01-01

    Oral bioavailability of a poorly water-soluble drug was greatly enhanced by using its solid dispersion in a surface-active carrier. The weakly basic drug (pK(a) approximately 5.5) had the highest solubility of 0.1mg/ml at pH 1.5, < 1 microg/ml aqueous solubility between pH 3.5 and 5.5 at 24+/-1 degrees C, and no detectable solubility (< 0.02 microg/ml) at pH greater than 5.5. Two solid dispersion formulations of the drug, one in Gelucire 44/14 and another one in a mixture of polyethylene glycol 3350 (PEG 3350) with polysorbate 80, were prepared by dissolving the drug in the molten carrier (65 degrees C) and filling the melt in hard gelatin capsules. From the two solid dispersion formulations, the PEG 3350-polysorbate 80 was selected for further development. The oral bioavailability of this formulation in dogs was compared with that of a capsule containing micronized drug blended with lactose and microcrystalline cellulose and a liquid solution in a mixture of PEG 400, polysorbate 80 and water. For intravenous administration, a solution in a mixture of propylene glycol, polysorbate 80 and water was used. Absolute oral bioavailability values from the capsule containing micronized drug, the capsule containing solid dispersion and the oral liquid were 1.7+/-1.0%, 35.8+/-5.2% and 59.6+/-21.4%, respectively. Thus, the solid dispersion provided a 21-fold increase in bioavailability of the drug as compared to the capsule containing micronized drug. A capsule formulation containing 25 mg of drug with a total fill weight of 600 mg was subsequently selected for further development. The selected solid dispersion formulation was physically and chemically stable under accelerated storage conditions for at least 6 months. It is hypothesized that polysorbate 80 ensures complete release of drug in a metastable finely dispersed state having a large surface area, which facilitates further solubilization by bile acids in the GI tract and the absorption into the enterocytes. Thus, the

  18. Fabrication of positively charged poly(ethylene glycol)-diacrylate hydrogel as a bone tissue engineering scaffold.

    PubMed

    Tan, Fei; Xu, Xiaoding; Deng, Ting; Yin, Miao; Zhang, Xianzheng; Wang, Jiawei

    2012-10-01

    To improve cell attachment and to understand the effects of positive charge on the behavior of osteoblasts, 2-(methacryloyloxy)ethyl-trimethylammonium chloride (MAETAC), a positively charged monomer, was incorporated into poly(ethylene glycol)-diacrylate (PEGDA) hydrogel. The physicochemical properties of the resultant polymers, including the degree of acrylation of PEGDA, pKa of MAETAC, swelling ratio, zeta potential, and protein adsorption were investigated. Meanwhile, osteoblast-like MC3T3-E1 cells were seeded on the hydrogel to evaluate the effect of the positive charge on the behavior of the cells, including attachment, proliferation, and differentiation. The results revealed that PEGDA was synthesized with 90 percent of acrylation and MAETAC had been successfully incorporated into PEGDA. The pKa value of MAETAC was 9.4 determined by acid-based titration. The electrically charged nature of modified hydrogels was confirmed by zeta potential. With increasing concentration of MAETAC, the swelling ratio of the hydrogel in deionized water increased, while the swelling ratio stayed constant in phosphate buffer solution. The protein adsorption of the hydrogel also increased with increasing concentration of MAETAC. The modification of positive charge not only enhanced the attachment and proliferation of osteoblast-like MC3T3-E1 cells on the hydrogel, but also up-regulated alkaline phosphatase activity in the cells as well as gene expression of focal adhesion kinase and osteogenic markers, including collagen I, osteopontin, and osteocalcin. These findings indicate that the positively charged PEGDA may not only be a promising scaffold candidate for bone tissue engineering, but also a good platform to study the effect of positive charge on cell behavior due to the controllable charge density. PMID:22945346

  19. Specific targeting and noninvasive magnetic resonance imaging of an asthma biomarker in the lung using polyethylene glycol functionalized magnetic nanocarriers.

