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Sample records for glycol unrefined polyethylene

  1. Polyethylene Glycol 3350

    MedlinePlus

    ... the stool. This increases the number of bowel movements and softens the stool so it is easier ... for polyethylene glycol 3350 to produce a bowel movement.To use the powder, follow these steps: If ...

  2. 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.

  3. 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

  4. Polyethylene Glycol Camouflaged Earthworm Hemoglobin

    PubMed Central

    Moges, Selamawit; Nacharaju, Parimala; Roche, Camille; Dantsker, David; Palmer, Andre; Friedman, Joel M.

    2017-01-01

    Nearly 21 million components of blood and whole blood and transfused annually in the United States, while on average only 13.6 million units of blood are donated. As the demand for Red Blood Cells (RBCs) continues to increase due to the aging population, this deficit will be more significant. Despite decades of research to develop hemoglobin (Hb) based oxygen (O2) carriers (HBOCs) as RBC substitutes, there are no products approved for clinical use. Lumbricus terrestris erythrocruorin (LtEc) is the large acellular O2 carrying protein complex found in the earthworm Lumbricus terrestris. LtEc is an extremely stable protein complex, resistant to autoxidation, and capable of transporting O2 to tissue when transfused into mammals. These characteristics render LtEc a promising candidate for the development of the next generation HBOCs. LtEc has a short half-life in circulation, limiting its application as a bridge over days, until blood became available. Conjugation with polyethylene glycol (PEG-LtEc) can extend LtEc circulation time. This study explores PEG-LtEc pharmacokinetics and pharmacodynamics. To study PEG-LtEc pharmacokinetics, hamsters instrumented with the dorsal window chamber were subjected to a 40% exchange transfusion with 10 g/dL PEG-LtEc or LtEc and followed for 48 hours. To study the vascular response of PEG-LtEc, hamsters instrumented with the dorsal window chamber received multiple infusions of 10 g/dL PEG-LtEc or LtEc solution to increase plasma LtEc concentration to 0.5, then 1.0, and 1.5 g/dL, while monitoring the animals’ systemic and microcirculatory parameters. Results confirm that PEGylation of LtEc increases its circulation time, extending the half-life to 70 hours, 4 times longer than that of unPEGylated LtEc. However, PEGylation increased the rate of LtEc oxidation in vivo. Vascular analysis verified that PEG-LtEc showed the absence of microvascular vasoconstriction or systemic hypertension. The molecular size of PEG-LtEc did not change the

  5. 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.

  6. 40 CFR 721.10518 - Diethylene glycol, polymer with diisocyanatoalkane, polyethylene glycol monomethyl ether- and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... diisocyanatoalkane, polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked (generic). 721.10518 Section... Substances § 721.10518 Diethylene glycol, polymer with diisocyanatoalkane, polyethylene glycol monomethyl... diisocyanatoalkane, polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked (PMN P-11-48) is subject...

  7. 40 CFR 721.10518 - Diethylene glycol, polymer with diisocyanatoalkane, polyethylene glycol monomethyl ether- and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... diisocyanatoalkane, polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked (generic). 721.10518 Section... Substances § 721.10518 Diethylene glycol, polymer with diisocyanatoalkane, polyethylene glycol monomethyl... diisocyanatoalkane, polyethylene glycol monomethyl ether- and fluorinatedalkanol-blocked (PMN P-11-48) is subject...

  8. 21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 and/or... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyethylene glycol (400) monolaurate. 178.3760...

  9. Polyethylene glycol as a cause of anaphylaxis.

    PubMed

    Wylon, Katharina; Dölle, Sabine; Worm, Margitta

    2016-01-01

    Polyethylene glycols (PEGs) or macrogols are polyether compounds and are widely used as additives in pharmaceuticals, cosmetics, and food. We report on a Caucasian patient experiencing recurrent severe allergic reactions to several drugs. An extensive diagnostic workup including skin prick tests, intradermal tests (IDT) and a double-blind oral challenge was performed to identify the trigger of anaphylaxis. In the present case hypersensitivity to the additive polyethylene glycol was confirmed by an IDT suggesting an Immunoglobulin E-dependent mechanism as a cause of the reaction. Potential life-threatening hypersensitivity reactions to hidden molecules like macrogol may be underdiagnosed. Cases of immediate-type PEG hypersensitivity were reported with increasing frequency. The awareness regarding the allergenic potential of PEG should be raised and a proper product labelling is crucial to prevent PEG mediated hypersensitivity.

  10. Polyethylene glycol antiglobulin test (PEG-AGT).

    PubMed

    Weldy, Larry

    2014-01-01

    Polyethylene glycol (PEG) ws described in 1987 as a new technique for immunohematology testing. The original paper described its use in detection and identification of weakly reactive antibodies. PEG is used as an additive to enhance reactivity and to reduce incubation time when testing for unexpected antibodies. PEG can be used as an alternative to low-ionic-strength saline and whenever weak reactions are encountered.

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. Polyethylene glycol as a solid polymer electrolyte

    SciTech Connect

    Cha, D.K.; Park, S.M.

    1997-12-01

    Polymer electrolytes were prepared from polyethylene glycol (PEG)-lithium perchlorate complexes and characterized at a stainless steel electrode using a variety of electrochemical techniques. The charge transfer process was affected by the oxide film on the stainless steel electrode surface in the early stages of redox processes. The polymer electrolytes showed a transference number of 0.2 for Li{sup +}. The conductivity of the PEG-10000 electrolyte has been determined to be 4.7 {times} 10{sup {minus}5} S/cm. This rather high value is attributed to the anionic end groups increasing the polarity of the matrix.

  17. Osmotic Pressure of Aqueous Polyethylene Glycols 1

    PubMed Central

    Money, Nicholas P.

    1989-01-01

    Osmotic pressures (II) of aqueous solutions of polyethylene glycols (PEGs) of average relative molecular weight (Mr) between 200 and 10,000 were measured using vapor pressure deficit osmometry. The relationships between molarity and II were described with high precision by second order polynomials for each of the PEGs studied. In contrast to previous reports, equivalent weights of different polymers in solution did not generate the same II; low Mr PEGs generated a higher II than the higher Mr PEGs. The effect of PEGs upon II represents an interaction between concentration and Mr. PMID:16667097

  18. 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... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

  19. 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... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

  20. 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... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

  1. 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 glycol (generic). 721.6493 Section 721.6493 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical...

  2. Polyethylene glycol-grafted polystyrene particles.

    PubMed

    Meng, Fenghua; Engbers, Gerard H M; Feijen, Jan

    2004-07-01

    Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS-COOH) using carbodiimide chemistry. PEG-modified particles (PS-PEG) were characterized by determination of the PEG surface concentration, zeta-potential, size, and morphology. Under optimized grafting conditions, a dense "brush-like" PEG layer was formed. A PEG surface concentration of approximately 60 pmol/cm2, corresponding with an average distance between grafted PEG chains of approximately 17 A can be realized. It was shown that grafting of PEG onto PS-COOH reduced the adsorption of proteins from human plasma (85 vol %) in phosphate-buffered saline up to 90%.

  3. Comparison of biodegradation of poly(ethylene glycol)s and poly(propylene glycol)s.

    PubMed

    Zgoła-Grześkowiak, Agnieszka; Grześkowiak, Tomasz; Zembrzuska, Joanna; Łukaszewski, Zenon

    2006-07-01

    The biodegradation of poly(ethylene glycol)s (PEGs) and poly(propylene glycol)s (PPGs), both being major by-products of non-ionic surfactants biodegradation, was studied under the conditions of the River Water Die-Away Test. PEGs were isolated from a water matrix using solid-phase extraction with graphitized carbon black sorbent, then derivatized with phenyl isocyanate and determined by HPLC with UV detection. PPGs were isolated from a water matrix by liquid-liquid extraction with chloroform, then derivatized with naphthyl isocyanate and determined by HPLC with fluorescence detection. The primary biodegradation of both PEGs and PPGs reached approximately 99% during the test. The tests show different biodegradation pathways of PEG and PPG. During PEG biodegradation, their chains are shortened leading to the formation of ethylene glycol and diethylene glycol. During PPG biodegradation, no short-chained biodegradation products were found.

  4. 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 reporting...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  11. 21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... percent total by weight of ethylene and diethylene glycols when tested by the analytical methods... the total ethylene and diethylene glycol content of polyethylene glycols having mean molecular weights.... Analytical Method ethylene glycol and diethylene glycol content of polyethylene glycols The analytical method...

  12. 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.

  13. Hydration of polyethylene glycol-grafted liposomes.

    PubMed Central

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

    1998-01-01

    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

  14. 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

  15. Purification and characterization of polyethylene glycol dehydrogenase involved in the bacterial metabolism of polyethylene glycol.

    PubMed Central

    Kawai, F; Kimura, T; Tani, Y; Yamada, H; Kurachi, M

    1980-01-01

    Polyethylene glycol (PEG) dehydrogenase in crude extracts of a PEG 20,000-utilizing mixed culture was purified 24 times by precipitation with ammonium sulfate, solubilization with laurylbetaine, and chromatography with diethylamino-ethyl-cellulose, hydroxylapatite, and Sephadex G-200. The purified enzyme was confirmed to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme, which appeared to consist of four identical subunits, was 2.4 X 10(5). The enzyme was stable below 35 degrees C and in the pH range of 7.5 to 9.0. The optimum pH and temperature of the activity were around 8.0 and 60 degrees C, respectively. The enzyme did not require any metal ions for activity and oxidized various kinds of PEGs, among which PEG 6,000 was the most active substrate. The apparent Km values for tetraethylene glycol and PEG 6,000 were about 10.0 and 3.0 mM, respectively. Images PMID:6999995

  16. Stabilization of solid dispersions of nimodipine and polyethylene glycol 2000.

    PubMed

    Urbanetz, Nora Anne

    2006-05-01

    Previous investigations revealed that solid dispersions consisting of 20% (m/m) nimodipine and 80% (m/m) polyethylene glycol 2000 prepared by the melting method, represent supersaturated solid solutions of nimodipine recrystallizing upon storage at +25 degrees C. The objective of this study was the improvement of the storage stability by preventing recrystallization. The first approach in order to prevent recrystallization was the development of thermodynamically stable solid solutions by using solvents aiming to enhance the solubility of nimodipine in the carrier material. As potential solubility enhancing additives, polyethylene glycol 300, poly(ethylene/propylene glycol) copolymer, polypropylene glycol 1020, propylene glycol, glycerol and ethyl acetate were evaluated. The second approach enhancing storage stability was the addition of recrystallization inhibitors to supersaturated solid solutions, thereby delaying the transformation of the metastable supersaturated system to the thermodynamically stable state. Macrogol cetostearyl ether, macrogol glycerol monostearate, polysorbate 60, cetostearyl alcohol, glycerol monostearate and sodium lauryl sulphate as well as hydroxypropylcellulose, butylmethacrylat-(2-dimethylaminoethyl)methacrylat-methylmethacrylat-copolymer, polyacrylic acid, polyvinyl alcohol and povidone K17 were included in the study. It could be shown that povidone K17 effectively prevents recrystallization in solid solutions containing 20% (m/m) of nimodipine during storage at +25 degrees C over silica gel thereby ensuring a substantial increase in the dissolution rate and degree of supersaturation in water. On the contrary, stabilization by solubility enhancement was only successful at drug loadings not exceeding 1% (m/m) using polyethylene glycol 300 as solubility enhancing additive.

  17. 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 (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and...

  18. 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 Section 178.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND...

  19. 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 Section 178.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND...

  20. 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 Section 178.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND...

  1. 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... Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol...)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (PMN P-09-628) is subject...

  2. 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... Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol...)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (PMN P-09-628) is subject...

  3. 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... Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol...)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (PMN P-09-628) is subject...

  4. 40 CFR 721.10546 - Pentenylated polyethylene glycol sulfate salt (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Pentenylated polyethylene glycol... 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...

  5. 40 CFR 721.10546 - Pentenylated polyethylene glycol sulfate salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Pentenylated polyethylene glycol... 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...

  6. 21 CFR 172.820 - Polyethylene glycol (mean molecular weight 200-9,500).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2768 Sorbitol SX850, or equivalent) 12 percent in H2O by weight on 60-80 mesh nonacid washed... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyethylene glycol (mean molecular weight 200-9... Multipurpose Additives § 172.820 Polyethylene glycol (mean molecular weight 200-9,500). Polyethylene glycol...

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl polyethylene glycol phosphate... 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 this...

  8. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl polyethylene glycol phosphate... 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 this...

  9. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl polyethylene glycol phosphate... 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 this...

  10. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl polyethylene glycol phosphate... 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 this...

  11. 40 CFR 721.3900 - Alkyl polyethylene glycol phosphate, potassium salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl polyethylene glycol phosphate... 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 this...

  12. Synthesis of Degradable Poly[(Ethylene Glycol)-co-(Glycolic Acid)] via the Post-Polymerization Oxyfunctionalization of Poly(Ethylene Glycol).

    PubMed

    Liu, Di; Bielawski, Christopher W

    2016-10-01

    To enhance the limited degradability of poly(ethylene glycol) (PEG), a straightforward method of synthesizing poly[(ethylene glycol)-co-(glycolic acid)] (P(EG-co-GA)) via a ruthenium-catalyzed, post-polymerization oxyfunctionalization of various PEGs is developed. Using this method, a set of copolymers with GA compositions of up to 8 mol% are prepared with minimal reduction in molecular weight (<10%) when compared to their commercially available starting materials. The P(EG-co-GA) copolymers are shown to undergo hydrolysis under mild conditions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Using polyethylene glycols as alternative inhibitors in copper electrorefining

    NASA Astrophysics Data System (ADS)

    Stelter, Michael; Bombach, Hartmut; Nesterov, Nikolay

    2002-04-01

    Polyethylene glycols (PEGs) with well-defined molecular weight ranges are interesting alternative additives for copper electrorefining. In comparison to glue, PEGs offer high thermal stability and slow chemical decomposition at higher temperatures, with high cathodic polarization. Thosefactors are advantages for an optimized process control in copper electrorefining. Investigations into cathodic polarization as a function of molecular weight and concentration at 500 A/m2, and also into the half-life of PEGs, were conducted in typical copper electrolyte.

  14. 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 Boric...

  15. 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 Boric...

  16. 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.

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3750 Polyethylene glycol (mean... ethylene and diethylene glycols if its mean molecular weight is below 350, when tested by the analytical... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyethylene glycol (mean molecular weight 200-9...

  18. 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.

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

    PubMed Central

    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

    2016-01-01

    Abstract 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

  20. 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.

  1. Polyethylene glycol enhanced refolding of the recombinant human tissue transglutaminase.

    PubMed

    Ambrus, A; Fésüs, L

    2001-02-01

    Tissue transglutaminase forms cross-links between lysine and glutamine side-chains of polypeptide chains in a Ca2+-dependent reaction; its structural basis is still not clarified. In this study, we demonstrate that the refolding of the human recombinant enzyme molecule to its catalytically active form from inclusion bodies needs the presence of a helper material with higher molecular mass, but only in the initiation phase. Ca2+ and nucleotides are ascribed as affector molecules also in the early phase of structural reconstitution. Two optimal concentrations of polyethylene glycol and a relatively long time scale for the evolution of the final structure were identified. The optimized refolding procedure is reported.

  2. 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

  3. 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.

  4. Micropatterning of poly(ethylene glycol) diacrylate hydrogels.

    PubMed

    Ali, Saniya; Cuchiara, Maude L; West, Jennifer L

    2014-01-01

    This protocol describes the techniques to synthesize and fabricate micropatterned poly(ethylene glycol) diacrylate-based hydrogels that can be used as substrates in cellular studies and tissue engineering scaffolds. These materials provide an essentially bioinert background material due to the very low protein adsorption characteristics of poly(ethylene glycol), but the materials can be modified with covalently grafted peptides, proteins, or other biomolecules of interest to impart specific biofunctionality to the material. Further, it is possible to use micropatterning technologies to control the localization of such covalent grafting of biomolecules to the hydrogel materials, thus spatially controlling the cell-material interactions. This protocol presents a relatively simple approach for mask-based photolithographic patterning, generally best suited for patterning the surface of hydrogel materials for 2D cell studies. A more sophisticated technique, two-photon laser scanning lithography, is also presented. This technique allows free-form, 3D micropatterning in hydrogels. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. 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 specifications...

  6. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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 specifications...

  7. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 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 specifications...

  8. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 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 specifications...

  9. 21 CFR 573.800 - Polyethylene glycol (400) mono- and dioleate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRINKING WATER OF ANIMALS Food Additive Listing § 573.800 Polyethylene glycol (400) mono- and dioleate. (a... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Polyethylene glycol (400) mono- and dioleate. 573.800 Section 573.800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  10. 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 weight...

  11. 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 200-9,500). 178.3750 Section 178.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND..., PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3750 Polyethylene glycol (mean...

  12. 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 200-9,500). 178.3750 Section 178.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND..., PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3750 Polyethylene glycol (mean...

  13. Identification of polypropylene glycols and polyethylene glycol carboxylates in flowback and produced water from hydraulic fracturing.

    PubMed

    Thurman, E Michael; Ferrer, Imma; Rosenblum, James; Linden, Karl; Ryan, Joseph N

    2017-02-05

    The purpose of the study was to separate and identify the unknown surfactants present in flowback and produced water from oil and gas wells in the Denver-Julesburg Basin (Niobrara Formation) in Weld County, Colorado, USA. Weld County has been drilled extensively during the last five years for oil and gas between 7000-8000 feet below land-surface. Polypropylene glycols (PPGs) and polyethylene glycols carboxylates (PEG-Cs) were found for the first time in these flowback and produced water samples. These ethoxylated surfactants may be used as friction reducers, clay stabilizers, and surfactants. Ultrahigh-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC/QTOF-MS) was used to separate and identify the different classes of PPGs, PEG-Cs, and their isomers. The Kendrick mass scale was applied along with mass spectrometry/mass spectrometry (MS-MS) with accurate mass for rapid and unequivocal identification. The PPGs and their isomers occur at the ppm concentration range and may be useful as "fingerprints" of hydraulic-fracturing. Comparing these detections to the compounds used in the fracturing process from FracFocus 3.0 (https://fracfocus.org), it appears that both PPGs and polyethylene glycols (PEGs) are commonly named as additives, but the PEG-Cs have not been reported. The PEG-Cs may be trace impurities or degradation products of PEGs.

  14. Polyethylene glycol as a promising synthetic material for repair of spinal cord injury.

    PubMed

    Kong, Xian-Bin; Tang, Qiu-Yan; Chen, Xu-Yi; Tu, Yue; Sun, Shi-Zhong; Sun, Zhong-Lei

    2017-06-01

    Polyethylene glycol is a synthetic, biodegradable, and water-soluble polyether. Owing to its good biological and material properties, polyethylene glycol shows promise in spinal cord tissue engineering applications. Although studies have examined repairing spinal cord injury with polyethylene glycol, these compelling findings have not been recently reviewed or evaluated as a whole. Thus, we herein review and summarize the findings of studies conducted both within and beyond China that have examined the repair of spinal cord injury using polyethylene glycol. The following summarizes the results of studies using polyethylene glycol alone as well as coupled with polymers or hydrogels: (1) polyethylene glycol as an adjustable biomolecule carrier resists nerve fiber degeneration, reduces the inflammatory response, inhibits vacuole and scar formation, and protects nerve membranes in the acute stage of spinal cord injury. (2) Polyethylene glycol-coupled polymers not only promote angiogenesis but also carry drugs or bioactive molecules to the injury site. Because such polymers cross both the blood-spinal cord and blood-brain barriers, they have been widely used as drug carriers. (3) Polyethylene glycol hydrogels have been used as supporting substrates for the growth of stem cells after injury, inducing cell migration, proliferation, and differentiation. Simultaneously, polyethylene glycol hydrogels isolate or reduce local glial scar invasion, promote and guide axonal regeneration, cross the transplanted area, and re-establish synaptic connections with target tissue, thereby promoting spinal cord repair. On the basis of the reviewed studies, we conclude that polyethylene glycol is a promising synthetic material for use in the repair of spinal cord injury.

  15. Poly(ethylene glycol)s as Ligands in Calcium-Catalyzed Cyclic Carbonate Synthesis.

    PubMed

    Steinbauer, Johannes; Werner, Thomas

    2017-08-10

    Herein the use of CaI2 in combination with poly(ethylene glycol) dimethyl ether (PEG DME 500) as an efficient catalyst system for the addition of CO2 to epoxides is reported. This protocol is based on a nontoxic and abundant metal in conjunction with a polymeric ligand. Fifteen terminal epoxides were converted at room temperature to give the desired products in yields up to 99 %. Notably, this system was also effective for the synthesis of twelve challenging internal carbonates in yields up to 98 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Anaphylactic shock caused by ingestion of polyethylene glycol.

    PubMed

    Lee, Sun Hee; Cha, Jae Myung; Lee, Joung Il; Joo, Kwang Ro; Shin, Hyun Phil; Baek, Il Hyun; Jeon, Jung Won; Lim, Jun Uk; Lee, Jung Lok; Lee, Hyae Min; Cho, Young-Hak

    2015-01-01

    Colonoscopy is the current standard method for evaluation of the colon. The diagnostic accuracy and therapeutic safety of colonoscopy depend on the quality of colonic cleansing and preparation. Generally, all these preparations have been demonstrated to be safe for use in healthy individuals without significant comorbid conditions. Based on safety and efficacy concerns, polyethylene glycol (PEG) is most commonly utilized as a bowel preparation solution for colonoscopy. Adverse events in patients receiving PEG are mostly clinically non-significant. However, fatal adverse events rarely have been shown to occur in the few individuals who experience vomiting or aspiration. Anaphylactic shock associated with ingestion of PEG electrolyte solution is an extremely rare fatal complication, and reported mainly in Western countries. Here, we report the first case of anaphylactic shock following the ingestion of PEG solution in Korea.

  17. Hansen solubility parameters for polyethylene glycols by inverse gas chromatography.

    PubMed

    Adamska, Katarzyna; Voelkel, Adam

    2006-11-03

    Inverse gas chromatography (IGC) has been applied to determine solubility parameter and its components for nonionic surfactants--polyethylene glycols (PEG) of different molecular weight. Flory-Huggins interaction parameter (chi) and solubility parameter (delta(2)) were calculated according to DiPaola-Baranyi and Guillet method from experimentally collected retention data for the series of carefully selected test solutes. The Hansen's three-dimensional solubility parameters concept was applied to determine components (delta(d), delta(p), delta(h)) of corrected solubility parameter (delta(T)). The molecular weight and temperature of measurement influence the solubility parameter data, estimated from the slope, intercept and total solubility parameter. The solubility parameters calculated from the intercept are lower than those calculated from the slope. Temperature and structural dependences of the entopic factor (chi(S)) are presented and discussed.

  18. Poly(ethylene glycol) self-assembled monolayer island growth.

    PubMed

    Rundqvist, Jonas; Hoh, Jan H; Haviland, David B

    2005-03-29

    Here, we report a study of the morphology and growth dynamics of a self-assembled monolayer (SAM) of the amide containing poly(ethylene glycol) (PEG) thiol (CH3O(CH2CH2O)17NHCO(CH2)2SH) on atomically flat Au(111) surfaces. SAM growth from a 20 muM ethanolic solution reveals island growth through three distinct steps: island nucleation, island growth, and coalescence. The coalescence-step, filling voids in the SAM, is by far slowest. The fine structure study reveals dendritic island formation, an observation which can be explained by attractive intermolecular interactions and surface diffusion-limited aggregation. We have also observed a change in the island height, which peaks during the island growth phase. This height change can be associated with a molecular conformational transition.

  19. Preparation and Characterization of Modified Soda Lignin with Polyethylene Glycol.

    PubMed

    Zhang, Fangda; Lin, Jian; Zhao, Guangjie

    2016-10-07

    Soda lignin does not have thermal flowing characteristics and it is impossible for it to be further thermally molded. To achieve the fusibility of soda lignin for fiber preparation by melt-spinning, an effective method for soda lignin modification was conducted by cooking it with polyethylene glycol (PEG) 400 at various ratios. The higher the ratio of PEG that was used, the more PEG molecular chains were grafted at the alpha carbon of the soda lignin through ether bonds, resulting in lower thermal transition temperatures and more excellent fusibility. The modified soda lignin with a weight ratio of lignin to PEG of 1:4 exhibited a relative thermal stability of molten viscosity at selected temperatures. Thereafter, the resultant fusible soda lignin was successfully melt-spun into filaments with an average diameter of 33 ± 5 μm, which is smaller than that of some industrial lignins. Accordingly, it is possible to utilize soda lignin to produce fibrous carbonaceous materials.

  20. Allergic reaction to polyethylene glycol in a painter.

    PubMed

    Antolin-Amerigo, D; Sánchez-González, M J; Barbarroja-Escudero, J; Rodríguez-Rodríguez, M; Álvarez-Perea, A; Alvarez-Mon, M

    2015-08-01

    We report a case of a male painter who visited our outpatient clinic after developing a distinct skin reaction 15 min after the ingestion of a laxative solution containing polyethylene glycol (PEG) prior to colonoscopy. He described suffering from the same skin reaction when he was previously exposed to paints that contained PEG-4000. An exposure challenge test with pure PEG-4000, simulating his workplace conditions, elicited a generalized urticarial reaction. Allergy to PEG should be considered in painters who develop urticarial or other systemic symptoms after handling PEG-containing products. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Magnetic fluid poly(ethylene glycol) with moderate anticancer activity

    NASA Astrophysics Data System (ADS)

    Závišová, Vlasta; Koneracká, Martina; Múčková, Marta; Lazová, Jana; Juríková, Alena; Lancz, Gábor; Tomašovičová, Natália; Timko, Milan; Kováč, Jozef; Vávra, Ivo; Fabián, Martin; Feoktystov, Artem V.; Garamus, Vasil M.; Avdeev, Mikhail V.; Kopčanský, Peter

    2011-05-01

    Poly(ethylene glycol) (PEG)-containing magnetic fluids - magnetite (Fe 3O 4) stabilized by sodium oleate - were prepared. Magnetic measurements confirmed superparamagnetic behaviour at room temperature. The structure of that kind of magnetic fluid was characterized using different techniques, including electron microscopy, photon cross correlation spectroscopy and small-angle neutron scattering, while the adsorption of PEG on magnetic particles was analyzed by differential scanning calorimetry and Fourier transform infrared spectroscopy. From the in vitro toxicity tests it was found that a magnetic fluid containing PEG (MFPEG) partially inhibited the growth of cancerous B16 cells at the highest tested dose (2.1 mg/ml of Fe 3O 4 in MFPEG).

  2. 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

  3. Effect of Polyethylene Glycol on the NiO Photocathode

    NASA Astrophysics Data System (ADS)

    Li, Shengjun; Chen, Zeng; Kong, Wenping; Jia, Xiyang; Cai, Junhao; Dong, Shaokang

    2017-08-01

    In this study, a uniform nanoporous NiO film, with a thickness of up to 2.6 μm, was prepared using polyethylene glycol (PEG). The addition of PEG significantly decreased the cracks in the NiO film and prevented the peeling of the NiO film from a fluorine-doped tin oxide substrate. The NiO cathode was prepared using CdSeS quantum dots (QDs) as the sensitizer, with an optimized photoelectric conversion of 0.80%. The optimized QD-sensitized NiO films were first assembled with the TiO2 anode to prepared QD-sensitized p-n-type tandem solar cells. The open circuit voltage was greater than that obtained using the separated NiO cathode or TiO2 anode.

  4. Horseradish peroxidase inactivation: heme destruction and influence of polyethylene glycol.

    PubMed

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

    2013-11-04

    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.

  5. Effect of Polyethylene Glycol on the NiO Photocathode.

    PubMed

    Li, Shengjun; Chen, Zeng; Kong, Wenping; Jia, Xiyang; Cai, Junhao; Dong, Shaokang

    2017-08-17

    In this study, a uniform nanoporous NiO film, with a thickness of up to 2.6 μm, was prepared using polyethylene glycol (PEG). The addition of PEG significantly decreased the cracks in the NiO film and prevented the peeling of the NiO film from a fluorine-doped tin oxide substrate. The NiO cathode was prepared using CdSeS quantum dots (QDs) as the sensitizer, with an optimized photoelectric conversion of 0.80%. The optimized QD-sensitized NiO films were first assembled with the TiO2 anode to prepared QD-sensitized p-n-type tandem solar cells. The open circuit voltage was greater than that obtained using the separated NiO cathode or TiO2 anode.

  6. 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.

  7. Silk fibroin and polyethylene glycol-based biocompatible tissue adhesives

    PubMed Central

    Serban, Monica A.; Panilaitis, Bruce; Kaplan, David L.

    2012-01-01

    Tissue sealants have emerged in recent years as strong candidates for hemostasis. A variety of formulations are currently commercially available and though they satisfy many of the markets’ needs there are still key aspects of each that need improvement. Here we present a new class of blends, based on silk fibroin and chemically active polyethylene glycols (PEGs) with strong adhesive properties. These materials are cytocompatible, crosslink within seconds via chemical reaction between thiols and maleimides present on the constituent PEGs and have the potential to further stabilize through β-sheet formation by silk. Based on the silk concentration in the final formulation, the adhesive properties of these materials are comparable or better than the current leading PEG-based sealant. In addition, the silk-PEG based materials show decreased swelling and longer degradation times. Such properties would make them suitable for applications for which the current sealants are contraindicated. PMID:21681949

  8. 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

    2001-09-04

    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.

  9. 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.

  10. 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.

  11. Influence of polyethylene glycol-300 addition on nanostructured lead sulfide thin films properties

    NASA Astrophysics Data System (ADS)

    Kaci, S.; Keffous, A.; Trari, M.; Menari, H.; Manseri, A.; Mahmoudi, B.; Guerbous, L.

    2010-09-01

    The concentration of polyethylene glycol-300 was found to play a crucial role in the formation of nanoparticles in PbS-chemical bath deposition process. We report here an endeavor to set up a relation between the variation of lead sulfide (PbS) nanocrystalline thin film properties, grown by (CBD) process at room temperature on corning glass and Si(100) substrates, with amount fluctuations of polyethylene glycol-300 in the solution. The transmittance of the films, for a fixed reaction time, increased up to ˜ 80% with the increase of % polyethylene glycol-300 in the solution, indicating the formation of very thin films due to the decrease of reaction rate with the increase of the concentration of polyethylene glycol-300. The optical band gaps were found to strongly rely on the composition of the bath deposition and increase with the increase of the polyethylene glycol-300 amount in the solution. Particle sizes between 2.8 and 8.7 nm were obtained by varying the % of polyethylene glycol-300 from 0.2 to 1.5. The concentration of polyethylene glycol-300 not only affects the reaction rate but also the morphology of the obtained films. PbS nanoparticles were found to be oriented preferentially along the < 200> plane. The absorption shifts towards short wavelength indicating a blue-shifting as a consequence of quantum confinement.

  12. 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)).

  13. Zinc phthalocyanine labelled polyethylene glycol: preparation, characterization, interaction with bovine serum albumin and near infrared fluorescence imaging in vivo.

    PubMed

    Lv, Feng; Cao, Bo; Cui, Yanli; Liu, Tianjun

    2012-05-25

    Zinc phthalocyanine labelled polyethylene glycol was prepared to track and monitor the in vivo fate of polyethylene glycol. The chemical structures were characterized by nuclear magnetic resonance and infrared spectroscopy. Their light stability and fluorescence quantum yield were evaluated by UV-Visible and fluorescence spectroscopy methods. The interaction of zinc phthalocyanine labelled polyethylene glycol with bovine serum albumin was evaluated by fluorescence titration and isothermal titration calorimetry methods. Optical imaging in vivo, organ aggregation as well as distribution of fluorescence experiments for tracking polyethylene glycol were performed with zinc phthalocyanine labelled polyethylene glycol as fluorescent agent. Results show that zinc phthalocyanine labelled polyethylene glycol has good optical stability and high emission ability in the near infrared region. Imaging results demonstrate that zinc phthalocyanine labelled polyethylene glycol can track and monitor the in vivo process by near infrared fluorescence imaging, which implies its potential in biomaterials evaluation in vivo by a real-time noninvasive method.

  14. Miscibility studies of Polyethylene Glycol with Polystyrene in Toluene by Various Physical and Advanced Techniques

    NASA Astrophysics Data System (ADS)

    Padmanaban, R.; Venkatramanan, K.

    2016-10-01

    Polyethylene glycol (PEG) is a chemical that has an extensive variety of applications in the world of medicine. It is used as a base to manufacture certain medicines, assist in drug delivery, and is also used as an agent in some medical procedures. It is an osmotic laxative. Polyethylene glycol works by retaining water in the stool, resulting in softer stools and more frequent bowel movements. Polyethylene glycol does not affect glucose and electrolytes in the body. PEG refers to a hydrocarbon molecule that can have a variable size, and different sizes can have different physical properties, giving this compound a great deal of flexibility in its application. In the present study, Polyethylene Glycol (PEG) (Molar mass: 1500) is blended with Polystyrene (PS) (Molar mass: 35000) in Toluene. The miscibility nature of the poly blend is analyzed by Ultrasonic velocity, viscosity, density and refractive index techniques at 303K. The compatibility nature of the blend is confirmed by Differential Scanning Calorimetry (DSC) studies.

  15. Highly conductive solid polymer electrolyte membranes based on polyethylene glycol-bis-carbamate dimethacrylate networks

    NASA Astrophysics Data System (ADS)

    Fu, Guopeng; Dempsey, Janel; Izaki, Kosuke; Adachi, Kaoru; Tsukahara, Yasuhisa; Kyu, Thein

    2017-08-01

    In an effort to fabricate highly conductive, stable solid-state polymer electrolyte membranes (PEM), polyethylene glycol bis-carbamate (PEGBC) was synthesized via condensation reaction between polyethylene glycol diamine and ethylene carbonate. Subsequently, dimethacrylate groups were chemically attached to both ends of PEGBC to afford polyethylene glycol-bis-carbamate dimethacrylate (PEGBCDMA) precursor having crosslinking capability. The melt-mixed ternary mixtures consisting of PEGBCDMA, succinonitrile plasticizer, and lithium trifluorosulphonyl imide salt were completely miscible in a wide compositional range. Upon photo-crosslinking, the neat PEGBCDMA network was completely amorphous exhibiting higher tensile strength, modulus, and extensibility relative to polyethylene glycol diacrylate (PEGDA) counterpart. Likewise, the succinonitrile-plasticized PEM network containing PEGBCDMA remained completely amorphous and transparent upon photo-crosslinking, showing superionic conductivity, improved thermal stability, and superior tensile properties with improved capacity retention during charge/discharge cycling as compared to the PEGDA-based PEM.

  16. 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.

  17. Degradation of polyethylene glycol by Fenton reaction: a comparative study.

    PubMed

    Haseneder, R; Fdez-Navamuel, B; Härtel, G

    2007-01-01

    Photochemical advanced oxidation processes (AOPs) utilising different Fenton systems were investigated in laboratory-scale experiments for the degradation of polyethylene glycol (PEG). The results of the study showed that the degradation rate of PEG was strongly accelerated by the homogeneous system, and this proved to be advantageous in comparison to the heterogeneous system. Between Fenton and photo-Fenton heterogeneous systems, the photo-Fenton process reached the highest removal rate of the organic compound, due to the enhanced reduction efficiency of Fe(III) to Fe(II) under UV-irradiation. The oxidation rate in the heterogeneous system was investigated using varying different parameters, such as the pH value, the concentration of hydrogen peroxide and the amount of Fe(OH)3 as the catalyst. For the homogeneous Fenton system the rate of degradation is significantly higher. At the same time of operation the elimination rates can be found to be 30% over the rates of the heterogeneous system. Optimising the typical influence parameters mentioned before, a degradation of about 93% of PEG can be achieved by using the homogeneous Fenton system.

  18. Polyethylene glycol protects primary hepatocytes during supercooling preservation.

    PubMed

    Puts, C F; Berendsen, T A; Bruinsma, B G; Ozer, Sinan; Luitje, Martha; Usta, O Berk; Yarmush, M L; Uygun, K

    2015-08-01

    Cold storage (at 4°C) offers a compromise between the benefits and disadvantages of cooling. It allows storage of organs or cells for later use that would otherwise quickly succumb to warm ischemia, but comprises cold ischemia that, when not controlled properly, can result in severe damage as well by both similar and unique mechanisms. We hypothesized that polyethylene glycol (PEG) 35 kDa would ameliorate these injury pathways and improve cold primary hepatocyte preservation. We show that reduction of the storage temperature to below zero by means of supercooling, or subzero non-freezing, together with PEG supplementation increases the viable storage time of primary rat hepatocytes in University of Wisconsin (UW) solution from 1 day to 4 days. We find that the addition of 5% PEG 35 kDa to the storage medium prevents cold-induced lipid peroxidation and maintains hepatocyte viability and functionality during storage. These results suggest that PEG supplementation in combination with supercooling may enable a more optimized cell and organ preservation.

  19. 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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. 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

  1. Fractionation of dextrin by gradient polyethylene glycol precipitation.

    PubMed

    Hu, Xiuting; Liu, Chengmei; Jin, Zhengyu; Tian, Yaoqi

    2016-02-19

    This work aimed at developing a novel approach, named gradient polyethylene glycol (PEG) precipitation, to fractionate dextrin into fractions with narrower molecular weight distribution. This approach was based on the incompatibility between PEG and dextrin in aqueous solution; this incompatibility is positively correlated with the molecular weight of dextrin. Theoretically, dextrin can be precipitated in descending order of molecular weight by the gradual addition of PEG into the dextrin solution. Specifically, this study investigated the effects of molecular weight and its distribution of PEG on dextrin fractionation with the molecular-weight dispersity (DM) as index. The parent dextrin could be fractionated by PEG into several fractions with different molecular weights and lower DM. The average DM of fractions obtained by PEG2000, PEG4000, PEG6000, PEG10000, and PEG20000 was 1.471, 1.352, 1.286, 1.453, and 2.028, respectively, while the DM of the parent dextrin was 2.052. These data suggest that PEG6000 was the optimal precipitant, while PEG20000 was unsuitable for fractionating dextrin. Furthermore, narrowly-distributed PEG resulted in optimum fractionation results. Therefore, gradient PEG precipitation is an efficient method for fractionating dextrin. Additionally, narrowly-distributed PEG of suitable molecular weight should be selected to obtain superior fractionation results.

  2. The gas phase structure of coulombically stretched polyethylene glycol ions.

    PubMed

    Larriba, Carlos; de la Mora, Juan Fernandez

    2012-01-12

    Prior ion-mobility mass-spectrometry (IMS-MS) studies of polyethylene glycol (PEG) ions have identified only two out of many sharply different observed structures: Linear shapes with several individually solvated singly charged cations at high charge states z (beads on a string), and single multiply charged globules at low z. The present study is devoted to assign all other existing structures of PEG ions, for the first time reaching masses of 100 kDa and charge states up to z = 10. There are at most z different structures at charge state z. All involve a single globule carrying n charges, tied to one or several appendices bearing z - n separate charges in a beads-on-a-string configuration. All sharp shape transitions observed at decreasing ion mass involve ejection of one elementary charge (sometimes two) from the shrinking globule into the growing linear appendage. This picture is supported by molecular dynamics simulations and approximate calculations of electrical mobilities for computed structures.

  3. Method for determination of polyethylene glycol molecular weight.

    PubMed

    Pihlasalo, Sari; Hänninen, Pekka; Härmä, Harri

    2015-04-07

    A method utilizing competitive adsorption between polyethylene glycols (PEGs) and labeled protein to nanoparticles was developed for the determination of PEG molecular weight (MW) in a microtiter plate format. Two mix-and-measure systems, time-resolved luminescence resonance energy transfer (TR-LRET) with donor europium(III) polystyrene nanoparticles and acceptor-labeled protein and quenching with quencher gold nanoparticles and fluorescently labeled protein were compared for their performance. MW is estimated from the PEG MW dependent changes in the competitive adsorption properties, which are presented as the luminescence signal vs PEG mass concentration. The curves obtained with the TR-LRET system overlapped for PEGs larger than 400 g/mol providing no information on MW. Distinctly different curves were obtained with the quenching system enabling the assessment of PEG MW within a broad dynamic range. The data was processed with and without prior knowledge of the PEG concentration to measure PEGs over a MW range from 62 to 35,000 g/mol. The demonstration of the measurement independent of the PEG concentration suggests that the estimation of MW is possible with quenching nanoparticle system for neutrally charged and relatively hydrophilic polymeric molecules widening the applicability of the simple and cost-effective nanoparticle-based methods.

  4. Mechanistic insights into acyclovir-polyethylene glycol 20000 binary dispersions

    PubMed Central

    Venkateskumar, Krishnamoorthy; Parasuraman, Subramani; Gunasunderi, Raju; Sureshkumar, Krishnan; Nayak, M. Muralidhar; Shah, Syed Adnan Ali; Kassen, Khoo; Kai, Heng Wei

    2016-01-01

    Objective: The objective of this study is to provide a mechanistic insight into solubility enhancement and dissolution of acyclovir (ACY) by polyethylene glycol20000 (PEG20000). Materials and Methods: Solid dispersions with differing ratios of drug (ACY) and carrier (PEG20000) were prepared and evaluated by phase solubility, in vitro release studies, kinetic analysis, in situ perfusion, and in vitro permeation studies. Solid state characterization was also done by Powder X-Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared spectroscopy (FT-IR) analysis and surface morphology was assessed by Polarizing Microscopic Image (PMI) analysis, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Nuclear Magnetic Resonance (NMR) analysis. Results: Thermodynamic parameters proved the solubilization effect of carrier. The aqueous solubility and dissolution of ACY were increased in all samples. Formation of solid solution, crystallinity reduction, and absence of interaction between drug and carrier was proved by XRD, DSC, and FTIR analysis. The particle size reduction and change in surface morphology were confirmed by SEM and AFM and analysis. The permeation coefficient and amount of drug diffused was higher in samples as compared to ACY. The stability was high in dispersions, and it was proved by NMR analysis. Conclusion: The mechanical insights into the enhancement of solubility and dissolution could be used as a platform to improve the aqueous solubility for other poor water soluble drugs. PMID:28123988

  5. [Interferon alpha-2b modified with polyethylene glycol].

    PubMed

    Wu, Yingxin; Zhai, Yanqin; Lei, Jiandu; Ma, Guanghui; Su, Zhiguo

    2008-09-01

    In order to obtain a more stable PEGylated interferon alpha-2b, and prolong its half life, interferon alpha-2b (IFN alpha-2b) was modified with monomethoxy polyethylene glycol propionaldehyde (mPEG-ALD) 20000. It was found that the optimized reaction condition for the maximum bioactivity and highest PEGylation degree of the mono PEGylated interferon alpha-2b was as follows: in 20 mmol/L, pH 6.5, citric acid and sodium dihydrogen phosphate buffer, the concentration of IFN alpha-2b was 4 mg/mL, and the molar ratio of PEG/IFN alpha-2b was 8:1, and the reaction time was 20 h at 4 degrees C. Under the optimized reaction condition, the mono PEGylation degree reached to 55%. Ion exchange chromatography was used to separate and purify mono PEGylated interferon alpha-2b from the reaction mixture. The purity of mono PEGylated interferon alpha-2b was higher than 97% characterized by HPLC. The bioactivity of the mono PEGylated interferon alpha-2b was 13.4% of the native IFN alpha-2b, while its half life in SD rat is much longer than the native IFN alpha-2b. The mono PEGylated interferon alpha-2b is also stable in aqueous.

  6. Physicochemical characterization of nimodipine-polyethylene glycol solid dispersion systems.

    PubMed

    Barmpalexis, Panagiotis; Kachrimanis, Kyriakos; Georgarakis, Emanouil

    2014-07-01

    This study investigates the solid-solid interactions between nimodipine (NIM) and polyethylene glycol (PEG) of different mean molecular weights (PEG 2000, 4000 and 6000), in solid dispersion systems, applying differential scanning calorimetry (DSC), Fourier-Transform infrared spectroscopy, powder X-ray diffraction (PXRD), hot stage microscopy (HSM) and theoretical modeling by the Flory-Huggins (FH) solution theory. Phase diagrams constructed with the aid of DSC and FH solution theory showed sensitivity on the estimated values of the FH interaction parameter (χ). When χ is considered a constant number (χ = α, α ≠ 0), formation of a eutectic mixture is predicted in the 70-80% w/w PEG concentration region, while when χ was considered as a function of concentration and temperature (χ = f(φ,Τ)), the model predicts the formation of monotectic systems. Construction of more precise phase diagrams by HSM to the aid of Kofler's "contact preparation" method confirmed the monotectic nature of the examined systems. Studies on NIM's re-crystallization process in the solid dispersions revealed a strong dependence of the crystallization rate, as well as the resulting crystal form, on the mean molecular weight and concentration of PEG: NIM crystallization rates decrease as PEG's MW increases, while NIM mod II crystals predominate in dispersions prepared at temperatures above NIM's liquidus and growth of NIM mod I prevailing in PEG-rich samples.

  7. Preparation and Characterization of Modified Soda Lignin with Polyethylene Glycol

    PubMed Central

    Zhang, Fangda; Lin, Jian; Zhao, Guangjie

    2016-01-01

    Soda lignin does not have thermal flowing characteristics and it is impossible for it to be further thermally molded. To achieve the fusibility of soda lignin for fiber preparation by melt-spinning, an effective method for soda lignin modification was conducted by cooking it with polyethylene glycol (PEG) 400 at various ratios. The higher the ratio of PEG that was used, the more PEG molecular chains were grafted at the alpha carbon of the soda lignin through ether bonds, resulting in lower thermal transition temperatures and more excellent fusibility. The modified soda lignin with a weight ratio of lignin to PEG of 1:4 exhibited a relative thermal stability of molten viscosity at selected temperatures. Thereafter, the resultant fusible soda lignin was successfully melt-spun into filaments with an average diameter of 33 ± 5 μm, which is smaller than that of some industrial lignins. Accordingly, it is possible to utilize soda lignin to produce fibrous carbonaceous materials. PMID:28773943

  8. Polyethylene glycol on stability of chitosan microparticulate carrier for protein.

    PubMed

    Luangtana-Anan, Manee; Limmatvapirat, Sontaya; Nunthanid, Jurairat; Chalongsuk, Rapeepun; Yamamoto, Keiji

    2010-09-01

    Stability enhancement of protein-loaded chitosan microparticles under storage was investigated. Chitosan glutamate at 35 kDa and bovine serum albumin as model protein drug were used in this study. The chitosan microparticles were prepared by ionotropic gelation, and polyethylene glycol 200 (PEG 200) was applied after the formation of the particles. All chitosan microparticles were kept at 25°C for 28 days. A comparison was made between those preparations with PEG 200 and without PEG 200. The changes in the physicochemical properties of the microparticles such as size, zeta potential, pH, and percent loading capacity were investigated after 0, 3, 7, 14, and 28 days of storage. It was found that the stability decreased upon storage and the aggregation of microparticles could be observed for both preparations. The reduction in the zeta potential and the increase in the pH, size, and loading capacity were observed when they were kept at a longer period. The significant change of those preparations without PEG 200 was evident after 7 days of storage whereas those with PEG 200 underwent smaller changes with enhanced stability after 28 days of storage. Therefore, this investigation gave valuable information on the stability enhancement of the microparticles. Hence, enhanced stability of chitosan glutamate microparticles for the delivery of protein could be achieved by the application of PEG 200.