    PubMed

    Al Faraj, Achraf; Shaik, Asma Sultana; Afzal, Sibtain; Al-Muhsen, Saleh; Halwani, Rabih

    2016-05-01

    Simultaneous inhibition of IL4 and IL13 via the common receptor chain IL4Rα to block adequately their biologic effects presents a promising therapeutic approach to give the additional relief required for asthma patients. In this study, superparamagnetic iron oxide nanoparticles were conjugated with anti-IL4Rα blocking antibodies via polyethylene glycol (PEG) polymers. The delivery of these blocking antibodies to the inflammatory sites in the lung via the developed nanocarriers was assessed using noninvasive free-breathing pulmonary MRI. Biocompatibility assays confirmed the safety of the developed nanocarriers for pre-clinical investigations. For all the investigated formulations, nanocarriers were found to be very stable at neutral pH. However, the stability noticeably decreased with the PEG length in acidic environment and thus the loaded antibodies were preferentially released. Immunofluorescence and fluorimetry assays confirmed the binding of the nanocarriers to the IL4Rα asthma biomarker. Pulmonary MRI performed using an ultra-short echo time sequence allowed simultaneous noninvasive monitoring of inflammatory responses induced by ovalbumin challenge and tracking of the developed nanocarriers, which were found to colocalize with the inflammatory sites in the lung. Targeting of the developed nanocarriers to areas rich in IL4Rα positive inflammatory cells was confirmed using histological and flow cytometry analyses. The anti-IL4Rα-conjugated nanocarriers developed here have been confirmed to be efficient in targeting key inflammatory cells during chronic lung inflammation following intrapulmonary administration. Targeting efficiency was monitored using noninvasive MRI, allowing detection of the nanocarriers' colocalizations with the inflammatory sites in the lung of ovalbumin-challenged asthmatic mice. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26708935

  20. Entrance effects at nanopores of nanocapsules functionalized with poly(ethylene glycol) and their flow through nanochannels.

    PubMed

    Popa, Raluca; Vrânceanu, M; Nikolaus, S; Nirschl, H; Leneweit, G

    2008-11-18

    We studied the effect of poly(ethylene glycol) (PEG) on the extrusion of large, multilamellar nanocapsules (also called liposomes or vesicles) through nanochannels with a length of 6 microm. For the generation of the nanocapsules, we used a lipid mixture with lecithin consisting of saturated and unsaturated fatty acids (dipalmitoylphosphatidylcholine (DPPC) and dioleoylphosphatidylcholine (DOPC)), cholesterol, and 2-8 mol % PEG linked to a lipid anchor (distearoylphosphatidylethanolamine (DSPE)) or the plain lipid anchor without PEG. An increase in PEG leads to a decrease of the critical tension for nanocapsule rupture (lysis tension) between 20-30%, whereas the pure lipid anchor does not produce any differences. We interpret these findings to be produced by a partial intrusion of the polymeric chain into the phospholipid bilayer of the nanocapsule which weakens its tensile strength. We evaluate statistically the discrepancies of lysis tensions found for different channels widths (50-100 nm) and two or four channels in series. Comparing our results on the flow resistance of either nanocapsules or pure water with lubrication theory, we find that the calculated viscous forces are not sufficient to account for the measured friction of nanocapsules. This shows that the nanocapsules are decelerated in the nanochannels by van der Waals interactions between channel and capsule walls and the intermediate water layer. The strength of these forces is 24 times higher for PEG and 94 times higher for the pure lipid anchor than the respective calculated viscous forces alone, showing that nanocapsule flow in nanochannels cannot be considered under the classical continuum assumption of the intermediate water layer. PMID:18950201

  1. Design of poly(ethylene glycol)/streptavidin coimmobilized upconversion nanophosphors and their application to fluorescence biolabeling.