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

    PubMed

    Choi, Eunsong; Mondal, Jagannath; Yethiraj, Arun

    2014-01-09

    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.

  10. Surface modification of polypropylene membrane by polyethylene glycol graft polymerization.

    PubMed

    Abednejad, Atiye Sadat; Amoabediny, Ghasem; Ghaee, Azadeh

    2014-09-01

    Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H2 and O2 plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37°C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Use of polyethylene glycol coatings for optical fibre humidity sensing

    NASA Astrophysics Data System (ADS)

    Acikgoz, Sabriye; Bilen, Bukem; Demir, Mustafa Muamer; Menceloglu, Yusuf Ziya; Skarlatos, Yani; Aktas, Gulen; Inci, Mehmet Naci

    2008-03-01

    Humidity induced change in the refractive index and thickness of the polyethylene glycol (PEG) coatings are in situ investigated for a range from 10 to 95%, using an optical waveguide spectroscopic technique. It is experimentally demonstrated that, upon humidity change, the optical and swelling characteristics of the PEG coatings can be employed to build a plastic fibre optic humidity sensor. The sensing mechanism is based on the humidity induced change in the refractive index of the PEG film, which is directly coated onto a polished segment of a plastic optical fibre with dip-coating method. It is observed that PEG, which is a highly hydrophilic material, shows no monotonic linear response to humidity but gives different characteristics for various ranges of humidity levels both in index of refraction and in thickness. It undergoes a physical phase change from a semi-crystalline structure to a gel one at around 80% relative humidity. At this phase change point, a drastic decrease occurs in the index of refraction as well as a drastic increase in the swelling of the PEG film. In addition, PEG coatings are hydrogenated in a vacuum chamber. It is observed that the hydrogen has a preventing effect on the humidity induced phase change in PEG coatings. Finally, the possibility of using PEG coatings in construction of a real plastic fibre optic humidity sensor is discussed.

  12. Detecting Sonolysis of Polyethylene Glycol Upon Functionalizing Carbon Nanotubes.

    PubMed

    Wang, Ruhung; Murali, Vasanth S; Draper, Rockford

    2017-01-01

    Polyethylene glycol (PEG) and related polymers are often used in the solubilization and noncovalent functionalization of carbon nanomaterials by sonication. For example, carbon nanotubes are frequently sonicated with PEG-containing surfactants of the Pluronic(®) series or phospholipid-PEG polymers to noncovalently functionalize the nanotubes. However, PEG is very sensitive to degradation upon sonication and the degradation products can be toxic to mammalian cells and to organisms such as zebrafish embryos. It is therefore useful to have a simple and inexpensive method to determine the extent of potential PEG sonolysis, as described in this chapter. Intact PEG polymers and degraded fragments are resolved on sodium dodecyl sulfate polyacrylamide gels by electrophoresis and visualized by staining with barium iodine (BaI2). Digitized images of gels are acquired using a flatbed photo scanner and the intensities of BaI2-stained PEG bands are quantified using ImageJ software. Degradation of PEG polymers after sonication is readily detected by the reduction of band intensities in gels compared to those of non-sonicated, intact PEG polymers. In addition, the approach can be used to rapidly screen various sonication conditions to identify those that might minimize PEG degradation to acceptable levels.

  13. Polyethylene glycol protects primary hepatocytes during supercooling preservation

    PubMed Central

    Puts, C.F.; Berendsen, T.A.; Bruinsma, B.G.; Ozer, Sinan; Luitje, Martha; Usta, O. Berk; Yarmush, M.L.; Uygun, K.

    2015-01-01

    Cold storage (at 4 °C) offers a compromise between the benefits and disadvantages of cooling. It allows storage of organs or cells for later use that would otherwise quickly succumb to warm ischemia, but comprises cold ischemia that, when not controlled properly, can result in severe damage as well by both similar and unique mechanisms. We hypothesized that polyethylene glycol (PEG) 35 kDa would ameliaorate these injury pathways and improve cold primary hepatocyte preservation. We show that reduction of the storage temperature to below zero by means of supercooling, or subzero non-freezing, together with PEG supplementation increases the viable storage time of primary rat hepatocytes in University of Wisconsin (UW) solution from 1 day to 4 days. We find that the addition of 5% PEG 35 kDa to the storage medium prevents cold-induced lipid peroxidation and maintains hepatocyte viability and functionality during storage. These results suggest that PEG supplementation in combination with supercooling may enable a more optimized cell and organ preservation. PMID:25936340

  14. The effect of polyethylene glycol on the characteristics of kenaf cellulose/low-density polyethylene biocomposites.

    PubMed

    Tajeddin, Behjat; Rahman, Russly Abdul; Abdulah, Luqman Chuah

    2010-08-01

    Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites. Copyright 2010 Elsevier B.V. All rights reserved.

  15. The "New Polyethylene Glycol Dilemma": Polyethylene Glycol Impurities and Their Paradox Role in mAb Crystallization.

    PubMed

    Hildebrandt, Christian; Joos, Lea; Saedler, Rainer; Winter, Gerhard

    2015-06-01

    Polyethylene glycols (PEG) represent the most successful and frequently applied class of excipients used for protein crystallization. PEG auto-oxidation and formation of impurities such as peroxides and formaldehydes that foster protein drug degradation is known. However, their effect on mAb crystallization has not been studied in detail before. During the present study, a model IgG1 antibody (mAb1) was crystallized in PEG solutions. Aggregate formation was observed during crystallization and storage that was ascribed to PEG degradation products. Reduction of peroxide and formaldehyde levels prior to crystallization by vacuum and freeze-drying was investigated for its effect on protein degradation. Vacuum drying was superior in removal of peroxides but inferior in reducing formaldehyde residues. Consequently, double purification allowed extensive removal of both impurities. Applying of purified PEG led to 50% lower aggregate fractions. Surprisingly, PEG double purification or addition of methionine prior to crystallization prevented crystal formation. With increased PEG concentration or spiking with peroxides and formaldehydes, crystal formation could be recovered again. With these results, we demonstrate that minimum amounts of oxidizing impurities and thus in consequence chemically altered proteins are vital to initiate mAb1 crystallization. The present study calls PEG as good precipitant for therapeutic biopharmaceuticals into question. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  16. 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.

  17. Acyclovir-Polyethylene Glycol 6000 Binary Dispersions: Mechanistic Insights.

    PubMed

    Venkateskumar, Krishnamoorthy; Parasuraman, Subramani; Gunasunderi, Raju; Sureshkumar, Krishnan; Nayak, M Muralidhar; Shah, Syed Adnan Ali; Khoo, Khassen; Kai, Heng Wei

    2016-12-21

    The dissolution and subsequent oral bioavailability of acyclovir (ACY) is limited by its poor aqueous solubility. An attempt has been made in this work to provide mechanistic insights into the solubility enhancement and dissolution of ACY by using the water-soluble carrier polyethylene glycol 6000 (PEG6000). Solid dispersions with varying ratios of the drug (ACY) and carrier (PEG6000) were prepared and evaluated by phase solubility, in vitro release studies, kinetic analysis, in situ perfusion, and in vitro permeation studies. Solid state characterization was done by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) analysis, and surface morphology was assessed by polarizing microscopic image analysis, scanning electron microscopy, atomic force microscopy, and nuclear magnetic resonance analysis. Thermodynamic parameters indicated the solubilization effect of the carrier. The aqueous solubility and dissolution of ACY was found to be higher in all samples. The findings of XRD, DSC, FTIR and NMR analysis confirmed the formation of solid solution, crystallinity reduction, and the absence of interaction between the drug and carrier. SEM and AFM analysis reports ratified the particle size reduction and change in the surface morphology in samples. The permeation coefficient and amount of ACY diffused were higher in samples in comparison to pure ACY. Stability was found to be higher in dispersions. The results suggest that the study findings provided clear mechanical insights into the solubility and dissolution enhancement of ACY in PEG6000, and such findings could lay the platform for resolving the poor aqueous solubility issues in formulation development.

  18. A novel nicotinoprotein aldehyde dehydrogenase involved in polyethylene glycol degradation.

    PubMed

    Ohta, T; Tani, A; Kimbara, K; Kawai, F

    2005-09-01

    A gene (pegC) encoding aldehyde dehydrogenase (ALDH) was located 3.4 kb upstream of a gene encoding polyethylene glycol (PEG) dehydrogenase (pegA) in Sphingomonas macrogoltabidus strain 103. ALDH was expressed in Escherichia coli and purified on a Ni-nitrilotriacetic acid agarose column. The recombinant enzyme was a homotetramer consisting of four 46.1-kDa subunits. The alignment of the putative amino acid sequence of the cloned enzyme showed high similarity with a group of NAD(P)-dependent ALDHs (identity 36-52%); NAD-binding domains (Rossmann fold and four glycine residues) and catalytic residues (Glu225 and Cys259) were well conserved. The cofactor, which was extracted from the purified enzyme, was tightly bound to the enzyme and identified as NADP. The enzyme contained 0.94 mol NADP per subunit. The enzyme was activated by Ca(2+), but by no other metals; no metal (Zn, Fe, Mg, or Mn) was detected in the purified recombinant enzyme. Activity was inhibited by p-chloromercuric benzoate, and heavy metals such as Hg, Cu, Pb and Cd, indicating that a cysteine residue is involved in the activity. Enzyme activity was independent of N,N-dimethyl-p-nitrosoaniline as an electron acceptor. Trans-4-(N,N-dimethylamino)-cinnamaldehyde was not oxidized as a substrate, but the compound worked as an inhibitor for the enzyme, as did pyrazole. The enzyme acted on n-aldehydes C(2)-C(14)) and PEG-aldehydes. Thus the enzyme was concluded to be a novel Ca(2+)-activating nicotinoprotein (NADP-containing) PEG-aldehyde dehydrogenase involved in the degradation of PEG in S. macrogoltabidus strain 103.

  19. Noncovalent adducts of poly(ethylene glycols) with proteins.

    PubMed

    Topchieva, I N; Sorokina, E M; Efremova, N V; Ksenofontov, A L; Kurganov, B I

    2000-01-01

    A new method of preparation of noncovalent complexes between poly(ethylene glycol) (PEG) and proteins (alpha-chymotrypsin (ChT), lysozyme, bovine serum albumine) under high pressure has been developed. The involvement of polymer in the complexes was proved using (3)H-labeled PEG. The composition of the complexes (the number of polymer chains per one ChT molecule) depends on the molecular mass of PEG and decreases with the increase in molecular mass from 300 to 4000, whereas the portion of the protein (wt %) in complexes does not depend on the molecular mass of incorporated PEG and corresponds to approximately 70 wt %. The kinetic constants for enzymatic hydrolysis of N-benzoyl-L-tyrosine ethyl ester and azocasein catalyzed by the PEG-ChT complexes are identical with the corresponding values for the native ChT. According to the data obtained by the method of circular dichroism, the enzyme in the complexes fully retains its secondary structure. The steric availability of PEG polymer chains in the complexes was evaluated by their complexation with alpha-cyclodextrin (CyD) or polymer derivatives of beta-CyD modified with PEG (PEG-beta-CyD). In contrast to free PEG, only part of PEG polymer chains ( approximately 10%) interact with alpha-CyD. Thus, the complexation of PEG with ChT proceeds by means of multipoint interaction with surface groups of the protein globule located far from the active site and results in the sufficient decrease in the availability of polymer chains. The complexes between PEG chains in PEG-protein adducts and PEG-beta-CyD may be considered as a novel type of dendritic structures.

  20. 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.

  1. SANS study of highly resilient poly(ethylene glycol) hydrogels.

    PubMed

    Saffer, Erika M; Lackey, Melissa A; Griffin, David M; Kishore, Suhasini; Tew, Gregory N; Bhatia, Surita R

    2014-03-28

    Polymer networks are critically important for numerous applications including soft biomaterials, adhesives, coatings, elastomers, and gel-based materials for energy storage. One long-standing challenge these materials present lies in understanding the role of network defects, such as dangling ends and loops, developed during cross-linking. These defects can negatively impact the physical, mechanical, and transport properties of the gel. Here we report chemically cross-linked poly(ethylene glycol) (PEG) gels formed through a unique cross-linking scheme designed to minimize defects in the network. The highly resilient mechanical properties of these systems (discussed in a previous publication) [J. Cui, M. A. Lackey, A. E. Madkour, E. M. Saffer, D. M. Griffin, S. R. Bhatia, A. J. Crosby and G. N. Tew, Biomacromolecules, 2012, 13, 584-588], suggests that this cross-linking technique yields more homogeneous network structures. Four series of gels were formed based on chains of 35,000 g mol(-1), (35k), 12,000 g mol(-1) (12k) g mol(-1), 8000 g mol(-1) (8k) and 4000 g mol(-1) (4k) PEG. Gels were synthesized at five initial polymer concentrations ranging from 0.077 g mL(-1) to 0.50 g mL(-1). Small-angle neutron scattering (SANS) was utilized to investigate the network structures of gels in both D2O and d-DMF. SANS results show the resulting network structure is dependent on PEG length, transitioning from a more homogeneous network structure at high molecular weight PEG to a two phase structure at the lowest molecular weight PEG. Further investigation of the transport properties inherent to these systems, such as diffusion, will aid to further confirm the network structures.

  2. Polyethylene glycol restores axonal conduction after corpus callosum transection

    PubMed Central

    Bamba, Ravinder; Riley, D. Colton; Boyer, Richard B.; Pollins, Alonda C.; Shack, R. Bruce; Thayer, Wesley P.

    2017-01-01

    Polyethylene glycol (PEG) has been shown to restore axonal continuity after peripheral nerve transection in animal models. We hypothesized that PEG can also restore axonal continuity in the central nervous system. In this current experiment, coronal sectioning of the brains of Sprague-Dawley rats was performed after animal sacrifice. 3Brain high-resolution microelectrode arrays (MEA) were used to measure mean firing rate (MFR) and peak amplitude across the corpus callosum of the ex-vivo brain slices. The corpus callosum was subsequently transected and repeated measurements were performed. The cut ends of the corpus callosum were still apposite at this time. A PEG solution was applied to the injury site and repeated measurements were performed. MEA measurements showed that PEG was capable of restoring electrophysiology signaling after transection of central nerves. Before injury, the average MFRs at the ipsilateral, midline, and contralateral corpus callosum were 0.76, 0.66, and 0.65 spikes/second, respectively, and the average peak amplitudes were 69.79, 58.68, and 49.60 μV, respectively. After injury, the average MFRs were 0.71, 0.14, and 0.25 spikes/second, respectively and peak amplitudes were 52.11, 8.98, and 16.09 μV, respectively. After application of PEG, there were spikes in MFR and peak amplitude at the injury site and contralaterally. The average MFRs were 0.75, 0.55, and 0.47 spikes/second at the ipsilateral, midline, and contralateral corpus callosum, respectively and peak amplitudes were 59.44, 45.33, 40.02 μV, respectively. There were statistically differences in the average MFRs and peak amplitudes between the midline and non-midline corpus callosum groups (P < 0.01, P < 0.05). These findings suggest that PEG restores axonal conduction between severed central nerves, potentially representing axonal fusion. PMID:28616031

  3. Polyethylene glycol restores axonal conduction after corpus callosum transection.

    PubMed

    Bamba, Ravinder; Riley, D Colton; Boyer, Richard B; Pollins, Alonda C; Shack, R Bruce; Thayer, Wesley P

    2017-05-01

    Polyethylene glycol (PEG) has been shown to restore axonal continuity after peripheral nerve transection in animal models. We hypothesized that PEG can also restore axonal continuity in the central nervous system. In this current experiment, coronal sectioning of the brains of Sprague-Dawley rats was performed after animal sacrifice. 3Brain high-resolution microelectrode arrays (MEA) were used to measure mean firing rate (MFR) and peak amplitude across the corpus callosum of the ex-vivo brain slices. The corpus callosum was subsequently transected and repeated measurements were performed. The cut ends of the corpus callosum were still apposite at this time. A PEG solution was applied to the injury site and repeated measurements were performed. MEA measurements showed that PEG was capable of restoring electrophysiology signaling after transection of central nerves. Before injury, the average MFRs at the ipsilateral, midline, and contralateral corpus callosum were 0.76, 0.66, and 0.65 spikes/second, respectively, and the average peak amplitudes were 69.79, 58.68, and 49.60 μV, respectively. After injury, the average MFRs were 0.71, 0.14, and 0.25 spikes/second, respectively and peak amplitudes were 52.11, 8.98, and 16.09 μV, respectively. After application of PEG, there were spikes in MFR and peak amplitude at the injury site and contralaterally. The average MFRs were 0.75, 0.55, and 0.47 spikes/second at the ipsilateral, midline, and contralateral corpus callosum, respectively and peak amplitudes were 59.44, 45.33, 40.02 μV, respectively. There were statistically differences in the average MFRs and peak amplitudes between the midline and non-midline corpus callosum groups (P < 0.01, P < 0.05). These findings suggest that PEG restores axonal conduction between severed central nerves, potentially representing axonal fusion.

  4. 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.

  5. Colonoscopy Preparation: Polyethylene Glycol with Gatorade is as Safe and Efficacious as 4 Liters of Polyethylene Glycol with Balanced Electrolytes

    PubMed Central

    McKenna, Thomas; Macgill, Alice; Porat, Gail; Friedenberg, Frank K.

    2013-01-01

    Background Four liters of polyethylene glycol 3350 with balanced electrolytes for colonoscopy preparation has had poor acceptance. Another approach is the use of electrolyte-free PEG combined with 1.9L of Gatorade. Despite its widespread use, there are no data on metabolic safety and minimal data on efficacy. Our aim was to assess the efficacy and electrolyte safety of these two PEG-based preparations. Methods This was a prospective, randomized, single-blind, non-inferiority trial. Patients were randomized to 238g PEG + 1.9L Gatorade or 4L of PEG-ELS containing 236g PEG. Split dosing was not performed. On procedure day blood was drawn for basic chemistries. The primary outcome was preparation quality from procedure photos using the Boston Bowel Preparation Scale. Results We randomized 136 patients (66 PEG + Gatorade, 70 PEG-ELS). There were no differences in preparation scores between the two agents in the ITT analysis (7.2 ± 1.9 for PEG-ELS and 7.0 ± 2.1 for PEG + Gatorade; p = 0.45). BBPS scores were identical for those who completed the preparation and dietary instructions as directed (7.4 ± 1.7 for PEG-ELS, and 7.4 ± 1.8 for PEG + Gatorade; p = 0.98). There were no statistical differences in serum electrolytes between the two preparations. Patients who received PEG + Gatorade gave higher overall satisfaction scores for the preparation experience (p = 0.001), and had fewer adverse effects. Conclusions Use of 238g PEG + 1.9L Gatorade appears to be safe, better tolerated, and non-inferior to 4L PEG-ELS. This preparation may be especially useful for patients who previously tolerated PEG-ELS poorly. PMID:22711499

  6. Administering Polyethylene Glycol Electrolyte Solution Via a Nasogastric Tube: Pulmonary Complications.

    PubMed

    Metheny, Norma A; Meert, Kathleen L

    2017-03-01

    Patients sometimes require insertion of a nasogastric tube for the administration of a large volume of a polyethylene glycol electrolyte solution. If the tube is malpositioned, the risk for direct instillation of the solution into the lung increases. The risk for aspiration also increases if the infusion rate exceeds gastrointestinal tolerance. To review published cases of patients' experiencing adverse pulmonary events after administration of polyethylene glycol electrolyte solution via a nasogastric tube and to offer suggestions to prevent these outcomes. A search of the literature from 1993 through 2014 was performed by using the PubMed, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, and Scopus databases. In the 12 case reports located, none of the patients had radiographs to verify tube location before infusion of polyethylene glycol electrolyte solution. After symptoms developed in 3 children (ages 8-11 years), radiographs showed their tubes incorrectly positioned in the bronchus, lung, or esophagus; ports of a fourth child's tube were in the oropharynx. The remaining 8 patients (ages 5-86 years) never had radiographs to determine tube placement. Pulmonary complications from the infusions of polyethylene glycol electrolyte solution contributed to the death of 5 of the patients. Relatively simple maneuvers to reduce the likelihood of adverse pulmonary events following the administration of large volumes of polyethylene glycol electrolyte solution via a nasogastric tube are well worth the cost and effort to protect patients from potential serious injury. ©2017 American Association of Critical-Care Nurses.

  7. Effect of poly(ethylene glycol) on phospholipid hydration and polarity of the external phase.

    PubMed

    Arnold, K; Pratsch, L; Gawrisch, K

    1983-02-09

    The hydration properties of phosphatidylcholine (PC)/water dispersions on the addition of poly(ethylene glycol) were studied by means of 2H-NMR. The quadrupole splittings and their temperature dependences correspond to measurements of PC/water dispersions at low water content. It is concluded that the bound water is partly extracted by poly(ethylene glycol) but the binding properties of the water in the inner hydration shell of about five water molecules are not changed. The ability of some phospholipid/water dispersions to undergo phase transitions to nonlamellar structures upon dehydration is discussed. Dipalmitoylphosphatidylcholine (DPPC) and egg phosphatidylcholine do not form nonlamellar structures on addition of purified poly(ethylene glycol), as was demonstrated by means of 31P-NMR. Poly(ethylene glycol) decreases the polarity of the aqueous phase and the partition of hydrophobic molecules between the membrane and the external phase is changed. This was demonstrated using the excimer fluorescence of pyrene in a ghost suspension. It is suggested that the changes in polarity and hydration on the addition of poly(ethylene glycol) can contribute to the alterations in the membrane surface observed under conditions of membrane contact and fusion.

  8. Crystallization Kinetics of Indomethacin/Polyethylene Glycol Dispersions Containing High Drug Loadings.

    PubMed

    Duong, Tu Van; Van Humbeeck, Jan; Van den Mooter, Guy

    2015-07-06

    The reproducibility and consistency of physicochemical properties and pharmaceutical performance are major concerns during preparation of solid dispersions. The crystallization kinetics of drug/polyethylene glycol solid dispersions, an important factor that is governed by the properties of both drug and polymer has not been adequately explored, especially in systems containing high drug loadings. In this paper, by using standard and modulated differential scanning calorimetry and X-ray powder diffraction, we describe the influence of drug loading on crystallization behavior of dispersions made up of indomethacin and polyethylene glycol 6000. Higher drug loading increases the amorphicity of the polymer and inhibits the crystallization of PEG. At 52% drug loading, polyethylene glycol was completely transformed to the amorphous state. To the best of our knowledge, this is the first detailed investigation of the solubilization effect of a low molecular weight drug on a semicrystalline polymer in their dispersions. In mixtures containing up to 55% indomethacin, the dispersions exhibited distinct glass transition events resulting from amorphous-amorphous phase separation which generates polymer-rich and drug-rich domains upon the solidification of supercooled polyethylene glycol, whereas samples containing at least 60% drug showed a single amorphous phase during the period in which crystallization normally occurs. The current study demonstrates a wide range in physicochemical properties of drug/polyethylene glycol solid dispersions as a result of the complex nature in crystallization of this system, which should be taken into account during preparation and storage.

  9. 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

  10. 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.

  11. Sol-gel synthesis of nanostructured hydroxyapatite powder in presence of polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Ruban Kumar, A.; Kalainathan, S.

    2010-07-01

    A study on the morphological changes of nanostructured hydroxyapatite in presence of polyethylene glycol synthesized by sol-gel technique is presented. Equimolar solutions of Ca(NO 3) 2·4H 2O and (NH 4) 2HPO 4 dissolved in ethanol were used in the synthesis at 85 °C. Polyethylene glycol is added as an organic modifier. The product was sintered at 400, 750 and 1100 °C. The XRD and FTIR results indicated the presence of amorphous hydroxyapatite in as dried gel precursor and single phase HAP was obtained after heat treatment at 1100 °C at 4 h. SEM images of the precursor appear agglomerated leaving sub micrometric pores between them and the small particles seen embedded in each agglomerated cluster with an average diameter of 50-70 nm. At high temperatures the more flexible polyethylene glycol molecules induced the orientation growth which leads to the formation of HAP platelets.

  12. FTIR studies on the effect of concentration of polyethylene glycol on polimerization of Shellac

    NASA Astrophysics Data System (ADS)

    Khairuddin; Pramono, E.; Utomo, S. B.; Wulandari, V.; Zahrotul W, A.; Clegg, F.

    2016-11-01

    In the present paper, it was reported the FTIR studies on the efect of polyethylene glycol on polimerization of shellac. The shellac was shellac waxfree, and the solvent was ethanol 96%. The shellac films were were prepared by solvent- evaporation method. The concentrations of polyethylene glycol having molecular weight of 400 were 10, 30, 60, and 90 w/w %. Three peak intensity bands of C= O stretching of ester at 1709 cm-1, O-H stretching of hydroxyl group at 3400 cm-1, and C-H stretching vibration at 2942 cm-1 were observed and related to polimerization of shellac. It was found that polymerization of shellac was slowed down by polyethyelene glycol, and the degree of polymerization of shellac decreased with increasing the concentration of polyethyelene glycol.

  13. 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.

  14. 40 CFR 721.10472 - 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1,3-Benzenedimethanamine, polymers...-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products. (a) Chemical substance and..., polymers with epichlorohydrin-polyethylene glycol reaction products (PMN P-03-645; CAS No. 652968-34-8) is...

  15. 40 CFR 721.10472 - 1,3-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1,3-Benzenedimethanamine, polymers...-Benzenedimethanamine, polymers with epichlorohydrin-polyethylene glycol reaction products. (a) Chemical substance and..., polymers with epichlorohydrin-polyethylene glycol reaction products (PMN P-03-645; CAS No. 652968-34-8) is...

  16. 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. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Multidimensional chromatographic techniques for hydrophilic copolymers II. Analysis of poly(ethylene glycol)-poly(vinyl acetate) graft copolymers.

    PubMed

    Knecht, Daniela; Rittig, Frank; Lange, Ronald F M; Pasch, Harald

    2006-10-13

    A large variety of hydrophilic copolymers is applied in different fields of chemical industry including bio, pharma and pharmaceutical applications. For example, poly(ethylene glycol)-poly(vinyl alcohol) graft copolymers that are used as tablet coatings are responsible for the controlled release of the active compounds. These copolymers are produced by grafting of vinyl acetate onto polyethylene glycol (PEG) and subsequent hydrolysis of the poly(ethylene glycol)-poly(vinyl acetate) graft copolymers. The poly(ethylene glycol)-poly(vinyl acetate) copolymers are distributed with regard to molar mass and chemical composition. In addition, they frequently contain the homopolymers polyethylene glycol and polyvinyl acetate. The comprehensive analysis of such complex systems requires hyphenated analytical techniques, including two-dimensional liquid chromatography and combined LC and nuclear magnetic resonance spectroscopy. The development and application of these techniques are discussed in the present paper.

  18. Polyethylene glycol-induced fusion of two-cell mouse embryo blastomeres

    SciTech Connect

    Spindle, A.

    1981-01-01

    Polyethylene glycol (PEG) was found to be an effective fusion-inducing agent for early mouse embryo blastomeres. A brief exposure of zona-intact 2-cell embryos to 40% PEG induced fusion of blastomeres in > 80% of embryos, and the treatment did not interfere with subsequent development of embryos to the blastocyst stage.

  19. 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...

  20. 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,…

  1. 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...

  2. 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 200-9,500). 178.3750 Section 178.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS Certain...

  3. 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,…

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

    USDA-ARS?s Scientific Manuscript database

    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...

  5. Tailoring Membrane Surface Properties and Ultrafiltration Performances via the Self-Assembly of Polyethylene Glycol-block-Polysulfone-block-Polyethylene Glycol Block Copolymer upon Thermal and Solvent Annealing.

    PubMed

    Wang, Ning; Wang, Tao; Hu, Yunxia

    2017-09-13

    Recently, ultrafiltration (UF) membranes have faced great challenges including the fine control of membrane surfaces for high filtration performances and antifouling properties in treating complex solution systems. Here, a particular type of amphiphilic block copolymer polyethylene glycol-block-polysulfone-block-polyethylene glycol (PEG-b-PSf-b-PEG) was synthesized through one-pot step-growth polymerization with mPEG [monomethylpoly(ethylene glycol)] as two ends to achieve the mobility of hydrophilic polymer chains. Without any other polymers or additives involved, the PEG-b-PSf-b-PEG triblock copolymer UF membrane was fabricated through the non-solvent-induced phase separation (NIPS) method. The surface properties and filtration performances of UF membranes were tailored through the self-assembly of PEG-b-PSf-b-PEG triblock copolymers combining the thermal and solvent annealing treatments in water at 90 °C for 16 h. The annealed PEG-b-PSf-b-PEG triblock copolymer membrane significantly enhanced its water flux resulting from the increased mean pore size with the improved porosity, as well as the decreased skin layer thickness, upon annealing. More importantly, the PEG-b-PSf-b-PEG triblock copolymer membrane surface turned from hydrophobic to hydrophilic upon annealing with the PEG enrichment on the surface, and exhibited improved protein antifouling performances. Our research opens a new avenue to tailor the membrane structure and surface properties by self-assembly of amphiphilic block copolymers upon thermal and solvent annealing treatments.

  6. Purification of papain by metal affinity partitioning in aqueous two-phase polyethylene glycol/sodium sulfate systems.

    PubMed

    Jiang, Zhi-Guo; Zhang, Hai-De; Wang, Wei-Tao

    2015-05-01

    A simple and inexpensive aqueous two-phase affinity partitioning system using metal ligands was introduced to improve the selectivity of commercial papain extraction. Polyethylene glycol 4000 was first activated using epichlorohydrin, then it was covalently linked to iminodiacetic acid. Finally, the specific metal ligand Cu(2+) was attached to the polyethylene glycol-iminodiacetic acid. The chelated Cu(2+) content was measured by atomic absorption spectrometry as 0.88 mol/mol (polyethylene glycol). The effects on the purification at different conditions, including polyethylene glycol molecular weight (2000, 4000, and 6000), concentration of phase-forming components (polyethylene glycol 12-20% w/w and sodium sulfate 12-20%, w/w), metal ligand type, and concentration, system pH and the commercial papain loading on papain extraction, were systematically studied. Under optimum conditions of the system, i.e. 18% w/w sodium sulfate, 18% w/w polyethylene glycol 4000, 1% w/w polyethylene glycol-iminodiacetic acid-Cu(2+) and pH 7, a maximum yield of 90.3% and a degree of purification of 3.6-fold were obtained. Compared to aqueous two phase extraction without ligands, affinity partitioning was found to be an effective technique for the purification of commercial papain with higher extraction efficiency and degree of purification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mixed Micelles made of Poly(ethylene glycol)-Phosphatidylethanolamine Conjugate and D-α-tocopheryl Polyethylene Glycol 1000 Succinate as Pharmaceutical Nanocarriers for Camptothecin

    PubMed Central

    Mu, L.; Elbayoumi, T.A.; Torchilin, V.P.

    2006-01-01

    Micelles from the mixture of poly(ethylene glycol)-phosphatidyl ethanolamine conjugate (PEG-PE) and D-α-tocopheryl polyetheyene glycol 1000 succinate (TPGS) were prepared loaded with the poorly soluble anticancer drug camptothecin (CPT). The solubilization of CPT by the mixed micelles was more efficient than with earlier described micelles made of PEG-PE alone. CPT-loaded mixed micelles were stable upon storage and dilution and firmly retained the incorporated drug. The cytotoxicity of the CPT-loaded mixed micelles against various cancer cells in vitro was remarkably higher than that of the free drug. PEG-PE/TPGS mixed micelles may serve as pharmaceutical nanocarriers with improved solubilization capacity for poorly soluble drugs. PMID:16242875

  8. 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. Copyright © 2015. Published by Elsevier B.V.

  9. 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.

  10. Highly efficient synthesis of monodisperse poly(ethylene glycols) and derivatives through macrocyclization of oligo(ethylene glycols).

    PubMed

    Zhang, Hua; Li, Xuefei; Shi, Qiuyan; Li, Yu; Xia, Guiquan; Chen, Long; Yang, Zhigang; Jiang, Zhong-Xing

    2015-03-16

    A macrocyclic sulfate (MCS)-based approach to monodisperse poly(ethylene glycols) (M-PEGs) and their monofunctionalized derivatives has been developed. Macrocyclization of oligo(ethylene glycols) (OEGs) provides MCS (up to a 62-membered macrocycle) as versatile precursors for a range of monofunctionalized M-PEGs. Through iterative nucleophilic ring-opening reactions of MCS without performing group protection and activation, a series of M-PEGs, including the unprecedented 64-mer (2850 Da), can be readily prepared. Synthetic simplicity coupled with versatility of this new strategy may pave the way for broader applications of M-PEGs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 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.

  12. Solubility of pioglitazone hydrochloride in binary mixtures of polyethylene glycol 400 with ethanol, propylene glycol, N-methyl-2-pyrrolidone, and water at 25 degrees C.

    PubMed

    Jouyban, Abolghasem; Soltanpour, Shahla

    2010-09-01

    The solubility of pioglitazone hydrochloride in binary mixtures of polyethylene glycol 400 with ethanol, N-methyl-2-pyrrolidone, propylene glycol, and water at 25 degrees C are reported. The generated data are fitted to the Jouyban-Acree model and the mean relative deviations are 2.6%, 1.5%, 5.8%, and 7.4%, respectively for ethanol, N-methyl-2-pyrrolidone, propylene glycol, and water.

  13. 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.

  14. 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.

  15. Additional of polyethylene glycol on the preparation of LaPO4:Eu3+ phosphor

    NASA Astrophysics Data System (ADS)

    Panatarani, Camellia; Joni, I. Made

    2013-09-01

    Solution phase method was used to synthesis nanocrystal LaPO4:Eu3+. Polyethylene glycol with vary molecular weight (MW) was added to allow an exothermic reaction to get a high crystalinity of LaPO4:Eu3+. The x-ray pattern of as prepared LaPO4 was obtained by using an X'pert PANalytical diffractometer with CuKα radiation (λ = 1.5406 Å) and the photoluminescent measurement spectra is obtained by using Fluorescence Spectrometer LS55, Perkin Elmer. The additional of various MW of polyethylene glycol into the precursor solution of LaPO4:Eu3+ affected the crystal structure and luminescent properties. Higher MW of PEG depressing the luminescent spectra. The emission origin from 5D0-7F4 transition vanished by additional 500,000 and 2,000,000 MW of PEG.

  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. 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.

  18. The Subchronic Inhalation Toxicity of Polyethylene Glycol 200 in the Rat and Mouse.

    DTIC Science & Technology

    1981-12-01

    glycol formula weights range from 200 to 10,000. The physical state ranges from water-white liquids (PEG 200) to waxy solids (CarbowaxR). Polyethylene...peroxides, and in suppositories, where they serve as the base and the carrier. In cosmetics , they are used in skin conditioning creams, aqueous hair dressing...cells, differential white count, hemoglobin and hematocrit. The following blood chemistry parameters were evaluated: glucose, urea nitrogen, creatinine

  19. Synthesis of Cu{sub 2}ZnSnS{sub 4} nanoparticles and controlling the morphology with polyethylene glycol

    SciTech Connect

    Rawat, Kusum; Kim, Hee-Joon; Shishodia, P.K.

    2016-05-15

    Highlights: • Cu{sub 2}ZnSnS{sub 4} nanoparticles were synthesized by wet chemical technique. • First report on the effect of using polyethylene glycol as a structure directing agent on Cu{sub 2}ZnSnS{sub 4} nanoparticles. • The morphology of Cu{sub 2}ZnSnS{sub 4} nanoparticles changes into nanoflakes and nanorods structures with polyethylene glycol concentration. • Polyethylene glycol assisted Cu{sub 2}ZnSnS{sub 4} nanoparticle film exhibits optical bandgap of 1.5 eV which is suitable for the application in solar cells. - Abstract: Cu{sub 2}ZnSnS{sub 4} nanoparticles were synthesized by wet chemical technique using metal thiourea precursor at 250 °C. The structural and morphological properties of as grown nanoparticles have been characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The influence of different concentration of polyethylene glycol as structure directing agent on the morphologies of Cu{sub 2}ZnSnS{sub 4} nanoparticles are investigated on thin films deposited by spin coating technique. The mean crystallite size of the Cu{sub 2}ZnSnS{sub 4} nanoparticles was found to improve with polyethylene glycol concentration. Scanning electron microscopy images of Cu{sub 2}ZnSnS{sub 4} revealed aggregated spherical shaped nanoparticles whereas the polyethylene glycol assisted Cu{sub 2}ZnSnS{sub 4} nanoparticle films show nanoflakes and nanorods structures with increasing concentration of polyethylene glycol. Transmission electron microscopy analysis has also been performed to determine the size and structure of nanorods. UV–vis absorption spectroscopy shows the broad band absorption with optical bandgap of 1.50 eV for polyethylene glycol assisted Cu{sub 2}ZnSnS{sub 4} films.

  20. A Comparison of Sodium Phosphosoda Purgative to Polyethylene Glycol Bowel Preparations Prior to Colonoscopy

    PubMed Central

    Brunelli, Steven M.; Feldman, Harold I.; Latif, Sherif M.; Gupta, Meera; Weiner, Mark G.; Lewis, James D.

    2010-01-01

    Background and Objectives Successful colonoscopy is contingent upon adequate bowel preparation, which is often achieved using either an oral sodium phosphate preparation or a polyethylene glycol-based preparation. Comparison of the relative performance of these two classes of agents has been assessed only in the context of clinical trials (and with mixed findings). However, efficacy measured in clinical trials often is not reflective of effectiveness in clinical practice. We undertook this analysis to determine the relative clinical effectiveness of oral sodium phosphosoda versus polyethylene glycol in clinical practice. Methods Subjects (n=343) were selected from among patients receiving outpatient colonoscopy at our institution between January 2004 and February 2006. Demographic, biochemical, and comorbid disease data were abstracted from the electronic medical record. Colonoscopy preparation, indication, and preparation quality were abstracted from colonoscopy reports. Results As compared to subjects receiving polyethylene glycol, those receiving oral sodium phosphosoda had an adjusted odds ratio (OR) (95% confidence intervals [CIs]) for adequate/good/excellent bowel preparation quality of 2.23 (1.18–4.22) and an adjusted OR (95% CIs) for good/excellent bowel preparation of 2.24 (1.26–3.97). There was no interaction on the basis of colonoscopy indication. Conclusions Oral sodium phosphate-based purgatives were associated with significantly better bowel preparation quality among outpatients at our center. PMID:19132571

  1. The excluded volume effect induced by poly(ethylene glycol) modulates the motility of actin filaments interacting with myosin.

    PubMed

    Munakata, Shinsuke; Hatori, Kuniyuki

    2013-11-01

    To examine the motility of actomyosin complexes in the presence of high concentrations of polymers, we investigated the effect of poly(ethylene glycol) on the sliding velocities of actin filaments and regulated thin filaments on myosin molecules in the presence of ATP. Increased concentrations and relative molecular masses of poly(ethylene glycol) decreased the sliding velocities of actin and regulated thin filaments. The decreased ratio of velocity in regulated thin filaments at - log[Ca(2+) ] of 4 was higher than that of actin filaments. Furthermore, in the absence of Ca(2+) , regulated thin filaments were moderately motile in the presence of poly(ethylene glycol). The excluded volume change (∆V), defined as the change in water volume surrounding actomyosin during the interactions, was estimated by determining the relationship between osmotic pressure exerted by poly(ethylene glycol) and the decreased ratio of the velocities in the presence and absence of poly(ethylene glycol). The ∆V increased up to 3.7 × 10(5) Å(3) as the Mr range of poly(ethylene glycol) was increased up to 20,000. Moreover, the ∆V for regulated thin filaments was approximately two-fold higher than that of actin filaments. This finding suggests that differences in the conformation of filaments according to whether troponin-tropomyosin complexes lie on actin filaments alter the ∆V during interactions of actomyosin complexes and influence motility. © 2013 FEBS.

  2. The Effect of Molecular Size, Concentration in Nutrient Solution, and Exposure Time on the Amount and Distribution of Polyethylene Glycol in Pepper Plants 12

    PubMed Central

    Janes, Byron E.

    1974-01-01

    Pepper plants Capsicum annuum L. var. California Wonder were grown in nutrient solutions of either −3.0 or −5.0 bars osmotic potential, using polyethylene glycol with molecular weights of 400, 600, 1000, 1540, or 4000 as osmotica. Polyethylene glycol with molecular weights of 1000 or 1540 proved most satisfactory as osmotica to decrease the water potential of nutrient solutions. There was no relationship between the small amount of polyethylene glycol accumulated in the plants and the amount of water transpired. The concentration of polyethylene glycol in the expressed sap of the leaves and the total accumulated was inversely related to molecular weight of polyethylene glycol, was greater at lower osmotic potential of nutrient solution, and increased with time in solution. Except for plants grown in polyethylene glycol 4000, there was more polyethylene glycol in leaves than roots. The indications were that, when the concentration of polyethylene glycol reached a value of 1 to 2 mg per ml, any additional quantity absorbed was transferred to the leaves. The major proportion of polyethylene glycol 4000 absorbed was retained in the roots. The results of Sephadex gel chromatographs showed that the passage of polyethylene glycol through the plants did not alter the average molecular weight. This indicated that there was no selective absorption of small molecules that might be present as contaminates in the commercial product. PMID:16658865

  3. Poly(ethylene glycol) analogs grafted with low molecular weight poly(ethylene imine) as non-viral gene vectors.

    PubMed

    Zhang, Zhenfang; Yang, Cuihong; Duan, Yajun; Wang, Yanming; Liu, Jianfeng; Wang, Lianyong; Kong, Deling

    2010-07-01

    A novel class of non-viral gene vectors consisting of low molecular weight poly(ethylene imine) (PEI) (molecular weight 800 Da) grafted onto degradable linear poly(ethylene glycol) (PEG) analogs was synthesized. First, a Michael addition reaction between poly(ethylene glycol) diacrylates (PEGDA) (molecular weight 258 Da) and d,l-dithiothreitol (DTT) was carried out to generate a linear polymer (PEG-DTT) having a terminal thiol, methacrylate and pendant hydroxyl functional groups. Five PEG-DTT analogs were synthesized by varying the molar ratio of diacrylates to thiols from 1.2:1 to 1:1.2. Then PEI (800 Da) was grafted onto the main chain of the PEG-DTTs using 1,1'-carbonyldiimidazole as the linker. The above reaction gave rise to a new class of non-viral gene vectors, (PEG-DTT)-g-PEI copolymers, which can effectively complex DNA to form nanoparticles. The molecular weights and structures of the copolymers were characterized by gel permeation chromatography, (1)H nuclear magnetic resonance and Fourier transform infrared spectroscopy. The size of the nanoparticles was<200 nm and the surface charge of the nanoparticles, expressed as the zeta potential, was between+20 and+40 mV. Cytotoxicity assays showed that the copolymers exhibited much lower cytotoxicities than high molecular weight PEI (25 kDa). Transfection was performed in cultured HeLa, HepG2, MCF-7 and COS-7 cells. The copolymers showed higher transfection efficiencies than PEI (25 kDa) tested in four cell lines. The presence of serum (up to 30%) had no inhibitory effect on the transfection efficiency. These results indicate that this new class of non-viral gene vectors may be a promising gene carrier that is worth further investigation.

  4. 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)...

  5. 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)...

  6. 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)...

  7. 40 CFR 721.4040 - Glycols, polyethylene-, 3-sulfo-2-hydroxypropyl-p-(1,1,3,3-tetra-methylbutyl)phenyl ether, sodium...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 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)...

  8. 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.

  9. 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

  10. 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.

  11. 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. © 2013.

  12. Plasma proteins adsorption mechanism on polyethylene-grafted poly(ethylene glycol) surface by quartz crystal microbalance with dissipation.

    PubMed

    Jin, Jing; Jiang, Wei; Yin, Jinghua; Ji, Xiangling; Stagnaro, Paola

    2013-06-04

    Protein adsorption has a vital role in biomaterial surface science because it is directly related to the hemocompatibility of blood-contacting materials. In this study, monomethoxy poly(ethylene glycol) (mPEG) with two different molecular weights was grafted on polyethylene as a model to elucidate the adsorption mechanisms of plasma protein through quartz crystal microbalance with dissipation (QCM-D). Combined with data from platelet adhesion, whole blood clotting time, and hemolysis rate, the blood compatibility of PE-g-mPEG film was found to have significantly improved. Two adsorption schemes were developed for real-time monitoring of protein adsorption. Results showed that the preadsorbed bovine serum albumin (BSA) on the surfaces of PE-g-mPEG films could effectively inhibit subsequent adsorption of fibrinogen (Fib). Nonspecific protein adsorption of BSA was determined by surface coverage, not by the chain length of PEG. Dense PEG brush could release more trapped water molecules to resist BSA adsorption. Moreover, the preadsorbed Fib could be gradually displaced by high-concentration BSA. However, the adsorption and displacement of Fib was determined by surface hydrophilicity.

  13. Characterization, molecular dynamics, and encapsulation ability of β-cyclodextrin polymers crosslinked by polyethylene glycol.