    PubMed

    Kamimura, Masao; Miyamoto, Daisuke; Saito, Yu; Soga, Kohei; Nagasaki, Yukio

    2008-08-19

    Infrared-to-visible upconversion phosphors (i.e., rare earth ion-doped Y2O3 nanoparticles (UNPs)) were synthesized by the homogeneous precipitation method. Because the charge on the erbium (Er) ion-doped Y2O3 (Y2O3:Er) NP (UNP1) surface is positive under neutral conditions, the UNP1 surface was electrostatically PEGylated using negatively charged poly(ethylene glycol)- b-poly(acrylic acid) (PEG- b-PAAc). The adsorption of PEG- b-PAAc was confirmed by Fourier transform infrared (FT-IR) measurements and thermal gravimetric analysis (TGA). The surface charge of the PEGylated UNP1s (PEG-UNP1s) was effectively shielded by the PEGylation. The dispersion stability of the UNP1s was also significantly improved by the PEGylation. The PEG-UNP1s were dispersed over 1 week under physiological conditions as a result of the steric repulsion between the PEG chains on the UNP1 surface. The upconversion emission spectrum of PEG-UNP1s was observed under physiological conditions and was confirmed by near-infrared excited fluorescence microscope observation. Streptavidin (SA)-installed ytterbium (Yb) and Er ion-codoped Y2O3 (Y2O3:Yb,Er) NPs (UNP2s) were prepared by the coimmobilization of PEG- b-PAAc and streptavidin. The PEG/SA coimmobilized UNP2s (PEG/SA-UNP2s) specifically recognized biotinylated antibodies and emitted strong upconversion luminescence upon near-infrared excitation. The obtained PEG/streptavidin coimmobilized UNPs are promising as high-performance near-infrared biolabeling materials. PMID:18652424

  2. Glycolic acid peel therapy – a current review

    PubMed Central

    Sharad, Jaishree

    2013-01-01

    Chemical peels have been time-tested and are here to stay. Alpha-hydroxy peels are highly popular in the dermatologist’s arsenal of procedures. Glycolic acid peel is the most common alpha-hydroxy acid peel, also known as fruit peel. It is simple, inexpensive, and has no downtime. This review talks about various studies of glycolic acid peels for various indications, such as acne, acne scars, melasma, postinflammatory hyperpigmentation, photoaging, and seborrhea. Combination therapies and treatment procedure are also discussed. Careful review of medical history, examination of the skin, and pre-peel priming of skin are important before every peel. Proper patient selection, peel timing, and neutralization on-time will ensure good results, with no side effects. Depth of the glycolic acid peel depends on the concentration of the acid used, the number of coats applied, and the time for which it is applied. Hence, it can be used as a very superficial peel, or even a medium depth peel. It has been found to be very safe with Fitzpatrick skin types I–IV. All in all, it is a peel that is here to stay. PMID:24399880

  3. Practical preparation procedures for docetaxel-loaded nanoparticles using polylactic acid-co-glycolic acid

    PubMed Central

    Keum, Chang-Gu; Noh, Young-Wook; Baek, Jong-Suep; Lim, Ji-Ho; Hwang, Chan-Ju; Na, Young-Guk; Shin, Sang-Chul; Cho, Cheong-Weon

    2011-01-01

    Background Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), are the most intensively investigated polymers for drug delivery systems. The objective of this study was to explore fully the development of a PLGA nanoparticle drug delivery system for alternative preparation of a commercial formulation. In our nanoparticle fabrication, our purpose was to compare various preparation parameters. Methods Docetaxel-loaded PLGA nanoparticles were prepared by a single emulsion technique and solvent evaporation. The nanoparticles were characterized by various techniques, including scanning electron microscopy for surface morphology, dynamic light scattering for size and zeta potential, x-ray photoelectron spectroscopy for surface chemistry, and high-performance liquid chromatography for in vitro drug release kinetics. To obtain a smaller particle, 0.2% polyvinyl alcohol, 0.03% D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), 2% Poloxamer 188, a five-minute sonication time, 130 W sonication power, evaporation with magnetic stirring, and centrifugation at 8000 rpm were selected. To increase encapsulation efficiency in the nanoparticles, certain factors were varied, ie, 2–5 minutes of sonication time, 70–130 W sonication power, and 5–25 mg drug loading. Results A five-minute sonication time, 130 W sonication power, and a 10 mg drug loading amount were selected. Under these conditions, the nanoparticles reached over 90% encapsulation efficiency. Release kinetics showed that 20.83%, 40.07%, and 51.5% of the docetaxel was released in 28 days from nanoparticles containing Poloxamer 188, TPGS, or polyvinyl alcohol, respectively. TPGS and Poloxamer 188 had slower release kinetics than polyvinyl alcohol. It was predicted that there was residual drug remaining on the surface from x-ray photoelectron spectroscopy. Conclusion Our research shows that the choice of surfactant is important for controlled release of