    PubMed

    Kono, Hiroyuki; Nakamura, Taichi; Hashimoto, Hisaho; Shimizu, Yuuichi

    2015-09-05

    A series of water-insoluble cyclodextrin polymers (CDP) was prepared by crosslinking β-cyclodextrin (CD) with polyethylene glycol diglycidyl ether (PEGDE). Similarly, a reference CDP was prepared using ethylene glycol diglycidyl ether (EGDE). Increasing the feed ratio of PEGDE to CD in the reaction mixture led to high degrees of crosslinking. Relaxation measurements revealed structural homogeneity among the CDPs, which exhibited mobilities that strongly depended on the chain lengths of the crosslinking agents. In addition, all the CDPs displayed high encapsulation abilities toward bisphenol A (BPA) in aqueous media. In particular, the CDP sample with a low degree of crosslinking by PEGDE showed the highest encapsulation ability toward BPA. In contrast, the CDP crosslinked by EGDE exhibited low encapsulation ability because its highly dense structure, which results from the short chain lengths of the crosslinking agents, hinders the penetration of BPA molecules.

  14. 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.

  15. Plasma-modified and polyethylene glycol-grafted polymers for potential tissue engineering applications.

    PubMed

    Svorcík, V; Makajová, Z; Kasálková-Slepicková, N; Kolská, Z; Bacáková, L

    2012-08-01

    Modified and grafted polymers may serve as building blocks for creating artificial bioinspired nanostructured surfaces for tissue engineering. Polyethylene (PE) and polystyrene (PS) were modified by Ar plasma and the surface of the plasma activated polymers was grafted with polyethylene glycol (PEG). The changes in the surface wettability (contact angle) of the modified polymers were examined by goniometry. Atomic Force Microscopy (AFM) was used to determine the surface roughness and morphology and electrokinetical analysis (Zeta potential) characterized surface chemistry of the modified polymers. Plasma treatment and subsequent PEG grafting lead to dramatic changes in the polymer surface morphology, roughness and wettability. The plasma treated and PEG grafted polymers were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Biological tests, performed in vitro, show increased adhesion and proliferation of cells on modified polymers. Grafting with PEG increases cell proliferation, especially on PS. The cell proliferation was shown to be an increasing function of PEG molecular weight.

  16. Poly(ethylene) glycol-capped silver and magnetic nanoparticles: synthesis, characterization, and comparison of bactericidal and cytotoxic effects.

    PubMed

    Mandal, A; Sekar, S; Chandrasekaran, N; Mukherjee, A; Sastry, T P

    2013-11-01

    Silver and magnetic (Fe3O4) nanoparticles have attracted wide attention as novel antimicrobial agents due to their unique chemical and physical properties. In order to study the comparative effects on antibacterial and animal cytotoxicity, Staphylococcus aureus and NIH 3T3 fibroblasts were used, respectively. Both nanoparticles were synthesized via a novel matrix-mediated method using poly(ethylene) glycol. Formation of silver nanoparticles was confirmed by fluorescence and ultraviolet-visible spectroscopic techniques. The poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles were characterized by scanning electron microscope, transmission electron microscope, zeta potential, particle size analysis, Fourier-transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. The antimicrobial results indicate that both poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles inhibited S. aureus growth at the concentrations of 5 and 10 µg/mL at all time points without showing any significant cytotoxicity on NIH 3T3 fibroblasts. The particle size of both the poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles dominated in the range 10-15 nm, obtained by particle size analyzer. The poly(ethylene) glycol coating on the particles showed less aggregation of nanoparticles, as observed by scanning electron microscope and transmission electron microscope. The overall obtained results indicated that these two nanoparticles were stable and could be used to develop a magnetized antimicrobial scaffolds for biomedical applications.

  17. Functional polyethylene glycol derivatives nanostructured thin films synthesized by matrix-assisted pulsed laser evaporation

    NASA Astrophysics Data System (ADS)

    Cristescu, R.; Popescu, C.; Popescu, A.; Grigorescu, S.; Mihailescu, I. N.; Mihaiescu, D.; Gittard, S. D.; Narayan, R. J.; Buruiana, T.; Stamatin, I.; Chrisey, D. B.

    2009-09-01

    We report the thin film deposition by matrix-assisted pulsed laser evaporation (MAPLE) of a polymer conjugate with an hydrophilic sequence between metronidazole molecules that was covalently attached to both oligomer ends of carboxylate poly(ethylene glycol) (PEG 1.5-metronidazole). A pulsed KrF* excimer laser was used to deposit the drug-polymer composite films. Fourier transform infrared spectroscopy was used to demonstrate that MAPLE-transferred materials exhibited chemical properties similar to the starting materials. The dependence of the surface morphology on incident laser fluence is given.

  18. 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.

  19. 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.

  20. Preparation of polyion complex micelles from poly(ethylene glycol)-block-polyions.

    PubMed

    Bayó-Puxan, Núria; Dufresne, Marie-Hélène; Felber, Arnaud E; Castagner, Bastien; Leroux, Jean-Christophe

    2011-12-10

    Polyion complex micelles (PICMs) arise from the spontaneous self-assembly of ionic polymers of opposite charges to form a condensate that is dispersed in aqueous media by a hydrophilic segment, usually poly(ethylene glycol) (PEG), present on at least one of the two ionic polymers. PICMs are used for many applications, especially drug delivery. This protocol paper describes the preparation by atom transfer radical polymerization (ATRP) of diblock copolymers of PEG bearing either positive or negative charges, both of which have been shown to form PICMs. Furthermore, methods of preparation and characterization of PICMs loaded with nucleic acid drugs are presented.

  1. Biofunctionalization of polyelectrolyte microcapsules with biotinylated polyethylene glycol-grafted liposomes.

    PubMed

    Gao, Jie; Reibetanz, Uta; Venkatraman, Subbu; Neu, Björn

    2011-08-11

    Hollow polyelectrolyte microcapsules (PEMC) are prepared using layer-by-layer self-assembly of polyelectrolytes on melamine formaldehyde templates, followed by template dissolution, and subsequent coating with biotinylated polyethylene glycol-grafted liposomes. These potential site-specific carrier systems show a high specificity for NeutrAvidin binding and a strong resistance against unspecific protein binding. It is concluded that this design with NeutrAvidin as the outermost layer of such capsules provides an ideal platform for the biofunctionalization of PEMC as drug delivery systems or as artificial cell-like structures for biomimetic studies.

  2. Complete Genome Sequence of Sphingopyxis macrogoltabida Strain 203N (NBRC 111659), 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

    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

  3. A fully biocompatible poly(ethylene glycol)-gold plasmonic crystal for optical sensing

    NASA Astrophysics Data System (ADS)

    Kwon, Hyunsoo; Ryu, Shinyoung; Lee, Soonil; Kim, Sunghwan

    2015-09-01

    A significant challenge in nano and biophotonics is to demonstrate fully biocompatible nano-optics devices that can perform biofunctions in vivo. Here we present a scalable, cost-effective, and large-area nanofabrication method for creating a quasi-3D plasmonic crystal using poly(ethylene glycol) (PEG) and gold (Au), both biocompatible materials. The plasmonic crystal was prepared by depositing an Au layer on the upper hemisphere of the replicated PEG nanospheres array. Additionally we demonstrated that the fabricated plasmonic crystal can behave as a label-free glucose sensor with sensitivity and figure-of-merit values comparable to other plasmonic crystal based sensors.

  4. Patterning protein molecules on poly(ethylene glycol) coated Si(111).

    PubMed

    Jun, Yongseok; Cha, Taewoon; Guo, Athena; Zhu, X-Y

    2004-08-01

    We demonstrate spatially localized immobilization of protein molecules on high-density poly(ethylene glycol) (PEG) coated Si(111). Patterns of HO- and CH3O-terminated PEG regions are formed on silicon surfaces based on soft lithography techniques and an efficient reaction between alcohol functional groups and chlorine-terminated silicon. Activation of the HO-terminated PEG brush is achieved via either partial oxidation to form aldehyde groups or via attachment of efficient leaving groups. Protein molecules are covalently immobilized to these activated regions on the PEG/Si surface.

  5. Polyethylene glycol submucosal irrigation: a novel approach to improve visibility during endoscopic submucosal dissection

    PubMed Central

    Arantes, Vitor; Toyonaga, Takashi; Piñeros, Elias Alfonso Forero

    2014-01-01

    In order to expand the availability of endoscopic submucosal dissection (ESD), measures to facilitate the procedure are necessary. When bleeding occurs, the examiner’s field of vision is critically impaired, and ESD becomes less efficient and more hazardous because of the presence of submucosal hematoma and covered blood clot. We propose the use of polyethylene glycol (PEG) irrigation as a simple and effective measure to improve visibility during submucosal dissection, particularly when bleeding occurs. PEG irrigation facilitates further dissection by allowing a better recognition of the submucosal fibers and muscularis propria layer. PMID:26134968

  6. Polyethylene glycol submucosal irrigation: a novel approach to improve visibility during endoscopic submucosal dissection.

    PubMed

    Arantes, Vitor; Toyonaga, Takashi; Piñeros, Elias Alfonso Forero

    2014-09-01

    In order to expand the availability of endoscopic submucosal dissection (ESD), measures to facilitate the procedure are necessary. When bleeding occurs, the examiner's field of vision is critically impaired, and ESD becomes less efficient and more hazardous because of the presence of submucosal hematoma and covered blood clot. We propose the use of polyethylene glycol (PEG) irrigation as a simple and effective measure to improve visibility during submucosal dissection, particularly when bleeding occurs. PEG irrigation facilitates further dissection by allowing a better recognition of the submucosal fibers and muscularis propria layer.

  7. Thermo-reversible gelation of atactic poly(methyl methacrylate) in poly(ethylene glycol) oligomers.

    PubMed

    Gao, Yun; Yu, Chunhong; Chen, Minzhi; Wang, Xiaoliang; Zhou, Dongshan; Xue, Gi

    2013-04-01

    The temperature-concentration behavior of physical gel by atactic poly(methyl methacrylate) (aPMMA) in poly(ethylene glycol) oligomer (PEG400) was investigated. A liquid-liquid demixing interferes with a glass transition during cooling. The combination of demixing and T g leads to the formation of amorphous gels at low temperature. We suggest that the gelation of aPMMA/PEG400 is a glassy gel, in which short-range attractive depletion interaction in the polymer/oligomer system was the driving force at molecular level.

  8. 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

  9. Metabolism of polyethylene glycol by two anaerobic bacteria, Desulfovibrio desulfuricans and a Bacteroides sp

    SciTech Connect

    Dwyer, D.F.; Tiedje, J.M.

    1986-10-01

    Two anaerobic bacteria were isolated from polyethylene glycol (PEG)-degrading, methanogenic, enrichment cultures obtained from a municipal sludge digester. One isolate, identified as Desulfovibrio desulfuricans (strain DG2), metabolized oligomers ranging from ethylene glycol (EG) to tetraethylene glycol. The other isolate, identified as a Bacteroides sp. (strain PG1), metabolized diethylene glycol and polymers of PEG up to an average molecular mass of 20,000 g/mol (PEG 20000; HO-(CH/sub 2/-CH/sub 2/-O-)/sub n/H). Both strains produced acetaldehyde as an intermediate, with acetate, ethanol, and hydrogen as end products. In coculture with a Methanobacterium sp., the end products were acetate and methane. Polypropylene glycol (HO-(CH/sub 2/-CH/sub 2/-CH/sub 2/-O-)/sub n/H) was not metabolized by either bacterium, and methanogenic enrichments could not be obtained on this substrate. Cell extracts of both bacteria dehydrogenated EG, PEGs up to PEG 400 in size, acetaldehyde, and other mono- and dihydroxylated compounds. Extracts of Bacteroides strain PGI could not dehydrogenate long polymers of PEG (less than or equal to1000 g/mol), but the bacterium grew with PEG 1000 or PEG 20000 as a substrate and therefore possesses a mechanism for PEG depolymerization not present in cell extracts. In contrast, extracts of D. desulfuricans DG2 dehydrogenated long polymers of PEG, but whole cells did not grow with these polymerase substrates. This indicated that the bacterium could not convert PEG to a product suitable for uptake.

  10. Engineering of poly(ethylene glycol) chain-tethered surfaces to obtain high-performance bionanoparticles

    PubMed Central

    Nagasaki, Yukio

    2010-01-01

    A poly(ethylene glycol)-b-poly[2-(N,N-dimethylamino)ethyl methacrylate] block copolymer possessing a reactive acetal group at the end of the poly(ethylene glycol) (PEG) chain, that is, acetal-PEG-b-PAMA, was synthesized by a proprietary polymerization technique. Gold nanoparticles (GNPs) were prepared using the thus-synthesized acetal-PEG-b-PAMA block copolymer. The PEG-b-PAMA not only acted as a reducing agent of aurate ions but also attached to the nanoparticle surface. The GNPs obtained had controlled sizes and narrow size distributions. They also showed high dispersion stability owing to the presence of PEG tethering chains on the surface. The same strategy should also be applicable to the fabrication of semiconductor quantum dots and inorganic porous nanoparticles. The preparation of nanoparticles in situ, i.e. in the presence of acetal-PEG-b-PAMA, gave the most densely packed polymer layer on the nanoparticle surface; this was not observed when coating preformed nanoparticles. PEG/polyamine block copolymer was more functional on the metal surface than PEG/polyamine graft copolymer, as confirmed by angle-dependent x-ray photoelectron spectroscopy. We successfully solubilized the C60 fullerene into aqueous media using acetal-PEG-b-PAMA. A C60/acetal-PEG-b-PAMA complex with a size below 5 nm was obtained by dialysis. The preparation and characterization of these materials are described in this review. PMID:27877362

  11. 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.

  12. Preparation of Humidity-Sensitive Poly(Ethylene Glycol) Inverse Opal Micropatterns Using Colloidal Lithography.

    PubMed

    Yu, Bing; Cong, Hailin; Yang, Zhen; Yang, Shujing; Wang, Yuezhong; Zhai, Feng; Wang, Yifan

    2017-09-05

    Humidity-sensitive poly(ethylene glycol) (PEG) inverse opals with micropatterns of 2 μm wide anti-swell-broken grooves were prepared using polystyrene (PS) colloidal crystals as templates and colloidal lithography. Monodisperse PS colloids were deposited in an ordered manner onto glass slides using a double-substrate vertical deposition method to form colloidal crystal templates. Poly(ethylene glycol) diacrylate (PEGDA) with photoinitiator was infiltrated into the interspaces of the colloidal crystals and photo-crosslinked by UV irradiation through a photomask. After removal the PS templates and unexposed PEGDA by tetrahydrofuran (THF), PEG hydrogel micropatterns with three-dimensional ordered porous structures were obtained. The band gaps of the PS colloidal crystals and corresponding PEG hydrogel inverse opals were measured by UV-VIS reflection spectrometer, calculated by Bragg law and simulated by Band SOLVE. The obtained PEG hydrogel inverse opal micropatterns can be used as sensors for humidity sensing due to absorption and desorption of moisture in the band gap structures. The sensor had a very reliable performance after repeated humidity sensing, and could be mass produced facilely with very low cost. The photopatterned anti-swell-broken grooves play an important role in the reliability of the sensors.

  13. Cross-linked polystyrene sulfonic acid and polyethylene glycol as a low-fouling material.

    PubMed

    Alghunaim, Abdullah; Zhang Newby, Bi-min

    2016-04-01

    A negatively charged hydrophilic low fouling film was prepared by thermally cross-linking a blend consisting of polystyrene sulfonic acid (PSS) and polyethylene glycol (PEG). The film was found to be stable by dip-washing. The fouling resistance of this material toward bacterial (Escherichia coli) and colloidal (polystyrene particles) attachment, non-specific protein (fibronectin) adsorption and cell (3T3 NIH) adhesion was evaluated and was compared with glass slides modified with polyethylene glycol (PEG) brushes, oxidized 3-mercaptopropyltrimethoxysilane (sulfonic acid, SA), and n-octadecyltrichlorosilane (OTS). The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and thermodynamic models based on surface energy were used to explain the interaction behaviors of E. coli/polystyrene particles-substrate and protein-substrate interactions, respectively. The cross-linked PSS-PEG film was found to be slightly better than SA and PEG toward resisting non-specific protein adsorption, and showed comparable low attachment results as those of PEG toward particle, bacterial and NIH-3T3 cells adhesion. The low-fouling performance of PSS-PEG, a cross-linked film by a simple thermal curing process, could allow this material to be used for applications in aqueous environments, where most low fouling hydrophilic polymers, such as PSS or PEG, could not be easily retained.

  14. Modification of polysulfone membranes with polyethylene glycol and lignosulfate: electrical characterization by impedance spectroscopy measurements.

    PubMed

    Benavente, J; Zhang, X; Garcia Valls, R

    2005-05-01

    Two sets of composite membranes having an asymmetric sulfonated polysulfone membrane as support layer have been obtained and electrically characterized (membranes SPS-PEG and PA-LIGS). The skin layer of the membrane SPS-PEG contains different percentages of polyethylene glycol in the casting solution (5, 25, 40, and 60 wt%), while lignosulfonate was used for manufacturing PA-LIGS membranes (5, 10, 20, and 40 wt%). Membrane electrical characterization was done by means of impedance spectroscopy (IS) measurements, which were carried out with the membranes in contact with NaCl solutions at different concentrations (10(-3) < or = c(M) < or = 5x10(-2)). Electrical resistance and equivalent capacitance of the different membrane samples were determined from IS plots by using equivalent circuits as models. Results show a clear decrease in the membrane electrical resistance as a result of both polysulfone sulfonation and the increase of the concentration of modifying substances, although a kind of limit concentration was obtained for both polyethylene glycol and lignosulfonate (40 and 20%, respectively). Results also show a decrease of around 90% in electrical resistance due to polysulfone sulfonation, while the value of the dielectric constant (hydrated state) clearly increases.

  15. Synthesis and In Vitro Evaluation of Polyethylene Glycol-Paclitaxel Conjugates for Lung Cancer Therapy.

    PubMed

    Luo, Tian; Magnusson, Johannes; Préat, Véronique; Frédérick, Raphael; Alexander, Cameron; Bosquillon, Cynthia; Vanbever, Rita

    2016-07-01

    Pulmonary drug delivery is considered an attractive route of drug administration for lung cancer chemotherapy. However, fast clearance mechanisms result in short residence time of small molecule drugs in the lung. Therefore, achieving a sustained presence of chemotherapeutics in the lung is very challenging. In this study, we synthesized two different polyethylene glycol-paclitaxel ester conjugates with molecular weights of 6 and 20 kDa in order to achieve sustained release of paclitaxel in the lung. One structure was synthesized with azide linker using "click" chemistry and the other structure was synthesized with a succinic spacer. The physicochemical and biological properties of the conjugates were characterized in vitro. Conjugation to polyethylene glycol improved the solubility of paclitaxel by up to four orders of magnitude. The conjugates showed good stability in phosphate buffer saline pH 6.9 (half-life ≥72 h) and in bronchoalveolar lavage (half-life of 3 to 9 h) at both molecular weights, but hydrolyzed quickly in mouse serum (half-life of 1 to 3 h). The conjugates showed cytotoxicity to B16-F10 melanoma cells and LL/2 Lewis lung cancer cells but less than free paclitaxel or Taxol, the commercial paclitaxel formulation. These properties imply that the conjugates have the potential to retain paclitaxel in the lung for a prolonged duration and to sustain its release locally for a better efficacy.

  16. Self-assembled hydrogel nanoparticles composed of dextran and poly(ethylene glycol) macromer.

    PubMed

    Kim, I S; Jeong, Y I; Kim, S H

    2000-09-15

    Biodegradable hydrogel nanoparticles were prepared from glycidyl methacrylate dextran (GMD) and dimethacrylate poly(ethylene glycol) (DMP). GMD was synthesized by coupling of glycidyl methacrylate to dextran in the presence of 4-(N,N-dimethylamino)pyridine (DMAP) using dimethylsulfoxide (DMSO) as an aprotic solvent. DMP was synthesized from poly(ethylene glycol) (PEG) and methacryloyl chloride. GMD/DMP (abbreviated as DP) hydrogel was prepared by radical polymerization of GMD and DMP using ammonium peroxydisulfate (APS) as an initiator and UV curing. DP hydrogel nanoparticles were obtained by diafiltration method using DMSO solution. The GMD and DMP were characterized by fourier transform infrared spectroscopy. Fluorescence probe technique was used to investigate the self-assembly of DP in water using pyrene as a hydrophobic probe. The critical association concentration (CAC) was determined to be 5.6 x 10(-2) g/l. The shape of DP hydrogel nanoparticles was spherical when observed by transmission electron microscope (TEM). The size range of DP hydrogel nanoparticles was about 20 approximately 50 nm. The hydrodynamic size of DP hydrogel nanoparticles was measured by photon correlation spectroscopy (PCS) and gradually increased with time in PBS (0.1 M, pH 7.4). Drug release study was performed using clonazepam (CNZ) as a hydrophobic model drug. In vitro release rate of CNZ from the DP hydrogel nanoparticles was dependent on the existence of dextranase and the pH of the release medium.

  17. Preparation of monodisperse and size-controlled poly(ethylene glycol) hydrogel nanoparticles using liposome templates.

    PubMed

    An, Se Yong; Bui, Minh-Phuong Ngoc; Nam, Yun Jung; Han, Kwi Nam; Li, Cheng Ai; Choo, Jaebum; Lee, Eun Kyu; Katoh, Shigeo; Kumada, Yoichi; Seong, Gi Hun

    2009-03-01

    Liposomes were used as templates to prepare size-controlled and monodisperse poly(ethylene glycol) (PEG) hydrogel nanoparticles. The procedure for the preparation of PEG nanoparticles using liposomes consists of encapsulation of photopolymerizable PEG hydrogel solution into the cavity of the liposomes, extrusion through a membrane with a specific pore size, and photopolymerization of the contents inside the liposomes by UV irradiation. The size distributions of the prepared particles were 1.32+/-0.16 microm (12%), 450+/-62 nm (14%), and 94+/-12 nm (13%) after extrusion through membrane filters with pore sizes of 1 microm, 400 nm, and 100 nm, respectively. With this approach, it is also possible to modify the surface of the hydrogel nanoparticles with various functional groups in a one-step procedure. To functionalize the surface of a PEG nanoparticle, methoxy poly(ethylene glycol)-aldehyde was added as copolymer to the hydrogel-forming components and aldehyde-functionalized PEG nanoparticles could be obtained easily by UV-induced photopolymerization, following conjugation with poly-L-lysine-FITC through amine-aldehyde coupling. The prepared PEG particles showed strong fluorescence from FITC on the edge of the particles using confocal microscopy. The immobilization of biomaterials such as enzymes in hydrogel particles could be performed with loading beta-galactosidases during the hydration step for liposome preparation without additional procedures. The resorufin produced by applying resorufin beta-D-galactopyranoside as the substrate showed the fluorescence under the confocal microscopy.

  18. Polyethylene glycol-grafted bovine pericardium: a novel hybrid tissue resistant to calcification.

    PubMed

    Vasudev, S C; Chandy, T

    1999-02-01

    Calcification is a frequent cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde pretreated bovine pericardium (GATBP). An investigation was made of the grafting of different molecular weight polyethylene glycol (PEG 600, 1500, 4000 and 6000) via glutaraldehyde (GA) linkages to bovine pericardium (BP) and of their stability and calcification. The process of the calcification profile was studied by in vitro experiments via incubating pericardial samples in a metastable solution of calcium phosphate. Calcification of bovine pericardium grafted with PEG 6000 was significantly decreased compared to low molecular weight PEG grafts or Sodium dodecyl sulphate- (SDS) and GA-treated tissues. The mechanical properties of these modified tissues after enzyme (Trypsin) digestion and calcification were investigated. The biocompatibility aspects of grafted tissues were also established by monitoring the platelet adhesion, octane contact angle and water of hydration. PEG 6000-grafted tissues retained the maximum strength in trypsin buffer and calcium phosphate solutions. Scanning electron micrographs revealed that the PEG-grafted bovine pericardium had substantially inhibited the platelet-surface attachment and their spreading. It is conceivable that high molecular weight polyethylene glycol-grafted pericardium (a hybrid tissue) may be a suitable calcium-resistant material for developing prosthetic valves due to their stability and biocompatibility.

  19. 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

  20. Characterization and solubility study of norfloxacin-polyethylene glycol, polyvinylpyrrolidone and carbopol 974p solid dispersions.

    PubMed

    Gorajana, Adinarayana; Kit, Wong W; Dua, Kamal

    2015-01-01

    Norfloxacin has a low aqueous solubility which leads to poor dissolution. Keeping this fact in mind the purpose of the present study is to formulate and evaluate norfloxacin solid dispersion. Solid dispersions were prepared using hydrophilic carriers like polyethylene glycol (PEG) 4000, polyvinylpyrrolidone (PVP) k30 and carbopol 974pNF (CP) in various ratios using solvent evaporation technique. These formulations were evaluated using solubility studies, dissolution studies; Fourier transmitted infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetery (DSC). The influence of polymer type and drug to polymer ratio on the solubility and dissolution rate of norfloxacin was also evaluated. FTIR analysis showed no interaction of all three polymers with norfloxacin. The results from XRD and DSC analyses of the solid dispersion preparations showed that norfloxacin existsin its amorphous form. Among the Norfloxacin: PEG solid dispersions, Norfloxacin: PEG 1:14 ratio showed the highest dissolution rate at pH 6.8. For norfloxacin: PVP solid dispersions, norfloxacin: PVP 1:10 ratio showed the highest dissolution rate at pH 6.8. For Norfloxacin: CP solid dispersions, norfloxacin: P 1:2 ratio showed the highest dissolution rate at pH 6.8. The solid dispersion of norfloxacin with polyethylene glycol (PEG) 4000, polyvinylpyrrolidone (PVP) k30 and carbopol 974p NF (CP), lends an ample credence for better therapeutic efficacy.

  1. Permselective properties for aqueous ethanol solutions through copolymer membranes from benzyl methacrylate and polyethylene glycol dimethacrylate

    SciTech Connect

    Okuno, Hiroshi; Okado, Takashi; Matsumoto, Akira; Oiwa, Masayoshi; Uragami, Tadashi )

    1992-10-01

    Copolymer membranes prepared by bulk copolymerization of polyethylene glycol dimethacrylates of three different degrees of polymerization as macromonomer and benzyl methacrylate as comonomer were used for the separation of aqueous ethanol solutions in both pervaporation and evapomeation. The copolymer membranes preferentially permeated water from an aqueous ethanol solutions in both pervaporation and evapomeation. The copolymer membranes preferentially permeated water from an aqueous ethanol solution in evapomeation. In pervaporation, ethanol was predominantly permeated from an aqueous ethanol solution through the copolymer membranes containing a long polyethylene glycol (PEG) chain above about 20 wt% PEG content in a copolymer. This result was attributed to a remarkable swelling of the copolymer membrane containing a long PEG chain by the aqueous ethanol solution in pervaporation. In evapomeation, both the separation factors and the permeation rates through these membranes are not much affected by the ethanol concentration in the feed vapor. In pervaporation, they were significantly dependent on the ethanol concentration in the feed solution. The above results are discussed from the viewpoint of the physical structure of the membrane in evapomeation and pervaporation.

  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. 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.

  4. Characterization of Indomethacin Release from Polyethylene Glycol Tablet Fabricated With Mold Technique

    PubMed Central

    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

  5. 1H-NMR characterization of poly(ethylene glycol) and polydimethylsiloxane copolymer

    NASA Astrophysics Data System (ADS)

    Zainuddin, Ain Athirah; Othaman, Rizafizah; Noor, Wan Syaidatul Aqma Wan Mohd; Anuar, Farah Hannan

    2016-11-01

    This paper describes the synthesis and characterization of poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) copolymers. The copolymers were synthesized by reacting hydroxyl group (-OH) of poly(ethylene glycol) (PEG) and polydimetylsiloxane (PDMS) with isocyanate group (R-N=C=O) of 1,6-hexamethylene diisocyanate (HMDI). The reaction was carried out at room temperature. The copolymers were synthesized in three different compositions which differ in molar ratios of PEG to PDMS. The ratios (PEG:PDMS) used were 2:6. 3:5 and 4:4. The formation of the copolymers was characterized by 1H Nuclear Magnetic Resonance (1H-NMR) for structural determination. The presence of proton signal at 4.80 ppm which belongs to the proton of urethane group indicates the formation of urethane links. The formation of urethane links showed that two homopolymers were linked together by HMDI to form longer copolymer chains. It is worth to note that the sequence of PEG and PDMS along the copolymer chain is random.

  6. 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.

  7. Cross-linked Polystyrene Sulfonic Acid and Polyethylene Glycol as a Low-fouling Material

    PubMed Central

    Alghunaim, Abdullah; Newby, Bi-min Zhang

    2016-01-01

    A negatively charged hydrophilic low fouling film was prepared by thermally cross-linking a blend consisting of polystyrene sulfonic acid (PSS) and polyethylene glycol (PEG). The film was found to be stable by dip-washing. The fouling resistance of this material towards bacterial (Escherichia coli) and colloidal (polystyrene particles) attachment, non-specific protein (fibronectin) adsorption and cell (3T3 NIH) adhesion was evaluated and was compared with glass slides modified with polyethylene glycol (PEG) brushes, oxidized 3-mercaptopropyltrimethoxysilane (sulfonic acid, SA), and n-octadecyltrichlorosilane (OTS). The extended Derjaguin-Landau- Verwey-Overbeek (XDLVO) theory and thermodynamic models based on surface energy were used to explain the interaction behaviors of E. coli/polystyrene particles–substrate and protein–substrate interactions, respectively. The cross-linked PSS-PEG film was found to be slightly better than SA and PEG towards resisting non-specific protein adsorption, and showed comparable low attachment results as those of PEG towards particle, bacterial and NIH-3T3 cells adhesion. The low-fouling performance of PSS-PEG, a cross-linked film by a simple thermal curing process, could allow this material to be used for applications in aqueous environments, where most low fouling hydrophilic polymers, such as PSS or PEG, could not be easily retained. PMID:26812639

  8. 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.

  9. Integrative design of a poly(ethylene glycol)-poly(propylene glycol)-alginate hydrogel to control three dimensional biomineralization.

    PubMed

    Cha, Chaenyung; Kim, Eun-Seok; Kim, Il Won; Kong, Hyunjoon

    2011-04-01

    A mineralized polymeric matrix has been extensively studied to understand biomineralization processes and to further regulate phenotypic functions of various cells involved in osteogenesis and physiological homeostasis. It has been often proposed that several matrix variables including charge density, hydrophobicity, and pore size play vital roles in modulating composition and morphology of minerals formed within a three dimensional (3D) matrix. However, the aspects have not yet been systematically examined because a tool enabling the independent control of the matrix variables is lacking. This study presents an advanced integrative strategy to control morphology and composition of biominerals with matrix properties, by using a hydrogel formulated to independently control charge density, hydrophobicity, and porosity. The hydrogel consists of poly(ethylene glycol) monomethacrylate (PEGmM), poly(propylene glycol) monomethacrylate (PPGmM), and methacrylic alginate (MA), so the charge density and hydrophobicity of the hydrogel can be separately controlled with mass fractions of MA and PPGmM. Also, hydrogels which present only nano-sized pores, termed nanoporous hydrogels, are lyophilized and rehydrated to prepare the hydrogels containing micro-sized pores, termed microporous hydrogels. We find that increasing the mass fractions of MA and PPGmM of the microporous hydrogel promotes the growth of apatite layers because of the increases in the charge density, hydrophobicity and pore size. In contrast, increasing mass fractions of MA and PPGmM of the nanoporous hydrogel enhances the formation of calcium carbonate minerals. The dependency of the mineralization on hydrogel variables is related to the change in supersaturation of mineral ions. Overall, the results of this study will be highly useful to better understand the interplay of matrix variables in biomineralization and to design a wide array of mineralized matrix potentially used in cell therapies and tissue

  10. Morphology and surface properties of blends of Eudragit RS with different poly(ethylene glycol)s.

    PubMed

    Lovrecich, M; Rubessa, F

    1998-02-01

    The purpose of this study was to investigate the morphology and surface properties of blends of Eudragit RS, a hydrophobic polymer mainly used for film coating, and poly(ethylene glycol)s (PEG), amphiphilic polymers used as softeners for films. Blends of Eudragit RS and PEGs were prepared as films using the casting technique from methylene chloride. The morphology of those films was evaluated by scanning electron microscopy before and after treatment with water. Sessile drop technique was used to measure solid/liquid contact angles in order to calculate surface free-energy parameters and to investigate phase separation using the Cassie-Baxter approach. Films containing 20, 40, 50, and 60% PEG 3400 and PEG 6000 appeared morphologically unchanged after treatment with water; no phase separation was noticed. Films containing PEG 14,000 after treatment with water showed the presence of a solid emulsion in the range 40, 50, and 60% PEG; a multiple solid emulsion was shown for films containing 60% PEG 20,000. The presence of two-phase systems was shown using contact angle measurements and results were in agreement with microscopic analysis. Calculated surface free-energy parameters indicated that PEG 3400 and 20,000 in a critical concentration of 10% can modify surface parameters of Eudragit RS: for PEG 6000 and 14,000 this critical concentration was found to be between 10 and 20%. The surface polarity of PEG 3400, 6000, and 14,000 was found to be drastically reduced upon addition of 5% Eudragit RS; spontaneous surface layering of Eudragit RS could be reasonably hypothesized for PEG 3400. This study revealed that surface parameters of a polymer can be modified in the presence of a relatively small amount of a second material.

  11. Synthesis and characterization of novel biotinylated biodegradable poly(ethylene glycol)-b-poly(carbonate-lactic acid) copolymers.

    PubMed

    Xie, Zhigang; Guan, Huili; Lü, Changhai; Chen, Xuesi; Jing, Xiabin

    2005-11-01

    Poly(ethylene glycol)-b-poly(5-benzyloxy-trimethylene carbonate-lactic acid) copolymers (PEG-b-P(BTMC-LA)) were synthesized by ring-opening polymerization of lactide and 5-benzyloxy trimethylene carbonate in the presence of mono-hydroxyl poly(ethylene glycol) with diethyl zinc as catalyst. They were further converted into deprotected copolymers with the pendant hydroxyl groups by hydrogenolysis in the presence of Pd(OH)2/C, and finally conjugated with biotin through the free hydroxyl groups. Gel permeation chromatography, Fourier transform infrared, differential scanning calorimetry and 1H nuclear magnetic resonance studies confirmed the copolymer structures and successful attachment of biotin to the copolymer.

  12. Intermolecular interactions at early stage of protein/detergent particle association induced by salt/polyethylene glycol mixtures.

    PubMed

    Odahara, Takayuki; Odahara, Koji

    2016-04-01

    Mixtures of neutral salts and polyethylene glycol are used for various purposes in biological studies. Although the effects of each component of the mixtures are theoretically well investigated, comprehension of their integrated effects remains insufficient. In this work, their roles and effects as a precipitant were clarified by studying dependence of precipitation curves on salt concentration for integral membrane protein/detergent particles of different physicochemical properties. The dependence of precipitation curves was reasonably related to intermolecular interactions among relevant molecules such as protein, detergent and polyethylene glycol by considering their physicochemical properties. The obtained relationships are useful as basic information to learn the early stage of biological macromolecular associations.

  13. 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.

  14. Click chemistry grafting of poly(ethylene glycol) brushes to alkyne-functionalized pseudobrushes.

    PubMed

    Ostaci, Roxana-Viorela; Damiron, Denis; Grohens, Yves; Léger, Liliane; Drockenmuller, Eric

    2010-01-19

    A versatile method for the grafting of azide-terminated polymer chains to alkyne-functionalized pseudobrushes by the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition has been developed. First, poly[(propargyl methacrylate)-r-(glycidyl methacrylate)-r-(methyl methacrylate)] random copolymers with monomer ratios of respectively 27/27/46, 41/31/28, and 45/55/0 were synthesized by RAFT polymerization. Then, dense alkyne-functionalized pseudobrushes were grafted in melt by thermal ring-opening of the glycidyl groups by the silanols from the silicon substrate. Finally, the grafting of tailor-made alpha-methoxy-omega-azido-poly(ethylene glycol)s (M(w) approximately 5000, 20,000, and 50,000 g/mol) by Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition was performed in sealed reactors at 60 degrees C for 72 h using a polymer weight fraction of 10% in tetrahydrofuran and Cu(PPh(3))(3)Br/DIPEA as the catalytic system. Alkyne-functionalized pseudobrushes and poly(ethylene glycol) brushes were characterized by ellipsometry, scanning probe microscopy, and water contact angle measurements. This "grafting-to" approach represents a fast and versatile method to provide thick and homogeneous polymer brushes with a high surface coverage. A major benefit of this strategy is the tunable and versatile tethering of alkyne functionalities to silicon substrates using a straightforward spin-coating procedure.

  15. Membranes of Polymers of Intrinsic Microporosity (PIM-1) Modified by Poly(ethylene glycol)

    PubMed Central

    Bengtson, Gisela; Neumann, Silvio; Filiz, Volkan

    2017-01-01

    Until now, the leading polymer of intrinsic microporosity PIM-1 has become quite famous for its high membrane permeability for many gases in gas separation, linked, however, to a rather moderate selectivity. The combination with the hydrophilic and low permeable poly(ethylene glycol) (PEG) and poly(ethylene oxides) (PEO) should on the one hand reduce permeability, while on the other hand enhance selectivity, especially for the polar gas CO2 by improving the hydrophilicity of the membranes. Four different paths to combine PIM-1 with PEG or poly(ethylene oxide) and poly(propylene oxide) (PPO) were studied: physically blending, quenching of polycondensation, synthesis of multiblock copolymers and synthesis of copolymers with PEO/PPO side chain. Blends and new, chemically linked polymers were successfully formed into free standing dense membranes and measured in single gas permeation of N2, O2, CO2 and CH4 by time lag method. As expected, permeability was lowered by any substantial addition of PEG/PEO/PPO regardless the manufacturing process and proportionally to the added amount. About 6 to 7 wt % of PEG/PEO/PPO added to PIM-1 halved permeability compared to PIM-1 membrane prepared under similar conditions. Consequently, selectivity from single gas measurements increased up to values of about 30 for CO2/N2 gas pair, a maximum of 18 for CO2/CH4 and 3.5 for O2/N2. PMID:28587247

  16. Fabrication and characterization of plasma-polymerized poly(ethylene glycol) film with superior biocompatibility.

    PubMed

    Choi, Changrok; Hwang, Inseong; Cho, Young-Lai; Han, Sang Y; Jo, Dong H; Jung, Donggeun; Moon, Dae W; Kim, Eun J; Jeon, Chang S; Kim, Jeong H; Chung, Taek D; Lee, Tae G

    2013-02-01

    A newly fabricated plasma-polymerized poly(ethylene glycol) (PP-PEG) film shows extremely low toxicity, low fouling, good durability, and chemical similarity to typical PEG polymers, enabling live cell patterning as well as various bioapplications using bioincompatible materials. The PP-PEG film can be overlaid on any materials via the capacitively coupled plasma chemical vapor deposition (CCP-CVD) method using nontoxic PEG200 as a precursor. The biocompatibility of the PP-PEG-coated surface is confirmed by whole blood flow experiments where no thrombi and less serum protein adsorption are observed when compared with bare glass, polyethylene (PE), and polyethylene terephthalate (PET) surfaces. Furthermore, unlike bare PE films, less fibrosis and inflammation are observed when the PP-PEG-coated PE film is implanted into subcutaneous pockets of mice groin areas. The cell-repellent property of PP-PEG is also verified via patterning of mammalian cells, such as fibroblasts and hippocampal neurons. These results show that our PP-PEG film, generated by the CCP-CVD method, is a biocompatible material that can be considered for broad applications in biomedical and functional materials fields.

  17. 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 mono...

  18. 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 mono...

  19. 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.

  20. Influence of polyethylene glycol chain length on compatibility and release characteristics of ternary solid dispersions of itraconazole in polyethylene glycol/hydroxypropylmethylcellulose 2910 E5 blends.

    PubMed

    Janssens, Sandrien; Denivelle, Samgar; Rombaut, Patrick; Van den Mooter, Guy

    2008-10-02

    The present study aims to elucidate the influence of the polyethylene glycol chain length on the miscibility of PEG/HPMC 2910 E5 polymer blends, the influence of polymer compatibility on the degree of molecular dispersion of itraconazole, and in vitro dissolution. PEG 2000, 6000, 10,000 and 20,000 were included in the study. Solid dispersions were prepared by spray drying and characterized with MDSC, XRPD and in vitro dissolution testing. The polymer miscibility increased with decreasing chain length due to a decrease in the Gibbs free energy of mixing. Recrystallization of itraconazole occurred as soon as a critical temperature of ca. 75 degrees C was reached for the glass transition that represents the ternary amorphous phase. Due to the lower miscibility degree between the longer PEG types and HPMC 2910 E5, the ternary amorphous phase was further separated, leading to a more rapid decrease of the ternary amorphous phase glass transition as a function of PEG and itraconazole weight percentage and hence, itraconazole recrystallization. In terms of release, an advantage of the shorter chain length PEG types (2000, 6000) over the longer chain length PEG types (10,000, 20,000) was observed for the polymer blends with 5% of PEG with respect to the binary itraconazole/HPMC 2910 E5 solid dispersion. Among the formulations with a 15/85 (w/w) PEG/HPMC 2910 E5 ratio on the other hand, there was no difference in the release profile.

  1. Application of poly(ethylene glycol)-b-poly(epsilon-caprolactone) copolymers with different Poly(ethylene glycol) contents for the preparation of PEG-coated nanoparticles.

    PubMed

    Hou, Jingwen; Qian, Changyun; Zhang, Yanting; Guo, Shengrong

    2013-02-01

    This work used one poly(ethylene glycol)-b-poly(epsilon-caprolactone) (PEG-b-PCL) copolymer with low PEG content as matrix material and the copolymers with high PEG content as emulsifier to prepare PEG-coated nanoparticles for controlled release of paclitaxel by solvent evaporation technique. The copolymers were synthesized by ring-opening polymerization and characterized by 1H NMR and gel permeation chromatography (GPC). The effects of the composition and concentration of the copolymers used as emulsifier on the diameters and encapsulation efficiency of nanoparticles were investigated. The mean hydrodynamic diameters of the nanoparticles measured by dynamic light scattering ranged from 70 to 160 nm. The higher PEG content of emulsifier led to bigger diameter of nanoparticles and the emulsifier concentration (0.1%-1.0%) had no obvious influence on the diameters. The paclitaxel-loaded nanoparticles could achieve a sustained drug release for 7 days. When 2%-30% (w/v) of inulin was used as cryoprotectant during freeze drying process, the lyophilized nanoparticles could be well reconstituted into aqueous solution and the hydrodynamic diameter was not obviously changed.

  2. 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.

  3. Universal concept for the implementation of a single cleavable unit at tunable position in functional poly(ethylene glycol)s.

    PubMed

    Dingels, Carsten; Müller, Sophie S; Steinbach, Tobias; Tonhauser, Christine; Frey, Holger

    2013-02-11

    Poly(ethylene glycol) (PEG) with acid-sensitive moieties gained attention particularly for various biomedical applications, such as the covalent attachment of PEG (PEGylation) to protein therapeutics, the synthesis of stealth liposomes, and polymeric carriers for low-molecular-weight drugs. Cleavable PEGs are favored over their inert analogues because of superior pharmacodynamic and/or pharmacokinetic properties of their formulations. However, synthetic routes to acetal-containing PEGs published up to date either require enormous efforts or result in ill-defined materials with a lack of control over the molecular weight. Herein, we describe a novel methodology to implement a single acetaldehyde acetal in well-defined (hetero)functional poly(ethylene glycol)s with total control over its position. To underline its general applicability, a diverse set of initiators for the anionic polymerization of ethylene oxide (cholesterol, dibenzylamino ethanol, and poly(ethylene glycol) monomethyl ether (mPEG)) was modified and used to synthesize the analogous labile PEGs. The polyether bearing the cleavable lipid had a degree of polymerization of 46, was amphiphilic and exhibited a critical micelle concentration of 4.20 mg·L(-1). From dibenzylamino ethanol, three heterofunctional PEGs with different molecular weights and labile amino termini were generated. The transformation of the amino functionality into the corresponding squaric acid ester amide demonstrated the accessibility of the cleavable functional group and activated the PEG for protein PEGylation, which was exemplarily shown by the attachment to bovine serum albumin (BSA). Furthermore, turning mPEG into a macroinitiator with a cleavable hydroxyl group granted access to a well-defined poly(ethylene glycol) derivative bearing a single cleavable moiety within its backbone. All the acetal-containing PEGs and PEG/protein conjugates were proven to degrade upon acidic treatment.

  4. Gene transcription and steviol glycoside accumulation in Stevia rebaudiana under polyethylene glycol-induced drought stress in greenhouse cultivation.

    PubMed

    Hajihashemi, Shokoofeh; Geuns, Jan M C

    2016-09-01

    Stevia rebaudiana is a sweet herb of the Astraceae family, which is cultivated for the natural sweeteners it contains. The aim of this study was to assess the effect of drought, simulated by the application of polyethylene glycol (5%, 10%, and 15% w/v), on the content of steviol glycosides (SVglys) and transcription levels of six genes involved in the biosynthesis of these natural sweeteners. The transcription levels of ent-kaurene synthase, ent-kaurene oxidase, ent-kaurenoic acid hydroxylase, and three UDP-dependent glycosyltransferases, UGT85C2,UGT74G1 and UGT76G1 were downregulated under polyethylene glycol treatment. Polyethylene glycol treatment significantly decreased the amount of stevioside, rebaudioside A, B, C and F, steviolbioside, dulcoside A, rubusoside, and total SVglys. These results strongly suggest a close relationship of SVglys content with the transcription of genes involved in the SVglys biosynthesis pathway. Comparing the observations of the present study with other reports provided the knowledge that the Stevia response to drought stress can be influenced by different environmental and experimental factors, in addition to intensity of drought stress. In conclusion, these results strongly suggest that polyethylene glycol-induced drought stress has a negative effect on the content of SVglys and transcription of SVglys biosynthetic genes and that this should be investigated further. We recommend that sufficient irrigation of Stevia is required to obtain a high content of SVglys.

  5. Comparison of the migration behavior of nanoparticles based on polyethylene glycol and silica using micellar electrokinetic chromatography.

    PubMed

    Kato, Masaru; Sasaki, Minoru; Ueyama, Yukari; Koga, Ayaka; Sano, Akira; Higashi, Tatsuya; Santa, Tomofumi

    2015-02-01

    Nanoparticles, spherical particles with diameters less than 100 nm, are promising theranostic devices for noninvasive diagnosis and therapy. In this study, nanoparticles composed of polyethylene glycol and silica were prepared, and their migration behavior was examined using capillary electrophoresis. The effects of the sodium dodecyl sulfate concentration in the electrolyte, the nanoparticle size, and the encapsulated molecule on the migration were examined. The addition of sodium dodecyl sulfate into the electrolyte had a significant effect on the electrophoretic mobility of polyethylene glycol nanoparticles, but a small effect on that of silica nanoparticles. As for the size effect, the mobility became a little faster for smaller nanoparticle sizes for both polyethylene glycol and silica nanoparticles. The encapsulated molecule affected the mobility of the nanoparticles through interactions between the encapsulated molecules and sodium dodecyl sulfate. We propose that the large effect of sodium dodecyl sulfate on the migration of the polyethylene glycol nanoparticles was due to the large spaces within the nanoparticles. These results indicate that nanoparticle migration is mainly determined by the nanoparticle components.

  6. 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

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

    PubMed

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

    2015-12-10

    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. Copyright © 2015 Ohtsubo et al.

  8. Effect of ablation parameters on infrared pulsed laser deposition of poly(ethylene glycol) films

    NASA Astrophysics Data System (ADS)

    Bubb, Daniel M.; Papantonakis, M. R.; Toftmann, B.; Horwitz, J. S.; McGill, R. A.; Chrisey, D. B.; Haglund, R. F., Jr.

    2002-06-01

    Polymer thin films were deposited by laser ablation using infrared radiation both resonant (2.90, 3.40, 3.45, and 8.96 mum) and nonresonant (3.30, 3.92, and 4.17 mum) with vibrational modes in the starting material, polyethylene glycol. The chemical structure of the films was characterized by Fourier transform infrared spectroscopy, while the molecular weight distribution was investigated using gel permeation chromatography. The films deposited by resonant irradiation are superior to those deposited with nonresonant radiation with respect to both the chemical structure and the molecular weight distribution of the films. However, the molecular-weight distributions of films deposited at nonresonant infrared wavelengths show marked polymer fragmentation. Fluence and wavelength dependence studies show that the effects may be related to the degree of thermal confinement, and hence to the relative absorption strengths of the targeted vibrational modes.

  9. Fabrication of anti-protein-fouling poly(ethylene glycol) microfluidic chip electrophoresis by sandwich photolithography

    PubMed Central

    Cong, Hailin; Xu, Xiaodan; Yu, Bing; Liu, Huwei

    2016-01-01

    Microfluidic chip electrophoresis (MCE) is a powerful separation tool for biomacromolecule analysis. However, adsorption of biomacromolecules, particularly proteins onto microfluidic channels severely degrades the separation performance of MCE. In this paper, an anti-protein-fouling MCE was fabricated using a novel sandwich photolithography of poly(ethylene glycol) (PEG) prepolymers. Photopatterned microchannel with a minimum resolution of 10 μm was achieved. After equipped with a conventional online electrochemical detector, the device enabled baseline separation of bovine serum albumin, lysozyme (Lys), and cytochrome c (Cyt-c) in 53 s under a voltage of 200 V. Compared with a traditional polydimethylsiloxane MCE made by soft lithography, the PEG MCE made by the sandwich photolithography not only eliminated the need of a master mold and the additional modification process of the microchannel but also showed excellent anti-protein-fouling properties for protein separation. PMID:27493702

  10. Synthesis of Aluminium Nanoparticles in A Water/Polyethylene Glycol Mixed Solvent using μ-EDM

    NASA Astrophysics Data System (ADS)

    Sahu, R. K.; Hiremath, Somashekhar S.

    2017-08-01

    Nanoparticles present a practical way of retaining the results of the property at the atomic or molecular level. Due to the recent use of nanoparticles in scientific, industrial and medical applications, synthesis of nanoparticles and their characterization have become considerably important. Currently, aluminium nanoparticles have attracted significant research attention because of their reasonable cost, unique properties and interdisciplinary emerging applications. The present paper reports the synthesis of aluminium nanoparticles in the mixture of Deionized water (DI water) and Polyethylene Glycol (PEG) using a developed micro-Electrical Discharge Machining (μ-EDM) method. PEG was used as a stabilizer to prevent nanoparticles from agglomeration produced during the μ -EDM process. The synthesized aluminium nanoparticles were examined by Transmission Electron Microscopy (TEM), Energy Dispersive Analysis by X-rays (EDAX) and Selected Area Electron Diffraction (SAED) pattern to determine their size, shape, chemical nature and crystal structure. The average size of the polyhedral aluminium nanoparticles is found to be 196 nm.

  11. Fabrication of anti-protein-fouling poly(ethylene glycol) microfluidic chip electrophoresis by sandwich photolithography.

    PubMed

    Cong, Hailin; Xu, Xiaodan; Yu, Bing; Liu, Huwei; Yuan, Hua

    2016-07-01

    Microfluidic chip electrophoresis (MCE) is a powerful separation tool for biomacromolecule analysis. However, adsorption of biomacromolecules, particularly proteins onto microfluidic channels severely degrades the separation performance of MCE. In this paper, an anti-protein-fouling MCE was fabricated using a novel sandwich photolithography of poly(ethylene glycol) (PEG) prepolymers. Photopatterned microchannel with a minimum resolution of 10 μm was achieved. After equipped with a conventional online electrochemical detector, the device enabled baseline separation of bovine serum albumin, lysozyme (Lys), and cytochrome c (Cyt-c) in 53 s under a voltage of 200 V. Compared with a traditional polydimethylsiloxane MCE made by soft lithography, the PEG MCE made by the sandwich photolithography not only eliminated the need of a master mold and the additional modification process of the microchannel but also showed excellent anti-protein-fouling properties for protein separation.

  12. Poly(ethylene glycol)-salt aqueous two-phase systems with easily recyclable volatile salts.

    PubMed

    van Berlo, M; Luyben, K C; van der Wielen, L A

    1998-06-26

    Aqueous two-phase systems (ATPSs) have great potential in the downstream processing of fermentation products. However, the consumption of large amounts of auxiliary materials limits application in industrial practice. Promising alternatives to the salts used so far are volatile salts such as ammonium bicarbonate and ammonium carbamate, which can be recycled to the extraction system as gaseous carbon dioxide and ammonia. In this work, it is demonstrated that ammonium carbamate in combination with poly(ethylene glycol) (PEG, molecular masses of 2000, 4000 and 10000) indeed produces aqueous two-phase systems (ATPSs) at a temperature of 25 degrees C and atmospheric pressure. Ammonium bicarbonate is clearly not suitable as a phase-forming salt, because of its too-low solubility in water.

  13. 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.

  14. Anaphylactic reaction to polyethylene-glycol conjugated-asparaginase: premedication and desensitization may not be sufficient.

    PubMed

    Sahiner, Umit M; Yavuz, S Tolga; Gökce, Muge; Buyuktiryaki, Betul; Altan, Ilhan; Aytac, Selin; Tuncer, Murat; Tuncer, Ayfer; Sackesen, Cansin

    2013-08-01

    In hypersensitive reactions to native L-asparaginase, either premedication and desensitization or substitution with polyethylene glycol conjugated asparaginase (PEG-ASP) is preferred. Anaphylaxis with PEG-ASP is rare. An 8-year-old girl and a 2.5-year-old boy, both diagnosed as having acute lymphoblastic leukemia, presented with native L-asparaginase hypersensitivity and substitution with PEG-ASP was preferred. They received a premedication (methylprednisolone, hydroxyzine and ranitidine) followed by desensitization with PEG-ASP infusion. Both patients developed anaphylaxis with peg-asparaginase. These are the first reported cases of anaphylactic reaction to PEG-ASP, despite the application of both premedication and desensitization. Anaphylaxis with PEG-ASP is very rare and premedication and desensitization protocols may not prevent these hypersensitive reactions.

  15. 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

  16. 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.

  17. Characteristics of precipitation-formed polyethylene glycol microgels are controlled by molecular weight of reactants.

    PubMed

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

    2013-12-23

    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.

  18. 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.

  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. Determination of retinol-binding protein in serum by kinetic immunonephelometry with polyethylene glycol pretreatment.

    PubMed

    Hallworth, M J; Calvin, J; Price, C P

    1984-11-01

    This work describes the use of polyethylene glycol as a pretreatment reagent to remove endogenous light scattering material from serum samples prior to automated immunonephelometric analysis on a centrifugal analyser. An assay system for retinol-binding protein is described, which allows rapid (10 minutes) quantitation of retinol-binding protein in serum samples with a detection limit of 5 mg/L and between-assay coefficients of variation ranging from 2.9% to 4.0%. The assay range is 5-80 mg/L and accuracy comparisons with a Mancini single radial immunodiffusion method yield a regression line y = 0.89 x + 0.52 (r = 0.98, n = 22). The problem of analyte precipitation associated with use of pretreatment regimes is discussed.

  1. 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.

  2. The effect of polyethylene glycol Mw 400 and 600 on stability of Shellac Waxfree

    NASA Astrophysics Data System (ADS)

    Khairuddin; Pramono, E.; Utomo, S. B.; Wulandari, V.; Zahrotul W, A.; Clegg, F.

    2016-11-01

    The effect of polyethylene glycol (PEG) having molecular weight of 400 and 600 on stability of shellac waxfree prepared by solvent-evaporation method was reported in the present paper. The stability of shellac was tested by life under heat at 125 °C for 10,30,90, and 180 minutes. It was found that that stability of shellac decreased with heating time at 125 °C. PEG400 gave the most stable effect of shellac for 30 minutes of heating, whereas at 90 minutes and above PEG600 gave the most effect of shellac stability as shown by insoluble solid test and FTIR. The WVTR showed that water vapour barrier properties of PEG600/shellac was beter than that of PEG400/shellac system.

  3. Insertion Testing of Polyethylene Glycol Microneedle Array into Cultured Human Skin with Biaxial Tension

    NASA Astrophysics Data System (ADS)

    Takano, Naoki; Tachikawa, Hiroto; Miyano, Takaya; Nishiyabu, Kazuaki

    Aiming at the practical use of polyethylene glycol (PEG) microneedles for transdermal drug delivery system (DDS), a testing apparatus for their insertion into cultured human skin has been developed. To simulate the variety of conditions of human skin, biaxial tension can be applied to the cultured human skin. An adopted testing scheme to apply and control the biaxial tension is similar to the deep-draw forming technique. An attention was also paid to the short-time setup of small, thin and wet cultured skin. One dimensional array with four needles was inserted and influence of tension was discussed. It was found that tension, deflection of skin during insertion and original curvature of skin are the important parameters for microneedles array design.

  4. 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.

  5. 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.

  6. Purification of antibodies by precipitating impurities using Polyethylene Glycol to enable a two chromatography step process.

    PubMed

    Giese, Glen; Myrold, Adam; Gorrell, Jeffrey; Persson, Josefine

    2013-11-01

    The purification of antibodies by precipitating impurities using Polyethylene Glycol (PEG) was assessed with the objective of developing a two chromatography column purification process. A PEG precipitation method was evaluated for use in the industrial purification of recombinant monoclonal antibodies (MAbs). Effective and robust precipitation conditions including PEG concentration, pH, temperature, time, and protein concentration were identified for several different MAbs. A recovery process using two chromatography steps in combination with PEG precipitation gave acceptable yield and purity levels for IgG1 and IgG4 antibodies with a broad range of isoelectric points (pI). PEG precipitation removed host cell proteins (HCPs), high molecular weight species (HMWS), leached Protein A ligand, and host cell DNA to acceptable levels when run under appropriate conditions, and some endogenous virus removal was achieved.

  7. Poly(ethylene glycol)-stabilized silver nanoparticles for bioanalytical applications of SERS spectroscopy.

    PubMed

    Shkilnyy, Andriy; Soucé, Martin; Dubois, Pierre; Warmont, Fabienne; Saboungi, Marie-Louise; Chourpa, Igor

    2009-09-01

    The present work depicts the efficient one-step synthesis and detailed evaluation of stable aqueous colloids of silver nanoparticles (NPs) coated with poly(ethylene glycol) (PEG) covalently attached to their surface. Due to steric repulsion between polymer-modified surfaces, the stability of the nanoparticle suspension was preserved even at high ionic strength (0.1 M NaCl). At the same time, the PEG coating remains sufficiently permeable to allow surface-enhanced Raman scattering (SERS) from micromolar concentrations of small molecules such as the anticancer drug mitoxantrone (MTX). The enhancement efficiency of the hot spot-free Ag-PEG was compared to that of citrate-stabilized Ag colloids used after pre-aggregation. The potential of the polymer-stabilized colloids developed in this study is discussed in terms of bioanalytical applications of SERS spectroscopy.

  8. Management of constipation in palliative care patients undergoing opioid therapy: is polyethylene glycol an option?

    PubMed

    Wirz, Stefan; Klaschik, Eberhard

    2005-01-01

    This study assessed the efficacy of laxative use for treatment of constipation in patients receiving opioid therapy, with special attention to polyethylene glycol 3350/electrolyte solution (PEG-ES). Computerized data from 206 patients were analyzed using descriptive statistics. Subgroups were analyzed using confirmatory statistics. Constipation occurred in 42.7 percent of patients. Laxatives were administered to 74.3 percent of these patients using a standardized step scheme, with good results in 78.4 percent. As a therapy for constipation, the combined administration of PEG-ES, sodium picosulphate, and liquid paraffin proved most effective, although statistical analysis yielded no significance. Early use of PEG-ES using a step scheme holds promise for treatment of opioid-related constipation in palliative care patients, although further investigation is warranted.

  9. Interaction of CuCl2 with poly(ethylene glycol) under microwave radiation

    NASA Astrophysics Data System (ADS)

    Tverjanovich, A.; Grevtsev, A.; Bereznev, S.

    2017-01-01

    CuCl2 solutions various concentration in poly(ethylene glycol) (PEG) are treated with microwave (MW) radiation. Optical absorption and FT-IR spectra of the solutions before treatment and after treatment are discussed. It is proposed that before treatment Cu2+ ions have rhombic distorted octahedral coordination in solution with four oxygen atoms of PEG and two Cl‑ ions. These oxygen atoms can be from hydroxyl or ether groups of PEG, depending on the relative ration OH‑ groups and Cu2+ ions. MW treatment of the solution results in a two-step reaction divided in time. The first stage of MW treatment leads to the reduction of Cu2+ ions to Cu+ ions. At the second stage Cu+ ions are reduced to Cu0 forming high-purity copper nanoparticles. In the same time PEG transforms with a formation of carbonyl groups. The shape of the obtained nanoparticles depends on the molecular weight of the used PEG.

  10. Dissolution of biomacromolecules in organic solvents by nano-complexing with poly(ethylene glycol).

    PubMed

    Mok, Hyejung; Kim, Ho Jeong; Park, Tae Gwan

    2008-05-22

    Various biomacromolecules (BMs) such as proteins, DNA, and carbohydrates are extremely difficult to be dissolved in a single organic solvent phase for sustained release or targeted delivery formulation. In this study, three different BMs could be solubilized in selected organic solvents by forming poly(ethylene glycol) (PEG)-assisted nano-complexes while maintaining their structural integrity. Dynamic light scattering (DLS) and atomic force microscopy (AFM) analysis revealed that proteins, DNA, and carbohydrate polymers could be nano-complexed with PEG in various organic solvents. The diameter of nano-complexes decreased roughly from approximately 600 nm to approximately 100 nm with increasing weight ratio of PEG/BM. The present solubilization technique could be potentially applied for sustained release formulations of various therapeutic biological drugs.

  11. 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

    2012-04-07

    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.

  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. Catechol-grafted poly(ethylene glycol) for PEGylation on versatile substrates.

    PubMed

    Lee, Hyukjin; Lee, Kang Dae; Pyo, Kyung Bo; Park, Sung Young; Lee, Haeshin

    2010-03-16

    We report on catechol-grafted poly(ethylene) glycol (PEG-g-catechol) for the preparation of nonfouling surfaces on versatile substrates including adhesion-resistant PTFE. PEG-g-catechol was prepared by the step-growth polymerization of PEO to which dopamine, a mussel-derived adhesive molecule, was conjugated. The immersion of substrates into an aqueous solution of PEG-g-catechol resulted in robust PEGylation on versatile surfaces of noble metals, oxides, and synthetic polymers. Surface PEGylation was unambiguously confirmed by various surface analytical tools such as ellipsometry, goniometry, infrared spectroscopy, and X-ray photoelectron spectroscopy. Contrary to existing PEG derivatives that are difficult-to-modify synthetic polymer surfaces, PEG-g-catechol can be considered to be a new class of PEGs for the facile surface PEGylation of various types of surfaces.

  14. Formation of protein complex with the aid of polyethylene glycol for deproteinized natural rubber latex

    NASA Astrophysics Data System (ADS)

    Wei, Lim Keuw; Ing, Wong Kwee; Badri, Khairiah Haji; Ban, Wong Chong

    2013-11-01

    The effect of polyethylene glycol (PEG) as a deproteinizing agent in commercial natural rubber latex (NRL) onto the physicochemical properties of the NRL was investigated. Three types of PEG were used namely PEG200, PEG4000 and PEG20000 (molecular weight of 200, 4000 and 20000 g/mol respectively). The optimum amount of PEG in NRL was determined from viscosity changes, protein content and Fourier Transform Infrared spectroscopy. Level of protein reduction was affected by molecular weight of PEG. The addition of PEG in NRL reduced the protein content of NRL (3.30 %) to the lowest (2.01 %) at 0.40 phr of PEG200 due to more attractive hydrophobic interactions between short chains PEG compared to PEG4000 (2.24%) and PEG20000 (2.15%). This was verified through FTIR spectroscopy analysis by observing the primary and secondary amide peak where PEG4000 has lesser absorption at the region compared to with PEG20000.

  15. Improved isolation of Chlamydia trachomatis from a low-prevalence population by using polyethylene glycol.

    PubMed

    Gibson, J P; Egerer, R M; Wiedbrauk, D L

    1993-02-01

    The effect of polyethylene glycol (PEG) on the isolation of Chlamydia trachomatis was evaluated in our laboratory. Initial range-finding experiments demonstrated that the number of chlamydial inclusion bodies increased with increasing PEG concentrations. However, PEG concentrations above 10.5% became progressively more toxic to the McCoy cell monolayers. When 50 frozen clinical Chlamydia isolates were inoculated onto McCoy cell cultures with and without 7% PEG, the PEG-treated cultures produced three- to fivefold more chlamydial inclusions than cultures without PEG. This enhancement was also observed when 1,144 fresh clinical specimens from a low-prevalence population were tested. With fresh clinical specimens, PEG-treated cultures produced two- to sixfold more inclusions than standard cultures. The addition of 7% PEG to the chlamydial overlay medium significantly increased the number of inclusions in each culture, improved the sensitivity of the culture, and decreased the probability of missing a weakly positive specimen.

  16. Synthesis and Characterization of Polyethylene Glycol Mediated Silver Nanoparticles by the Green Method

    PubMed Central

    Shameli, Kamyar; Ahmad, Mansor Bin; Jazayeri, Seyed Davoud; Sedaghat, Sajjad; Shabanzadeh, Parvaneh; Jahangirian, Hossein; Mahdavi, Mahnaz; Abdollahi, Yadollah

    2012-01-01

    The roles of green chemistry in nanotechnology and nanoscience fields are very significant in the synthesis of diverse nanomaterials. Herein, we report a green chemistry method for synthesized colloidal silver nanoparticles (Ag NPs) in polymeric media. The colloidal Ag NPs were synthesized in an aqueous solution using silver nitrate, polyethylene glycol (PEG), and β-D-glucose as a silver precursor, stabilizer, and reducing agent, respectively. The properties of synthesized colloidal Ag NPs were studied at different reaction times. The ultraviolet-visible spectra were in excellent agreement with the obtained nanostructure studies performed by transmission electron microscopy (TEM) and their size distributions. The Ag NPs were characterized by utilizing X-ray diffraction (XRD), zeta potential measurements and Fourier transform infrared (FT-IR). The use of green chemistry reagents, such as glucose, provides green and economic features to this work. PMID:22837654

  17. [Electrolyte solution with polyethylene glycol to cleanse the colon for colonoscopy or enema].

    PubMed

    Valdovinos, M A; Male, R; Gil, S; Gallo, S; Tielve, M; Ferral, H

    1990-01-01

    The efficacy and safety of an electrolyte-polyethylene glycol solution (SE-PEG) for colonic lavage, was compared with standard bowel preparation (SBP) in a randomized blinded study of volunteers and patients undergoing colonoscopy and barium enema examination. Side effects, biochemical and hematologic changes and quality of examinations were monitored. Colonoscopy and barium enema was scored by colonic segment for type of residual stool and percentage of bowel wall visualized. For colonoscopy and barium enema, preparation with SE-PEG allowed better visualization and produced more optimal exams (8 vs 3; p less than 0.03) and (6 vs 4; p = NS) respectively. We conclude that colonic lavage with SE-PEG is an alternative bowel preparation method and is cheaper, more safe and effective than SBP procedure.

  18. Polyethylene glycol modified PAMAM dendrimer delivery of kartogenin to induce chondrogenic differentiation of mesenchymal stem cells.

    PubMed

    Hu, Qing; Ding, Bomei; Yan, Xiuyun; Peng, Liyuan; Duan, Jia; Yang, Shu; Cheng, Lifang; Chen, Dawei

    2017-10-01

    Partly PEGylated polyamidoamine (PAMAM) dendrimer was used as the nanocarrier for the cytoplasmic delivery of kartogenin (KGN) to induce chondrogenic differentiation of mesenchymal stem cells (MSCs). Here, KGN was conjugated to the surface of PAMAM and the end group of polyethylene glycol (PEG) to obtain PEG-PAMAM-KGN (PPK) and KGN-PEG-PAMAM (KPP) conjugate, respectively. The effects of PPK and KPP on the in vitro chondrogenic differentiation of MSCs were evaluated. KPP induced higher expression of chondrogenic markers than PPK and free KGN. In particular, after treatment of KPP, CBF β nuclear localization intensity was significantly increased, indicating enhanced efficacy of chondrogenesis. The fluorescein labeled PEG-PAMAM was capable to persist in the joint cavity for a prolonged time of both healthy and osteoarthritis (OA) rats. Thus, PEG-PAMAM could be a useful nanocarrier for intra-articular (IA) delivery of drug to treat OA. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. 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

  20. Efficiency and biocompatibility of a polyethylene glycol grafted cellulosic membrane during hemodialysis.

    PubMed

    Akizawa, T; Kino, K; Koshikawa, S; Ikada, Y; Kishida, A; Yamashita, M; Imamura, K

    1989-01-01

    Dialytic efficiency and biocompatibility of a new modified cellulose membrane (NMC) were examined in vitro and clinically. NMC was obtained by grafting polyethylene-glycol (PEG) chains to the membrane surface of ordinary cellulose (OC), and it was expected that the random movement of PEG chains would prevent blood cells and large plasma proteins from coming into contact with the membrane surface, resulting in improving the biocompatibility and thrombogenicity of the membrane. Surface characteristics of NMC were rendered anionic and hydrophilic, however, the activations of complement and platelet systems were clearly suppressed in NMC. Minimum heparin requirement for hemodialysis was significantly lower with NMC than with OC dialyzer. No significant difference in solute and water removal was observed between the two dialyzers. These results indicate that NMC can provide increased biocompatibility and antithrombogenic effect while retaining the essential dialysis efficiency of OC.

  1. Polyethylene glycol-grafted poly-L-lysine as polymeric gene carrier.

    PubMed

    Choi, Y H; Liu, F; Kim, J S; Choi, Y K; Park, J S; Kim, S W

    1998-06-01

    A new series of gene carriers, polyethylene glycol (PEG)-grafted poly-L-lysine (PLL, mol. wt. = 25000) with three different PEG-grafted ratios (5, 10 and 25 mole%, which means 5, 10 and 25% of epsilon-amino group of PLL was modified by PEG), was synthesized. These new gene carriers, named comb-shaped PEG-g-PLL copolymer, showed a 5- to 30-fold increase in transfection efficiency compared to PLL alone on a human carcinoma cell line. It is likely that Hep G2 cells were transfected by plasmid DNA/PEG-g-PLL complexes through an endocytosis mechanism due to the fact that chloroquine increased transfection efficiency. Although Lipofectin, a cationic lipid formulation, showed slightly higher transfection efficiency than PEG-g-PLL in Hep G2 cells, our designed PEG-g-PLL demonstrated lower cytotoxicity, early gene expression and maintenance of gene expression for up to 96 h.

  2. Clinical effects of a polyethylene glycol grafted cellulose membrane on thrombogenicity and biocompatibility during hemodialysis.

    PubMed

    Akizawa, T; Kino, K; Kinugasa, E; Koshikawa, S; Ikada, Y; Kishida, A; Hatanaka, Y; Imamura, K

    1990-01-01

    The biocompatibility and thrombogenicity of polyethylene-glycol (PEG)-grafted cellulose hemodialysis (HD) membranes (PEGC) were investigated in cross-over HD of five HD patients with ordinary cellulose (OC). The PEGC significantly suppressed transient leukocyte and thrombocytopenia, and release of C3a, beta-thromboglobulin and platelet factor 4, in corresponding with the quantity of grafted PEG. HD with PEGC resulted in lower granulocyte elastase production, protein and blood cells adsorption on the membrane surface than those with OC. Minimum heparin in HD with PEGC was three times lower than that with OC, with the thrombin-antithrombin III complex elevation lower than that in HD with OC. The results indicate that the grafted PEG effectively suppresses blood and membrane interaction, thus improving biocompatibility and reducing thrombogenicity in clinical HD.

  3. Properties of diffraction gratings holographically recorded in poly(ethylene glycol)dimethacrylate-ionic liquid composites

    NASA Astrophysics Data System (ADS)

    Ellabban, Mostafa A.; Glavan, Gašper; Flauger, Peter; Klepp, Jürgen; Fally, Martin

    2017-05-01

    We investigated recording and readout of transmission gratings in composites of poly(ethylene glycol) dimethacrylate (PEGDMA) and ionic liquids (IL) in detail. Gratings were recorded using a two-wave mixing technique for different grating periods, exposures and a series of film thicknesses. The recording kinetics as well as the post-exposure behavior of the gratings were studied by diffraction experiments. We found that - depending on the parameters - different grating types (pure phase or mixed) are generated, and at elevated thicknesses strong light-induced scattering develops. Gratings with thicknesses up to 85 micrometers are of the required quality with excellent optical properties, thicker gratings exhibit strong detrimental light-induced scattering. The obtained results are particularly valuable when considering PEGDMA-ionic liquid composites for applications as e.g., holographic storage materials or as neutron optic diffractive elements.

  4. Development of Macroporous Poly(ethylene glycol) Hydrogel Arrays Within Microfluidic Channels

    PubMed Central

    Lee, Andrew G.; Arena, Christopher P.; Beebe, David J.; Palecek, Sean P.

    2010-01-01

    The mass transport of solutes through hydrogels is an important design consideration in materials used for tissue engineering, drug delivery, and protein arrays used to quantify protein concentration and activity. We investigated the use of poly(ethylene glycol) (PEG) as a porogen to enhance diffusion of macromolecules into the interior of polyacrylamide and PEG hydrogel posts photopatterned within microfluidic channels. The diffusion of GST–GFP and dextran–FITC into hydrogels was monitored and effective diffusion coefficients were determined by fitting to the Fickian diffusion equations. PEG-diacrylate (Mr 700) with porogen formed a macroporous structure and permitted significant penetration of 250 kDa dextran. Proteins copolymerized in these macroporous hydrogels retained activity and were more accessible to antibody binding than proteins copolymerized in nonporous gels. These results suggest that hydrogel macroporosity can be tuned to regulate macromolecular transport in applications such as tissue engineering and protein arrays. PMID:21028794

  5. 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.

  6. Size exclusion chromatography with Corona charged aerosol detector for the analysis of polyethylene glycol polymer.

    PubMed

    Kou, Dawen; Manius, Gerald; Zhan, Shangdong; Chokshi, Hitesh P

    2009-07-10

    A technique of using size exclusion chromatography (SEC) with the Corona charged aerosol detector (CAD) was developed and evaluated in comparison with refractive index (RI) and evaporative light scattering detection (ELSD) for fast screening of polyethylene glycol (PEG), a polymer used in preparing pegylated pharmaceutical compounds. These detection techniques were used in the analysis of multiple lots of PEG reagents. CAD was found to provide more accurate impurity and polydispersity profiles of PEG reagents that better differentiate their quality, while RI was not suitable for this application due to its low sensitivity and ELSD led to underestimation of the impurity and polydispersity. The accuracy of polydispersity determination by SEC-CAD was validated against a commercial reference standard of known polydispersity. The SEC-CAD technique and the observed differences between the three detectors can also be applied to polymer analysis in general.

  7. Adsorption of polyethylene glycol (PEG) onto cellulose nano-crystals to improve its dispersity.

    PubMed

    Cheng, Dong; Wen, Yangbing; Wang, Lijuan; An, Xingye; Zhu, Xuhai; Ni, Yonghao

    2015-06-05

    In this work, the adsorption of polyethylene glycol (PEG) onto cellulose nano-crystals (CNC) was investigated for preparing re-dispersible dried CNC. Results showed that the re-dispersity of CNC in water can be significantly enhanced using a PEG1000 dosage of 5wt% (based on the dry weight of CNC). The elemental analysis confirmed the adsorption of PEG onto the CNC surface. Transmission electron microscopy (TEM) was used to characterize the dry powder and indicated that the irreversible agglomeration of CNC after drying was essentially eliminated based on the PEG adsorption concept. Thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD) suggested that CNC crystallinity and thermal stability were not affected by the adsorption of PEG. Thus, the adsorption of PEG has great potential for producing re-dispersible powder CNC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Identification of polyethylene glycol-resistant macrophages on stealth imaging in vitro using fluorescent organosilica nanoparticles.

    PubMed

    Nakamura, Michihiro; Hayashi, Koichiro; Nakano, Mutsuki; Kanadani, Takafumi; Miyamoto, Kazue; Kori, Toshinari; Horikawa, Kazuki

    2015-02-24

    An in vitro imaging system to evaluate the stealth function of nanoparticles against mouse macrophages was established using fluorescent organosilica nanoparticles. Surface-functionalized organosilica nanoparticles with polyethylene glycol (PEG) were prepared by a one-step process, resulting in a brush-type PEG layer. A simultaneous dual-particle administration approach enabled us to evaluate the stealth function of nanoparticles with respect to single cells using time-lapse fluorescent microscopic imaging and flow cytometry analyses. Single-cell imaging and analysis revealed various patterns and kinetics of bare and PEGylated nanoparticle uptake. The PEGylated nanoparticles revealed a stealth function against most macrophages (PEG-sensitive macrophages); however, a stealth function against certain macrophages (PEG-insensitive macrophages) was not observed. We identified and characterized the PEG-resistant macrophages that could take up PEGylated nanoparticles at the same level as bare nanoparticles.

  9. Influence of polyethylene glycol on the ligation reaction with calf thymus DNA ligases I and II.

    PubMed

    Teraoka, H; Tsukada, K

    1987-01-01

    High concentrations of the nonspecific macromolecule polyethylene glycol 6000 (PEG 6000) enabled DNA ligases I and II from calf thymus to catalyze intermolecular blunt-end ligation of duplex DNA. Intermolecular cohesive-end ligation with these enzymes was markedly stimulated in the presence of 10-16% (w/v) PEG 6000. The effect of PEG 6000 (4-16%) on the sealing of single-stranded breaks in duplex DNA with DNA ligases I and II was not appreciably stimulatory but rather inhibitory. PEG 6000 (15%) enhanced more twofold the rate of DNA ligase II-AMP complex formation, but moderately suppressed the rate of formation of DNA ligase 1-AMP complex. Polyamines and KCl inhibited blunt-end and cohesive-end ligations with DNA ligases I and II in the presence of PEG 6000.

  10. Multiphoton microscopy guides neurotrophin modification with poly(ethylene glycol) to enhance interstitial diffusion

    NASA Astrophysics Data System (ADS)

    Stroh, Mark; Zipfel, Warren R.; Williams, Rebecca M.; Ma, Shu Chin; Webb, Watt W.; Saltzman, W. Mark

    2004-07-01

    Brain-derived neurotrophic factor (BDNF) is a promising therapeutic agent for the treatment of neurodegenerative diseases. However, the limited distribution of this molecule after administration into the brain tissue considerably hampers its efficacy. Here, we show how multiphoton microscopy of fluorescently tagged BDNF in brain-tissue slices provides a useful and rapid screening method for examining the diffusion of large molecules in tissues, and for studying the effects of chemical modifications-for example, conjugating with polyethylene glycol (PEG)-on the diffusion constant. This single variable, obtained by monitoring short-term diffusion in real time, can be effectively used for rational drug design. In this study on fluorescently tagged BDNF and BDNF-PEG, we identify slow diffusion as a major contributing factor to the limited penetration of BDNF, and demonstrate how chemical modification can be used to overcome this barrier.

  11. Preparative purification of polyethylene glycol derivatives with polystyrene-divinylbenzene beads as chromatographic packing.

    PubMed

    Yu, Pengzhan; Li, Xingqi; Li, Xiunan; Lu, Xiuling; Ma, Guanghui; Su, Zhiguo

    2007-10-15

    A clear and powerful chromatographic approach to purify polyethylene glycol derivatives at a preparative scale was reported, which was based on the polystyrene-divinylbenzene beads with ethanol/water as eluants. The validity of this method was verified with the reaction mixture of mPEG-Glu and mPEG propionaldehyde diethylacetal (ALD-PEG) as the model. The target products were one-step achieved with the purity of >99% on the polymer resins column at gram scale. The method developed was free from such disadvantages as utility of toxic solvent and narrow application scope, which was combined with conventional approaches. The method developed provided an appealing and attractive alternative methods for purification of PEG derivatives at a preparative scale.

  12. Analysis of polyethylene glycol (PEG) fusion in cultured neuroblastoma cells via flow cytometry: Techniques & optimization.

    PubMed

    Hoffman, Ashley N; Bamba, Ravinder; Pollins, Alonda C; Thayer, Wesley P

    2017-02-01

    Polyethylene glycol (PEG) has long been used as a membrane fusogen, but recently it has been adopted as a technique for peripheral nerve repair. Vertebrate models using PEG fusion have shown improved outcomes when PEG is applied during repair of severed peripheral nerves. The cellular mechanism of PEG fusion in the peripheral nerve repair model has not previously been assessed via flow cytometry. PEG fusion was assessed in this experiment by dying B35 rat neuroblastoma cells with different color fluorescent labels. The different color cells were combined and PEG was applied in concentrations of 50%, 75% and 100%. The amount of cell fusion was assessed via flow cytometry as the percentage of double positive cells. Results showed increasing fusion and decreasing viability with increasing concentrations of PEG.

  13. Characterization of polyethylene glycol plasticized carboxymethyl cellulose-ammonium fluoride solid biopolymer electrolytes

    NASA Astrophysics Data System (ADS)

    Ramlli, M. A.; Maksud, M. A.; Isa, M. I. N.

    2017-03-01

    An attempt to increase the ionic conductivity of solid biopolymer electrolyte (SBE) from carboxyl methylcellulose (CMC) doped with 9 wt. % of ammonium fluoride (AF) has been made by the plasticizing with polyethylene glycol (PEG). Electrochemical Impedance Spectroscopy (EIS) was used to investigate the ionic conductivity of the CMC-AF-PEG SBEs. The study shows that the highest conductivity achieved is 6.62×10-7 S cm-1 at room temperature for SBE with 25 % wt. PEG. X-Ray Diffraction (XRD) study proved that the highest conductive SBE has the highest amorphous nature which contributes to the high conductivity of the SBE. The interaction of CMC and AF was enhanced by the addition of PEG at C-O band in the CMC.

  14. Low-molecular-weight polyethylene glycol improves survival in experimental sepsis.

    PubMed

    Ackland, Gareth L; Gutierrez Del Arroyo, Ana; Yao, Song T; Stephens, Robert C; Dyson, Alexander; Klein, Nigel J; Singer, Mervyn; Gourine, Alexander V

    2010-02-01

    For several chronic inflammatory disease states, therapy is enhanced by improving the pharmacokinetic properties of anti-inflammatory drugs through conjugation with polyethylene glycol. We hypothesized that part of the beneficial action of PEGylated drugs may be derived from the anti-inflammatory properties of polyethylene glycol (PEG) itself. Randomized, double-blinded, controlled ex vivo and in vivo laboratory studies. University research laboratories. Human neutrophils and mononuclear cells, macrophage cell line, and adult rats and mice. The effect of PEG (either low-molecular-weight [200-400] or high-molecular-weight [>4000]) was assessed on survival after systemic inflammation induced by lipopolysaccharide or zymosan. The effects of PEG on zymosan, lipopolysaccharide, or streptolysin-induced inflammatory and bioenergetic responses of immune cells were also assessed. Low-molecular-weight PEG reduced inflammatory cytokine expression, pyrexia, and mortality by >50% in both lipopolysaccharide and zymosan models of sepsis. Low-molecular-weight PEG reduced cytokine expression both in vivo and in vitro, and attenuated activation of human neutrophils in response to lipopolysaccharide or zymosan. By contrast, high-molecular-weight PEG conferred less significant survival effects after lipopolysaccharide and zymosan, and it did not exhibit such profound anti-inflammatory effects. Low-molecular-weight PEG attenuated lipopolysaccharide-induced activation of pro-apoptotic pathways (lysophosphatidic acid receptor and caspase-domain signaling) in the livers of endotoxemic rats. Streptolysin-induced necrosis of human neutrophils was reduced by low-molecular-weight PEG, indicating a mechanism that involves coating and/or stabilizing the cellular membrane. Low-molecular-weight PEG preserved human neutrophil responses to septic serum and bioenergetic function in macrophages and neutrophils. PEG is a commonly used, safe, nonimmunogenic molecule possessing hitherto unappreciated

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

    NASA Astrophysics Data System (ADS)

    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

    2012-03-01

    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 (Mw) PEG molecules. By use of magnetic resonance imaging, we show coating-dependent in vivo uptake in murine tumors with an optimal coating Mw of 10 000 Da.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 (Mw) PEG molecules. By use of magnetic resonance imaging, we show coating-dependent in vivo uptake in murine tumors with an optimal coating Mw of 10 000 Da. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11554a

  16. Novel method of decellularization of porcine valves using polyethylene glycol and gamma irradiation.

    PubMed

    Ota, Takeyoshi; Taketani, Satoshi; Iwai, Shigemitsu; Miyagawa, Shuji; Furuta, Masakazu; Hara, Masayuki; Uchimura, Eiichiro; Okita, Yutaka; Sawa, Yoshiki

    2007-04-01

    Recent tissue-engineered valves are in need of a breakthrough to overcome several limitations against clinical applications. We have developed a new method of decellularization using polyethylene glycol and gamma irradiation. Fresh porcine aortic valves were decellularized using polyethylene glycol and gamma irradiation. These were evaluated by histologic, biochemical (DNA, solubilized protein and collagen content), mechanical (strength test, transmission electron microscopy) and immunologic (porcine endogenous retrovirus and the alpha-1.3 galactosyl epitope) analyses. Implantations into the subcutaneous tissue of rats (1 week, n = 10; 2 months, n = 10) and into the descending aorta of dogs (2 months, n = 6; 6 months, n = 3) were used as in vivo studies. Complete decellularization was confirmed by histologic examination and by determining the DNA and solubilized protein content. The decellularized valve showed no significant differences in its mechanical strength or collagen content compared with native porcine tissues. The ultrastructure was well preserved in transmission electron microscope images. The DNA sequence of a porcine endogenous retrovirus and the alpha-1.3 galactosyl epitope were eliminated after the decellularizing process. No acute rejection and little calcification was noted in the rat model. In the dog model at 2 months, the surface of the graft was completely covered with a monolayer of endothelial cells. In addition, several layers of vimentin-positive cells lay under the endothelial cells. At 6 months after implantation, many smooth muscle cells, monolayer endothelial cells, and some vasculogenesis were seen. The decellularizing method provided low immunogenicity, low risk of unknown infections, and was little subject to calcification. The decellularized tissues showed acceptable durability and recellularization.

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

    PubMed Central

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

    2016-01-01

    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

  18. 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

  19. 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.

  20. Swelling, sealing, and hemostatic ability of a novel biomaterial: A polyethylene glycol-coated collagen pad.

    PubMed

    Lewis, Kevin M; Spazierer, Daniel; Slezak, Paul; Baumgartner, Bernhard; Regenbogen, Johannes; Gulle, Heinz

    2014-11-01

    Trends in the development of hemostatic agents are towards self-adhering pads. This study investigates a novel biomaterial made of a polyethylene glycol-coated collagen pad (PCC). The swelling and adherence of PCC were investigated in vitro, and the hemostatic and sealing ability was investigated in vivo. In vitro, the maximum swell of PCC submerged in human plasma for 24 h is 65%. The greatest swell was in thickness, averaging 24% to a mean thickness of 2.5 ± 0.19 mm (mean±SD) (N = 20). PCC withstood clinically relevant pressures when applied to a collagen casing washed with bile, lymph, urine, saline, and cerebrospinal fluid mixed at 33% and 67% with blood. In vivo, PCC provided complete hemostasis when applied to severe, arterial bleeds of actively ventilated pulmonary parenchyma at 3, 5, 8, and 10 min after application in a heparinized porcine pulmonary segmentectomy model. The mean rate of bleeding was 17.7 ± 8.6 ml/min. The lungs were ventilated at 15 ± 4 breaths per min and an airway pressure of 19 ± 2 cm H2O. PCC had no incidence of hematoma and an 11% incidence of intraoperative air leak (N = 36). These data are promising for future clinical application of a new versatile, self-adhering hemostatic sealing pad consisting of a polyethylene glycol-coated collagen.

  1. Development of an AMBER-compatible transferable force field for poly(ethylene glycol) ethers (glymes).

    PubMed

    Barbosa, Nathalia S V; Zhang, Yong; Lima, Eduardo R A; Tavares, Frederico W; Maginn, Edward J

    2017-06-01

    An all-atom force field consistent with the general AMBER force field (GAFF) format for poly(ethylene glycol) dimethyl ether (diglyme or G2) was developed by fitting to experimental liquid densities and dielectric constants. Not surprisingly, the new force field gives excellent agreement with experimental liquid phase densities and dielectric constants over a wide temperature range. Other dynamic and thermodynamic properties of liquid G2 such as its self-diffusion coefficient, shear viscosity, and vaporization enthalpy were also calculated and compared to experimental data. For all of the properties studied, the performance of the proposed new force field is better than that of the standard GAFF force field. The force field parameters were transferred to model two other poly(ethylene glycol) ethers: monoglyme (G1) and tetraglyme (G4). The predictive ability of the modified force field for G1 and G4 was significantly better than that of the original GAFF force field. The proposed force field provides an alternative option for the simulation of mixtures containing glymes using GAFF-compatible force fields, particularly for electrochemical applications. The accuracy of a previously published force field based on the OPLS-AA format and the accuracies of two modified versions of that force field were also examined for G1, G2, and G4. It was found that the original OPLS-AA force field is superior to the modified versions of it, and that it has a similar accuracy to the proposed new GAFF-compatible force field. Graphical abstract Transferability of an AMBER-compatible force field parameterized for G2 to other glymes.

  2. Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation

    PubMed Central

    Attar, A; Lemann, M; Ferguson, A; Halphen, M; Boutron, M; Flourie, B; Alix, E; Salmeron, M; Guillemot, F; Chaussade, S; Menard, A; Moreau, J; Naudin, G; Barthet, M

    1999-01-01

    Background—Polyethylene glycol (PEG) 3350 is a non-absorbable, non-metabolised osmotic agent used in lavage solutions for gut cleansing. 
Aims—To compare the efficacy of PEG and lactulose in chronic constipation. 
Methods—A total of 115 patients with chronic constipation entered a multicentre, randomised, comparative trial. They initially received two sachets containing either PEG (13 g/sachet) or lactulose (10 g/sachet) and were given an option to change the dose to one or three sachets/day, depending on response. 
Results—Ninety nine patients completed the trial. After four weeks, patients in the PEG group (n=50) had a higher number of stools and a lower median daily score for straining at stool than patients in the lactulose group (n=49). Overall improvement was greater in the PEG group. Clinical tolerance was similar in the two groups, but flatus was less frequently reported in the PEG group. The mean number of liquid stools was higher in the PEG group but the difference was significant only for the first two weeks. There were no serious adverse events and no significant change in laboratory tests in either group. At the end of the study, the number of sachets used by the patients was 1.6 (0.7)/day in the PEG group and 2.1 (0.7)/day in the lactulose group. Sixty one patients completed a further two months open study of one to three sachets PEG daily; there was no loss of efficacy and no serious toxicity. 
Conclusion—Low dose PEG 3350 was more effective than lactulose and better tolerated. 

 Keywords: constipation; polyethylene glycol; lactulose; cathartics; randomised trial PMID:9895382

  3. Methoxy polyethylene glycol-epoetin beta for anemia with chronic kidney disease.

    PubMed

    Ohashi, Naro; Sakao, Yukitoshi; Yasuda, Hideo; Kato, Akihiko; Fujigaki, Yoshihide

    2012-01-01

    Chronic kidney disease (CKD) is a risk factor for end-stage renal failure and cardiovascular events. In patients with CKD, anemia is often caused by decreased erythropoietin production relative to hemoglobin levels. As correction of anemia is associated with improved cardiac and renal function and quality of life, erythropoiesis-stimulating agents (ESAs) are standard therapy for anemia in CKD patients. However, traditional ESAs such as epoetin or darbepoetin have short half-lives and require frequent administration, dose changes, and close monitoring of hemoglobin concentration to maintain target hemoglobin levels. Methoxy polyethylene glycol-epoetin beta (MPG-EPO) is the only ESA that is generated by chemical modification of glycosylated erythropoietin through the integration of one specific, long, linear chain of polyethylene glycol. This ESA induces continuous erythropoietin receptor activation and has a long half-life (approximately 130 hours). Subcutaneous or intravenous administration of MPG-EPO once every 2 weeks or monthly achieved a high hemoglobin response rate in patients with anemia associated with CKD, regardless of whether the patient was undergoing dialysis. According to data from an observational time and motion study, MPG-EPO maintains hemoglobin levels when the same dose is administered, however infrequently. This suggests that compared with the use of traditional ESAs, administration of MPG-EPO reduces the overall time and cost associated with the management of anemia in CKD patients undergoing dialysis. MPG-EPO is generally well tolerated and most adverse events are of mild to moderate severity. The most commonly reported adverse effects are hypertension, nasopharyngitis, and diarrhea. Subcutaneous injection of MPG-EPO is significantly less painful than subcutaneous injection of darbepoetin. In conclusion, MPG-EPO is as effective and safe as traditional ESAs in managing renal anemia, irrespective of whether the patient is undergoing dialysis.