  4. Polyethylene glycol-induced internalization of bacteria into fungal protoplasts: Electron microscopic study and optimization of experimental conditions

    SciTech Connect

    Guerra-Tschuschke, I.; Martin, I.; Gonzalez, M.T. )

    1991-05-01

    The authors studied the mechanism of internalization of Escherichia coli into Saccharomyces cerevisiae induced by polyethylene glycol (PEG) and optimized the experimental conditions. Transmission electron microscope studies revealed that the principal factor involved in the internalization was the degree of cell aggregation attained. Internalization occurred mainly by an endocytosis-like mechanism and took place during the elimination of PEG. The optimum conditions were to treat a mixed pellet of both microorganisms with 15% PEG and then gradually dilute the polymer. The same conditions were applied to E. coli and Aspergillus nidulans, with similar results.

  5. Corrosion Protection of Electro-Galvanized Steel by Ceria-Based Coatings: Effect of Polyethylene Glycol (PEG) Addition

    NASA Astrophysics Data System (ADS)

    Hamlaoui, Y.; Tifouti, L.; Pedraza, F.

    2013-09-01

    A cerium oxide thin layer was deposited onto galvanized steel by cathodic electrodeposition from 0.1 M concentrated cerium nitrate solution. In this work, the influence of polyethylene glycol (PEG) addition on the composition and morphology of the deposits is examined. The results showed that the addition of PEG to the cerium nitrate solutions leads to a decrease in the cracks in the deposits by decreasing the hydrogen reduction reaction and by decreasing the film thickness which provided enhanced corrosion protection. Moreover, the substrate dissolution reaction is inhibited.

  6. Improved dissolution and anti-inflammatory activity of ibuprofen-polyethylene glycol 8000 solid dispersion systems

    PubMed Central

    Ofokansi, Kenneth C.; Kenechukwu, Franklin C.; Ezugwu, Richard O.; Attama, Anthony A.

    2016-01-01

    Background: The purpose of this study was to develop ibuprofen (IB)-polyethylene glycol (PEG) 8000 solid dispersions (SDs) and investigate them for in vitro dissolution and in vivo anti-inflammatory activity. Materials and Methods: IB-PEG 8000 SDs were prepared by fusion method using varying combination ratios of IB and PEG 8000. Characterization based on surface morphology, particle size, absolute drug content, and Fourier transform infrared (FT-IR) spectroscopy was carried out on the SDs. The in vitro release of IB from the SDs was performed in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4) without enzymes, whereas the anti-inflammatory activity was evaluated using egg albumin-induced rat paw edema model. Results: Greenish brown, discrete, and irregularly shaped SDs of mean particle size range 113.5 ± 2.5-252.5 ± 1.9 μm, which were stable over 3 months, were obtained. The drug content of the SDs ranged from 73.4 ± 2.9 % to 83.5 ± 2.7%. Although the drug content increased with increased concentration of PEG 8000 in the SDs, the mean particle size decreased with increased concentration of PEG 8000 in the SDs. The FT-IR results indicate no strong chemical interaction of IB and PEG 8000 in the SDs. There was marked increase in the dissolution rate of IB from the SDs (P < 0.05) as compared to pure IB and physical mixture. The dissolution was better in SIF than in SGF. The increased dissolution rate of IB may be due to the formation of microcrystals, increased wettability and dispersibility in PEG 8000. The SDs showed good anti-inflammatory properties achieving up to 90% edema inhibition at 6 h while the pure sample of IB had 77% edema inhibition at 6 h. Conclusion: SDs based on IB-PEG 8000 is a good approach to enhance the dissolution rate and anti-inflammatory activity of IB, thus, encouraging further development of the SDs. PMID:27606257

  7. Mechanical evaluation of newly developed mouthpiece using polyethylene terephthalate glycol for transoral robotic surgery.