  4. Low-volume hybrid bowel preparation combining saline laxatives with oral contrast agents versus standard polyethylene glycol lavage for colonoscopy.

    PubMed

    Lawrence, Edward M; Pickhardt, Perry J

    2010-08-01

    The aim of this study was to compare the quality of low-volume hybrid computed tomography colonography bowel preparation, using both laxatives and oral contrast, with standard polyethylene glycol lavage. The study group consisted of 300 consecutive adults (mean age, 58.3 years) who underwent colonoscopy immediately after positive computed tomography colonography. Hybrid bowel preparation for study group was <1 L in total volume, consisting of osmotic cathartic (sodium phosphate or magnesium citrate) in conjunction with oral contrast (2% barium and diatrizoate). A control group of 300 adults (mean age, 58.3 years) underwent primary colonoscopy after standard 4-liter polyethylene glycol lavage without oral contrast. The prospective preparation quality rating by the endoscopist served as the reference standard. A rating of poor/marginal was considered inadequate and adequate/good/excellent was considered diagnostic. The frequency of inadequate bowel preparation was 4.3% (13/300) in the study group vs 12.3% (37/300) for the control group (P < .001). Specifically, preparation was poor or marginal in 10 and 3 cases in the hybrid cohort, respectively, and in 29 and 8 cases in the polyethylene glycol cohort, respectively. Preparation quality was scored as excellent in 32% (96/300) in the hybrid cohort and 23.3% (70/300) in the polyethylene glycol cohort (P < .05). At colonoscopy, low-volume laxative-oral contrast hybrid preparations are effective for bowel cleansing, perhaps even more so than polyethylene glycol lavage. Beyond improvements in quality, the low-volume preparation may improve patient compliance and would allow for immediate computed tomography colonography if colonoscopy is incomplete, without the need for additional oral contrast tagging.

  5. Application of Oral Lactulose in Combination With Polyethylene Glycol Electrolyte Powder for Colonoscopy Bowel Preparation in Patients With Constipation.

    PubMed

    Lu, Juan; Cao, Qin; Wang, Xiaochun; Pu, Jianbin; Peng, Xuelian

    2016-01-01

    The aim of the study was to investigate the efficacy of combined application of lactulose oral solution and polyethylene glycol electrolyte powder compared with conventional method in preparing for colonoscopy bowel cleanliness in patients with constipation. Ninety patients, who had constipation and needed to have colonoscopy, were divided into study group and control group with 45 cases in each group, respectively. One day before the colonoscopy, patients in the experimental group were given lactulose oral solution and polyethylene glycol electrolyte powder, whereas the patients in the control group were given oral polyethylene glycol electrolyte powder only. The following parameters were then obtained: time of the first defecation (duration of the time from taking the drugs to the first bowel movement), defecation frequency, completion of bowel cleaning (duration from the first bowel movement to the stool becoming clear), and adverse reaction. Cleansing effect in the study group bowel preparation was significantly better than that in the control group (P < 0.05). Specifically, time of the first defecation and completion of bowel cleaning were statistically shorter in the study group than those in the control group (P < 0.05), and defecation frequency was significantly higher in the study group than that in the control group (P < 0.05). Incidence of adverse reaction, however, was not significantly different between the 2 groups (P > 0.05). Combined application of lactulose oral solution and polyethylene glycol electrolyte powder is superior to the conventional method of polyethylene glycol electrolyte powder alone for colonoscopy bowel preparation in patients with constipation. Therefore, combined clinical application of the 2 compounds is strongly recommended for colonoscopy bowel preparation in patients with constipation.

  6. Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins.

    PubMed

    Mascitti, Andrea; Lupacchini, Massimiliano; Guerra, Ruben; Taydakov, Ilya; Tonucci, Lucia; d'Alessandro, Nicola; Lamaty, Frederic; Martinez, Jean; Colacino, Evelina

    2017-01-01

    The mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins was investigated in the presence of various poly(ethylene) glycols (PEGs), as safe grinding assisting agents (liquid-assisted grinding, LAG). A comparative study under dry-grinding conditions was also performed. The results showed that the cyclization reaction was influenced by the amount of the PEG grinding agents. In general, cleaner reaction profiles were observed in the presence of PEGs, compared to dry-grinding procedures.

  7. Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

    PubMed Central

    Guerra, Ruben; Taydakov, Ilya; Tonucci, Lucia; d’Alessandro, Nicola; Lamaty, Frederic; Martinez, Jean

    2017-01-01

    The mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins was investigated in the presence of various poly(ethylene) glycols (PEGs), as safe grinding assisting agents (liquid-assisted grinding, LAG). A comparative study under dry-grinding conditions was also performed. The results showed that the cyclization reaction was influenced by the amount of the PEG grinding agents. In general, cleaner reaction profiles were observed in the presence of PEGs, compared to dry-grinding procedures. PMID:28179944

  8. 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.

  9. Effects of polyethylene glycol on bovine intestine alkaline phosphatase activity and stability.

    PubMed

    Sekiguchi, Satoshi; Yasukawa, Kiyoshi; Inouye, Kuniyo

    2011-01-01

    In this study, we evaluated the effects of polyethylene glycol (PEG) on bovine intestine alkaline phosphatase (BIALP) activity and stability. In the hydrolysis of p-nitrophenylphosphate (pNPP) at pH 9.8 at 20 °C, the k(cat)/K(m) values of BIALP plus 5-15% w/v free PEG with molecular masses of 1, 2, 6, and 20 kDa (PEG1000, PEG2000, PEG6000, and PEG20000 respectively) were 120-140%, 180-300%, 130-170%, and 110-140% respectively of that of BIALP without free PEG (1.8 µM(-1) s(-1)), indicating that activation by PEG2000 was the highest. Unmodified BIALP plus 5% PEG2000 and BIALP pegylated with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine exhibited 1.3-fold higher activity on average than that of BIALP without free PEG under various conditions, including pH 7.0-10.0 and 20-65 °C. The temperatures reducing initial activity by 50% in 30-min incubation of unmodified BIALP plus 5% PEG2000 and pegylated BIALP were 51 and 47 °C respectively, similar to that of BIALP without free PEG (49 °C). These results indicate that the addition of PEG2000 and pegylation increase BIALP activity without affecting its stability, suggesting that they can be used in enzyme immunoassay with BIALP to increase sensitivity and rapidity.

  10. 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.

  11. Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode.

    PubMed

    Bejankiwar, Rajesh S; Basu, Abir; Cementi, Max

    2004-01-01

    Electrochemical oxidation of polyethylene glycol (PEG) in an acidic (pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified (PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon (TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

  12. Modification of fibrinogen with poly(ethylene glycol) and its effects on fibrin clot characteristics.

    PubMed

    Barker, T H; Fuller, G M; Klinger, M M; Feldman, D S; Hagood, J S

    2001-09-15

    The suitability of existing topical fibrin glue preparations for tissue sealing or local drug delivery applications is greatly limited by their poor mechanical properties and the limited capacity of fibrinogen (Fgn) to actively bind growth factors or other therapeutic agents. Poly(ethylene glycol) (PEG) offers potential solutions to these problems by providing a mechanism for increasing the number of crosslinks between adjacent fibrin monomer molecules or for covalently crosslinking Fgn to therapeutic agents. The feasibility of this approach requires the full biological activity, or clottability, of PE glycolated Fgn. This study characterizes the clot characteristics of Fgn modified to varying degrees with monofunctional succinimidyl propionate PEG (5000 Da). The data indicate that, although thrombin clotting times are significantly altered, Fgn maintains 90% of its capacity to clot upon the addition of up to 5 PEG/Fgn. Further derivatization significantly decreases the Fgn clottability. The addition of up to 5 PEG/Fgn has little, if any, effect on the kinetics of degradation by plasmin. The results suggest that limited modification of Fgn with lysine-reactive PEG allows therapeutic enhancement of fibrin glues. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 56: 529--535, 2001

  13. Complement activation by sulfonated poly(ethylene glycol)-acrylate copolymers through alternative pathway.

    PubMed

    Jang, Hong Seok; Ryu, Kyu Eun; Ahn, Woong Shick; Chun, Heung Jae; Dal Park, Hyung; Park, Ki Dong; Kim, Young Ha

    2006-07-01

    Previously, novel poly(ethylene glycol) (PEG) and sulfonated PEG acrylate (PEG-SO(3)A/OA) copolymers were prepared as coating and/or blending materials for biomedical applications. Surfaces modified with copolymers exhibited increased anti-coagulation properties and decreased plasma adsorption level due to increased hydrophilic properties and reorientation characteristics of PEG/PEG-SO(3)A chains in water phase. As continuation study, anti-complement effects of PEG-SO(3)/OA copolymers were investigated in vitro, and compared with those of low-density polyethylene (LDPE) and PEG/OA. C3 activation by PEG-SO(3)/OA samples was lower than that by PEG/OA samples, which was attributed to decreased surface nucleophile level of samples. PEG-SO(3)/OA samples increased inhibition of Bb production, resulting in decreased C5 activation. Owing to reduced activations of C3 and C5, PEG-SO(3)/OA samples markedly decreased SC5b-9 levels in plasma.

  14. Spatially well-defined binary brushes of poly(ethylene glycol)s for micropatterning of active proteins on anti-fouling surfaces.

    PubMed

    Xu, F J; Li, H Z; Li, J; Teo, Y H Eric; Zhu, C X; Kang, E T; Neoh, K G

    2008-12-01

    We report a novel method for micropatterning of active proteins on anti-fouling surfaces via spatially well-defined and dense binary poly(ethylene glycol)s (PEGs) brushes with controllable protein-docking sites. Binary brushes of poly(poly(ethylene glycol) methacrylate-co-poly(ethylene glycol)methyl ether methacrylate), or P(PEGMA-co-PEGMEMA), and poly(poly(ethylene glycol)methyl ether methacrylate), or P(PEGMEMA), were prepared via consecutive surface-initiated atom transfer radical polymerizations (SI-ATRPs) from a resist-micropatterned Si(100) wafer surface. The terminal hydroxyl groups on the side chains of PEGMA units in the P(PEGMA-co-PEGMEMA) microdomains were activated directly by 1,1'-carbonyldiimidazole (CDI) for the covalent coupling of human immunoglobulin (IgG) (as a model active protein). The resulting IgG-coupled PEG microdomains interact only and specifically with target anti-IgG, while the other PEG microregions effectively prevent specific and non-specific protein fouling. When extended to other active biomolecules, microarrays for specific and non-specific analyte interactions with a high signal-to-noise ratio could be readily tailored.

  15. Novel chitosan hydrogel formed by ethylene glycol chitosan, 1,6-diisocyanatohexan and polyethylene glycol-400 for tissue engineering scaffold: in vitro and in vivo evaluation.

    PubMed

    Chen, Zhu; Zhao, Ming; Liu, Kang; Wan, Yuqing; Li, Xudong; Feng, Gang

    2014-08-01

    Traditional chitosan hydrogels were prepared by chemical or physical crosslinker, and both of the two kinds of hydrogels have their merits and demerits. In this study, researchers attempted to prepare one kind of chitosan hydrogel by slightly crosslinker, which could combine the advantages of the two kinds of hydrogels. In this experiment, the crosslinker was formed by a reaction between the isocyanate group of 1,6-diisocyanatohexan and the hydroxyl group of polyethylene glycol-400 (PEG-400), then the crosslinker reacted with the amidine and the hydroxyl group of ethylene glycol chitosan to form the network structure. Physical properties of the hydrogel were tested by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and biodegradation. Biocompatibility was assessed by cell implantation in vitro and the scaffold was used as a cartilage tissue engineering scaffold to repair a defect in rabbit knee joints in vivo. FTIR results show the formation of a covalent bond during thickening of the ethylene glycol chitosan. SEM and degradation experiments showed that the ethylene glycol chitosan hydrogel is a 3-D, porous, and degradable scaffold. The hydrogel contained 2% ethylene glycol chitosan and 10 μl crosslinker was selected for the biocompatibility experiment in vitro and in vivo. After chondrocytes were cultured in the ethylene glycol chitosan hydrogel scaffold for 1 week cells exhibited clustered growth and had generated extracellular matrix on the scaffold in vitro. The results in vivo showed that hydrogel-chondrocytes promoted the repair of defect in rabbits. Based on these results, it could be concluded that ethylene glycol chitosan hydrogel is a scaffold with excellent physicochemical properties and it is a promising tissue engineering scaffold.

  16. Evaluation of a chitosan-polyethylene glycol paste as a local antibiotic delivery device

    PubMed Central

    Rhodes, Cheyenne S; Alexander, Christopher M; Berretta, Joel M; Courtney, Harry S; Beenken, Karen E; Smeltzer, Mark S; Bumgardner, Joel D; Haggard, Warren O; Jennings, J Amber

    2017-01-01

    AIM To investigate the efficacy of a chitosan/polyethylene glycol blended paste as a local antibiotic delivery device, particularly in musculoskeletal wounds. METHODS Acidic (A) chitosan sponges and neutralized (N) chitosan/polyethylene glycol (PEG) blended sponges were combined in ratios of 3A:2N, 1A:1N, and 2A:3N; then hydrated with phosphate buffered saline to form a chitosan/PEG paste (CPP). Both in vitro and in vivo studies were conducted to determine the potential CPP has as a local antibiotic delivery device. In vitro biocompatibility was assessed by the cytotoxic response of fibroblast cells exposed to the experimental groups. Degradation rate was measured as the change in dry mass due to lysozyme based degradation over a 10-d period. The antibiotic elution profiles and eluate activity of CPP were evaluated over a 72-h period. To assess the in vivo antimicrobial efficacy of the CPP, antibiotic-loaded paste samples were exposed to subcutaneously implanted murine catheters inoculated with Staphylococcus aureus. Material properties of the experimental paste groups were evaluated by testing the ejection force from a syringe, as well as the adhesion to representative musculoskeletal tissue samples. RESULTS The highly acidic CPP group, 3A:2N, displayed significantly lower cell viability than the control sponge group. The equally distributed group, 1A:1N, and the highly neutral group, 2A:3N, displayed similar cell viability to the control sponge group and are deemed biocompatible. The degradation studies revealed CPP is more readily degradable than the chitosan sponge control group. The antibiotic activity studies indicated the CPP groups released antibiotics at a constant rate and remained above the minimum inhibitory concentrations of the respective test bacteria for a longer time period than the control chitosan sponges, as well as displaying a minimized burst release. The in vivo functional model resulted in complete bacterial infection prevention in all

  17. Lactulose vs Polyethylene Glycol 3350-Electrolyte Solution for Treatment of Overt Hepatic Encephalopathy

    PubMed Central

    Rahimi, Robert S.; Singal, Amit G.; Cuthbert, Jennifer A.; Rockey, Don C.

    2017-01-01

    IMPORTANCE Hepatic encephalopathy (HE) is a common cause of hospitalization in patients with cirrhosis. Pharmacologic treatment for acute (overt) HE has remained the same for decades. OBJECTIVE To compare polyethylene glycol 3350–electrolyte solution (PEG) and lactulose treatments in patients with cirrhosis admitted to the hospital for HE. We hypothesized that rapid catharsis of the gut using PEG may resolve HE more effectively than lactulose. DESIGN, SETTING, AND PARTICIPANTS The HELP (Hepatic Encephalopathy: Lactulose vs Polyethylene Glycol 3350-Electrolyte Solution) study is a randomized clinical trial in an academic tertiary hospital of 50 patients with cirrhosis (of 186 screened) admitted for HE. INTERVENTIONS Participants were block randomized to receive treatment with PEG, 4-L dose (n = 25), or standard-of-care lactulose (n = 25) during hospitalization. MAIN OUTCOMES AND MEASURES The primary end point was an improvement of 1 or more in HE grade at 24 hours, determined using the hepatic encephalopathy scoring algorithm (HESA), ranging from 0 (normal clinical and neuropsychological assessments) to 4 (coma). Secondary outcomes included time to HE resolution and overall length of stay. RESULTS A total of 25 patients were randomized to each treatment arm. Baseline clinical features at admission were similar in the groups. Thirteen of 25 patients in the standard therapy arm (52%) had an improvement of 1 or more in HESA score, thus meeting the primary outcome measure, compared with 21 of 23 evaluated patients receiving PEG (91%) (P < .01); 1 patient was discharged before final analysis and 1 refused participation. The mean (SD) HESA score at 24 hours for patients receiving standard therapy changed from 2.3 (0.9) to 1.6 (0.9) compared with a change from 2.3 (0.9) to 0.9 (1.0) for the PEG-treated groups (P = .002). The median time for HE resolution was 2 days for standard therapy and 1 day for PEG (P = .01). Adverse events were uncommon, and none was definitely

  18. 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

  19. Physical and structural characteristics of acrylated poly(ethylene glycol)-alginate conjugates.

    PubMed

    Davidovich-Pinhas, Maya; Bianco-Peled, Havazelet

    2011-07-01

    Transmucosal delivery of therapeutic agents is a non-invasive approach that utilizes human entry paths such as the nasal, buccal, rectal and vaginal routes. Mucoadhesive polymers have the ability to adhere to the mucus layer covering those surfaces and by that promote drug release, targeting and absorption. We have recently demonstrated that acrylated polymers display enhanced mucoadhesive properties due to their ability to covalently attach to mucus type glycoproteins. We have synthesized an acrylated poly(ethylene glycol)-alginate conjugate (alginate-PEGAc), a molecule which combines the gelation ability of alginate with the mucoadhesion properties arising from both the characteristics of poly(ethylene glycol) and the acrylate functionality. In the current investigation we introduce an in-depth characterization of the thermal, mechanical and structural properties of alginate-PEGAc aimed at gaining a better knowledge of its structure-function relations. The thermal stability, evaluated by thermal gravimetric analysis and differential scanning calorimetry, was compared with that of alginate and the intermediate product thiolated alginate. Dehydration at temperatures up to 200 °C was detected for all samples, followed by distinctive decomposition steps arising from the decomposition of the polymer backbone and side-chains. The nanostructure of the solutions and gels was evaluated from small angle X-ray scattering patterns, to which the "broken rod linked by flexible chain" model was fitted, and from rheology measurements. The maxima arising from electrostatic repulsion between the highly charged alginate chains was diminished for both modified alginate samples, suggesting that modification led to electrostatic screening. Alginate, thiolated alginate and alginate-PEGAc cross-linked with calcium ions demonstrated similar scattering patterns. However, different scattering intensities, gel strengths, and gelation kinetics were observed, suggesting a decrease in the

  20. Novel bone wax based on poly(ethylene glycol)-calcium phosphate cement mixtures.

    PubMed

    Brückner, Theresa; Schamel, Martha; Kübler, Alexander C; Groll, Jürgen; Gbureck, Uwe

    2016-03-01

    Classic bone wax is associated with drawbacks such as the risk of infection, inflammation and hindered osteogenesis. Here, we developed a novel self-setting bone wax on the basis of hydrophilic poly(ethylene glycol) (PEG) and hydroxyapatite (HA) forming calcium phosphate cement (CPC), to overcome the problems that are linked to the use of conventional beeswax systems. Amounts of up to 10 wt.% of pregelatinized starch were additionally supplemented as hemostatic agent. After exposure to a humid environment, the PEG phase dissolved and was exchanged by penetrating water that interacted with the HA precursor (tetracalcium phosphate (TTCP)/monetite) to form highly porous, nanocrystalline HA via a dissolution/precipitation reaction. Simultaneously, pregelatinized starch could gel and supply the bone wax with liquid sealing features. The novel bone wax formulation was found to be cohesive, malleable and after hardening under aqueous conditions, it had a mechanical performance (∼2.5 MPa compressive strength) that is comparable to that of cancellous bone. It withstood systolic blood pressure conditions for several days and showed antibacterial properties for almost one week, even though 60% of the incorporated drug vancomycin hydrochloride was already released after 8h of deposition by diffusion controlled processes. The study investigated the development of alternative bone waxes on the basis of a hydroxyapatite (HA) forming calcium phosphate cement (CPC) system. Conventional bone waxes are composed of non-biodegradable beeswax/vaseline mixtures that are often linked to infection, inflammation and hindered osteogenesis. We combined the usage of bioresorbable polymers, the supplementation with hemostatic agents and the incorporation of a mineral component to overcome those drawbacks. Self-setting CPC precursors (tetracalcium phosphate (TTCP), monetite) were embedded in a resorbable matrix of poly(ethylene glycol) (PEG) and supplemented with pregelatinized starch. This

  1. Insulin Particle Formation in Supersaturated Aqueous Solutions of Poly(Ethylene Glycol)

    PubMed Central

    Bromberg, Lev; Rashba-Step, Julia; Scott, Terrence

    2005-01-01

    Protein microspheres are of particular utility in the field of drug delivery. A novel, completely aqueous, process of microsphere fabrication has been devised based on controlled phase separation of protein from water-soluble polymers such as polyethylene glycols. The fabrication process results in the formation of spherical microparticles with narrow particle size distributions. Cooling of preheated human insulin-poly(ethylene glycol)-water solutions results in the facile formation of insulin particles. To map out the supersaturation conditions conducive to particle nucleation and growth, we determined the temperature- and concentration-dependent boundaries of an equilibrium liquid-solid phase separation. The kinetics of formation of microspheres were followed by dynamic and continuous-angle static light scattering techniques. The presence of PEG at a pH that was close to the protein's isoelectric point resulted in rapid nucleation and growth. The time elapsed from the moment of creation of a supersaturated solution and the detection of a solid phase in the system (the induction period, tind) ranged from tens to several hundreds of seconds. The dependence of tind on supersaturation could be described within the framework of classical nucleation theory, with the time needed for the formation of a critical nucleus (size <10 nm) being much longer than the time of the onset of particle growth. The growth was limited by cluster diffusion kinetics. The interfacial energies of the insulin particles were determined to be 3.2–3.4 and 2.2 mJ/m2 at equilibrium temperatures of 25 and 37°C, respectively. The insulin particles formed as a result of the process were monodisperse and uniformly spherical, in clear distinction to previously reported processes of microcrystalline insulin particle formation. PMID:16254391

  2. 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

  3. Self-nanoemulsifying drug delivery system of cefpodoxime proxetil containing tocopherol polyethylene glycol succinate.

    PubMed

    Bajaj, Amrita; Rao, Monica R P; Khole, Ishwar; Munjapara, Ghansham

    2013-05-01

    Lipid based drug delivery systems have gained prominence in last decade for drugs with dissolution rate limited oral bioavailability. To improve the solubility, permeability and oral bioavailability of cefpodoxime proxetil, β-lactam antibiotic. It is BCS Class IV drug having solubility 400 µg/mL and 50% oral bioavailability. Self-nanoemulsifying drug delivery system (SNEDDS) using various surfactant and cosurfactants such as tween 80, tocopheryl polyethylene glycol succinate (TPGS), propylene glycol and Capmul MCM as oil phase were prepared. Ternary phase diagrams were constructed to identify stable microemulsion region. Percent transmittance studies helped to shortlist the surfactant-cosurfactant combination. Tween 80 and TPGS as surfactants and Capmul MCM as oil phase were found to produce stable nanoemulsions. Five formulations of SNEDDS had globule size of 55-60 nm and zeta potential of -4 to -11 mV. Self-emulsification time was between 221 and 370 s, while viscosity was dependent on composition of SNEDDS. Cloud point was above 70°C which indicated the retention of in vivo self-emulsifying properties. Average flux for cefpodoxime proxetil (CP) and SNEDDS was 0.104 and 0.985 µg/cm(2) min. Permeability was 19.72 and 206 for CP and SNEDDS. Liquid SNEDDS spray coated onto micropellets of microcrystalline cellulose (18-20#) were analysed by scanning electron microscope (SEM), self-emulsification and in vitro dissolution. A 5.36-fold increase in area under curve AUC(0-∞) was observed for CP-SNEDDS than plain drug. Minimum inhibitory concentration (MIC) was lower for SNEDDS. Liquid and SNEDDS micropellets were stable under accelerated conditions. SNEDDS formulations led to improved oral bioavailability due to enhanced solubilization of selected drug.

  4. 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

  5. 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.

  6. Synthesis and characterization of injectable, water-soluble copolymers of tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates.

    PubMed

    Anderson, Brian C; Mallapragada, Surya K

    2002-11-01

    Several homopolymers and copolymers of 2-(diethylamino)ethyl methacrylate (DEAEM) and poly(ethylene glycol) methyl ether methacrylate (PEGMEM) were synthesized using anionic polymerization initiated by potassium t-butoxide. The polymers were characterized by average molecular weight, polydispersity and monomeric unit composition. A very narrow molecular weight distribution was achieved with a well-controlled composition. The glass transition temperatures and compositions of the copolymers followed a Gordon-Taylor relationship. The water solubility and biocompatibility of the copolymers was compared to their parent homopolymers to determine if the addition of a poly(ethylene glycol) group was sufficient to solubilize the polymers in aqueous buffer solutions and to increase the biocompatibility of the polymers. These water-soluble, injectable cationic copolymers have potential applications in gene delivery as well as other biomaterial applications.

  7. Thermoreversible sol-gel transition of an aqueous solution of polyrotaxane composed of highly methylated alpha-cyclodextrin and polyethylene glycol.

    PubMed

    Kidowaki, Masatoshi; Zhao, Changming; Kataoka, Toshiyuki; Ito, Kohzo

    2006-10-21

    Novel thermo-gelling aqueous solution systems are developed with a polyrotaxane, consisting of methylated alpha-cyclodextrin and polyethylene glycol, based on the slide-ring properties of the macrocycles along the linear chain.

  8. Water loss and polyethylene glycol-mediated acclimatization of in vitro-grown seedlings of 5 cultivars of date palm (Phoenix dactylifera L.) plantlets.

    PubMed

    Zaid, A; Hughes, H

    1995-03-01

    Plantlets derived from shoot-tips of seedlings from five cultivars of date palm, Phoenix dactylifera L., were subjected to polyethylene glycol in liquid medium. Comparisons of water loss of detached leaves among in vitro-grown, polyethylene glycol-treated and greenhouse-grown plants showed significant differences with treatment for all cultivars studied. For each treatment, significant differences were also found among cultivars. The common result was that the percent of moisture loss of non-treated in vitro-grown plantlets was almost twice that of greenhouse-grown plants. Polyethylene glycol-treated plantlets showed a water loss of approximately 27%, similar to that of greenhouse plants as compared to an average of 40% in control plants. This demonstrates the possibility of using polyethylene glycol as an osmoticum for in vitro acclimatization of plantlets prior to transfer to soil.

  9. 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.

  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. 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.

  12. Effect of Coffee Added to a Polyethylene glycol plus Ascorbic acid Solution for Bowel Preparation prior to Colonoscopy.

    PubMed

    Jung, Sung Won; Moh, In Ho; Yoo, Hana; Jang, Sung Ill; Shin, Su Rin; Kim, Jin Bae; Park, Sang Hoon; Lee, Myung Seok

    2016-03-01

    Conventional bowel cleansers for colonoscopy have an unpleasant taste and a large volume of solution must be ingested. Coffee increases bowel motility and has an intense flavor. The addition of coffee to a polyethylene glycol+ascorbic acid solution reduces the volume of the solution to be consumed without reducing efficacy, improves the taste of the solution and enhances patient comfort. Outpatients with clinical indication or people who wanted screening for cancer were considered eligible. Control group (PEGAS group) consumed a 1-L solution of polyethylene glycol+ascorbic acid twice. Study group (COF group) consumed 750 mL of coffee+polyethylene glycol+ascorbic acid twice. Bowel cleansing was rated using the Aronchick, Ottawa scale, polyp detection rate and colonoscopic insertion time. Tolerability, acceptability, preference, and adverse events were investigated by questionnaires. The COF group had non-inferiority in efficacy (non-inferiority margin, -15%; lower limit of 95% confidence interval for difference between success rates, -4.7% and -8.4% from both scales, respectively). Polyp detection rates were 0.48 and 0.60, respectively (P=0.067). Colonoscopic insertion times were 323.6+/-166.8 s and 330.7+/-243.6 s, respectively (P=0.831). Significant improvement was observed with respect to ease of drinking (P=0.012), taste (P=0.026) and preference (P=0.046) in the COF group. Adverse events occurred in 52.4% and 60.4% in the two groups, respectively (P = 0.251). The addition of coffee to polyethylene glycol+ascorbic acid solution reduces the required volume for bowel preparation without reduced efficacy and enhances patient comfort in coffee-drinkers.

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

    PubMed

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

    2013-12-07

    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.

  14. Pervaporation separation of n-heptane/thiophene mixtures by polyethylene glycol membranes: Modeling and experimental.

    PubMed

    Lin, Ligang; Zhang, Yuzhong; Kong, Ying

    2009-11-01

    Gasoline desulfurization by membrane processes is a newly emerged technology, which has provided an efficient new approach for sulfur removal and gained increasing attention of the membrane and petrochemical field. A deep understanding of the solution/diffusion of gasoline molecules on/in the membrane can provide helpful information in improving or optimizing membrane performance. In this study, a desulfurization mechanism of polyethylene glycol (PEG) membranes has been investigated by the study of sorption and diffusion behavior of typical sulfur and hydrocarbon species through PEG membranes. A solution-diffusion model based on UNIFAC and free volume theory has been established. Pervaporation (PV) and sorption experiments were conducted to compare with the model calculation results and to analyze the mass transport behavior. The dynamic sorption curves for pure components and the sorption experiments for binary mixtures showed that thiophene, which had a higher solubility coefficient than n-heptane, was the preferential sorption component, which is key in the separation of thiophene/hydrocarbon mixtures. In all cases, the model calculation results fit well the experimental data. The UNIFAC model was a sound way to predict the solubility of solvents in membranes. The established model can predict the removal of thiophene species from hydrocarbon compounds by PEG membranes effectively.

  15. Comparative study of the viscoelastic mechanical behavior of agarose and poly(ethylene glycol) hydrogels.

    PubMed

    Roberts, Justine J; Earnshaw, Audrey; Ferguson, Virginia L; Bryant, Stephanie J

    2011-10-01

    This study presents a comparative investigation into differences in the mechanical properties between two hydrogels commonly used in cartilage tissue engineering [agarose vs. poly(ethylene glycol) (PEG)], but which are formed through distinctly different crosslinking mechanisms (physical vs. covalent, respectively). The effects of hydrogel chemistry, precursor concentration, platen type (nonporous vs. porous) used in compression bioreactors, and degradation (for PEG) on the swelling properties and static and dynamic mechanical properties were examined. An increase in precursor concentration resulted in decreased equilibrium mass swelling ratios but increased equilibrium moduli and storage moduli for both hydrogels (p < 0.05). Agarose displayed large stress relaxations and a frequency dependence indicating its viscoelastic properties. Contrarily, PEG hydrogels displayed largely elastic behavior with minimal stress relaxation and frequency dependence. In biodegradable PEG hydrogels, the largely elastic behavior was retained during degradation. The type of platen did not affect static mechanical properties, but porous platens led to a reduced storage modulus for both hydrogels implicating fluid flow. In summary, agarose and PEG exhibit vastly different mechanical behaviors; a finding largely attributed to differences in their chemistries and fluid movement. Taken together, these design choices (hydrogel chemistry/structure, loading conditions) will likely have a profound effect on the tissue engineering outcome. Copyright © 2011 Wiley Periodicals, Inc.

  16. Rheological and recovery properties of poly(ethylene glycol) diacrylate hydrogels and human adipose tissue.

    PubMed

    Patel, Parul Natvar; Smith, Connie Kathleen; Patrick, Charles W

    2005-06-01

    The viscosity and elastic and viscous moduli of poly(ethylene glycol) diacrylate (PEGDA) hydrogels and human abdominal adipose tissue are measured as a function of shear rate and frequency. Results indicate that both materials exhibit shear thinning and are viscoelastic in nature. Rheological tests suggest that the hydrogels become firmer as strain and frequency increase. Adipose tissue, however, begins to fail at higher strains and frequencies. This behavior is confirmed by measuring the complex modulus of both materials as a function of strain. Recovery properties are also measured for each material as a function of deformation. Although PEGDA hydrogels are able to recover up to 78% of their original height after 15% deformation, adipose tissue is not able to recover over the range of deformations tested. The frequencies and strains over which the tests are conducted are those physiologically experienced by the human body. The hydrogels are able to withstand this range of forces and, hence, are appropriate for use as a soft tissue filler material. In addition, the hydrogels swell 38.1% +/- 0.9% independent of surface area. The complex modulus of hydrogels of varying polymer concentrations is also measured as a function of strain to determine the effects of changing polymer content. These results indicate that as polymer content increases, the hydrogels become firmer due to the higher number of polymer chains and behave more elastically. Copyright 2005 Wiley Periodicals, Inc.

  17. 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.

  18. 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.

  19. Partitioning of alcohol ethoxylates and polyethylene glycols in the marine environment: field samplings vs laboratory experiments.

    PubMed

    Traverso-Soto, Juan M; Brownawell, Bruce J; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2014-08-15

    Nowadays, alcohol ethoxylates (AEOs) constitute the most important group of non-ionic surfactants, used in a wide range of applications such as household cleaners and detergents. Significant amounts of these compounds and their degradation products (polyethylene glycols, PEGs, which are also used for many other applications) reach aquatic environments, and are eliminated from the water column by degradation and sorption processes. This work deals with the environmental distribution of AEOs and PEGs in the Long Island Sound Estuary, a setting impacted by sewage discharges from New York City (NYC). The distribution of target compounds in seawater was influenced by tides, consistent with salinity differences, and concentrations in suspended solid samples ranged from 1.5 to 20.5 μg/g. The more hydrophobic AEOs were mostly attached to the particulate matter whereas the more polar PEGs were predominant in the dissolved form. Later, the sorption of these chemicals was characterized in the laboratory. Experimental and environmental sorption coefficients for AEOs and PEGs showed average values from 3607 to 164,994 L/kg and from 74 to 32,862 L/kg, respectively. The sorption data were fitted to a Freundlich isotherm model with parameters n and log KF between 0.8-1.2 and 1.46-4.39 L/kg, respectively. AEO and PEG sorptions on marine sediment were also found to be mostly not affected by changes in salinity.

  20. Limitations of polyethylene glycol-induced precipitation as predictive tool for protein solubility during formulation development.

    PubMed

    Hofmann, Melanie; Winzer, Matthias; Weber, Christian; Gieseler, Henning

    2017-01-20

    Polyethylene glycol (PEG)-induced protein precipitation is often used to extrapolate apparent protein solubility at specific formulation compositions. The procedure was used for several fields of application such as protein crystal growth but also protein formulation development. Nevertheless, most studies focused on applicability in protein crystal growth. In contrast, this study focuses on applicability of PEG-induced precipitation during high-concentration protein formulation development. In this study, solubility of three different model proteins was investigated over a broad range of pH. Solubility values predicted by PEG-induced precipitation were compared to real solubility behaviour determined by either turbidity or content measurements. Predicted solubility by PEG-induced precipitation was confirmed for an Fc fusion protein and a monoclonal antibody. In contrast, PEG-induced precipitation failed to predict solubility of a single-domain antibody construct. Applicability of PEG-induced precipitation as indicator of protein solubility during formulation development was found to be not valid for one of three model molecules. Under certain conditions, PEG-induced protein precipitation is not valid for prediction of real protein solubility behaviour. The procedure should be used carefully as tool for formulation development, and the results obtained should be validated by additional investigations. © 2017 Royal Pharmaceutical Society.

  1. Low doses of TiO2-polyethylene glycol nanoparticles stimulate proliferation of hepatocyte cells.

    PubMed

    Sun, Qingqing; Kanehira, Koki; Taniguchi, Akiyoshi

    2016-01-01

    This paper describes the effect of low concentrations of 100 nm polyethylene glycol-modified TiO2 nanoparticles (TiO2-PEG NPs) on HepG2 hepatocellular carcinoma cells. Proliferation of HepG2 cells increased significantly when the cells were exposed to low doses (<100 μg ml(-1)) of TiO2-PEG NPs. These results were further confirmed by cell counting experiments and cell cycle assays. Cellular uptake assays were performed to determine why HepG2 cells proliferate with low-dose exposure to TiO2-PEG NPs. The results showed that exposure to lower doses of NPs led to less cellular uptake, which in turn decreased cytotoxicity. We therefore hypothesized that TiO2-PEG NPs could affect the activity of hepatocyte growth factor receptors (HGFRs), which bind to hepatocyte growth factor and stimulate cell proliferation. The localization of HGFRs on the surface of the cell membrane was detected via immunofluorescence staining and confocal microscopy. The results showed that HGFRs aggregate after exposure to TiO2-PEG NPs. In conclusion, our results indicate that TiO2-PEG NPs have the potential to promote proliferation of HepG2 cells through HGFR aggregation and suggest that NPs not only exhibit cytotoxicity but also affect cellular responses.

  2. 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%.

  3. Chemical dechlorination of hexachlorobenzene with polyethylene glycol and hydroxide: Dominant effect of temperature and ionic potential

    NASA Astrophysics Data System (ADS)

    Xiao, Ye; Jiang, Jianguo; Huang, Hai

    2014-09-01

    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.

  4. 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

  5. Synthesis and characterization of macroporous poly(ethylene glycol)-based hydrogels for tissue engineering application.

    PubMed

    Sannino, A; Netti, P A; Madaghiele, M; Coccoli, V; Luciani, A; Maffezzoli, A; Nicolais, L

    2006-11-01

    Peptide activated poly(ethylene glycol) (PEG)-based hydrogels have received wide attention as material for tissue engineering application. However, the close structure of these materials may pose severe barriers to tissue invasion and nutrient transport. The aim of this work was to synthesize highly interconnected macroporous PEG hydrogels, suitable for use as tissue engineering scaffolds, by combining the photocrosslinking reaction with a foaming process. In particular, various porous samples, differing for both the polymer molecular weight and concentration in the starting precursor solution, have been prepared and characterized by means of scanning electron microscopy and mercury porosimetry. Moreover, water swelling properties have been evaluated and compared with those of the conventional nonporous ones, by performing both equilibrium and kinetic swelling measurements in distilled water. Results indicated that foamed hydrogels display a well-interconnected porous network, suitable for tissue invasion and free molecular trafficking within them. Pores dimension as well as swelling rate can be modulated by polymer concentrations and bubbling agent composition in the precursor solution.

  6. Production of L-phenylacetylcarbinol by microbial transformation in polyethylene glycol-induced cloud point system.

    PubMed

    Zhang, Wenzhi; Wang, Zhilong; Li, Wei; Zhuang, Baohua; Qi, Hanshi

    2008-02-01

    Microbial transformation of benzaldehyde into L: -phenylacetylcarbinol by whole cell Saccharomyces cerevisiae has been carried out in a novel polyethylene glycol (PEG)-induced cloud point system. The system is composed of 80 g PEG 20,000, 75 ml Triton X-100, 20 g peptone, 10 g yeast extract, 25 g glucose, 1 g MgSO(4).7H(2)O, 0.05 g CaCl(2).2H(2)O, 35 g Na(2)HPO(4).12H(2)O, and 10.7 g citric acid per liter of tap water. The microbial transformation is conducted at 0.6 ml of acetaldehyde (35% volume content), 0.9 ml of benzaldehyde, and 7 g of wet cell per 100 ml of the PEG-induced cloud point system. Under the conditions, a relatively longer-term bioactivity of whole cell microorganism in the PEG-induced cloud point system has been achieved. A fed-batch microbial transformation process with a discrete addition of glucose and substrate gets a high final product concentration of about 8 g/l.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. Differential immunotoxicities of poly(ethylene glycol)-vs. poly(carboxybetaine)-coated nanoparticles

    PubMed Central

    Elsabahy, Mahmoud; Li, Ang; Zhang, Fuwu; Sultan, Deborah; Liu, Yongjian; Wooley, Karen L.

    2013-01-01

    Although the careful selection of shell-forming polymers for the construction of nanoparticles is an obvious parameter to consider for shielding of core materials and their payloads, providing for prolonged circulation in vivo by limiting uptake by the immune organs, and thus, allowing accumulation at the target sites, the immunotoxicities that such shielding layers elicit is often overlooked. For instance, we have previously performed rigorous in vitro and in vivo comparisons between two sets of nanoparticles coated with either non-ionic poly(ethylene glycol) (PEG) or zwitterionic poly(carboxybetaine) (PCB), but only now report the immunotoxicity and anti-biofouling properties of both polymers, as homopolymers or nanoparticle-decorating shell, in comparison to the uncoated nanoparticles, and Cremophor-EL, a well-known low molecular weight surfactant used for formulation of several drugs. It was found that both PEG and PCB polymers could induce the expression of cytokines in vitro and in vivo, with PCB being more immunotoxic than PEG, which corroborates the in vivo pharmacokineties and biodistribution profiles of the two sets of nanoparticles. This is the first study to report on the ability of PEG, the most commonly utilized polymer to coat nanomaterials, and PCB, an emerging zwitterionic anti-biofouling polymer, to induce the secretion of cytokines and be of potential immunotoxicity. Furthermore, we report here on the possible use of immunotoxicity assays to partially predict in vivo pharmacokineties and biodistribution of nanomaterials. PMID:24056145

  12. Amphiphilic copolymers reduce aggregation of unfolded lysozyme more effectively than polyethylene glycol

    NASA Astrophysics Data System (ADS)

    Chin, Jaemin; Mustafi, Devkumar; Poellmann, Michael J.; Lee, Raphael C.

    2017-02-01

    Certain amphiphilic block copolymers are known to prevent aggregation of unfolded proteins. To better understand the mechanism of this effect, the optical properties of heat-denatured and dithiothreitol reduced lysozyme were evaluated with respect to controls using UV–Vis spectroscopy, transmission electron microscopy (TEM) and circular dichroism (CD) measurements. Then, the effects of adding Polyethylene Glycol (8000 Da), the triblock surfactant Poloxamer 188 (P188), and the tetrablock copolymer Tetronic 1107 (T1107) to the lysozyme solution were compared. Overall, T1107 was found to be more effective than P188 in inhibiting aggregation, while PEG exhibited no efficacy. TEM imaging of heat-denatured and reduced lysozymes revealed spherical aggregates with on average 250–450 nm diameter. Using CD, more soluble lysozyme was recovered with T1107 than P188 with β-sheet secondary structure. The greater effectiveness of the larger T1107 in preventing aggregation of unfolded lysozyme than the smaller P188 and PEG points to steric hindrance at play; signifying the importance of size match between the hydrophobic region of denatured protein and that of amphiphilic copolymers. Thus, our results corroborate that certain multi-block copolymers are effective in preventing heat-induced aggregation of reduced lysozymes and future studies warrant more detailed focus on specific applications of these copolymers.

  13. Synthesis and Thermal Responses of Polygonal Poly(ethylene glycol) Analogues.

    PubMed

    Kawasaki, Shunichi; Muraoka, Takahiro; Hamada, Tsutomu; Shigyou, Kazuki; Nagatsugi, Fumi; Kinbara, Kazushi

    2016-04-05

    As a new type of topological poly(ethylene glycol) (PEG) analogue, a series of polygonal PEGs with digonal to hexagonal structures were developed. Polygonal PEGs with structures between the digonal and tetragonal types showed molecular-level dispersion in water at 20 °C, whereas the pentagonal and hexagonal PEGs aggregated, which is suggestive of enhanced hydrophobicity by ring expansion. Heating induced conformational changes in the polygonal PEGs and increased their hydrophobicity. Among the polygonal PEGs, only the trigonal and hexagonal PEGs showed a distinct thermal response to form and increase the size of the aggregates, respectively. Given that tetragonal and pentagonal PEGs only marginally responded to heat treatment, the thermal responses are likely due to a topological effect. At low temperatures, the larger polygonal PEGs are more restricted despite the expanded rings. The trigonal PEG showed the largest change in mobility, whereas the tetragonal PEG exhibited the smallest change. Hence, the topology of the polygonal PEGs influences the intramolecular packing and the local dynamics.

  14. 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

  15. Evaluation and modeling of the eutectic composition of various drug-polyethylene glycol solid dispersions.

    PubMed

    Baird, Jared A; Taylor, Lynne S

    2011-06-01

    The purpose of this study was to gain a better understanding of which factors contribute to the eutectic composition of drug-polyethylene glycol (PEG) blends and to compare experimental values with predictions from the semi-empirical model developed by Lacoulonche et al. Eutectic compositions of various drug-PEG 3350 solid dispersions were predicted, assuming athermal mixing, and compared to experimentally determined eutectic points. The presence or absence of specific interactions between the drug and PEG 3350 were investigated using Fourier transform infrared (FT-IR) spectroscopy. The eutectic composition for haloperidol-PEG and loratadine-PEG solid dispersions was accurately predicted using the model, while predictions for aceclofenac-PEG and chlorpropamide-PEG were very different from those experimentally observed. Deviations in the model prediction from ideal behavior for the systems evaluated were confirmed to be due to the presence of specific interactions between the drug and polymer, as demonstrated by IR spectroscopy. Detailed analysis showed that the eutectic composition prediction from the model is interdependent on the crystal lattice energy of the drug compound (evaluated from the melting temperature and the heat of fusion) as well as the nature of the drug-polymer interactions. In conclusion, for compounds with melting points less than 200°C, the model is ideally suited for predicting the eutectic composition of systems where there is an absence of drug-polymer interactions.

  16. Increased absorption of polyethylene glycol 600 deposited in the colon in active ulcerative colitis.

    PubMed Central

    Almer, S; Franzén, L; Olaison, G; Smedh, K; Ström, M

    1993-01-01

    A defect in the barrier function of the intestinal mucosa has been proposed as important in both the pathogenesis and systemic manifestations of inflammatory bowel disease. After colonoscopy, polymers of polyethylene glycol (PEG) with molecular weights of 414-810 (mean 600), were instilled in the descending colon of patients with ulcerative colitis (n = 17) and in controls without intestinal inflammation (n = 8). The patients with active ulcerative colitis (n = 6) had a significantly increased uptake of PEGs in the molecular weight range 458-810, measured as urinary excretion over the first 6 hours after instillation. The median values for their excretion were 2.85-3.80% of PEGs instilled compared with 0.32-0.94% for patients in remission (n = 11) (p < 0.05-0.01) and 0.17-0.60% for the controls (p < 0.05-0.01). The differences in absorption of PEG 414 did not reach the present level of statistical significance. There was a positive correlation between PEG absorption and the endoscopic and histological grading of inflammatory activity in the sigmoid colon (p < 0.01-0.001). These findings support a correlation between the presence of active inflammation and PEG absorption. There was little evidence to support the presence of a primary defect in the colonic barrier in patients with ulcerative colitis. PMID:8491399

  17. Effect of poly(ethylene glycol) length on the in vivo behavior of coated quantum dots.

    PubMed

    Daou, T Jean; Li, Liang; Reiss, Peter; Josserand, Véronique; Texier, Isabelle

    2009-03-03

    The use of nanoparticles, either for the delivery of drugs or for imaging contrast agents, or a combination of both (theranostics), is very appealing in biological and biomedical research. The design of high-quality NIR-emitting quantum dots (QDs), with outstanding optical properties in comparison to that of organic dyes, should lead to novel contrast agents with improved performance for optical and multimodal imaging. Moreover, these nanocrystals could also be used for exploring therapeutic applications, such as drug delivery or phototherapy. In this article, we report the coating of commercial ITK705-amino QDs with methoxy-terminated poly(ethylene glycol) (PEG) of different chain lengths. Homogeneous QD solutions that are stable over extended periods of time were prepared. The impact of the particle coating on their in vivo fate after tail i.v. injection was studied by fluorescence imaging. The speed of the first pass extraction of the coated QDs toward the liver decreased with the PEG length, whereas the hydrodynamic diameter of the particles was increased.

  18. Reduction of Streptococcus mutans adherence and dental biofilm formation by surface treatment with phosphorylated polyethylene glycol.

    PubMed

    Shimotoyodome, Akira; Koudate, Takashi; Kobayashi, Hisataka; Nakamura, Junji; Tokimitsu, Ichiro; Hase, Tadashi; Inoue, Takashi; Matsukubo, Takashi; Takaesu, Yoshinori

    2007-10-01

    Initial attachment of the cariogenic Streptococcus mutans onto dental enamel is largely promoted by the adsorption of specific salivary proteins on enamel surface. Some phosphorylated salivary proteins were found to reduce S. mutans adhesion by competitively inhibiting the adsorption of S. mutans-binding salivary glycoproteins to hydroxyapatite (HA). The aim of this study was to develop antiadherence compounds for preventing dental biofilm development. We synthesized phosphorylated polyethylene glycol (PEG) derivatives and examined the possibility of surface pretreatment with them for preventing S. mutans adhesion in vitro and dental biofilm formation in vivo. Pretreatment of the HA surface with methacryloyloxydecyl phosphate (MDP)-PEG prior to saliva incubation hydrophilized the surface and thereby reduced salivary protein adsorption and saliva-promoted bacterial attachment to HA. However, when MDP-PEG was added to the saliva-pretreated HA (S-HA) surface, its inhibitory effect on bacterial binding was completely diminished. S. mutans adhesion onto S-HA was successfully reduced by treatment of the surface with pyrophosphate (PP), which desorbs salivary components from S-HA. Treatment of S-HA surfaces with MDP-PEG plus PP completely inhibited saliva-promoted S. mutans adhesion even when followed by additional saliva treatment. Finally, mouthwash with MDP-PEG plus PP prevented de novo biofilm development after thorough teeth cleaning in humans compared to either water or PP alone. We conclude that MDP-PEG plus PP has the potential for use as an antiadherence agent that prevents dental biofilm development.

  19. pH-Responsive globular poly(ethylene glycol) for photodynamic tumor therapy.

    PubMed

    Ku, Eun Bi; Lee, Dong Jin; Na, Kun; Choi, Sung-Wook; Youn, Yu Seok; Bae, Soo Kyung; Oh, Kyung Taek; Lee, Eun Seong

    2016-12-01

    In this study, we report the development of extremely small-sized globular poly(ethylene glycol) (gPEG) that can specifically recognize tumor acidic pH. gPEG coupled with chlorin e6 (Ce6, a photosensitizing drug) and 2,3-dimethylmaleic acid (DMA, as a pH-responsive moiety) (gPEG-Ce6-DMA, particle size: 3-4nm in diameter) was easily dispersed in phosphate buffered saline (PBS) without any of the nanoparticle fabrication steps. We observed that gPEG-Ce6-DMA displayed pH-dependent zeta-potential changes due to coupling (at pH 7.4) or decoupling (at pH 6.8-6.0) of DMA. As a result, the uptake of gPEG-Ce6-DMA was significantly increased in tumors at acidic pH, likely due to the decoupling of DMA (backing cationic primary amines). As a result, the preferential cellular uptake of gPEG-Ce6-DMA at acidic pH allowed for a significant enhancement of in vitro/in vivo photodynamic tumor cell ablation under light illumination.

  20. Surface modification of plastic, glass and titanium by photoimmobilization of polyethylene glycol for antibiofouling.

    PubMed

    Ito, Yoshihiro; Hasuda, Hirokazu; Sakuragi, Makoto; Tsuzuki, Saki

    2007-11-01

    Photoreactive poly(ethylene glycol) (PEG) was prepared and the polymer was photoimmobilized on organic, inorganic and metal surfaces to reduce their interaction with proteins and cells. The photoreactive PEG was synthesized by co-polymerization of methacrylate-PEG and acryloyl 4-azidobenzene. Surface modification was carried in the presence and the absence of a micropatterned photomask. It was then straightforward to confirm the immobilization using the micropatterning. Using the micropatterning method, immobilization of the photoreactive PEG on plastic (Thermanox), glass and titanium was confirmed by time-of-flight secondary ion mass spectroscopy and atomic force microscopy observations. The contact angle on an unpatterned surface was measured. Although the original surfaces have different contact angles, the contact angle on PEG-immobilized surfaces was the same on all surfaces. This result demonstrated that the surface was completely covered with PEG by the photoimmobilization. To assess non-specific protein adsorption on the micropatterned surface, horseradish peroxidase (HRP)-conjugated proteins were adsorbed. Reduced protein adsorption was confirmed by vanishingly small staining of HRP substrates on the immobilized regions. COS-7 cells were cultured on the micropatterned surface. The cells did not adhere to the PEG-coated regions. In conclusion, photoreactive PEG was immobilized on various surfaces and tended to reduce interactions with proteins and cells.

  1. 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.

  2. Poly(ethylene glycol)-block-cationic polylactide nanocomplexes of differing charge density for gene delivery.

    PubMed

    Chen, Chih-Kuang; Jones, Charles H; Mistriotis, Panagiotis; Yu, Yun; Ma, Xiaoni; Ravikrishnan, Anitha; Jiang, Ming; Andreadis, Stelios T; Pfeifer, Blaine A; Cheng, Chong

    2013-12-01

    Representing a new type of biodegradable cationic block copolymer, well-defined poly(ethylene glycol)-block-cationic polylactides (PEG-b-CPLAs) with tertiary amine-based cationic groups were synthesized by thiol-ene functionalization of an allyl-functionalized diblock precursor. Subsequently the application of PEG-b-CPLAs as biodegradable vectors for the delivery of plasmid DNAs (pDNAs) was investigated. Via the formation of PEG-b-CPLA:pDNA nanocomplexes by spontaneous electrostatic interaction, pDNAs encoding luciferase or enhanced green fluorescent protein were successfully delivered to four physiologically distinct cell lines (including macrophage, fibroblast, epithelial, and stem cell). Formulated nanocomplexes demonstrated high levels of transfection with low levels of cytotoxicity and hemolysis when compared to a positive control. Biophysical characterization of charge densities of nanocomplexes at various polymer:pDNA weight ratios revealed a positive correlation between surface charge and gene delivery. Nanocomplexes with high surface charge densities were utilized in an in vitro serum gene delivery inhibition assay, and effective gene delivery was observed despite high levels of serum. Overall, these results help to elucidate the influence of charge, size, and PEGylation of nanocomplexes upon the delivery of nucleic acids in physiologically relevant conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. 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.

  4. Comparing reduced-dose sodium phosphate tablets to 2 L of polyethylene glycol: A randomized study

    PubMed Central

    Ako, Soichiro; Takemoto, Koji; Yasutomi, Eriko; Sakaguchi, Chihiro; Murakami, Mayu; Sunami, Tomoko; Oka, Shohei; Kenta, Hamada; Okazaki, Noriko; Baba, Yuki; Yamasaki, Yasushi; Asato, Toshiyuki; Kawai, Daisuke; Takenaka, Ryuta; Tsugeno, Hirohumi; Hiraoka, Sakiko; Kato, Jun; Fujiki, Shigeatsu

    2017-01-01

    AIM To compare the tolerability and quality of bowel cleansing between 2 L polyethylene glycol (PEG) and reduced-dose sodium phosphate (NaP) tablets as a preparation for colonoscopy. METHODS Two hundred patients were randomly assigned to the PEG or NaP groups at the same ratio. The NaP group patients took 30 tablets with 2 L of clear liquid, while the PEG group patients took 2L of PEG. Tolerability was assessed by a questionnaire about taste, volume, and the overall impression. The bowel cleansing quality was evaluated by colonoscopists. RESULTS Although NaP showed better tolerability in terms of taste, volume and overall impression (P < 0.01, P < 0.01 and P = 0.02, respectively), the overall cleansing quality was better in the PEG group (P < 0.01). A subgroup analysis, stratified by sex and age, indicated that NaP was associated with better tolerability and equivalent bowel cleansing quality in females of < 50 years of age. CONCLUSION Despite the better tolerability, the use of 30 NaP tablets with 2 L of clear liquid should be limited due to its lower cleansing quality; however, in certain cases the regimen may deserve consideration, particularly in cases involving young women. PMID:28706429

  5. An improved cryosection method for polyethylene glycol hydrogels used in tissue engineering.

    PubMed

    Ruan, Jia-Ling; Tulloch, Nathaniel L; Muskheli, Veronica; Genova, E Erin; Mariner, Peter D; Anseth, Kristi S; Murry, Charles E

    2013-10-01

    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.

  6. 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

  7. Polyethylene-glycol-modified single-walled carbon nanotubes for intra-articular delivery to chondrocytes.

    PubMed

    Sacchetti, Cristiano; Liu-Bryan, Ru; Magrini, Andrea; Rosato, Nicola; Bottini, Nunzio; Bottini, Massimo

    2014-12-23

    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.

  8. Bone resorptive activity of human peripheral blood mononuclear cells after fusion with polyethylene glycol.

    PubMed

    Manrique, Edwin; Castillo, Luz M; Lazala, Oswaldo; Guerrero, Carlos A; Acosta, Orlando

    2017-03-01

    The bone remodeling process occurs through bone formation by osteoblasts and bone resorption by osteoclasts, a process involving the contribution of endocrine and nervous systems. The mechanisms associated to differentiation and proliferation of osteoclasts and osteoblasts are considered a potential therapeutic target for treating some erosive bone diseases. The aim of the present study is to explore the feasibility of generating active osteoclast-like cells from peripheral blood mononuclear cells (PBMCs) following polyethylene glycol (PEG)-induced fusion. PEG-fused PBMCs showed TRAP(+)-multinucleated cells and bone resorption activity, and were also positive for osteoclast markers such as carbonic anhydrase II, calcitonin receptor, vacuolar ATPase, and cathepsin K, when examined by reverse transcription-polymerase chain reaction, immunochemistry and Western blotting. TRAP expression and bone resorptive activity were higher in whole PEG-fused PBMCs than in separated T lymphocytes, B lymphocytes or monocytes. Both TRAP expression and bone resorptive activity were also higher in osteogenesis imperfecta patients compared to PEG-fused PBMCs from healthy individuals. PEG-induced fusion was more efficient in inducing TRAP and bone resorptive activities than macrophage colony-stimulating factor or dexamethasone treatment. Bone resorptive activity of PEG-fused PMBCs was inhibited by bisphosphonates. Evidence is provided that the use of PEG-based cell fusion is a straightforward and amenable method for studying human osteoclast differentiation and testing new therapeutic strategies.

  9. Doxycycline loaded poly(ethylene glycol) hydrogels for healing vesicant-induced ocular wounds

    PubMed Central

    Anumolu, SivaNaga S; DeSantis, Andrea S; Menjoge, Anupa R; Hahn, Rita A; Beloni, John A; Gordon, Marion K; Sinko, Patrick J

    2015-01-01

    Half mustard (CEES) and nitrogen mustard (NM) are commonly used surrogates and vesicant analogs of the chemical warfare agent sulfur mustard. In the current study, in situ forming poly(ethylene glycol) (PEG)-based doxycycline hydrogels are developed and evaluated for their wound healing efficacy in CEES and NM exposed rabbit corneas in organ culture. The hydrogels, characterized by UV-Vis spectrophotometry, rheometry, and swelling kinetics, showed that the hydrogels are optically transparent, have good mechanical strength and a relatively low degree of swelling (<7%). In vitro doxycycline release from the hydrogel disks (0.25% w/v) was found to be biphasic with release half times of ~12 and 72 h, respectively, with 80–100% released over a 7-day period. Permeation of doxycycline through vesicant wounded corneas was found to be 2.5 to 3.4 fold higher than non-wounded corneas. Histology and immunofluorescence studies showed a significant reduction of matrix metalloproteinase-9 (MMP-9) and improved healing of vesicant exposed corneas by doxycycline hydrogels compared to a similar dose of doxycycline delivered in phosphate buffered saline (PBS, pH 7.4). In conclusion, the current studies demonstrate that the doxycycline-PEG hydrogels accelerate corneal wound healing after vesicant injury offering a therapeutic option for ocular mustard injuries. PMID:19853296

  10. Molecular dynamics simulation of adsorption of pyrene-polyethylene glycol onto graphene.

    PubMed

    Xu, Liyan; Yang, Xiaoning

    2014-03-15

    The nonvalent interaction between amphiphilic polymers and graphenes is important to provide the surface functionalization of graphene. Herein, molecular dynamics simulations were carried out to investigate the interaction of pyrene-polyethylene glycol (Py-PEG) with graphene. The dynamic adsorption process and self-assembly morphology of Py-PEG onto nanoscale graphene surface have been demonstrated. The effects of the graphene size and the length of polymer chain were explored. It was shown that Py-PEG could spontaneously adsorb onto graphene surface. The Py-PEG polymer generally exhibits a coil structure with the hydrophobic pyrene surrounded by the PEG chain. However, once the Py-PEG molecule approaches the graphene surface, the PEG chain can unfold its structure on the graphene surface and the pyrene group can display a flat binding mode with the surface. Comparatively, the water solvent has an obvious impeding effect on the surface adsorption due to the hydrogen bonding interaction between PEG chain and water molecules. The thermodynamic free energy shows that the interaction between pyrene and carbon surface provides the main interaction contribution to the adsorption performance.

  11. Evaluation of diclofenac sodium sustained release matrix pellets: impact of polyethylene glycols molecular weight.

    PubMed

    Ibrahim, A; Shazly, A

    2014-01-01

    Sustained release matrix pellets loaded with 5% w/w diclofenac sodium (DS) were prepared using extrusion/spheronization technique. Different polyethylene glycols (PEGs) of different molecular weight, namely PEG 2000, PEG 4000 and PEG 6000, were mixed with avicel PH 101 in different weight ratios to manufacture the pellet formulations and water was used as a binder. Mix torque rheometer was used to characterize the pellets' wet mass. Also, the prepared pellets were characterized for their particle sizes, DS content, shape and morphology as well as the in vitro drug release. The results showed increasing PEG weight ratio resulted in a reduction of wet mass torque as well as binder ratio, especially at PEG high weight ratios (30% and 50%) and the extent of lowering wet mass peak torque was inversely proportional to PEG molecular weight. The manufactured pellets exhibited size range of 993 μm to 1085 μm with small span values. The drug release from pellets was governed by the molecular weight of PEG used, since increasing PEG molecular weight resulted in slowing the drug release rate from pellets, but increasing its level resulted in enhancing release rate. This was attributed to increasing pellet wet mass peak torque by increasing PEG molecular weight and lowering it by increasing PEG level. The prepared pellets showed non-Fickian or anomalous drug release or the coupled diffusion/polymer relaxation.

  12. Effect of inorganic salts on crystallization of poly(ethylene glycol) in frozen solutions.

    PubMed

    Izutsu, Ken-ichi; Aoyagi, Nobuo

    2005-01-06

    The effect of inorganic salts on eutectic crystallization of poly(ethylene glycol) (PEG) 1500-20,000 in frozen solution was studied to model the polymer and inorganic salt interaction in freeze-dried formulations. Thermal analysis of an aqueous PEG 3000 solution showed a eutectic PEG crystallization exotherm at approximately -47 degrees C and a subsequent PEG crystal melting endotherm at -14.9 degrees C. Addition of sodium chloride prevented the PEG crystallization in the freeze-concentrated solution surrounding ice crystals. Higher concentration NaCl was required to retain higher molecular weight PEG in the amorphous state. Various inorganic salts prevented the PEG crystallization to varying degrees depending mainly on the position of the anion in the Hofmeister's lyotropic series. Some salting-in and 'intermediate' salts (NaSCN, NaI, NaBr, NaCl, LiCl, KCl, and RbCl) inhibited the crystallization of PEG 7500 in frozen solutions. On the other hand, salting-out salts (NaH2PO4, Na2HPO4, Na2SO4, and NaF) did not show an apparent effect on the PEG crystallization. Some salting-out salts induced PEG crystallization in PEG and sucrose combination frozen solutions. The varying abilities of salts to prevent the PEG crystallization in frozen solutions strongly suggested that the solutes had different degrees of miscibility in the freeze-concentrates.

  13. Effects of free radical initiators on polyethylene glycol dimethacrylate hydrogel properties and biocompatibility.

    PubMed

    Wilems, Thomas S; Lu, Xi; Kurosu, Yuki E; Khan, Zara; Lim, Hyun Ju; Smith Callahan, Laura A

    2017-07-26

    Many studies have utilized Irgacure 2959 photopolymerized poly(ethylene glycol) (PEG) hydrogels for tissue engineering application development. Due to the limited penetration of ultraviolet light through tissue, Irgacure 2959 polymerized hydrogels are not suitable for use in tissues where material injection is desirable, such as the spinal cord. To address this, several free radical initiators (thermal initiator VA044, ammonium persulfate (APS)/TEMED reduction-oxidation reaction, and Fenton chemistry) are evaluated for their effects on the material and mechanical properties of PEG hydrogels compared with Irgacure 2959. To emulate the effects of endogenous thiols on in vivo polymerization, the effects of chain transfer agent (CTA) dithiothreitol on gelation rates, material properties, Young's and shear modulus, are examined. Mouse embryonic stem cells and human induced pluripotent stem cell derived neural stem cells were used to investigate the cytocompatibility of each polymerization. VA044 and Fenton chemistry polymerization of PEG hydrogels both had gelation rates and mechanical properties that were highly susceptible to changes in CTA concentration and showed poor cytocompatibility. APS/TEMED polymerized hydrogels maintained consistent gelation rates and mechanical properties at high CTA concentration and had a similar cytocompatibility as Irgacure 2959 when cells were encapsulated within the PEG hydrogels. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2017. © 2017 Wiley Periodicals, Inc.

  14. 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

  15. 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

  16. Hyaluronic Acid (HA)-Polyethylene glycol (PEG) as injectable hydrogel for intervertebral disc degeneration patients therapy

    NASA Astrophysics Data System (ADS)

    Putri Kwarta, Cityta; Widiyanti, Prihartini; Siswanto

    2017-05-01

    Chronic Low Back Pain (CLBP) is one health problem that is often encountered in a community. Inject-able hydrogels are the newest way to restore the disc thickness and hydration caused by disc degeneration by means of minimally invasive surgery. Thus, polymers can be combined to improve the characteristic properties of inject-able hydrogels, leading to use of Hyaluronic Acid (a natural polymer) and Polyethylene glycol (PEG) with Horse Radish Peroxide (HRP) cross linker enzymes. The swelling test results, which approaches were the ideal disc values, were sampled with variation of enzyme concentrations of 0.25 µmol/min/mL. The enzyme concentrations were 33.95%. The degradation test proved that the sample degradation increased along with the decrease of the HRP enzyme concentration. The results of the cytotoxicity assay with MTT assay method showed that all samples resulted in the 90% of living cells are not toxic. In vitro injection, models demonstrated that higher concentration of the enzymes was less state of gel which would rupture when released from the agarose gel. The functional group characterization shows the cross linking bonding in sample with enzyme adding. The conclusion of this study is PEG-HA-HRP enzyme are safe polymer composites which have a potential to be applied as an injectable hydrogel for intervertebral disc degeneration.

  17. 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.

  18. Polyethylene glycol modification of adenovirus reduces platelet activation, endothelial cell activation, and thrombocytopenia.

    PubMed

    Hofherr, Sean E; Mok, Hoyin; Gushiken, Francisca C; Lopez, Jose A; Barry, Michael A

    2007-09-01

    Thrombocytopenia is one of the complications for in vivo administration of adenovirus serotype 5 (Ad5) vectors after intravenous injection. In this paper, we investigated the mechanism of Ad5-induced thrombocytopenia and how these effects are attenuated by polyethylene glycol (PEG) modification of Ad5 (Ad-PEG). After intravenous injection, accelerated platelet loss was observed in Ad-injected mice but not in their Ad-PEG-injected counterparts. This platelet loss induced by Ad5 corresponded with increases in coagulation D-dimer levels, splenomegaly, and, later, production of megakaryocytes in the bone marrow. In contrast, these responses were blunted or ablated after injection of Ad-PEG. Ad5 activated both platelets and endothelial cells directly in vitro as evidenced by induction of P-selectin and the formation of von Willebrand factor-platelet strings and in vivo as evidenced by the induction of E-selectin messenger RNA. PEGylation blunted these observed activations. These data suggest that Ad5 may induce thrombocytopenia by direct activation of endothelial cells in addition to its direct effects on platelets. This link provides an important clue for the understanding of the mechanisms of thrombocytopenia associated with Ad5. Given that PEGylation blunted interactions of Ad with platelets and endothelial cells, reduced D-dimer formation, reduced thrombocytopenia, and reduced splenomegaly, these data suggest that this simple vector modification may have utility to improve the safety of Ad vectors for human gene therapy.

  19. 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.

  20. 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). © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  1. Ab Initio Investigation of Polyethylene Glycol Coating of TiO2 Surfaces

    PubMed Central

    2016-01-01

    In biomedical applications, TiO2 nanoparticles are generally coated with polymers to prevent agglomeration, improve biocompatibility, and reduce cytotoxicity. Although the synthesis processes of such composite compounds are well established, there is still a substantial lack of information on the nature of the interaction between the titania surface and the organic macromolecules. In this work, the adsorption of polyethylene glycol (PEG) on the TiO2 (101) anatase surface is modeled by means of dispersion-corrected density functional theory (DFT-D2) calculations. The two extreme limits of an infinite PEG polymer [−(OCH2CH2)n], on one side, and of a short PEG dimer molecule [H(OCH2CH2)2OH], on the other, are analyzed. Many different molecular configurations and modes of adsorption are compared at increasing surface coverage densities. At low and medium coverage, PEG prefers to lay down on the surface, while at full coverage, the adsorption is maximized when PEG molecules bind perpendicularly to the surface and interact with each other through lateral dispersions, following a mushroom to brush transition. Finally, we also consider the adsorption of competing water molecules at different coverage densities, assessing whether PEG would remain bonded to the surface or desorb in the presence of the aqueous solvent. PMID:28058086

  2. Two surface gradients of polyethylene glycol for a reduction in protein adsorption

    PubMed Central

    Gooch, Nathan W.; Hlady, Vladimir

    2016-01-01

    Polyethylene glycol (PEG) coatings have been commonly used in reducing protein adsorption with the intent of improving a biomaterial’s biocompatibility. To elucidate the role of PEG surface density in reducing protein adsorption, two types of grafted PEG surface density gradients were evaluated for the adsorption and desorption of albumin and fibrinogen, two blood proteins. PEG density gradients were characterized using contact angle measurements and X-ray photoelectron spectroscopy. Total internal reflection fluorescence was used to measure protein adsorption kinetics and adsorption profiles on the two types of PEG gradients. The PEG gradient generated by the flow method decreased adsorption of both proteins in proportion to the PEG surface density; however, their desorption by buffer solution from the grafted PEG layer was not complete. In contrast, desorption of two proteins from the grafted PEG layer generated by a UV oxidation method resulted in near-zero adsorbed amount. The difference between the two types of gradients might have originated from counter-diffusion of PEG and water molecules occurring during the flow method procedure.

  3. Poly(ethylene glycol) hydrogels with cell cleavable groups for autonomous cell delivery

    PubMed Central

    Kar, Mrityunjoy; Shih, Yu-Ru Vernon; Velez, Daniel Ortiz; Cabrales, Pedro; Varghese, Shyni

    2015-01-01

    Cell-responsive hydrogels hold tremendous potential as cell delivery devices in regenerative medicine. In this study, we developed a hydrogel-based cell delivery vehicle, in which the encapsulated cell cargo control its own release from the vehicle in a protease-independent manner. Specifically, we have synthesized a modified poly(ethylene glycol) (PEG) hydrogel that undergoes degradation responding to cell-secreted molecules by incorporating disulfide moieties onto the backbone of the hydrogel precursor. Our results show the disulfide-modified PEG hydrogels disintegrate seamlessly into solution in presence of cells without any external stimuli. The rate of hydrogel degradation, which ranges from hours to months, is found to be dependent upon the type of encapsulated cells, cell number, and fraction of disulfide moieties present in the hydrogel backbone. The differentiation potential of human mesenchymal stem cells released from the hydrogels is maintained in vitro. The in vivo analysis of these cell-laden hydrogels, through a dorsal window chamber and intramuscular implantation, demonstrated autonomous release of cells to the host environment. The hydrogel-mediated implantation of cells resulted in higher cell retention within the host tissue when compared to that without a biomaterial support. Biomaterials that function as a shield to protect cell cargos and assist their delivery in response to signals from the encapsulated cells could have a wide utility in cell transplantation and could improve the therapeutic outcomes of cell-based therapies. PMID:26606444

  4. In situ formation of leak-free polyethylene glycol (PEG) membranes in microfluidic fuel cells.

    PubMed

    Ho, W F; Lim, K M; Yang, K-L

    2016-11-29

    Membraneless microfluidic fuel cells operated under two co-laminar flows often face serious fuel cross-over problems, especially when flow rates are close to zero. In this study, we show that polyethylene glycol (PEG) monomers can be cross-linked inside microfluidic channels to form leak-free PEG membranes, which prevent mixing of two incompatible electrolyte solutions while allowing diffusion of certain molecules (e.g. glucose) and ions. By using PEG monomers of different molecular weights and cross-linking conditions, we are able to tailor selectivity of the membrane to allow passage of glucose while blocking larger molecules such as trypan blue. As a proof of principle, a microfluidic fuel cell with a PEG membrane and two incompatible electrolytes (acid and base) is demonstrated. Thanks to the leak-free nature of the PEG membrane, these two electrolytes do not mix together even at very slow flow rates. This microfluidic fuel cell is able to generate a voltage up to ∼450 mV from 10 mM of glucose with a flow rate of 20 μL min(-1). This microfluidic fuel cell is potentially useful as a miniature power source for many applications.

  5. 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

  6. Dynamic properties of the polyethylene glycol molecules on the oscillating solid-liquid interface.

    PubMed

    Yoshimoto, Minoru; Yuda, Yukiko; Aizawa, Hidenobu; Sato, Hiroaki; Kurosawa, Shigeru

    2012-06-20

    The dynamic properties of polyethylene glycol (PEG) molecules on the solid-liquid interface oscillating at MHz were investigated using the quartz crystal microbalance (QCM). The number-average molecular weights (M(n)) of the PEG molecules were systematically varied over 4 orders of magnitude. This study makes it clear that the series-resonant frequency shift, ΔF, of the QCM against the square root of the density-viscosity product of the PEG solution is linear and has the intercept. Moreover, systematical analysis reveals that the ΔF slope rapidly decreases with M(n) and that the ΔF intercept becomes constant above 4.0×10(3) g mol(-1). As a result, those reveal that the resonant length of the PEG molecule moving with the oscillating plate of 9 MHz is 54.2 Å. We also find that the behaviors of ΔF due to M(n) are mainly caused by the length of the PEG molecule. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Nanocomposites of Molybdenum Disulfide/Methoxy Polyethylene Glycol-co-Polypyrrole for Amplified Photoacoustic Signal.

    PubMed

    Lee, Hohyeon; Kim, Haemin; Nguyen, Thang Phan; Chang, Jin Ho; Kim, Soo Young; Kim, Hyuncheol; Kang, Eunah

    2016-11-02

    Photoacoustic activity is the generation of an ultrasonic signal via thermal expansion or bubble formation, stimulated by laser irradiation. Photoacoustic nanoplatforms have recently gained focus for application in bioelectric interfaces. Various photoacoustic material types have been evaluated, including gold nanoparticles, semiconductive π-conjugating polymers (SP), etc. In this study, surfactant-free methoxy-polyethylene glycol-co-polypyrrole copolymer (mPEG-co-PPyr) nanoparticles (NPs) and mPEG-co-PPyr NP/molybdenum disulfide (mPEG-co-PPyr/MoS2) nanocomposites (NCs) were prepared and their photoacoustic activity was demonstrated. The mPEG-co-PPyr NPs and mPEG-co-PPyr/MoS2 NCs both showed photoacoustic signal activity. The mPEG-co-PPyr/MoS2 NCs presented a higher photoacoustic signal amplitude at 700 nm than the mPEG-co-PPyr NPs. The enhanced photoacoustic activity of the mPEG-co-PPyr/MoS2 NCs might be attributed to heterogeneous interfacial contact between mPEG-co-PPyr and the MoS2 nanosheets due to complex formation. Laser ablation of MoS2 might elevate the local temperature and facilitate the thermal conductive transfer in the mPEG-co-PPyr/MoS2 NCs, amplifying PA signal. Our study, for the first time, demonstrates enhanced PA activity in SP/transition metal disulfide (TMD) composites as photoacoustic nanoplatforms.

  8. Poly(ethylene glycol) hydrogels with cell cleavable groups for autonomous cell delivery.

    PubMed

    Kar, Mrityunjoy; Vernon Shih, Yu-Ru; Velez, Daniel Ortiz; Cabrales, Pedro; Varghese, Shyni

    2016-01-01

    Cell-responsive hydrogels hold tremendous potential as cell delivery devices in regenerative medicine. In this study, we developed a hydrogel-based cell delivery vehicle, in which the encapsulated cell cargo control its own release from the vehicle in a protease-independent manner. Specifically, we have synthesized a modified poly(ethylene glycol) (PEG) hydrogel that undergoes degradation responding to cell-secreted molecules by incorporating disulfide moieties onto the backbone of the hydrogel precursor. Our results show the disulfide-modified PEG hydrogels disintegrate seamlessly into solution in presence of cells without any external stimuli. The rate of hydrogel degradation, which ranges from hours to months, is found to be dependent upon the type of encapsulated cells, cell number, and fraction of disulfide moieties present in the hydrogel backbone. The differentiation potential of human mesenchymal stem cells released from the hydrogels is maintained in vitro. The in vivo analysis of these cell-laden hydrogels, through a dorsal window chamber and intramuscular implantation, demonstrated autonomous release of cells to the host environment. The hydrogel-mediated implantation of cells resulted in higher cell retention within the host tissue when compared to that without a biomaterial support. Biomaterials that function as a shield to protect cell cargos and assist their delivery in response to signals from the encapsulated cells could have a wide utility in cell transplantation and could improve the therapeutic outcomes of cell-based therapies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. 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

  10. Preparation of poly(ethylene glycol) protected nanoparticles with variable bioconjugate ligand density.

    PubMed

    Gindy, Marian E; Ji, Shengxiang; Hoye, Thomas R; Panagiotopoulos, Athanassios Z; Prud'homme, Robert K

    2008-10-01

    Maleimide-functional poly(ethylene glycol)-b-poly(epsilon-caprolactone) nanoparticles (NPs) were prepared via the Flash NanoPrecipitation technique. Subsequent reaction with a model ligand, bovine serum albumin (BSA), was conducted using thiol-maleimide conjugation. Reaction of up to 22% of NP surface maleimide-PEG tethers was obtained, with the percent conversion being essentially independent of the ratio of maleimide-PEG to methyl-PEG over the range 30-100%, respectively. At the highest surface coverage, BSA is calculated to essentially cover the NP surface area. Reaction parameters (reaction order and docking constant) describing the extent of ligand conjugation were determined. The reaction order is applicable to the conjugation of ligands presenting free thiol functionalities, while the value of the docking constant is ligand-dependent and accounts for physical and dynamic properties of the ligand-PEG interaction. Jointly, the particle formation process, using block copolymer-directed kinetically controlled assembly and surface functionalization represent a versatile new platform for the preparation of bioconjugated NPs with accurate control of ligand density and minimal processing steps.

  11. 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.

  12. Poly(ethylene glycol) (PEG) conjugated arginine deiminase: effects of PEG formulations on its pharmacological properties.

    PubMed

    Holtsberg, Frederick W; Ensor, Charles Mark; Steiner, Marion R; Bomalaski, John S; Clark, Mike A

    2002-04-23

    Some tumors, such as melanomas and hepatocellular carcinomas, have a unique nutritional requirement for arginine. Thus, enzymatic degradation of extracellular arginine is one possible means for inhibiting these tumors. Arginine deiminase is an arginine degrading enzyme (ADI) that has been studied as an anti-cancer enzyme. However, ADI has a short serum half-life and, as a microbial enzyme, is highly immunogenic. Formulation of other therapeutic proteins with poly(ethylene glycol) (PEG) has overcome these problems. Here, ADI-PEGs were synthesized using PEGs of varying size, structure (linear or branched chain) and linker chemistries. All ADI-PEGs retained approximately 50% of enzyme activity when PEG was covalently attached to approximately 40% of the primary amines irrespective of the PEG molecular weight or attachment chemistry used. However, it was observed that, as the PEG size increases to 20 kDa, there was a corresponding increase in the pharmacokinetic (pK) and pharmacodynamic (pD) properties of the formulation. Variation in PEG linker or structure, or the use of PEGs >20,000 mw, did not affect the pK or pD. As has been shown with other therapeutic proteins, repeated injection of ADI-PEG into experimental animals resulted in significantly lower titers of antibodies against this protein than unmodified ADI. These data suggest that formulation of ADI with PEG of 20,000 mw results is the optimal method for formulating this promising therapeutic agent.

  13. 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

  14. Drying and Storage Effects on Poly(ethylene glycol) Hydrogel Mechanical Properties and Bioactivity

    PubMed Central

    Luong, P.T.; Browning, M.B.; Bixler, R.S.; Cosgriff-Hernandez, E.

    2014-01-01

    Hydrogels based on poly(ethylene glycol) (PEG) are increasingly used in biomedical applications due to the ability to control cell-material interactions by tuning hydrogel physical and biological properties. Evaluation of stability after drying and storage are critical in creating an off-the-shelf biomaterial that functions in vivo according to original specifications. However, there has not been a study that systematically investigates the effects of different drying conditions and hydrogel compositional variables. In the first part of this study, PEG-diacrylate hydrogels underwent common processing procedures (vacuum-drying, lyophilizing, hydrating then vacuum-drying) and the effect of this processing on the mechanical properties and swelling ratios was measured. Significant changes in compressive modulus, tensile modulus, and swelling ratio only occurred for select processed hydrogels. No consistent trends were observed after processing for any of the formulations tested. The effect of storage conditions on cell adhesion and spreading on collagen- and streptococcal collagen-like protein (Scl2-2)-PEG-diacrylamide hydrogels was then evaluated to characterize bioactivity retention after storage. Dry storage conditions preserved bioactivity after 6 weeks of storage; whereas, storage in PBS significantly reduced bioactivity. This loss of bioactivity was attributed to ester hydrolysis of the protein linker, acrylate-PEG-N-hydroxysuccinimide. These studies demonstrate that these processing methods and dry storage conditions may be used to prepare bioactive PEG hydrogel scaffolds with recoverable functionality after storage. PMID:24123725

  15. 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.

  16. 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

  17. Beyond poly(ethylene glycol): linear polyglycerol as a multifunctional polyether for biomedical and pharmaceutical applications.

    PubMed

    Thomas, Anja; Müller, Sophie S; Frey, Holger

    2014-06-09

    Polyglycerols (sometimes also called "polyglycidols") represent a class of highly biocompatible and multihydroxy-functional polymers that may be considered as a multifunctional analogue of poly(ethylene glycol) (PEG). Various architectures based on a polyglycerol scaffold are feasible depending on the monomer employed. While polymerization of glycidol leads to hyperbranched polyglycerols, the precisely defined linear analogue is obtained by using suitably protected glycidol as a monomer, followed by removal of the protective group in a postpolymerization step. This review summarizes the properties and synthetic approaches toward linear polyglycerols (linPG), which are at present mainly based on the application of ethoxyethyl glycidyl ether (EEGE) as an acetal-protected glycidol derivative. Particular emphasis is placed on the manifold functionalization strategies including, e.g., the synthesis of end-functional linPGs or multiheterofunctional modifications at the polyether backbone. Potential applications like bioconjugation and utilization as a component in degradable biomaterials or for diagnostics, in which polyglycerol acts as a promising PEG substitute are discussed. In the last section, the important role of linear polyglycerol as a macroinitiator or as a highly hydrophilic segment in block co- or terpolymers is highlighted.

  18. Preparation and characterization of imidacloprid lignin-polyethylene glycol matrices coated with ethylcellulose.

    PubMed

    Flores-Céspedes, Francisco; Figueredo-Flores, Cristina Isabel; Daza-Fernández, Isabel; Vidal-Peña, Fernando; Villafranca-Sánchez, Matilde; Fernández-Pérez, Manuel

    2012-02-01

    Imidacloprid, a systemic insecticide that has a water solubility of 610 mg L(-1), has been formulated in lignin-polyethylene glycol matrices by a melting process. This formulation was coated in a Wurster type fluidized-bed equipment using ethylcellulose and dibutyl sebacate. Imidacloprid has been entrapped, with an entrapment efficiency higher than 87% in all cases. Thermogravimetric analysis, differential scanning calorimetry, and Fourier transformed infrared spectroscopy studies indicate the stability and compatibility of polymers and imidacloprid. Scanning electron microscopy images show a homogeneous film of ethylcellulose in coated formulations. From T(50) values (the time taken for 50% of the active ingredient to be released into water), the release rate of imidacloprid is controlled by changing the thickness of the coating film and modifying its surface properties by adding a plasticizer. T(50) values, ranging from 3.02 to 168.6 h, allow supplying the appropriate amount of imidacloprid in each specific agronomic practice to increase the efficiency of this bioactive material and minimize the risk of environmental pollution.

  19. Inhibition of Cariogenic Plaque Formation on Root Surface with Polydopamine-Induced-Polyethylene Glycol Coating

    PubMed Central

    Mei, May Lei; Li, Quan-Li; Chu, Chun Hung

    2016-01-01

    Root caries prevention has been a challenge for clinicians due to its special anatomical location, which favors the accumulation of dental plaque. Researchers are looking for anti-biofouling material to inhibit bacterial growth on exposed root surfaces. This study aimed to develop polydopamine-induced-polyethylene glycol (PEG) and to study its anti-biofouling effect against a multi-species cariogenic biofilm on the root dentine surface. Hydroxyapatite disks and human dentine blocks were divided into four groups for experiments. They received polydopamine-induced-PEG, PEG, polydopamine, or water application. Contact angle, quartz crystal microbalance, and Fourier transform infrared spectroscopy were used to study the wetting property, surface affinity, and an infrared spectrum; the results indicated that PEG was induced by polydopamine onto a hydroxyapatite disk. Salivary mucin absorption on hydroxyapatite disks with polydopamine-induced-PEG was confirmed using spectrophotometry. The growth of a multi-species cariogenic biofilm on dentine blocks with polydopamine-induced-PEG was assessed and monitored by colony-forming units, confocal laser scanning microscopy, and scanning electron microscopy. The results showed that dentine with polydopamine-induced-PEG had fewer bacteria than other groups. In conclusion, a novel polydopamine-induced-PEG coating was developed. Its anti-biofouling effect inhibited salivary mucin absorption and cariogenic biofilm formation on dentine surface and thus may be used for the prevention of root dentine caries. PMID:28773535

  20. Inhibition of Cariogenic Plaque Formation on Root Surface with Polydopamine-Induced-Polyethylene Glycol Coating.

    PubMed

    Mei, May Lei; Li, Quan-Li; Chu, Chun Hung

    2016-05-25

    Root caries prevention has been a challenge for clinicians due to its special anatomical location, which favors the accumulation of dental plaque. Researchers are looking for anti-biofouling material to inhibit bacterial growth on exposed root surfaces. This study aimed to develop polydopamine-induced-polyethylene glycol (PEG) and to study its anti-biofouling effect against a multi-species cariogenic biofilm on the root dentine surface. Hydroxyapatite disks and human dentine blocks were divided into four groups for experiments. They received polydopamine-induced-PEG, PEG, polydopamine, or water application. Contact angle, quartz crystal microbalance, and Fourier transform infrared spectroscopy were used to study the wetting property, surface affinity, and an infrared spectrum; the results indicated that PEG was induced by polydopamine onto a hydroxyapatite disk. Salivary mucin absorption on hydroxyapatite disks with polydopamine-induced-PEG was confirmed using spectrophotometry. The growth of a multi-species cariogenic biofilm on dentine blocks with polydopamine-induced-PEG was assessed and monitored by colony-forming units, confocal laser scanning microscopy, and scanning electron microscopy. The results showed that dentine with polydopamine-induced-PEG had fewer bacteria than other groups. In conclusion, a novel polydopamine-induced-PEG coating was developed. Its anti-biofouling effect inhibited salivary mucin absorption and cariogenic biofilm formation on dentine surface and thus may be used for the prevention of root dentine caries.

  1. 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.

  2. Tocopheryl Polyethylene Glycol Succinate as a Safe, Antioxidant Surfactant for Processing Carbon Nanotubes and Fullerenes

    PubMed Central

    Yan, Aihui; Von Dem Bussche, Annette; Kane, Agnes B.; Hurt, Robert H.

    2008-01-01

    This work investigates the physical interactions between carbon nanomaterials and tocopheryl polyethylene glycol succinate (TPGS). TPGS is a synthetic amphiphile that undergoes enzymatic cleavage to deliver the lipophilic antioxidant, α-tocopherol (vitamin E) to cell membranes, and is FDA approved as a water-soluble vitamin E nutritional supplement and drug delivery vehicle. Here we show that TPGS 1000 is capable of dispersing multi-wall and single-wall carbon nanotubes in aqueous media, and for multiwall tubes is more effective than the commonly used non-ionic surfactant Triton X-100. TPGS is also capable of solubilizing C60 in aqueous phases by dissolving fullerene in the core of its spherical micelles. Drying of these solutions leads to fullerene/TPGS phase separation and the self-assembly of highly ordered asymmetric nanoparticles, with fullerene nanocrystals attached to the hydrophobic end of crystalline TPGS nanobrushes. The article discusses surface charge, colloidal stability, and the potential applications of TPGS as a safe surfactant for “green” processing of carbon nanomaterials. PMID:19081834

  3. Covalent enzyme immobilization by poly(ethylene glycol) diglycidyl ether (PEGDE) for microelectrode biosensor preparation.

    PubMed

    Vasylieva, Natalia; Barnych, Bogdan; Meiller, Anne; Maucler, Caroline; Pollegioni, Loredano; Lin, Jian-Sheng; Barbier, Daniel; Marinesco, Stéphane

    2011-06-15

    Poly(ethylene glycol) diglycidyl ether (PEGDE) is widely used as an additive for cross-linking polymers bearing amine, hydroxyl, or carboxyl groups. However, the idea of using PEGDE alone for immobilizing proteins on biosensors has never been thoroughly explored. We report the successful fabrication of microelectrode biosensors based on glucose oxidase, d-amino acid oxidase, and glutamate oxidase immobilized using PEGDE. We found that biosensors made with PEGDE exhibited high sensitivity and a response time on the order of seconds, which is sufficient for observing biological processes in vivo. The enzymatic activity on these biosensors was highly stable over several months when they were stored at 4 °C, and over at least 3d at 37 °C. Glucose microelectrode biosensors implanted in the central nervous system of anesthetized rats reliably monitored changes in brain glucose levels induced by sequential administration of insulin and glucose. PEGDE provides a simple, low cost, non-toxic alternative for the preparation of in vivo microelectrode biosensors.

  4. EVALUATION OF DICLOFENAC SODIUM SUSTAINED RELEASE MATRIX PELLETS: IMPACT OF POLYETHYLENE GLYCOLS MOLECULAR WEIGHT.

    PubMed

    Ibrahim, Mohamed A; Shazly, Gamal A

    2015-01-01

    Sustained release matrix pellets loaded with 5% w/w diclofenac sodium (DS) were prepared using extrusion/spheronization technique. Different polyethylene glycols (PEGs) of different molecular weight, namely PEG 2000, PEG 4000 and PEG 6000 were mixed with avicel PH 101® in different weight ratios to manufacture the pellet formulations and water was used as a binder. Mix torque rheomter was used to characterize the pellets' wet mass. Also, the prepared pellets were characterized for their particle sizes, DS content, shape and morphology as well as the in vitro drug release. The results showed that increasing PEG weight ratio resulted in a reduction of wet mass torque as well as binder ratio, especially at PEG high weight ratios (30% and 50%) and the extent of lowering wet mass peak torque was inversely proportional to PEG molecular weight. The manufactured pellets exhibited size range of 993 to 1085 µm with small span values. The drug release from pellets was governed by the molecular weight of PEG used, since increasing PEG molecular weight resulted in slowing the drug release rate from pellets, but increasing its level resulted in enhancing release rate. This was attributed to increasing pellet wet mass peak torque by increasing PEG molecular weight and lowering it by increasing PEG level. The prepared pellets showed non-Fickian or anomalous drug release or the coupled diffusion/polymer relaxation.