    PubMed

    Fujiwara, Kazunori; Fukuhara, Takahiro; Niimi, Koji; Sato, Takahiro; Kataoka, Hideyuki; Kitano, Hiroya; Takeuchi, Hiromi

    2015-12-01

    Transoral robotic surgery (TORS), performed with the da Vinci surgical system (da Vinci), has been classified as a surgical approach for benign and malignant lesions of the oral cavity and laryngopharynx. It provides several unique advantages, which include a three-dimensional magnified view, ability to see and work around curves or angles, and the availability of two or three robotic arms. At present, however, the da Vinci surgical system does not provide haptic feedback. The potential risks specific to the transoral use of the da Vinci include tooth injury, mucosal laceration, ocular injury, and mandibular fracture. To prevent such intra-operative tooth injuries, we created a mouthpiece made of polyethylene terephthalate glycol (PETG) individually shaped for the patient's teeth. We compared the safety and efficacy of the PETG mouthpiece with those of a conventional mouthpiece made of ethylene-vinyl acetate (EVA). To determine the difference in tooth injury resulting from the two types of mouthpiece, we constructed an experimental system to measure load and strain. We measured the dynamic load and the strain from the rod to the tooth using the PETG and EVA mouthpiece. The rod was pressed against the tooth model outfitted with two types of mouthpiece and the dynamic load was measured with a load cell and the strain with a strain gage. The maximum dynamic load was 1.29 ± 0.03 kgf for the PETG mouthpiece and 2.24 ± 0.05 kgf for the EVA mouthpiece. The load against the tooth was thus less for the EVA mouthpiece. The strain was -166.84 ± 3.94 and 48.24 ± 7.77 με, respectively, while the load direction was parallel to that of the tooth axis for the PETG mouthpiece and perpendicular to the tooth axis for the EVA mouthpiece. The PETG mouthpiece reduced the tooth load compared with the EVA mouthpiece and the load direction was in parallel to the tooth axis. The PETG mouthpiece thus enhances tooth safety for TORS. PMID:26530849

  8. Acrylic bone cements modified with beta-TCP particles encapsulated with poly(ethylene glycol).

    PubMed

    Vázquez, Blanca; Ginebra, María Pau; Gil, Xavier; Planell, Josep Antón; San Román, Julio

    2005-07-01

    Beta-tricalcium phosphate (beta-TCP) has been encapsulated with poly(ethylene glycol) (PEG) to improve the filler/cement interface, and it was later incorporated to a poly(methyl methacrylate) bone cement in order to obtain cements with improved stability in the long term. Size and size distribution of the agglomerates forming the initial powder was drastically changed after its dispersion in a PEG aqueous solution. Whereas the initial beta-TCP particles had a 584 microm average diameter, the treated particles (TCP-PEG) presented more than 60% of the particles in a range of 2-6 microm. The effect of adding the treated particles to an acrylic cement was evaluated in terms of curing parameters, in vitro behaviour and mechanical performance. The presence of the TCP-PEG particles did not affect either peak temperature or setting time, indicating a good homogeneity of polymerising mass in contrast to the effect observed with the plain beta-TCP particles, which gave rise to higher setting times. In vitro behaviour studies revealed hydration degree values of the modified cements comparable to that of PMMA cements. Early stages of water uptake was Fickian in nature for all the experimental formulations indicating that the water absorption followed a diffusion controlled mechanism. After 3 months of storage in SBF the experimental formulations presented values of compressive strength in the range 76-78 MPa, higher than the minimum required by ISO 5833 (70 MPa) and those of tensile strength in the range 42-48 MPa, higher than the minimum reported for commercial formulations (30 MPa), but no significant differences in the strengths and elastic modulus were observed with the treatment of the filler particles. This observation was confirmed by ESEM analysis of the tensile fracture surfaces, which revealed a rather good cohesion between the bioceramic particles with some gaps around them, independently of the type of particles. The themogravimetric analysis of dry and wet

  9. Insertion stability of poly(ethylene glycol)-cholesteryl-based lipid anchors in liposome membranes.

    PubMed

    Molnar, Daniel; Linders, Jürgen; Mayer, Christian; Schubert, Rolf

    2016-06-01

    Liposomes consist of a hydrophilic core surrounded by a phospholipid (PL) bilayer. In human blood, the half-life of such artificial vesicles is limited. To prolong their stability in the circulation, liposomal bilayers can be modified by inserting poly(ethylene glycol) (PEG) molecules using either PL or sterols as membrane anchors. This establishes a hydrophilic steric barrier, reducing the adsorption of serum proteins, recognition and elimination by cells of the immune system. In addition, targeting ligands (such as antibodies) are frequently coupled to the distal end of the PEG chains to direct the vesicles (then called 'immuno-liposomes') to specific cell types, such as tumor cells. To our knowledge, experiments on the stability of ligand anchoring have so far only been conducted with PL-based PEGs and not with sterol-based PEGs after insertion via the sterol-based post-insertion technique (SPIT). Therefore, our study examines the insertion stability of PEG-cholesteryl ester (Chol-PEG) molecules with PEG chains of 1000, 1500 and 2000Da molecular mass which have been inserted into the membranes of liposomes using SPIT. For this study we used different acceptor media and multiple analytical techniques, including pulsed-field-gradient nuclear magnetic resonance (PFG-NMR), free-flow electrophoresis, size exclusion chromatography and ultracentrifugation. The obtained data consistently showed that a higher molar mass of PEG chains positively correlates with higher release from the liposome membranes. Furthermore, we could detect and quantify the migration of Chol-PEG molecules from radioactively double-labeled surface-modified liposomes to negatively charged acceptor liposomes via free-flow electrophoresis. Insertion of Chol-PEG molecules into the membrane of preformed liposomes using SPIT is an essential step for the functionalization of liposomes with the aim of specific targeting. For the first time, we present a kinetic analysis of this insertion process using PFG

  10. Mechanical properties of polyurethane film exposed to solutions of nonoxynol-9 surfactant and polyethylene glycol

    NASA Astrophysics Data System (ADS)

    McDermott, Martin Kendrick

    Changes in physical properties (tensile strength, strain to failure, elastic modulus, diffusion kinetics and soft segment glass transition temperature (Tg)) were examined for polyetherurethane block copolymers Estane and Tecoflex. These polymer chains consist of 2 mutually incompatible blocks or segments which form microphases consisting of rigid/hard segments in an elastomeric matrix of soft segments. The polyurethanes were exposed to mixtures of nonoxynol 9 (N9) surfactant in polyethylene glycol 400 (PEG) at various concentrations and for various times. The purpose was to estimate the effect of exposure to mixtures of N9 spermicide and PEG lubricant on breakage of condoms made from films of these elastomers. Mechanical properties of Estane varied with direction because of molecular orientation induced during manufacturing, suggesting that condoms should be cut from the film in a way that optimizes this property-orientation relationship. Large amounts of N9 were absorbed from N9/PEG solutions. The polymer fraction of the swollen Estane film versus soak solution composition did not follow a linear rule of mixtures. As the percentage of N9 in the PEG/N9 soak solution increased, Estane absorbed more liquid and its properties decreased more than did Tecoflex. This may not matter for low concentrations of N9 where the mechanical properties of Estane were superior to those of Tecoflex. The loss of mechanical properties with increased N9 concentration was likely due to plasticization of the soft segment domains. Hard segment domain disruption was probably not occurring because the relationship between the elastic modulus and polymer volume fraction followed the Flory-Rehner relationship for swollen elastic rubber networks and diffusion of neat N9 and neat PEG followed a Fickian behavior. This is expected because hard domains are much more difficult to disrupt due to strong hydrogen bonding and/or crystallization. Most of the absorption and decrease in mechanical

  11. Polyethylene Glycol Modified, Cross-Linked Starch Coated Iron Oxide Nanoparticles for Enhanced Magnetic Tumor Targeting

    PubMed Central

    Cole, Adam J.; David, Allan E.; Wang, Jianxin; Galbán, Craig J.; Hill, Hannah L.; Yang, Victor C.