  5. Endocytosis of PEGylated nanoparticles accompanied by structural and free energy changes of the grafted polyethylene glycol.

    PubMed

    Li, Ying; Kröger, Martin; Liu, Wing Kam

    2014-10-01

    Nanoparticles (NPs) are in use to efficiently deliver drug molecules into diseased cells. The surfaces of NPs are usually grafted with polyethylene glycol (PEG) polymers, during so-called PEGylation, to improve water solubility, avoid aggregation, and prevent opsonization during blood circulation. The interplay between grafting density σp and grafted PEG polymerization degree N makes cellular uptake of PEGylated NPs distinct from that of bare NPs. To understand the role played by grafted PEG polymers, we study the endocytosis of 8 nm sized PEGylated NPs with different σp and N through large scale dissipative particle dynamics (DPD) simulations. The free energy change Fpolymer of grafted PEG polymers, before and after endocytosis, is identified to have an effect which is comparable to, or even larger than, the bending energy of the membrane during endocytosis. Based on self-consistent field theory Fpolymer is found to be dependent on both σp and N. By incorporating Fpolymer, the critical ligand-receptor binding strength for PEGylated NPs to be internalized can be correctly predicted by a simple analytical equation. Without considering Fpolymer, it turns out impossible to predict whether the PEGylated NPs will be delivered into the diseased cells. These simulation results and theoretical analysis not only provide new insights into the endocytosis process of PEGylated NPs, but also shed light on the underlying physical mechanisms, which can be utilized for designing efficient PEGylated NP-based therapeutic carriers with improved cellular targeting and uptake.

  6. 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.

  7. [Effect of polyethylene glycol-lipid derivatives on the stability of grafted liposomes].

    PubMed

    Xu, Yang; Shi, Li; Deng, Yi-hui

    2011-10-01

    It is reported that polyethylene glycol-lipid (PEG-lipid) derivatives increase liposomes stability, prolong the blood circulation of liposomes, enhance their tumor-targeting efficiency, and improve drug efficacy. Therefore, it is of great importance to investigate the influence of modified PEG-lipid derivatives on the physical, chemical, and biological characteristics of liposomes for the promotion of dealing with the existed problems, such as the accelerated blood clearance (ABC) phenomenon when repeated intravous injection at a certain time-interval, and developing novel targeted pharmaceutical preparations. In this review, the effects of modified PEG-lipid derivatives were summarized in many aspects. It indicats that the chemical bonds (amide, ether, ester, and disulfide) between PEG and lipid, as well as the species of lipids, such as the commonly used phosphatidylethanolamine, cholesterol, and diacylglycerol have substantial effects on the grafted liposomes stability in vitro and in vivo. Besides, the properties of lipids (the fatty acid chain length and saturation) and the groups (methoxy, carboxylic and amino) at the distal ends of the PEG chains were also considered to be important factors. In the end, the influence of the average molecular weight of PEG and the molar ratio of PEG-lipid derivatives in the total lipid were further focused.

  8. Effect of grafted polyethylene glycol (PEG) on the size, encapsulation efficiency and permeability of vesicles.

    PubMed

    Nicholas, A R; Scott, M J; Kennedy, N I; Jones, M N

    2000-01-15

    Liposomes have been prepared by the vesicle extrusion method (VETs) from mixtures of dipalmitoylphosphatidylcholine (DPPC), phosphatidylinositol (PI) and dipalmitoylphosphatidylethanolamine with covalently linked poly(ethylene glycol) molecular mass 5000 and 2000 (DPPE-PEG 5000 and DPPE-PEG 2000) covering a range of 0-7.5 mole%. The encapsulation of D-glucose has been studied and found to be markedly dependent on the mole% DPPE-PEG. The permeability of the liposomes to D-glucose has been measured both as a function of temperature and liposome composition. The permeability coefficients for D-glucose increase with mole% DPPE-PEG 5000 and with temperature over the range 25-50 degrees C. The activation energies for glucose permeability range from 90 to 23 kJ mol(-1). The decrease in activation energy with increasing temperature is attributed to an increasing number of bilayer defects as the liposome content of PEG-grafted lipid is increased. The dependence of D-glucose encapsulation as a function of PEG-grafted lipid content is discussed in terms of the conformation of the PEG molecules on the inner surface of the bilayer. For liposomes containing DPPE-PEG 5000 the relative percentage encapsulation of glucose, assuming that the PEG surface layer excludes glucose, is comparable to that predicted from the mushroom and brush conformational models.

  9. The antithrombotic versus calcium antagonistic effects of polyethylene glycol grafted bovine pericardium.

    PubMed

    Vasudev, S C; Chandy, T; Sharma, C P

    1999-07-01

    Cardiovascular calcification, the formation of calcium phosphate deposits in cardiovascular tissue, is a common end stage phenomenon affecting a wide variety of bioprosthesis. This study proposes a novel approach of reducing pericardial calcification and thrombosis via coupling polyethylene glycols (PEG) to glutaraldehyde treated bovine pericardium via acetal linkages. The calcification of the PEG modified tissue and the control pericardium (extracted and glutaraldehyde treated) was investigated by in vivo rat subcutaneous implantation models and by in vitro meta stable calcium phosphate solutions. Scanning electron microscopy showed that calcification primarily involved the surface of collagen fibrils and the intrafibrillar spaces. However, the grafting of pericardium with PEG-20,000 had dramatically modified the surface and subsequently inhibited the deposits of calcium. Further, the modified tissue had also reduced the platelet surface attachment. Such a reduced calcification of PEG modified tissues can be explained by decrease of free aldehyde groups, a space filling effect and therefore improved biostability and synergistic blood compatible effects of PEG after coupling to the tissues. This simple method can be a useful anticalcification treatment for implantable tissue valves.

  10. Developmental toxicity of polyethylene glycol-g-polyvinyl alcohol grafted copolymer in rats and rabbits.

    PubMed

    Heuschmid, Franziska F; Schneider, Steffen; Schuster, Paul; Lauer, Birthe; van Ravenzwaay, Bennard

    2013-07-01

    Polyethylene glycol-g-polyvinyl alcohol (PEG-PVA) grafted copolymer was evaluated in developmental toxicity studies with Wistar rats and Himalayan rabbits. Pregnant Wistar rats were gavaged with 0 (vehicle control), 100, 300, or 1000 mg PEG-PVA grafted copolymer/kg bw/day from gestation day (GD) 6-15. Pregnant Himalayan rabbits received the same treatment from GD 6 to 19. On GD 20 and 29 for rats and rabbits, respectively, the animals were euthanized and were examined grossly. For each dam, corpora lutea were counted and number and distribution of implantation sites were determined. The fetuses were removed, sexed, weighed, and evaluated for any external, soft tissue, and skeletal findings. No significant findings were found that could be attributed to administration of PEG-PVA grafted copolymer. Under the conditions of these studies, the no-observed-adverse-effect level (NOAEL) for maternal and developmental toxicity in both species was the highest dose tested of 1000 mg/kg bw/day.

  11. Polyethylene glycol-g-polyvinyl alcohol grafted copolymer: reproductive toxicity study in Wistar rats.

    PubMed

    Heuschmid, Franziska F; Schneider, Steffen; Schuster, Paul; Lauer, Birthe; van Ravenzwaay, Bennard

    2013-07-01

    Polyethylene glycol-g-polyvinyl alcohol (PEG-PVA) grafted copolymer was administered by gavage to groups of 25 male and 25 female young Wistar rats at doses of 0 (vehicle control), 100, 300, or 1000 mg/kg bw/day for one generation (F0). The study followed the treated F0 generation through mating, gestation, lactation, and weaning of the F1 generation. F1 animals were mated and followed to gestation day (GD) 15-17 at which time F2 implants were evaluated. There were no indications from the various clinical and gross pathological examinations that the oral administration of PEG-PVA grafted copolymer to the F0-parental rats produced any signs of general, reproductive, or developmental toxicity in the F0 or F1 animals or F2 implants. Based on the lack of any dose-related or biologically relevant effects on fertility, reproduction, development, and overall health of rats gavaged with PEG-PVA grafted copolymer and their progeny, the no-observed-adverse effect level (NOAEL) was determined to be the highest dose tested of 1000 mg/kg bw/day.

  12. Effect of polyethylene glycol grafted onto islet capsules on prevention of splenocyte and cytokine attacks.

    PubMed

    Lee, Dong Yun; Nam, Jong Hee; Byun, Youngro

    2004-01-01

    In the graft rejection of transplanted islets, the host's immune cells recognize the islets as antigens, which then stimulate the immune cells to begin the cytokine secretion and also the proliferation of immune cells. To prevent the recognition of islets by the immune cells, we grafted biocompatible polyethylene glycol (PEG) onto the collagen capsule of islets without incurring any changes in the morphology and function of islets. To evaluate the efficiency of PEG grafting, PEG-grafted islets were cultured with splenocytes consisting mainly of lymphocytes and macrophages. A splenocyte proliferation assessment using a BrdU incorporation assay showed that the PEG-grafted islets did not stimulate the splenocytes. In addition, the viability and microorganisms in islet cells of co-cultured PEG-grafted islets were not altered. However, in the co-culture of free islets (control) splenocytes were stimulated; they mainly secreted TNF-alpha and strongly affected the viability and structure of free islets. Furthermore, when islets were treated with the rat recombinant TNF-alpha for 7 days, the viabilities of PEG-grafted and free islets were significantly damaged, although the viability of PEG-grafted islets was higher than that of free islets by nearly three times. These results demonstrate that PEG grafted on the surface of islets could prevent the recognition of islets by splenocytes, but could not completely protect islets from cytokines.

  13. 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

    2015-12-14

    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.

  14. Polyethylene glycol-grafted polyethylenimine used to enhance adenovirus gene delivery.

    PubMed

    Singarapu, Kumar; Pal, Ivy; Ramsey, Joshua D

    2013-07-01

    An improved adenoviral-based gene delivery vector was developed by complexing adenovirus (Ad) with a biocompatible, grafted copolymer PEG-g-PEI composed of polyethylene glycol (PEG) and polyethylenimine (PEI). Although an Ad-based gene vector is considered relatively safe, its native tropism, tendency to elicit an immune response, and susceptibility to inactivating antibodies makes the virus less than ideal. The goal of the current study was to determine whether Ad could be complexed with a PEG-g-PEI copolymer that would enable the virus to transduce cells lacking the Ad receptor, while avoiding the issues commonly associated with PEI. A copolymer library was synthesized using 2 kDa PEG and either linear or branched PEI (25 kDa) with a PEG to PEI grafting ratio of 10, 20, or 30. The results of the study indicate that PEG-g-PEI/Ad complexes are indeed able to transduce CAR-negative NIH 3T3 cells. The results also demonstrate that the PEG-g-PEI/Ad complexes are less toxic, less hemolytic, and more appropriately sized than PEI/Ad complexes.

  15. Subchronic toxicity of polyethylene glycol-g-polyvinyl alcohol grafted copolymer.

    PubMed

    Heuschmid, Franziska F; Schuster, Paul; Lauer, Birthe; Buesen, Roland; Mellert, Werner; Groeters, Sibylle; van Ravenzwaay, Bennard

    2013-07-01

    The safety of polyethylene glycol-g-polyvinyl alcohol (PEG-PVA) grafted copolymer was evaluated in a 13-week oral toxicity study in rats and in a 9-month oral toxicity study in dogs. Wistar rats were administered 600, 3000, or 15,000 ppm PEG-PVA grafted copolymer in their drinking water whereas beagle dogs were fed 3000, 10,000, or 30,000 ppm PEG-PVA grafted copolymer in the diet. There were no mortalities, no adverse clinical signs, no toxicologically adverse effects on body weight or body weight gain, feed consumption, hematological, clinical chemistry or urinary parameters, or histopathology in either species. In rats, no treatment-related effects were observed in the functional observational battery (FOB) or related measurements of motor activity. Increased water consumption observed in rats at the highest dose was the only test substance-induced effect noted. The no-observed-adverse-effect level (NOAEL) was the highest concentration tested in both species: 15,000 ppm in rats (corresponding to a daily intake of 1611 mg/kg bw for males and 2191 mg/kg bw for females) and 30,000 ppm in dogs (corresponding to a mean daily intake of 783 mg/kg bw for males and 811 mg/kg bw for females).

  16. 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

  17. 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

  18. Minibody-Indocyanine Green Based Activatable Optical Imaging Probes: The Role of Short Polyethylene Glycol Linkers

    PubMed Central

    2014-01-01

    Minibodies show rapider blood clearance than IgGs due to smaller size that improves target-to-background ratio (TBR) in in vivo imaging. Additionally, the ability to activate an optical probe after binding to the target greatly improves the TBR. An optical imaging probe based on a minibody against prostate-specific membrane antigen (PSMA-MB) and conjugated with an activatable fluorophore, indocyanine green (ICG), was designed to fluoresce only after binding to cell-surface PSMA. To further reduce background signal, short polyethylene glycol (PEG) linkers were employed to improve the covalent bonding ratio of ICG. New PSMA-MBs conjugated with bifunctional ICG derivatives specifically visualized PSMA-positive tumor xenografts in mice bearing both PSMA-positive and -negative tumors within 6 h postinjection. The addition of short PEG linkers significantly improved TBRs; however, it did not significantly alter the biodistribution. Thus, minibody-ICG conjugates could be a good alternative to IgG-ICG in the optical cancer imaging for further clinical applications. PMID:24900850

  19. 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

  20. Macrogol (polyethylene glycol) laxatives in children with functional constipation and faecal impaction: a systematic review

    PubMed Central

    Candy, D; Belsey, J

    2009-01-01

    As the evidence base supporting the use of laxatives in children is very limited, we undertook an updated systematic review to clarify the issue. A comprehensive literature search was carried out to identify randomised controlled trials of polyethylene glycol (PEG) versus either placebo or active comparator, in patients aged <18 years with primary chronic constipation. Outcomes were assessed as either global assessments of effectiveness or differences in defaecation rates. Seven qualifying studies involving 594 children were identified. Five were comparisons of PEG with lactulose, one with milk of magnesia and one with placebo. Study duration ranged from 2 weeks to 12 months. PEG was significantly more effective than placebo and either equivalent to (two studies) or superior to (four studies) active comparator. Differences in study design precluded meaningful meta-analysis. Lack of high quality studies has meant that the management of childhood constipation has tended to rely on anecdote and empirical treatment choice. Recent publication of well designed randomised trials now permits a more evidence-based approach, with PEG-based treatments having been proven to be effective and well-tolerated first-line treatment. PMID:19019885

  1. Drying and storage effects on poly(ethylene glycol) hydrogel mechanical properties and bioactivity.

    PubMed

    Luong, P T; Browning, M B; Bixler, R S; Cosgriff-Hernandez, E

    2014-09-01

    Hydrogels based on poly(ethylene glycol) (PEG) are increasingly used in biomedical applications because of their ability to control cell-material interactions by tuning hydrogel physical and biological properties. Evaluation of stability after drying and storage are critical in creating an off-the-shelf biomaterial that functions in vivo according to original specifications. However, there has not been a study that systematically investigates the effects of different drying conditions on hydrogel compositional variables. In the first part of this study, PEG-diacrylate hydrogels underwent common processing procedures (vacuum-drying, lyophilizing, hydrating then vacuum-drying), and the effect of this processing on the mechanical properties and swelling ratios was measured. Significant changes in compressive modulus, tensile modulus, and swelling ratio only occurred for select processed hydrogels. No consistent trends were observed after processing for any of the formulations tested. The effect of storage conditions on cell adhesion and spreading on collagen- and streptococcal collagen-like protein (Scl2-2)-PEG-diacrylamide hydrogels was then evaluated to characterize bioactivity retention after storage. Dry storage conditions preserved bioactivity after 6 weeks of storage; whereas, storage in PBS significantly reduced bioactivity. This loss of bioactivity was attributed to ester hydrolysis of the protein linker, acrylate-PEG-N-hydroxysuccinimide. These studies demonstrate that these processing methods and dry storage conditions may be used to prepare bioactive PEG hydrogel scaffolds with recoverable functionality after storage.

  2. A novel rapamycin-polymer conjugate based on a new poly(ethylene glycol) multiblock copolymer

    PubMed Central

    Tai, Wanyi; Chen, Zhijin; Barve, Ashutosh; Peng, Zhonghua; Cheng, Kun

    2014-01-01

    Purpose Rapamycin has demonstrated potent anti-tumor activity in preclinical and clinical studies. However, the clinical development of its formulations was hampered due to its poor solubility and undesirable distribution in vivo. Chemical modification of rapamycin presents an opportunity for overcoming the obstacles and improving its therapeutic index. The objective of this study is to develop a drug-polymer conjugate to increase the solubility and cellular uptake of rapamycin. Methods We developed the rapamycin-polymer conjugate using a novel, linear, poly(ethylene glycol) (PEG) based multiblock copolymer. Cytotoxicity and cellular uptake of the rapamycin-polymer conjugate were evaluated in various cancer cells. Results The rapamycin-polymer conjugate provides enhanced solubility in water compared with free rapamycin and shows profound activity against a panel of human cancer cell lines. The rapamycin-polymer conjugate also presents high drug loading capacity (wt% ~ 26%) when GlyGlyGly is used as a linker. Cellular uptake of the conjugate was confirmed by confocal microscopy examination of PC-3 cells that were cultured in the presence of FITC-labled polymer (FITC-polymer). Conclusion This study suggests that the rapamycin-polymer conjugate is a novel anti-cancer agent that may provide an attractive strategy for treatment of a wide variety of tumors. PMID:24072263

  3. Crosslinking density influences chondrocyte metabolism in dynamically loaded photocrosslinked poly(ethylene glycol) hydrogels.

    PubMed

    Bryant, Stephanie J; Chowdhury, Tina T; Lee, David A; Bader, Dan L; Anseth, Kristi S

    2004-03-01

    In approaches to tissue engineer articular cartilage, an important consideration for in situ forming cell carriers is the impact of mechanical loading on the cell composite structure and function. Photopolymerized hydrogel scaffolds based on poly(ethylene glycol) (PEG) may be synthesized with a range of crosslinking densities and corresponding macroscopic properties. This study tests the hypothesis that changes in the hydrogel crosslinking density influences the metabolic response of encapsulated chondrocytes to an applied load. PEG hydrogels were formulated with two crosslinking densities that resulted in gel compressive moduli ranging from 60 to 670 kPa. When chondrocytes were encapsulated in these PEG gels, an increase in crosslinking density resulted in an inhibition in cell proliferation and proteoglycan synthesis. Moreover, when the gels were dynamically loaded for 48 h in unconfined compression with compressive strains oscillating from 0 to 15% at a frequency of 1 Hz, cell proliferation and proteoglycan synthesis were affected in a crosslinking-density-dependent manner. Cell proliferation was inhibited in both crosslinked gels, but was greater in the highly crosslinked gel. In contrast, dynamic loading did not influence proteoglycan synthesis in the loosely crosslinked gel, but a marked decrease in proteoglycan production was observed in the highly crosslinked gel. In summary, changes in PEG hydrogel properties greatly affect how chondrocytes respond to an applied dynamic load.

  4. Efficient biodegradation of high-molecular-weight polyethylene glycols by pure cultures of Pseudomonas stutzeri.

    PubMed Central

    Obradors, N; Aguilar, J

    1991-01-01

    Biodegradation of polyethylene glycols (PEGs) of up to 13,000 to 14,000 molecular weight has been shown to be performed by a river water bacterial isolate (strain JA1001) identified as Pseudomonas stutzeri. A pure culture of strain JA1001 grew on PEG 1000 or PEG 10000 at 0.2% (wt/vol) as a sole source of carbon and energy with a doubling time of 135 or 150 min, respectively. Cultures metabolized 2 g of polymer per liter in less than 24 h and 10 g/liter in less than 72 h. The limit of 13,500 molecular weight in the size of the PEG sustaining growth and the presence of a PEG-oxidative activity in the periplasmic space indicated that PEGs cross the outer membrane and are subsequently metabolized in the periplasm. PEG oxidation was found to be catalyzed by PEG dehydrogenase, an enzyme that has been shown to be a single polypeptide. Characterization of PEG dehydrogenase revealed glyoxylic acid as the product of the PEG-oxidative cleavage. Glyoxylate supported growth by entering the cell and introducing its carbons in the general metabolism via the dicarboxylic acid cycle, as indicated by the ability of strain JA1001 to grow on this compound and the presence of malate synthase, the first enzyme in the pathway, in extracts of PEG-grown cells. Images PMID:1768106

  5. Patterned Array of Poly(ethylene glycol) Silane Monolayer for Label-Free Detection of Dengue

    PubMed Central

    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

  6. Second-step concentration of viruses in drinking and surface waters using polyethylene glycol hydroextraction.

    PubMed

    Ramia, S; Sattar, S A

    1979-05-01

    In our laboratory, virus adsorbed to talc--Celite layers is eluted with 100 mL of 10% fetal calf serum (FCS) in normal saline (pH 9.0). A further 10-fold reduction in the volume of the eluate was necessary before its inoculation into cell cultures. A 100-mL volume of an experimentally contaminated sample was placed in a dialysis sac and hydroextracted overnight (4 degrees C) with polyethylene glycol (PEG) 6000. The viscous material remaining in the sac was resuspended in 10 mL of Earle's balanced salt solution. After membrane filtration (0.2 micron), the concentrate was plaque assayed in BS-C-1 cells. Using this technique, recoveries of five laboratory-adapted enteric viruses (polio 1, echo 6, coxsackie B5, coxackie A9, and reo 3) and four freshly isolated enteric virus strains (polio 1, echo 1, coxsackie B3, and reo) ranged from 87 to 97%. In comparative tests, PEG hydroextraction was simpler and superior to organic flocculation.

  7. Surface modification of PDMS microchips with poly(ethylene glycol) derivatives for μTAS applications.

    PubMed

    de Campos, Richard Piffer Soares; Yoshida, Inez Valeria Pagotto; da Silva, José Alberto Fracassi

    2014-08-01

    In this work is presented a method for the modification of native PDMS surface in order to improve its applicability as a substrate for microfluidic devices, especially in the analysis of nonpolar analytes. Therefore, poly(ethylene glycol) divinyl ether modified PDMS substrate was obtained by surface modification of native PDMS. The modified substrate was characterized by attenuated total reflectance infrared spectroscopy, water contact angle measurements, and by evaluating the adsorption of rhodamine B and the magnitude of the EOF mobility. The reaction was confirmed by the spectroscopic evaluation. The formation of a well-spread water film over the surface immediately after the modification was an indicative of the modified surface hydrophilicity. This characteristic was maintained for approximately ten days, with a gradual return to a hydrophobic state. Fluorescence assays showed that the nonpolar adsorption property of PDMS was significantly decreased. The EOF mobility obtained was 3.6 × 10(-4) cm(2) V(-1) s(-1) , higher than the typical values found for native PDMS. Due to the better wettability promoted by the modification, the filling of the microchannels with aqueous solutions was facilitated and trapping of air bubbles was not observed.

  8. 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

  9. 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.

  10. Doxycycline loaded poly(ethylene glycol) hydrogels for healing vesicant-induced ocular wounds.

    PubMed

    Anumolu, SivaNaga S; DeSantis, Andrea S; Menjoge, Anupa R; Hahn, Rita A; Beloni, John A; Gordon, Marion K; Sinko, Patrick J

    2010-02-01

    Half mustard (CEES) and nitrogen mustard (NM) are commonly used surrogates and vesicant analogs of the chemical warfare agent sulfur mustard. In the current study, in situ forming poly(ethylene glycol) (PEG)-based doxycycline hydrogels are developed and evaluated for their wound healing efficacy in CEES and NM-exposed rabbit corneas in organ culture. The hydrogels, characterized by UV-Vis spectrophotometry, rheometry, and swelling kinetics, showed that the hydrogels are optically transparent, have good mechanical strength and a relatively low degree of swelling (<7%). In vitro doxycycline release from the hydrogel disks (0.25% w/v) was found to be biphasic with release half times of approximately 12 and 72h, respectively, with 80-100% released over a 7-day period. Permeation of doxycycline through vesicant wounded corneas was found to be 2.5 to 3.4 fold higher than non-wounded corneas. Histology and immunofluorescence studies showed a significant reduction of matrix metalloproteinase-9 (MMP-9) and improved healing of vesicant-exposed corneas by doxycycline hydrogels compared to a similar dose of doxycycline delivered in phosphate buffered saline (PBS, pH 7.4). In conclusion, the current studies demonstrate that the doxycycline-PEG hydrogels accelerate corneal wound healing after vesicant injury offering a therapeutic option for ocular mustard injuries.

  11. Chitosan/polyethylene glycol fumarate blend film: physical and antibacterial properties.

    PubMed

    Hashemi Doulabi, Azadehsadat; Mirzadeh, Hamid; Imani, Mohammad; Samadi, Nasrin

    2013-01-30

    The objective of this work was to prepare chitosan/polyethylene glycol fumarate (chitosan/PEGF) blend films as wound dressings and to evaluate the influence of composition ratio on the blending properties of the films. Blending chitosan with PEGF obviated the brittleness of neat chitosan film. Film topography performed by atomic force microscopy illustrated that blending could increase and control the surface roughness of the neat film. Their water vapor transmission rates were close to the range of 904-1447 g(-2)day(-1) found to be proper candidates for dressing the wounds with moderate exudates. Controlled water solubility, swelling, wettability and surface tension of the blend films were also evaluated. The blend films showed a powerful antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus (Kill%>99.76 ± 0.16%). Physical properties as well as antibacterial activity assessments showed that among different compositions, the film comprising 80 wt% chitosan and 20 wt% PEGF is a suitable candidate for biomedical applications as a wound dressing material.

  12. Polyethylene glycol enhances axolemmal resealing following transection in cultured cells and in ex vivo spinal cord.

    PubMed

    Nehrt, Ashley; Hamann, Kristin; Ouyang, Hui; Shi, Riyi

    2010-01-01

    The integrity of the neuronal membrane is critical for its function as well as survival, and ineffective repair of damaged membranes may be one of the key factors underlying the neuronal degeneration and overall functional loss that occurs after spinal cord injury and traumatic brain injury. Previously, we showed that polyethylene glycol (PEG) can reseal axonal membranes following compression in isolated guinea pig spinal cord white matter. We now report that 10 mM PEG can also significantly enhance membrane resealing following transection in the clinically relevant conditions of low extracellular Ca(2+) and low temperature. Such beneficial effects were demonstrated both functionally, through membrane potential measured by double sucrose gap apparatus, and anatomically, through horseradish peroxidase and tetramethyl rhodamine dextran dye exclusion assays. We further noted that axons with small diameters preferentially benefited from PEG-mediated axolemmal resealing. Using atomic force microscopy, we further showed that PEG can effectively reduce neuronal membrane surface tension. We hypothesize that PEG may promote axolemmal resealing by increasing membrane line tension and reducing membrane tension, thus creating conditions more favorable to membrane resealing. In summary, these studies suggest that PEG is effective under the clinically relevant conditions of low Ca(2+) and temperature, and thus has the potential to be used in combination with other more established interventions in spinal cord and traumatic brain injury.

  13. Enhanced antioxidant effect of trans-resveratrol: potential of binary systems with polyethylene glycol and cyclodextrin.

    PubMed

    Moyano-Mendez, Josè Ramon; Fabbrocini, Gabriella; De Stefano, Daniela; Mazzella, Caterina; Mayol, Laura; Scognamiglio, Immacolata; Carnuccio, Rosa; Ayala, Fabio; La Rotonda, Maria Immacolata; De Rosa, Giuseppe

    2014-10-01

    Trans-resveratrol, a polyphenol extracted from Vitis vinifera, has different beneficial effects following its administration on the skin. Here the potential use of binary systems to enhance in vitro and in vivo activity of trans-resveratrol was investigated. Thus the aqueous solubility of trans-resveratrol was investigated in the presence of growing concentrations of polyethylene glycol (PEG) or β-cyclodextrin (βCD) as solubilizing excipients. Then, the solid dispersion of trans-resveratrol with PEG or inclusion complexes trans-resveratrol/βCD were prepared and characterised by different methods. Cytotoxicity and inhibition of reactive oxygen species (ROS) following H2O2 challenge in the presence of trans-resveratrol, alone or associated to the excipients, was evaluated on human keratinocyte HaCaT cell line. Both the trans-resveratrol-containing binary systems induced significant reduction of H2O2-induced ROS production, especially in the case of βCD that was selected for the following phase of the study. Thus, the effect of a cream containing trans-resveratrol, alone or associated to βCD, on different skin parameters such as corneometry, colorimetry and elastometry, was evaluated on human volunteers. All patients showed a visible improvement of clinical conditions with a remarkable decrease of aging signs, but this effect was higher of the hemi face treated with the βCD-containing formulation versus formulation containing trans-resveratrol alone.

  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

    2013-02-05

    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.

  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. 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

  17. 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.

  18. Modification of crystallization behavior in drug/polyethylene glycol solid dispersions.

    PubMed

    Zhu, Qing; Harris, Michael T; Taylor, Lynne S

    2012-03-05

    The crystallization kinetics of various active pharmaceutical ingredient/polyethylene glycol (API/PEG) solid dispersions has been investigated using wide-angle X-ray diffraction (XRD) and Raman spectroscopy. APIs with different physicochemical properties and crystallization tendency were employed to form solid dispersions with PEG. The crystallization rate of benzocaine (BZC) in BZC/PEG (20/80 wt %) solid dispersions was decreased substantially in comparison to that of the pure API, while the PEG matrix did not affect the crystallization behavior of haloperidol (HLP). The induction time for crystallization of ibuprofen (IBP) and fenofibrate (FNB) in a PEG matrix was decreased relative to the induction times for pure IBP and FNB. For the latter systems, it appears that crystalline PEG acted as a favorable heterogeneous nucleation site. The crystallization behavior of PEG in the API/PEG systems was also affected to different extents, depending on the API studied. These results suggest that PEG can delay, promote or have no influence on the crystallization kinetics of different APIs, and that any effects on crystallization behavior should be investigated in order to be able to produce a solid dispersion with consistent properties.

  19. Electrospun polyamide-polyethylene glycol nanofibers for headspace solid-phase microextration.

    PubMed

    Bagheri, Habib; Najarzadekan, Hamid; Roostaie, Ali

    2014-07-01

    A solution of polyamide (PA) containing polyethylene glycol (PEG) as a side low-molecular-weight polymer was electrospun. After synthesizing the PA-PEG nanofibers, the constituent was subsequently removed (modified PA) and confirmed by Fourier transform infrared spectroscopy. The scanning electron microscopy images showed an average diameter of 640 and 148 nm for PA and PA-PEG coatings, respectively, while the latter coating structure was more homogeneous and porous. The extraction efficiencies of PA, PA-PEG, and the modified PA fiber coatings were assayed by headspace solid-phase microextraction of a number of chlorophenols from real water samples followed by their determination by gas chromatography with mass spectrometry. To prepare the most appropriate coatings, the amounts and the flow rate of the electrospinning solution were investigated. Various extraction parameters, such as the salt content, desorption condition, extraction temperature, and time were optimized. The limits of detection of the method were in the range of 0.8-25 ng/L, while the RSDs at two concentration levels of 200 and 80 ng/L were between 2.1 and 12.2%. The analysis of real water samples led to relative recoveries between 85 and 98% with a linearity of 8-1500 ng/L.

  20. Immobilization of oriented protein molecules on poly(ethylene glycol)-coated Si(111).

    PubMed

    Cha, Taewoon; Guo, Athena; Jun, Yongseok; Pei, Duanqing; Pei, Duanquing; Zhu, Xiao-Yang

    2004-07-01

    A high-density poly(ethylene glycol) (PEG)-coated Si(111) surface is used for the immobilization of polyhistidine-tagged protein molecules. This process features a number of properties that are highly desirable for protein microarray technology: (i) minimal nonspecific protein adsorption; (ii) highly uniform surface functionality; (iii) controlled protein orientation; and (iv) highly specific immobilization reaction without the need of protein purification. The high-density PEG-coated silicon surface is obtained from the reaction of a multi-arm PEG (mPEG) molecule with a chlorine terminated Si(111) surface to give a mPEG film with thickness of 5.2 nm. Four out of the eight arms on each immobilized mPEG molecule are accessible for linking to the chelating iminodiacetic acid (IDA) groups for the binding of Cu(2+) ions. The resulting Cu(2+)-IDA-mPEG-Si(111) surface is shown to specifically bind 6x histidine-tagged protein molecules, including green fluorescent protein (GFP) and sulfotransferase (ST), but otherwise retains its inertness towards nonspecific protein adsorption. We demonstrate a particular advantage of this strategy: the possibility of protein immobilization without the need of prepurification. Surface concentrations of relevant chemical species are quantitatively characterized at each reaction step by X-ray photoelectron spectroscopy (XPS). This kind of quantitative analysis is essential in tuning surface concentration and chemical environment for optimal sensitivity in probe-target interaction.

  1. 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.

  2. Action of Humicola lanuginosa lipase on mixed monomolecular films of tricaprylin and polyethylene glycol stearate.

    PubMed

    Ivanova, Tz; Mircheva, K; Dobreva, G; Panaiotov, I; Proust, J E; Verger, R

    2008-05-01

    The hydrolysis catalyzed by Humicola lanuginosa lipase (HLL) of pure tricaprylin (TC) or stearate of polyethylene glycol 1500 (PEG-St) as well as their mixtures spread as monomolecular films were studied. The catalytic transformation of the two substrates TC or PEG-St into their respective reaction products was detected by measuring simultaneously the decrease in the film area and the surface potential using the "zero order" trough at constant surface pressure. A kinetic model describing the enzymatic hydrolysis was developed. The surface concentrations of the two substrates and their respective reaction products as well as the values of the global kinetic constants of hydrolysis were determined. The experimentally obtained global kinetic constants of the catalytic action of HLL against TC and PEG-St present in mixed monolayers of TC/PEG-St are approximately the same as in the case of pure monolayers. These obtained results give some indications that the activity of enzyme is not significantly affected by the different molecular environments in the mixed monolayers.

  3. k-Carrageenan/poly vinyl pyrollidone/polyethylene glycol/silver nanoparticles film for biomedical application.

    PubMed

    Fouda, Moustafa M G; El-Aassar, M R; El Fawal, G F; Hafez, Elsayed E; Masry, Saad Hamdy Daif; Abdel-Megeed, Ahmed

    2015-03-01

    Biopolymer composite film containing k-carrageenan (KC), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) was formulated by dissolving KC and PVP in water containing PEG. Silver nanoparticles (AgNPs), was produced by Honeybee and added to solution. Finally, all solutions were poured onto dishes and dried overnight at 40°C to form the final films. Tensile strength (TS) and elongation (E %) is evaluated. The water contact angle is inspected. Thermal properties (TGA) and swelling behavior for water were considered. Fungal activity is also examined. Morphology of all films was also explored using scanning electron microscope. AgNPs induced significant hydrophilicity to KC-PVP-PEG film with contact angle of 41.6 and 34.7 for KC-PVP-PEG-AgNPs. Films with AgNPs exhibited higher thermal stability and strength properties than other films without. Films with AgNPs explore lower swelling behavior than other films without. Both SEM and EDX proved the deposition of AgNPs on the surface of films. Films with AgNPs showed higher activity against pathogenic fungi compared with the chemical fungicide; fluconazole. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Effects of surfactant micelles on viscosity and conductivity of poly(ethylene glycol) solutions

    NASA Astrophysics Data System (ADS)

    Wang, Shun-Cheng; Wei, Tzu-Chien; Chen, Wun-Bin; Tsao, Heng-Kwong

    2004-03-01

    The neutral polymer-micelle interaction is investigated for various surfactants by viscometry and electrical conductometry. In order to exclude the well-known necklace scenario, we consider aqueous solutions of low molecular weight poly(ethylene glycol) (2-20)×103, whose radial size is comparable to or smaller than micelles. The single-tail surfactants consist of anionic, cationic, and nonionic head groups. It is found that the viscosity of the polymer solution may be increased several times by micelles if weak attraction between a polymer segment and a surfactant exists, ɛ

  5. FTIR, XRD and DSC studies of nanochitosan, cellulose acetate and polyethylene glycol blend ultrafiltration membranes.

    PubMed

    Vinodhini, P Angelin; K, Sangeetha; Thandapani, Gomathi; P N, Sudha; Jayachandran, Venkatesan; Sukumaran, Anil

    2017-03-29

    In the present work, a series of novel nanochitosan/cellulose acetate/polyethylene glycol (NCS/CA/PEG) blend flat sheet membranes were fabricated in different ratios (1:1:1, 1:1:2, 2:1:1, 2:1:2, 1:2:1, 2:2:1) in a polar solvent of N,N'-dimethylformamide (DMF) using the most popular phase inversion method. Nanochitosan was prepared by the ionotropic gelation method and its average particle size has been analyzed using Dynamic Light Scattering (DLS) method. The effect of blending of the three polymers was investigated using FTIR and XRD studies. FTIR results confirmed the formation of well-blended membranes and the XRD analysis revealed enhanced amorphous nature of the membrane ratio 2:1:2. DSC study was conducted to find out the thermal behavior of the blend membranes and the results clearly indicated good thermal stability and single glass transition temperature (Tg) of all the prepared membranes. Asymmetric nature and rough surface morphology was confirmed using SEM analysis. From the results it was evident that the blending of the polymers with higher concentration of nanochitosan can alter the nature of the resulting membranes to a greater extent and thus amorphous membranes were obtained with good miscibility and compatibility.

  6. Single-Monomer Formulation of Polymerized Polyethylene Glycol Diacrylate as a Nonadsorptive Material for Microfluidics

    PubMed Central

    Rogers, Chad I.; Pagaduan, Jayson V.; Nordin, Gregory P.; Woolley, Adam T.

    2011-01-01

    Nonspecific adsorption in microfluidic systems can deplete target molecules in solution and prevent analytes, especially those at low concentrations, from reaching the detector. Polydimethylsiloxane (PDMS) is a widely used material for microfluidics, but is prone to nonspecific adsorption, necessitating complex chemical modification processes to address this issue. An alternative material to PDMS that does not require subsequent chemical modification is presented here. Poly(ethylene glycol) diacrylate (PEGDA) mixed with photoinitiator forms on exposure to UV radiation a polymer with inherent resistance to nonspecific adsorption. Optimization of the polymerized PEGDA (poly-PEGDA) formula imbues this material with some of the same properties, including optical clarity, water stability, and low background fluorescence, that make PDMS so popular. Poly-PEGDA demonstrates less nonspecific adsorption than PDMS over a range of concentrations of flowing fluorescently tagged bovine serum albumin solutions, and poly-PEGDA has greater resistance to permeation by small hydrophobic molecules than PDMS. Poly-PEGDA also exhibits long-term (hour scale) resistance to nonspecific adsorption compared to PDMS when exposed to a low (1 µg/mL) concentration of a model adsorptive protein. Electrophoretic separations of amino acids and proteins resulted in symmetrical peaks and theoretical plate counts as high as 4 × 105/m. Poly-PEGDA, which displays resistance to nonspecific adsorption, could have broad use in small volume analysis and biomedical research. PMID:21728310

  7. Plasma-induced graft-polymerization of polyethylene glycol acrylate on polypropylene substrates

    NASA Astrophysics Data System (ADS)

    Zanini, S.; Orlandi, M.; Colombo, C.; Grimoldi, E.; Riccardi, C.

    2009-08-01

    A detailed study of argon plasma-induced graft-polymerization of polyethylene glycol acrylate (PEGA) on polypropylene (PP) substrates (membranes and films) is presented. The process consists of four steps: (a) plasma pre-activation of the PP substrates; (b) immersion in a PEGA solution; (c) argon plasma-induced graft-polymerization; (d) washing and drying of the samples. Influence of the solution and plasma parameters on the process efficiency evaluated in terms of amount of grafted polymer, coverage uniformity and substrates wettability, are investigated. The plasma-induced graft-polymerization of PEGA is then followed by sample weighting, water droplet adsorption time and contact angle measurements, attenuated total reflection infrared spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses. The stability of the obtained thin films was evaluated in water and in phosphate buffer saline (PBS) at 37 °C. Results clearly indicates that plasma-induced graft-polymerization of PEGA is a practical methodology for anti-fouling surface modification of materials.

  8. Effects of the poly(ethylene glycol) hydrogel crosslinking mechanism on protein release†

    PubMed Central

    Lee, Soah; Tong, Xinming

    2016-01-01

    Poly(ethylene glycol) (PEG) hydrogels are widely used to deliver therapeutic biomolecules, due to high hydrophilicity, tunable physicochemical properties, and anti-fouling properties. Although different hydrogel crosslinking mechanisms are known to result in distinct network structures, it is still unknown how these various mechanisms influence biomolecule release. Here we compared the effects of chain-growth and step-growth polymerization for hydrogel crosslinking on the efficiency of protein release and diffusivity. For chain-growth-polymerized PEG hydrogels, while decreasing PEG concentration increased both the protein release efficiency and diffusivity, it was unexpected to find out that increasing PEG molecular weight did not significantly change either parameter. In contrast, for step-growth-polymerized PEG hydrogels, both decreasing PEG concentration and increasing PEG molecular weight resulted in an increase in the protein release efficiency and diffusivity. For step-growth-polymerized hydrogels, the protein release efficiency and diffusivity were further decreased by increasing crosslink functionality (4-arm to 8-arm) of the chosen monomer. Altogether, our results demonstrate that the crosslinking mechanism has a differential effect on controlling protein release, and this study provides valuable information for the rational design of hydrogels for sophisticated drug delivery. PMID:26539660

  9. Covalent functionalization of graphene oxide with biocompatible poly(ethylene glycol) for delivery of paclitaxel.

    PubMed

    Xu, Zhiyuan; Wang, Song; Li, Yongjun; Wang, Mingwei; Shi, Ping; Huang, Xiaoyu

    2014-10-08

    Graphene oxide (GO), a novel 2D nanomaterial prepared by the oxidation of natural graphite, has been paid much attention in the area of drug delivery due to good biocompatibility and low toxicity. In the present work, 6-armed poly(ethylene glycol) was covalently introduced into the surface of GO sheets via a facile amidation process under mild conditions, making the modified GO, GO-PEG (PEG: 65 wt %, size: 50-200 nm), stable and biocompatible in physiological solution. This nanosized GO-PEG was found to be nontoxic to human lung cancer A549 and human breast cancer MCF-7 cells via cell viability assay. Furthermore, paclitaxel (PTX), a widely used cancer chemotherapy drug, was conjugated onto GO-PEG via π-π stacking and hydrophobic interactions to afford a nanocomplex of GO-PEG/PTX with a relatively high loading capacity for PTX (11.2 wt %). This complex could quickly enter into A549 and MCF-7 cells evidenced by inverted fluorescence microscopy using Fluorescein isothiocyanate as a probe, and it also showed remarkably high cytotoxicity to A549 and MCF-7 cells in a broad range of concentration of PTX and time compared to free PTX. This kind of nanoscale drug delivery system on the basis of PEGylated GO may find potential application in biomedicine.

  10. 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

  11. A submicron lipid emulsion coated with amphipathic polyethylene glycol for parenteral administration of paclitaxel (Taxol).

    PubMed

    Lundberg, B B

    1997-01-01

    Paclitaxel is a promising anticancer agent with poor solubility in water and requires a suitable formulation for intravenous administration. Presently paclitaxel is formulated for clinical use in ethanol and Cremophor EL (Diluent 12), a solvent system associated with severe adverse effects. In this study paclitaxel was entrapped in lipid emulsion droplets with triolein as oil core and dipalmitoyl phosphatidylcholine as the principal emulsifier. The emulsion was further stabilized with polysorbate 80 and polyethylene glycol-dipalmitoyl phosphatidylethanolamine. The drug-emulsion droplets (diameter about 40 nm) were physically and chemically stable during several months at 4 degrees C. Lyophilized preparations in 5% glucose were completely restored by distilled water. Studies of the integrity of the drug-emulsion showed a release of the drug from emulsion globules and surface transfer was found to be the major mechanism for cellular uptake. The in-vitro antiproliferative activity of paclitaxel against T-47D cells was retained by the drug-emulsion with an ID50 value of 7 nM compared to 10 and 35 nM for paclitaxel in liposomes and Diluent 12, respectively. Long-circulating submicron lipid emulsions may prove useful, not only for replacement of the more toxic Cremophor EL vehicle, but also by improving the distribution of the drug to the tumour.

  12. Investigation and prediction of protein precipitation by polyethylene glycol using quantitative structure-activity relationship models.

    PubMed

    Hämmerling, Frank; Ladd Effio, Christopher; Andris, Sebastian; Kittelmann, Jörg; Hubbuch, Jürgen

    2017-01-10

    Precipitation of proteins is considered to be an effective purification method for proteins and has proven its potential to replace costly chromatography processes. Besides salts and polyelectrolytes, polymers, such as polyethylene glycol (PEG), are commonly used for precipitation applications under mild conditions. Process development, however, for protein precipitation steps still is based mainly on heuristic approaches and high-throughput experimentation due to a lack of understanding of the underlying mechanisms. In this work we apply quantitative structure-activity relationships (QSARs) to model two parameters, the discontinuity point m* and the β-value, that describe the complete precipitation curve of a protein under defined conditions. The generated QSAR models are sensitive to the protein type, pH, and ionic strength. It was found that the discontinuity point m* is mainly dependent on protein molecular structure properties and electrostatic surface properties, whereas the β-value is influenced by the variance in electrostatics and hydrophobicity on the protein surface. The models for m* and the β-value exhibit a good correlation between observed and predicted data with a coefficient of determination of R(2)≥0.90 and, hence, are able to accurately predict precipitation curves for proteins. The predictive capabilities were demonstrated for a set of combinations of protein type, pH, and ionic strength not included in the generation of the models and good agreement between predicted and experimental data was achieved.