    2010-01-01

    While successful magnetic tumor targeting of iron oxide nanoparticles has been achieved in a number of models, the rapid blood clearance of magnetically suitable particles by the reticuloendothelial system (RES) limits their availability for targeting. This work aimed to develop a long-circulating magnetic iron oxide nanoparticle (MNP) platform capable of sustained tumor exposure via the circulation and, thus, enhanced magnetic tumor targeting. Aminated, cross-linked starch (DN) and aminosilane (A) coated MNPs were successfully modified with 5 kDa (A5, D5) or 20 kDa (A20, D20) polyethylene glycol (PEG) chains using simple N-Hydroxysuccinimide (NHS) chemistry and characterized. Identical PEG-weight analogues between platforms (A5 & D5, A20 & D20) were similar in size (140–190 nm) and relative PEG labeling (1.5% of surface amines – A5/D5, 0.4% – A20/D20), with all PEG-MNPs possessing magnetization properties suitable for magnetic targeting. Candidate PEG-MNPs were studied in RES simulations in vitro to predict long-circulating character. D5 and D20 performed best showing sustained size stability in cell culture medium at 37°C and 7 (D20) to 10 (D5) fold less uptake in RAW264.7 macrophages when compared to previously targeted, unmodified starch MNPs (D). Observations in vitro were validated in vivo, with D5 (7.29 hr) and D20 (11.75 hr) showing much longer half-lives than D (0.12 hr). Improved plasma stability enhanced tumor MNP exposure 100 (D5) to 150 (D20) fold as measured by plasma AUC0-∞ Sustained tumor exposure over 24 hours was visually confirmed in a 9L-glioma rat model (12 mg Fe/kg) using magnetic resonance imaging (MRI). Findings indicate that both D5 and D20 are promising MNP platforms for enhanced magnetic tumor targeting, warranting further study in tumor models. PMID:21176955

  12. A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function.

    PubMed Central

    Rajagopalan, S; Gonias, S L; Pizzo, S V

    1985-01-01

    A series of new, covalent polyethylene glycol (PEG)-streptokinase adducts were synthesized and characterized. PEGs with average molecular weights of 2,000, 4,000, and 5,000 were activated with carbonyldiimidazole and coupled to the protein under standardized reaction conditions. Steady-state kinetic analysis demonstrated comparable Km values for the activation of plasminogen by streptokinase, PEG-2-streptokinase, and PEG-4-streptokinase. The kcat values were somewhat decreased when PEG-2 or PEG-4 was coupled to the streptokinase. Activation by the PEG-5 adduct did not follow Michaelis-Menten kinetics under the conditions employed in this study. Plasmin activity obtained by incubating streptokinase derivatives with plasminogen also was studied as a function of time with each of the PEG-streptokinase derivatives. By this assay, incubations containing PEG-5-streptokinase and unmodified streptokinase demonstrated comparable activity while reaction mixtures containing PEG-2-streptokinase and PEG-4-streptokinase were slightly more active. Streptokinase incubated with plasminogen at a 1:1 molar ratio was extensively degraded after 30 min whereas PEG-2-streptokinase was resistant to plasmin cleavage. The derivatized proteins were radioiodinated and incubated in plastic microtiter plates that were coated with an immunoglobulin fraction containing antibodies to streptokinase. Binding of the PEG-streptokinase adducts was decreased by greater than 95% compared with unmodified streptokinase. Plasminogen activator complexes were formed by reacting the streptokinases with human plasminogen in vitro and the clearance studied in mice. Radioiodinated plasmin in complex with the PEG-streptokinase adducts cleared at a slower rate than did plasmin complexed with unmodified streptokinase. Catabolism of the protease still occurred by a mechanism that involved reaction with alpha 2-macroglobulin as has been described for nonderivatized streptokinase-plasminogen complex (Gonias, S. L., M

  13. Biodegradable nanoparticles of methoxy poly(ethylene glycol)- b-poly( d, l-lactide)/methoxy poly(ethylene glycol)- b-poly(ɛ-caprolactone) blends for drug delivery

    NASA Astrophysics Data System (ADS)

    Baimark, Yodthong; Srisuwan, Yaowalak

    2012-05-01

    The effects of blend weight ratio and polyester block length of methoxy poly(ethylene glycol)- b-poly( d, l-lactide) (MPEG- b-PDLL)/methoxy poly(ethylene glycol)- b-poly(ɛ-caprolactone) (MPEG- b-PCL) blends on nanoparticle characteristics and drug release behaviors were evaluated. The blend nanoparticles were prepared by nanoprecipitation method for controlled release of a poorly water-soluble model drug, indomethacin. The drug-loaded nanoparticles were nearly spherical in shape. The particle size and drug loading efficiency slightly decreased with increasing MPEG- b-PCL blend weight ratio. Two distinct thermal decomposition steps from thermogravimetric analysis suggested different blend weight ratios. Thermal transition changes from differential scanning calorimetry revealed miscible blending between MPEG- b-PDLL and MPEG- b-PCL in an amorphous phase. An in vitro drug release study demonstrated that the drug release behaviors depended upon the PDLL block length and the blend weight ratios but not on PCL block length.

  14. Biodegradable nanoparticles of methoxy poly(ethylene glycol)-b-poly( d, l-lactide)/methoxy poly(ethylene glycol)- b-poly(ϵ-caprolactone) blends for drug delivery.

    PubMed

    Baimark, Yodthong; Srisuwan, Yaowalak

    2012-01-01

    The effects of blend weight ratio and polyester block length of methoxy poly(ethylene glycol)-b-poly( d, l-lactide) (MPEG- b-PDLL)/methoxy poly(ethylene glycol)- b-poly(ϵ-caprolactone) (MPEG- b-PCL) blends on nanoparticle characteristics and drug release behaviors were evaluated. The blend nanoparticles were prepared by nanoprecipitation method for controlled release of a poorly water-soluble model drug, indomethacin. The drug-loaded nanoparticles were nearly spherical in shape. The particle size and drug loading efficiency slightly decreased with increasing MPEG- b-PCL blend weight ratio. Two distinct thermal decomposition steps from thermogravimetric analysis suggested different blend weight ratios. Thermal transition changes from differential scanning calorimetry revealed miscible blending between MPEG- b-PDLL and MPEG- b-PCL in an amorphous phase. An in vitro drug release study demonstrated that the drug release behaviors depended upon the PDLL block length and the blend weight ratios but not on PCL block length. PMID:22647275

  15. 40 CFR 721.10111 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and diethylene glycol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... diesters with benzoic acid and diethylene glycol. 721.10111 Section 721.10111 Protection of Environment... diesters with benzoic acid and diethylene glycol. (a) Chemical substance and significant new uses subject... benzoic acid and diethylene glycol (PMN P-04-510; CAS No. 610787-78-5) is subject to reporting under...

  16. 40 CFR 721.10111 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and diethylene glycol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... diesters with benzoic acid and diethylene glycol. 721.10111 Section 721.10111 Protection of Environment... diesters with benzoic acid and diethylene glycol. (a) Chemical substance and significant new uses subject... benzoic acid and diethylene glycol (PMN P-04-510; CAS No. 610787-78-5) is subject to reporting under...

  17. 40 CFR 721.10110 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... diesters with benzoic acid and neopentlyl glycol. 721.10110 Section 721.10110 Protection of Environment... diesters with benzoic acid and neopentlyl glycol. (a) Chemical substance and significant new uses subject... benzoic acid and neopentlyl glycol (PMN P-04-509; CAS No. 610787-77-4) is subject to reporting under...

  18. 40 CFR 721.10110 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... diesters with benzoic acid and neopentlyl glycol. 721.10110 Section 721.10110 Protection of Environment... diesters with benzoic acid and neopentlyl glycol. (a) Chemical substance and significant new uses subject... benzoic acid and neopentlyl glycol (PMN P-04-509; CAS No. 610787-77-4) is subject to reporting under...

  19. 40 CFR 721.10111 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and diethylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... diesters with benzoic acid and diethylene glycol. 721.10111 Section 721.10111 Protection of Environment... diesters with benzoic acid and diethylene glycol. (a) Chemical substance and significant new uses subject... benzoic acid and diethylene glycol (PMN P-04-510; CAS No. 610787-78-5) is subject to reporting under...

  20. 40 CFR 721.10111 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and diethylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... diesters with benzoic acid and diethylene glycol. 721.10111 Section 721.10111 Protection of Environment... diesters with benzoic acid and diethylene glycol. (a) Chemical substance and significant new uses subject... benzoic acid and diethylene glycol (PMN P-04-510; CAS No. 610787-78-5) is subject to reporting under...