  13. Polyethylene glycol-modified arachidyl chitosan-based nanoparticles for prolonged blood circulation of doxorubicin.

    PubMed

    Termsarasab, Ubonvan; Yoon, In-Soo; Park, Ju-Hwan; Moon, Hyun Tae; Cho, Hyun-Jong; Kim, Dae-Duk

    2014-04-10

    Doxorubicin (DOX)-loaded nanoparticles based on polyethylene glycol-conjugated chitosan oligosaccharide-arachidic acid (CSOAA-PEG) were explored for potential application to leukemia therapy. PEG was conjugated with CSOAA backbone via amide bond formation and the final product was verified by (1)H NMR analysis. Using the synthesized CSOAA-PEG, nanoparticles having characteristics of a 166-nm mean diameter, positive zeta potential, and spherical shape were produced for the delivery of DOX. The mean diameter of CSOAA-PEG nanoparticles in the serum solution (50% fetal bovine serum) remained relatively constant over 72 h as compared with CSOAA nanoparticles (changes of 20.92% and 223.16%, respectively). The sustained release pattern of DOX from CSOAA-PEG nanoparticles was displayed at physiological pH, and the release rate increased under the acidic pH conditions. The cytotoxicity of the CSOAA-PEG conjugate was negligible in human leukemia cells (K562) at the concentrations tested (∼ 100 μg/ml). The uptake rate of DOX from the nanoparticles by K562 cells was higher than that from the solution. Judging from the results of pharmacokinetic studies in rats, in vivo clearance rate of DOX from the CSOAA-PEG nanoparticle group was slower than other groups, subsequently extending the circulation period. The PEGylated CSOAA-based nanoparticles could represent an effective nano-sized delivery system for DOX which has been used for the treatment of blood malignancies.

  14. Low doses of TiO2-polyethylene glycol nanoparticles stimulate proliferation of hepatocyte cells

    PubMed Central

    Sun, Qingqing; Kanehira, Koki; Taniguchi, Akiyoshi

    2016-01-01

    Abstract This paper describes the effect of low concentrations of 100 nm polyethylene glycol-modified TiO2 nanoparticles (TiO2-PEG NPs) on HepG2 hepatocellular carcinoma cells. Proliferation of HepG2 cells increased significantly when the cells were exposed to low doses (<100 μg ml–1) of TiO2-PEG NPs. These results were further confirmed by cell counting experiments and cell cycle assays. Cellular uptake assays were performed to determine why HepG2 cells proliferate with low-dose exposure to TiO2-PEG NPs. The results showed that exposure to lower doses of NPs led to less cellular uptake, which in turn decreased cytotoxicity. We therefore hypothesized that TiO2-PEG NPs could affect the activity of hepatocyte growth factor receptors (HGFRs), which bind to hepatocyte growth factor and stimulate cell proliferation. The localization of HGFRs on the surface of the cell membrane was detected via immunofluorescence staining and confocal microscopy. The results showed that HGFRs aggregate after exposure to TiO2-PEG NPs. In conclusion, our results indicate that TiO2-PEG NPs have the potential to promote proliferation of HepG2 cells through HGFR aggregation and suggest that NPs not only exhibit cytotoxicity but also affect cellular responses. PMID:27877913

  15. Formulation and evaluation of controlled release ethylcellulose and polyethylene glycol microspheres containing metoprolol tartrate

    PubMed Central

    Malipeddi, Venkata Ramana; Awasthi, Rajendra; Dua, Kamal

    2016-01-01

    Metoprolol tartrate is rapidly absorbed from both gastric and intestinal regions, after oral administration. To retard the release rate of the metoprolol tartrate, microspheres were prepared with varying concentrations of a mixture containing ethylcellulose and polyethylene glycol-6000. The prepared microspheres were evaluated for various physicochemical characteristics and in vitro drug release. The percent yield of microspheres was in the range of 75.2–87.3%. The particle size of microspheres was found to be in the range of 73.2–85.5 μm. Fourier transform-infrared spectral analysis and differential scanning calorimetry concluded the absence of any interaction between the drug and the carriers. The release time profile of metoprolol tartrate from microspheres in 0.1 N hydrochloric acid solution was to the extent of 33.4–60.2%. The complete release of metoprolol tartrate occurred from MPT-3 and MPT-4 in phosphate buffer solution (pH 7.4) within 8 and 7 h, respectively, whereas the incomplete release (72.3%) occurred from MPT-1. Nearly, the complete release (98.5%) of metoprolol occurred from MPT-2 in 10 h. Formulation MPT-2 would be a preferred formulation. The release of metoprolol involves diffusion rate limited (R2 = 0.9865) as a mechanism from drug release. The prepared microspheres of metoprolol tartrate eliminate the need for multiple dosing and provide patient compliance. PMID:28386461

  16. Sensitivity of PEGylated interferon detection by anti-polyethylene glycol (PEG) antibodies depends on PEG length.

    PubMed

    Cheng, Ta-Chun; Chuang, Kuo-Hsiang; Chen, Michael; Wang, Hsin-Ell; Tzou, Shey-Cherng; Su, Yu-Cheng; Chuang, Chih-Hung; Kao, Chien-Han; Chen, Bing-Mae; Chang, Long-Sen; Roffler, Steve R; Cheng, Tian-Lu

    2013-08-21

    Attachment of poly(ethylene glycol) to proteins can mask immune epitopes to increase serum half-life, reduce immunogenicity, and enhance in vivo biological efficacy. However, PEGylation mediated epitope-masking may also limit sensitivity and accuracy of traditional ELISA. We previously described an anti-PEG-based sandwich ELISA for universal assay of PEGylated molecules. Here, we compared the quantitative assessment of PEGylated interferons by anti-PEG and traditional anti-interferon sandwich ELISA. The detection limits for PEG-Intron (12k-PEG) and Pegasys (40k-PEG) were 1.9 and 0.03 ng/mL for anti-PEG ELISA compared to 0.18 and 0.42 ng/mL for traditional anti-interferon sandwich ELISA. These results indicate that the anti-PEG sandwich ELISA was insensitive to PEGylation mediated epitope-masking and the sensitivity increased in proportion to the length of PEG. By contrast, PEG-masking interfered with detection by traditional anti-interferon sandwich ELISA. Human and mouse serum did not affect the sensitivity of anti-PEG ELISA but impeded traditional anti-interferon sandwich ELISA. The anti-PEG sandwich ELISA was comparable to anti-interferon sandwich ELISA and radioassay of 131I-Pegasys in pharmacokinetic studies in mice. The anti-PEG sandwich ELISA provides a sensitive, accurate, and convenient quantitative measurement of PEGylated protein drugs.

  17. Novel prodrugs of SN38 using multiarm poly(ethylene glycol) linkers.

    PubMed

    Zhao, Hong; Rubio, Belen; Sapra, Puja; Wu, Dechun; Reddy, Prasanna; Sai, Prakash; Martinez, Anthony; Gao, Ying; Lozanguiez, Yoany; Longley, Clifford; Greenberger, Lee M; Horak, Ivan D

    2008-04-01

    CPT-11, also known as irinotecan, is a prodrug that is approved for the treatment of advanced colorectal cancer. The active metabolite of CPT-11, SN38 (7-ethyl-10-hydroxy-camptothecin), has 100- to 1000-fold more potent cytotoxic activity in tissue cell culture compared with CPT-11. However, parental administration of SN38 is not possible because of its inherently poor water solubility. It is reported here that a multiarm poly(ethylene glycol) (PEG) backbone linked to four SN38 molecules (PEG-SN38) has been successfully prepared with high drug loading and significantly improved water solubility (400- to 1000-fold increase). Three different protecting strategies have been developed in order to selectively acylate the 20-OH of SN38 to preserve its E-ring in the lactone form (the active form of SN38 with cytotoxic activities) while PEG is still attached. One chemical process has been optimized to make a large quantity of the PEG-SN38 conjugate with a high yield that can be readily adapted for scale-up production. The PEG-SN38 conjugates have shown excellent in vitro anticancer activity, with potency similar to that of native SN38, in a panel of cancer cell lines. The PEG-SN38 conjugates also have demonstrated superior anticancer activity in the MX-1 xenograft mice model compared with CPT-11. Among the four conjugates, PEG-Gly-(20)-SN38 (23) has been selected as the lead candidate for further preclinical development.

  18. Electron spin resonance studies of the effects of sterilization on poly(ethylene glycol) hydrogels.

    PubMed

    Kanjickal, Deenu; Lopina, Stephanie; Evancho-Chapman, Mary Michelle; Schmidt, Steven; Inbaraj, Johnson J; Cardon, Thomas B; Lorigan, Gary A

    2009-02-01

    The effects of several sterilization procedures on a poly(ethylene glycol) (PEG) hydrogel have been examined by electron spin resonance (ESR) spectroscopy. The crosslinked polyurethanes were synthesized by reacting PEG with a tri-functional isocyanate. The free radical concentration of unsterilized, ethylene oxide (EtO), hydrogen peroxide (H(2)O(2)), and gamma sterilized hydrogels were monitored over time. Free radical presence was observed for all the treatments, unsterilized and sterilized PEG hydrogels. The unsterilized and the EtO sterilized samples elicited similar levels of free radical intensity whereas, the H(2)O(2) and gamma sterilized samples had a significantly higher free radical concentration. The spectra reveal overlapping resonances of a peroxy and a triphenylmethyl radical. The concentration of the free radicals increase for all the treatments over time except for the gamma sterilized sample. The increase is significantly higher in the H(2)O(2) sterilized sample. A tentative model is proposed to explain the reaction pathway leading to the production of the free radicals. The observed increases in the free radical concentrations of the EtO and hydrogen peroxide sterilized hydrogels over a five-month-period make it difficult to predict properties that are affected by free radical concentrations. In that light, gamma sterilization, that does not induce a change in free radical concentrations over a five month period, could be the sterilization method of choice for PEG hydrogels that could potentially be stored for undetermined periods of time prior to application.

  19. Interconnected macroporous poly(ethylene glycol) cryogels as a cell scaffold for cartilage tissue engineering.

    PubMed

    Hwang, Yongsung; Sangaj, Nivedita; Varghese, Shyni

    2010-10-01

    Macroporous networks of poly(ethylene glycol) (PEG) with interconnected pores can be created by cryogelation techniques. In this study, we describe the potential application of such PEG cryogels as scaffolds for cartilage tissue engineering. Three-dimensional macroporous cryogels were evaluated for chondrocyte growth and production of cartilage-specific extracellular matrix (ECM). Seeded primary bovine chondrocytes showed homogeneous distribution throughout the cryogels. DNA content suggests continuous cell proliferation over 4 weeks of in vitro culture. Analysis of the composition of cell-secreted ECM showed a culture-time-dependent increase in the amount of glycosaminoglycan and collagen. The production of ECM by chondrocytes was confirmed using scanning electron microscopy analysis. Further histological and immunohistological analysis of the cell-laden scaffold confirmed the presence of accumulated cartilage-specific ECM within the scaffold. The interconnected macroporous network promoted diffusion of cell-secreted matrix within the cryogels. Our results indicated that interconnected macroporous PEG cryogels successfully supported attachment, viability, proliferation, and biosynthetic activity of seeded chondrocytes.

  20. Preparation of poly(ethylene glycol)-attached dendrimers encapsulating photosensitizers for application to photodynamic therapy.

    PubMed

    Kojima, Chie; Toi, Yoko; Harada, Atsushi; Kono, Kenji

    2007-01-01

    Photodynamic therapy (PDT) is a noninvasive treatment of some diseases including cancer. We have developed poly(ethylene glycol) (PEG)-attached dendrimers as a drug-carrier candidate. In this study, we prepared nanocapsules of photosensitizers using PEG-attached dendrimers for application to PDT. Two PEG-attached dendrimers derived from poly(amido amine) (PAMAM) and poly(propylene imine) (PPI) dendrimers (PEG-PAMAM and PEG-PPI) were synthesized, and rose bengal (RB) and protoporphyrin IX (PpIX) were used as photosensitizers. Results showed that fewer PpIX molecules were encapsulated by both PEG-attached dendrimers than RB, but the complexes were more stable under physiological conditions. Furthermore, we demonstrated that PEG-PPI held photosensitizers in a more stable manner than PEG-PAMAM because of their inner hydrophobicity. We described the cytotoxicity of the complexes of photosensitizers induced by light irradiation in vitro. The complex of PpIX with PEG-PPI exhibited efficient cytotoxicity, compared with free PpIX. It was suggested that the cytotoxicity was caused by the high level of singlet oxygen production and the efficient delivery to mitochondria. Our results suggest that these PEG-attached dendrimers are a promising vehicle for PDT.

  1. Highly porous and mechanically robust polyester poly(ethylene glycol) sponges as implantable scaffolds.

    PubMed

    Ozcelik, Berkay; Blencowe, Anton; Palmer, Jason; Ladewig, Katharina; Stevens, Geoffrey W; Abberton, Keren M; Morrison, Wayne A; Qiao, Greg G

    2014-06-01

    The development of suitable scaffolds plays a significant role in tissue engineering research. Although scaffolds with promising features have been produced via a variety of innovative methods, there are no fully synthetic tissue engineering scaffolds that possess all the desired properties in one three-dimensional construct. Herein, we report the development of novel polyester poly(ethylene glycol) (PEG) sponges that display many of the desirable scaffold characteristics. Our novel synthetic approach utilizes acidchloride/alcohol chemistry, whereby the reaction between a hydroxyl end-functionalized 4-arm PEG and sebacoyl chloride resulted in cross-linking and simultaneous hydrogen chloride gas production, which was exploited for the in situ formation of highly interconnected pores. Variation of the fabrication conditions, including the precursor volume and concentration, allowed the pore size and structure as well as the compressive properties to be tailored. The sponges were found to possess excellent elastic properties, preserving their shape even after 80% compressive strain without failure. The benign properties of the sponges were demonstrated in an in vivo subcutaneous rat model, which also revealed uniform infiltration of vascularized tissue by 8 weeks and complete degradation of the sponges by 16 weeks, with only a minimal inflammatory response being observed over the course of the experiments. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. Keratocyte behavior in three-dimensional photopolymerizable poly(ethylene glycol) hydrogels.

    PubMed

    Garagorri, Nerea; Fermanian, Sara; Thibault, Richard; Ambrose, Winnette McIntosh; Schein, Oliver D; Chakravarti, Shukti; Elisseeff, Jennifer

    2008-09-01

    The goal of this study was to evaluate three-dimensional (3-D) poly(ethylene glycol) (PEG) hydrogels as a culture system for studying corneal keratocytes. Bovine keratocytes were subcultured in DMEM/F-12 containing 10% fetal bovine serum (FBS) through passage 5. Primary keratocytes (P0) and corneal fibroblasts from passages 1 (P1) and 3 (P3) were photoencapsulated at various cell concentrations in PEG hydrogels via brief exposure to light. Additional hydrogels contained adhesive YRGDS and nonadhesive YRDGS peptides. Hydrogel constructs were cultured in DMEM/F-12 with 10% FBS for 2 and 4 weeks. Cell viability was assessed by DNA quantification and vital staining. Biglycan, type I collagen, type III collagen, keratocan and lumican expression were determined by reverse transcriptase-polymerase chain reaction. Deposition of type I collagen, type III collagen and keratan sulfate (KS)-containing matrix components was visualized using confocal microscopy. Keratocytes in a monolayer lost their stellate morphology and keratocan expression, displayed elongated cell bodies, and up-regulated biglycan, type I collagen and type III collagen characteristic of corneal fibroblasts. Encapsulated keratocytes remained viable for 4 weeks with spherical morphologies. Hydrogels supported production of KS, type I collagen and type III collagen matrix components. PEG-based hydrogels can support keratocyte viability and matrix production. 3-D hydrogel culture can stabilize but not restore the keratocyte phenotype. This novel application of PEG hydrogels has potential use in the study of corneal keratocytes in a 3-D environment.

  3. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. 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

  5. In situ-crosslinkable heparin-containing poly(ethylene glycol) hydrogels for sustained anticoagulant release

    PubMed Central

    Baldwin, Aaron D.; Robinson, Karyn G.; Militar, Jaimee; Derby, Christopher D.; Kiick, Kristi L.; Akins, Robert E.

    2014-01-01

    Low molecular weight heparin (LMWH) is widely used in anticoagulation therapies and for the prevention of thrombosis. LMWH is administered by subcutaneous injection usually once or twice per day. This frequent and invasive delivery modality leads to compliance issues for individuals on prolonged therapeutic courses, particularly pediatric patients. Here, we report a long-term delivery method for LMWH via subcutaneous injection of long-lasting hydrogels. LMWH is modified with reactive maleimide groups so that it can be crosslinked into continuous networks with four-arm thiolated polyethylene glycol (PEG-SH). Maleimide-modified LMWH (Mal-LMWH) retains bioactivity as indicated by prolonged coagulation time. Hydrogels comprising PEG-SH and Mal-LMWH degrade via hydrolysis, releasing bioactive LMWH by first-order kinetics with little initial burst release. Separately dissolved Mal-LMWH and PEG-SH solutions were co-injected subcutaneously in New Zealand White rabbits. The injected solutions successfully formed hydrogels in situ and released LMWH as measured via chromogenic assays on plasma samples, with accumulation of LMWH occurring at day two and rising to near-therapeutic dose equivalency by day 5. These results demonstrate the feasibility of using LMWH-containing, crosslinked hydrogels for sustained and controlled release of anticoagulants. PMID:22615105

  6. Micropatterning of Poly(Ethylene Glycol) Diacrylate Hydrogels with Biomolecules to Regulate and Guide Endothelial Morphogenesis

    PubMed Central

    Moon, James J.; Hahn, Mariah S.; Kim, Iris; Nsiah, Barbara A.

    2009-01-01

    Angiogenesis, which is morphogenesis undertaken by endothelial cells (ECs) during new blood vessel formation, has been traditionally studied on natural extracellular matrix proteins. In this work, we aimed to regulate and guide angiogenesis on synthetic, bioactive poly(ethylene glycol)-diacrylate (PEGDA) hydrogels. PEGDA hydrogel is intrinsically cell nonadhesive and highly resistant to protein adsorption, allowing a high degree of control over presentation of ligands for cell adhesion and signaling. Since these materials are photopolymerizable, a variety of photolithographic technologies may be applied to spatially control presentation of bioactive ligands. To manipulate EC adhesion, migration, and tubulogenesis, the surface of PEGDA hydrogels was micropatterned with a cell adhesive ligand, Arg-Gly-Asp-Ser (RGDS), in desired concentrations and geometries. ECs cultured on these RGDS patterns reorganized their cell bodies into cord-like structures on 50-μm-wide stripes, but not on wider stripes, suggesting that EC morphogenesis can be regulated by geometrical cues. The cords formed by ECs were reminiscent of capillaries with cells participating in the self-assembly and reorganization into multicellular structures. Further, endothelial cord formation was stimulated on intermediate concentration of RGDS at 20 μg/cm2, whereas it was inhibited at higher concentrations. This work has shown that angiogenic responses can be tightly regulated and guided by micropatterning of bioactive ligands and also demonstrated great potentials of micropatterned PEGDA hydrogels for various applications in tissue engineering, where vascularization prior to implantation is critical. PMID:18803481

  7. Biomimetic myocardial patches fabricated with poly(ɛ-caprolactone) and polyethylene glycol-based polyurethanes.

    PubMed

    Silvestri, Antonella; Sartori, Susanna; Boffito, Monica; Mattu, Clara; Di Rienzo, Anna M; Boccafoschi, Francesca; Ciardelli, Gianluca

    2014-07-01

    The production of efficient heart patches for myocardium repair requires the use of biomaterials with high elastomeric properties and controllable biodegradability. To fulfil these design criteria we propose biodegradable poly(ester urethanes) and poly(ether ester urethanes) from poly(ɛ-caprolactone) (PCL) and poly(ethylene glycol) (PEG) as macrodiols, 1,4-diisocyanatobutane as diisocyanate, l-Lysine Ethyl Ester and Alanine-Alanine-Lysine (AAK) as chain extenders. This peptide was used to tune biodegradability properties, since the Alanine-Alanine sequence is a target for the elastase enzyme. Enzymatic degradation tests demonstrated the feasibility of tuning biodegradability properties due to the introduction of AAK peptide in polyurethane backbone. Two formulations have been processed into porous scaffolds by Thermally-Induced Phase Separation (TIPS). Scanning Electron Microscopy micrographs revealed promising microstructures, which were characterized by stretched and unidirectional pores and mimicked the striated muscle tissue. Tensile tests showed that, although scaffolds are characterized by lower mechanical properties than films, these substrates have suitable elastomeric behaviors and elastic moduli for contractile and soft tissue regeneration. Viability tests on cardiomyocytes revealed the best cell response for dense film and porous scaffold obtained from PCL and Lysine Ethyl Ester-based polyurethane, with an increased viability for the porous substrate, which is ascribable to the morphological features of its microstructure. Future works will be addressed to study the in vivo behavior of these constructs and to confirm their applicability for myocardial tissue engineering. © 2013 Wiley Periodicals, Inc.

  8. Injectable and Photopolymerizable Tissue-Engineered Auricular Cartilage Using Poly(Ethylene Glycol) Dimethacrylate Copolymer Hydrogels

    PubMed Central

    Papadopoulos, Anestis; Bichara, David A.; Zhao, Xing; Ibusuki, Shinichi; Anseth, Kristi S.; Yaremchuk, Michael J.

    2011-01-01

    In this study we investigated the histological, biochemical, and integrative features of the neocartilage using swine auricular chondrocytes photoencapsulated into two poly(ethylene glycol) dimethacrylate (PEGDM) copolymer hydrogels of a different degradation profile: degradable (PEG-4,5LA-DM) and nondegradable (PEGDM) macromers in molar ratios of 60:40 and 70:30. Integration of the engineered tissue with existing native cartilage was examined using an articular cartilaginous ring model. Experimental group samples (total n = 96) were implanted subcutaneously into nude mice and harvested at 6, 12, and 18 weeks. Nonimplanted constructs (total n = 16) were used as controls for quantification of DNA, glycosaminoglycan, and hydroxyproline. Histologically, neocartilage resembled both the cellular population and composition of the extracellular matrix of the native swine auricular cartilage. DNA content demonstrated that the photoencapsulated chondrocytes were capable of survival and proliferation over time. Both glycosaminoglycan and hydroxyproline contents appeared higher in the neotissue, which was supported by less degradable PEGDM hydrogel. Integration of neocartilage with surrounding native cartilage improved with time, resulting in the development of tight integration interface. PEGDM copolymer hydrogels can support in vivo chondrogenesis by photoencapsulating auricular chondrocytes. PMID:20695772

  9. Photosensitive diazotized poly(ethylene glycol) covalent capillary coatings for analysis of proteins by capillary electrophoresis.

    PubMed

    Yu, Bing; Chen, Xin; Cong, Hailin; Shu, Xi; Peng, Qiaohong

    2016-09-01

    A new method for the fabrication of covalently cross-linked capillary coatings of poly(ethylene glycol) (PEG) is described using diazotized PEG (diazo-PEG) as a new photosensitive coating agent. The film of diazo-PEG depends on ionic bonding and was first prepared on the inner surface of capillary by self-assembly, and ionic bonding was converted into covalent bonding after reaction of ultraviolet light with diazo groups through unique photochemical reaction. The covalently bonded coating impedance adsorption of protein on the central surface of capillary and hence the four proteins ribonuclease A, cytochrome c, bovine serum albumin, and lysosome can be baseline separated by using capillary electrophoresis (CE). The covalently cross-linked diazo-PEG capillary column coatings not only improved the CE separation performance for proteins compared to non-covalently cross-linked coatings or bare capillary but also showed a remarkable chemical solidity and repeatability. Because photosensitive diazo-PEG took the place of the highly noxious and silane moisture-sensitive coating reagents in the fabrication of covalent coating, this technique shows the advantage of being environment-friendly and having a high efficiency for CE to make the covalently bonded capillaries.

  10. 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

  11. Protective Effect of Intravenous High Molecular Weight Polyethylene Glycol on Fatty Liver Preservation.

    PubMed

    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.

  12. 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

  13. Doxorubicin conjugate of poly(ethylene glycol)-block-polyphosphoester for cancer therapy.

    PubMed

    Sun, Chun-Yang; Dou, Shuang; Du, Jin-Zhi; Yang, Xian-Zhu; Li, Ya-Ping; Wang, Jun

    2014-02-01

    Polyphosphoesters with repeating phosphoester linkages in the backbone can be easily functionalized, are biodegradable and potentially biocompatible, and may be potential candidates as polymer carriers of drug conjugates. Here, the efficacy of a polyphosphoester drug conjugate as an anticancer agent in vivo is assessed for the first time. With controlled synthesis, doxorubicin conjugated to poly(ethylene glycol)-block-polyphosphoester (PPEH-DOX) via labile hydrazone bonds form spherical nanoparticles in aqueous solution with an average diameter of ≈60 nm. These nanoparticles are effectively internalized by MDA-MB-231 breast cancer cells and release the conjugated doxorubicin in response to the intracellular pH of endosomes and lysosomes, resulting in significant antiproliferative activity in cancer cells. Compared with free doxorubicin injection, PPEH-DOX injection exhibits much longer circulation behavior in the plasma of mice and leads to enhanced drug accumulation in tumor cells. In an MDA-MB-231 xenograft murine model, inhibition of tumor growth with systemic delivery of PPEH-DOX nanoparticles is more pronounced compared with free doxorubicin injection, suggesting the potential of polyphosphoesters as carriers of drug conjugates in cancer therapy.

  14. A Polyethylene Glycol-Mediated Protoplast Transformation System for Production of Fertile Transgenic Rice Plants 1

    PubMed Central

    Hayashimoto, Akio; Li, Zhijian; Murai, Norimoto

    1990-01-01

    We have established an efficient procedure for protoplast transformation and regeneration of fertile transgenic plants of rice (Oryza sativa L.) cultivars Nipponbare and Taipei 309. Protoplasts were mixed with a plant-expressible hygromycin resistance gene and treated with 25% (w/v) polyethylene glycol. Stringent selection of transformed colonies was applied to 14-day-old regenerated protoplasts in the presence of 95 micromolar of hygromycin B for 12 days. After selection, 450 and 200 resistant colonies were recovered per million treated Taipei 309 and Nipponbare protoplasts, respectively. Southern hybridization analysis of hygromycin-resistant cell lines and regenerated plants indicated that 1 to 10 copies of transferred DNA were integrated at 1 to 4 loci of the rice genome. Southern DNA analysis suggests that the introduced plasmid DNA may form concatemers by intermolecular recombination prior to integration. Four Taipei 309 and 39 Nipponbare transgenic rice plants were regenerated and grown to maturity in the greenhouse. Two Taipei 309 and 35 Nipponbare plants set viable seeds. Agronomic traits of Taipei 309 transgenic plants and inheritance of the hygromycin resistance trait by progeny of the selfed transgenic plants were analyzed. Images Figure 5 Figure 6 PMID:16667593

  15. Improved Biofilm Antimicrobial Activity of Polyethylene Glycol Conjugated Tobramycin Compared to Tobramycin in Pseudomonas aeruginosa Biofilms.

    PubMed

    Du, Ju; Bandara, H M H N; Du, Ping; Huang, Hui; Hoang, Khang; Nguyen, Dang; Mogarala, Sri Vasudha; Smyth, Hugh D C

    2015-05-04

    The objective of this study was to develop a functionally enhanced antibiotic that would improve the therapeutic activity against bacterial biofilms. Tobramycin was chemically conjugated with polyethylene glycol (PEG) via site-specific conjugation to form PEGylated-tobramycin (Tob-PEG). The antibacterial efficacy of Tob-PEG, as compared to tobramycin, was assessed on the planktonic phase and biofilms phase of Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC80) of Tob-PEG was higher (13.9 μmol/L) than that of tobramycin (1.4 μmol/L) in the planktonic phases. In contrast, the Tob-PEG was approximately 3.2-fold more effective in eliminating bacterial biofilms than tobramycin. Specifically, Tob-PEG had a MIC80 lower than those exhibited by tobramycin (27.8 μmol/L vs 89.8 μmol/L). Both confocal laser scanning microscopy and scanning electron microscopy further confirmed these data. Thus, modification of antimicrobials by PEGylation appears to be a promising approach for overcoming the bacterial resistance in the established biofilms of Pseudomonas aeruginosa.

  16. Adsorption of hydrophobically end-capped poly(ethylene glycol) on cellulose.

    PubMed

    Holappa, Susanna; Kontturi, Katri S; Salminen, Arto; Seppälä, Jukka; Laine, Janne

    2013-11-12

    Adsorption of poly(ethylene glycol), hydrophobically end-capped with octadecenylsuccinic anhydride (OSA-PEG-OSA), on an ultrathin film of cellulose has been studied by quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). Normally, PEG does not adsorb on cellulosic surfaces, but the use of the telechelic hydrophobic modification was found to promote adsorption. The influence of the conformation of the polymer in solution prior to adsorption and the subsequent properties of the adsorbed layer were investigated. The adsorption experiments were done at concentrations below and above the critical association concentration. The adsorption of OSA-PEG-OSA on cellulose was observed to occur in four distinct stages. Because of the amphiphilic nature of cellulose, further adsorption experiments were performed on hydrophobic (polystyrene) and hydrophilic (silica) model substrates to illuminate the contribution of hydrophobic and hydrophilic factors in the adsorption phenomenon. As expected, the kinetics and the mechanism of adsorption were strongly dependent on the chemical composition of the substrate.

  17. 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.

  18. 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.

  19. 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

    2016-06-29

    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.

  20. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds

    PubMed Central

    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

  1. Aggregation behavior of poly(ethylene glycol-bl-propylene sulfide) di- and triblock copolymers in aqueous solution.

    PubMed

    Cerritelli, Simona; O'Neil, Conlin P; Velluto, Diana; Fontana, Antonella; Adrian, Marc; Dubochet, Jacques; Hubbell, Jeffrey A

    2009-10-06

    Block copolymers of poly(ethylene glycol)-bl-poly(propylene sulfide) (PEG-PPS) have recently emerged as a new macromolecular amphiphile capable of forming a wide range of morphologies when dispersed in water. To understand better the relationship between stability and morphology in terms of the relative and absolute block compositions, we have synthesized a collection of PEG-PPS block copolymers and quantified their critical aggregation concentration and observed their morphology using cryogenic transmission electron microscopy after thin film hydration with extrusion and after solvent dispersion from tetrahydrofuran, a solvent for both blocks. By understanding the relationship between aggregate character and block copolymer architecture, we have observed that whereas the relative block lengths control morphology, the stability of the aggregates upon dilution is determined by the absolute block length of the hydrophobic PPS block. We have compared results obtained with PEG-PPS to those obtained with poly(ethylene glycol)-bl-poly(propylene oxide)-bl-poly(ethylene glycol) block copolymers (Pluronics). The results reveal that the PEG-PPS aggregates are substantially more stable than Pluronic aggregates, by more than an order of magnitude. PEG-PPS can form a wide variety of stable or metastable morphologies in dilute solution within normal time and temperature ranges, whereas Pluronics can generally form only spherical micelles under the same conditions. On the basis of these results, block copolymers of PEG with poly(propylene sulfide) may present distinct advantages over those with poly(propylene glycol) for a number of applications.

  2. A novel polyethylene glycol mediated lipid nanoemulsion as drug delivery carrier for paclitaxel.

    PubMed

    Jing, Xiaolong; Deng, Li; Gao, Baoan; Xiao, Lin; Zhang, Yingying; Ke, Xingfa; Lian, Jianhao; Zhao, Qiang; Ma, Lulu; Yao, Jianzhong; Chen, Jianming

    2014-02-01

    A novel polyethylene glycol 400 (PEG400) mediated lipid nanoemulsion as drug-delivery carrier for paclitaxel (PTX) was successfully developed. The formulation comprised a PEG400 solution of the drug (25mg/mL) that would be mixed with commercially 20% lipid emulsion to form PTX-loaded nanoemulsion (1mg/mL) prior to use. This two-vial formulation of PTX-loaded lipid nanoemulsion (TPLE) could significantly reduce extraction of reticuloendothelial system (RES) organs and increase tumor uptake, and exhibited more potent antitumor efficacy on bearing A2780 or Bcap-37 tumor nude mice compared to conventional PTX-loaded lipid nanoemulsion (CPLE). TPLE did not cause haematolysis and intravenous irritation response yet, and showed the same cytotoxicity against HeLa cells as Taxol®, and its LD50 was 2.7-fold higher than that of Taxol®, suggesting its good safety and druggability. In addition, TPLE displayed distinctly faster release of PTX, a greater proportion of PTX in phospholipids layer and a smaller share in oil phase than CPLE. From the Clinical Editor: This study demonstrates the feasibility and potential advantage of a novel PEG400-mediated two-vial formulation of lipid nanoemulsion as drug carrier for PTX in clinical application for the cancer therapy. This team of investigators convincingly demonstrates the feasibility and potential advantage of a PEG400-mediated two-vial formulation of lipid nanoemulsion as drug carrier for PTX in cancer therapy, documenting superior safety and faster release of PTX compared to commercially available formulations. © 2014.

  3. [Detection of circulating immune complexes using polyethylene glycol. Its value in the therapy of phlebology patients].

    PubMed

    Van der Molen, H R; Ritter, K E; Vriezen, J

    1981-01-01

    After a short exposition of the meaning and the technique for determination of immune complexes in circulating blood (after Hashkova, with polyethylene glycol) our first experience with phlebological patients is exposed. Positive reactions in a variety of cases (N = 122) includes atypical ulcus cruris, ulcerated vasculitis, Pyoderma gangrenosum, discoid lupus erythematodes, chronic rheumatoid polyarthritis (with, or without ulcus cruris), monoarthritis of the knee, pernicious anemia, chronic lymphedema (elephantiasis), some cases of sclerosis multiplex. In such positive cases the sedimentation rate of citrate blood may, or may not be elevated. Negative or uncertain reactions (below 10) were seen in 141 cases, in common's ulcus cruris cases, in vasculite nodulaire, in discopathy and most spondylarthroses and other arthrosis cases, in vasculite nodulaire, in discopathy and most spondylarthroses and other arthrosis cases, in various patients with rheumatoid complaints in coxarthrosis, osteoporosis and in a group of healthy young persons. Negative reactions were the rule in atherosclerotic and diabetic old persons with claudication or gangrene, in most dermatological cases, in necrobiosis lipoidica, in psoriasis, in postthrombotic phlebitis and in chronic rheumatism in a quiet stage. In vasculitis cases the reaction is often only slightly positive (between 10 and 20) but should be repeated as the values may vary. The determination of circulating immune complexes with polyethylenglycol is a useful screening method in the policlinic. Treatment is often directed in the right way sometimes prednisone, more often nivaquin (chloroquin) or other anti-inflammatory drugs and in pernicious anemia hepatotherapy can be of great help in the healing of complicated phlebological cases.

  4. 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.

  5. Fabrication of poly-DL-lactide/polyethylene glycol scaffolds using the gas foaming technique.

    PubMed

    Ji, Chengdong; Annabi, Nasim; Hosseinkhani, Maryam; Sivaloganathan, Sobana; Dehghani, Fariba

    2012-02-01

    The aim of this study was to prepare poly-DL-lactide/polyethylene glycol (PDLLA/PEG) blends to improve medium absorption and cell proliferation in the three-dimensional (3-D) structure of their scaffolds. Carbon dioxide (CO2) was used as a foaming agent to create porosity in these blends. The results of Fourier transform infrared (FTIR) spectroscopy demonstrated that the blends were homogeneous mixtures of PDLLA and PEG. The peak shifts at 1092 and 1744 cm(-1) confirmed the presence of molecular interactions between these two compounds. Increasing the PEG weight ratio enhanced the relative crystallinity and hydrophilicity. The PDLLA/PEG blends (especially 80/20 and 70/30 weight ratios) exhibited linear degradation profiles over an incubation time of 8 weeks. The mechanical properties of PDLLA/PEG blends having less than 30 wt.% PEG were suitable for the fabrication of porous scaffolds. Increasing the concentration of PEG to above 50% resulted in blends that were brittle and had low mechanical integrity. Highly porous scaffolds with controllable pore size were produced for 30 wt.% PEG samples using the gas foaming technique at temperatures between 25 and 55 °C and pressures between 60 and 160 bar. The average pore diameters achieved by gas foaming process were between 15 and 150 μm, and had an average porosity of 84%. The medium uptake and degradation rate of fabricated PDLLA/PEG scaffolds were increased compared with neat PDLLA film due to the presence of PEG and porosity. The porous scaffolds also demonstrated a lower modulus of elasticity and a higher elongation at break compared to the non-porous film. The fabricated PDLLA/PEG scaffolds have high potential for various tissue-engineering applications.

  6. Modulation of protein aggregation by polyethylene glycol conjugation: GCSF as a case study

    PubMed Central

    Rajan, Rahul S.; Li, Tiansheng; Aras, Mohini; Sloey, Christopher; Sutherland, Weston; Arai, Hiromi; Briddell, Robert; Kinstler, Olaf; Lueras, Alexis M.K.; Zhang, Yu; Yeghnazar, Heather; Treuheit, Michael; Brems, David N.

    2006-01-01

    Polyethylene glycol (PEG) conjugation to proteins has emerged as an important technology to produce drug molecules with sustained duration in the body. However, the implications of PEG conjugation to protein aggregation have not been well understood. In this study, conducted under physiological pH and temperature, N-terminal attachment of a 20 kDa PEG moiety to GCSF had the ability to (1) prevent protein precipitation by rendering the aggregates soluble, and (2) slow the rate of aggregation relative to GCSF. Our data suggest that PEG-GCSF solubility was mediated by favorable solvation of water molecules around the PEG group. PEG-GCSF appeared to aggregate on the same pathway as that of GCSF, as evidenced by (a) almost identical secondary structural transitions accompanying aggregation, (b) almost identical covalent character in the aggregates, and (c) the ability of PEG-GCSF to rescue GCSF precipitation. To understand the role of PEG length, the aggregation properties of free GCSF were compared to 5kPEG-GCSF and 20kPEG-GCSF. It was observed that even 5kPEG-GCSF avoided precipitation by forming soluble aggregates, and the stability toward aggregation was vastly improved compared to GCSF, but only marginally less stable than the 20kPEG-GCSF. Biological activity measurements demonstrated that both 5kPEG-GCSF and 20kPEG-GCSF retained greater activity after incubation at physiological conditions than free GCSF, consistent with the stability measurements. The data is most compatible with a model where PEG conjugation preserves the mechanism underlying protein aggregation in GCSF, steric hindrance by PEG influences aggregation rate, while aqueous solubility is mediated by polar PEG groups on the aggregate surface. PMID:16597829

  7. Antibodies against polyethylene glycol in healthy subjects and in patients treated with PEG-conjugated agents.

    PubMed

    Garay, Ricardo P; El-Gewely, Raafat; Armstrong, Jonathan K; Garratty, George; Richette, Pascal

    2012-11-01

    In contrast to the accepted general assumption that polyethylene glycol (PEG) is non-immunogenic and non-antigenic, animal studies clearly showed that uricase, ovalbumin and some other PEGylated agents can elicit antibody formation against PEG (anti-PEG). In humans, anti-PEG may limit therapeutic efficacy and/or reduce tolerance of PEG-asparaginase (PEG-ASNase) in patients with acute lymphoblastic leukemia and of pegloticase in patients with chronic gout, but did not impair hyposensitization of allergic patients with mPEG-modified ragweed extract or honeybee venom or the response to PEG-IFN in patients with hepatitis C. Of major importance is the recent finding of a 22 - 25% occurrence of anti-PEG in healthy blood donors, compared with a very low 0.2% occurrence two decades earlier. This increase may be due to an improvement of the limit of detection of antibodies during the years and to greater exposure to PEG and PEG-containing compounds in cosmetics, pharmaceuticals and processed food products. These results raise obvious concerns regarding the efficacy of PEG-conjugated drugs for a subset of patients. To address these concerns, the immunogenicity and antigenicity of approved PEGylated compounds should be carefully examined in humans. With all these data in hand, patients should be pre-screened and monitored for anti-PEG prior to and throughout a course of treatment with a PEGylated compound. Finally, protein conjugates with the poorly immunogenic hydroxy-PEG sequence or other hydrophilic polymers are in early phases of development and may represent an alternative to immunogenic PEGylated proteins.

  8. 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

  9. Randomized controlled trial of sodium phosphate tablets vs polyethylene glycol solution for colonoscopy bowel cleansing.

    PubMed

    Jung, Yoon Suk; Lee, Chang Kyun; Kim, Hyo Jong; Eun, Chang Soo; Han, Dong Soo; Park, Dong Il

    2014-11-14

    To compare efficacy, patient compliance, acceptability, satisfaction, safety, and adenoma detection rate of sodium phosphate tablets (NaP, CLICOLON(TM)) to a standard 4 L polyethylene glycol (PEG) solution for bowel cleansing for adults undergoing colonoscopy. 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. 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). 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.

  10. 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

  11. Two-step recrystallization of water in concentrated aqueous solution of poly(ethylene glycol).

    PubMed

    Gemmei-Ide, Makoto; Motonaga, Tetsuya; Kasai, Ryosuke; Kitano, Hiromi

    2013-02-21

    Crystallization behavior of water in a concentrated aqueous solution of poly(ethylene glycol) (PEG) with a water content of 37.5 wt % was investigated by temperature variable mid-infrared (mid-IR) spectroscopy in a temperature range of 298-170 K. The mid-IR spectrum of water at 298 K showed that a large water cluster was not formed and that most of the water molecules were associated with the PEG chain. Ice formation, however, occurred as found in previous studies by differential scanning calorimetory. Ice formations were grouped into three types: crystallization at 231 K during cooling, that at 198 K during heating, and that at 210 K during heating. The latter two were just recrystallization. These ice formations were the direct transition from hydration species to ice without condensation regardless of crystallization or recrystallization. This means that the recrystallized water in the present system was not generated from low-density amorphous solid water. At a low cooling rate, nearly complete crystallization at 231 K during cooling and no recrystallization were observed. At a high cooling rate, no crystallization and two-step recrystallization at 198 and 210 K were observed. The former and latter recrystallizations were found to be generated from water associated with the PEG chains with ttg (the sequence -O-CH(2)-CH(2)-O- having a trans (t) conformation about the -C-O- bond and a gauche (g) conformation about the -C-C- bond) and random conformations, respectively. These results indicate that recrystallizable water does not have a single specific water structure.

  12. Pharmacokinetics, clearance, and biosafety of polyethylene glycol-coated hollow gold nanospheres

    PubMed Central

    2014-01-01

    Objective Gold nanoparticles have attracted enormous interest as potential theranostic agents. However, little is known about the long-term elimination and systemic toxicity of gold nanoparticles in the literature. Hollow gold nanospheres (HAuNS) is a class of photothermal conducting agent that have shown promises in photoacoustic imaging, photothermal ablation therapy, and drug delivery. It’s very necessary to make clear the biosafety of HAuNS for its further application. Methods We investigated the cytotoxicity, complement activation, and platelet aggregation of polyethylene glycol (PEG)-coated HAuNS (PEG-HAuNS, average diameter of 63 nm) in vitro and their pharmacokinetics, biodistribution, organ elimination, hematology, clinical chemistry, acute toxicity, and chronic toxicity in mice. Results PEG-HAuNS did not induce detectable activation of the complement system and did not induce detectable platelet aggregation. The blood half-life of PEG-HAuNS in mice was 8.19 ± 1.4 hr. The single effective dose of PEG-HAuNS in photothermal ablation therapy was determined to be 12.5 mg/kg. PEG-HAuNS caused no adverse effects after 10 daily intravenous injections over a 2-week period at a dose of 12.5 mg/kg per injection (accumulated dose: 125 mg/kg). Quantitative analysis of the muscle, liver, spleen, and kidney revealed that the levels of Au decreased 45.2%, 28.6%, 41.7%, and 40.8%, respectively, from day 14 to day 90 after the first intravenous injection, indicating that PEG-HAuNS was slowly cleared from these organs in mice. Conclusion Our data support the use of PEG-HAuNS as a promising photothermal conducting agent. PMID:24886070

  13. Synthesis and characterization of ultrathin WO3 nanodisks utilizing long-chain poly(ethylene glycol).

    PubMed

    Wolcott, Abraham; Kuykendall, Tev R; Chen, Wei; Chen, Shaowei; Zhang, Jin Z

    2006-12-21

    Metal oxide nanostructures hold great potential for photovoltaic (PV), photoelectrochemical (PEC), and photocatalytic applications. Whereas thin films of various materials of both nanoparticle and nanorod morphologies have been widely investigated, there have been few inquiries into nanodisk structures. Here, we report the synthesis of ultrathin WO3 nanodisks using a wet chemical route with poly(ethylene glycol) (PEG) as a surface modulator. The reported nanodisk structure is based on the interaction of the nonionic 10000 g/mol PEG molecules with tungsten oxoanion precursors. The WO3 nanostructures formed are dominated by very thin disks with dimensions on the nanometer to micrometer scale. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images reveal the structures to have dimensions on the order of 350-1000 nm in length, 200-750 nm in width, and 7-18 nm in thickness and possessing textured single-crystalline features. A number of analytical techniques were used to characterize the WO3 nanodisks, including selected-area electron diffraction (SAED), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), Raman scattering spectroscopy, UV-visible spectrophotometry, and cyclic voltammetry (CV). The growth of the WO3 nanodisks was inhibited in the [010] crystal direction, leading to ultrathin morphologies in the monoclinic crystal phase. The large flat surface area and high aspect ratio of the WO3 nanodisks are potentially useful in PEC cells for hydrogen production via direct water splitting, as has been demonstrated in a preliminary experiment with external bias.

  14. 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

  15. Polyethylene glycol conjugation enhances the nitrite reductase activity of native and cross-linked hemoglobin.

    PubMed

    Lui, Francine E; Dong, Pengcheng; Kluger, Ronald

    2008-10-07

    Although stabilized hemoglobins have been evaluated as oxygen-carrying replacements for red cells in transfusions, in vivo evaluations have noted that these materials are associated with vasoactivity, a serious complication. Scavenging of endogenous nitric oxide by the deoxyheme sites of the stabilized proteins is one likely source of vasoactivity. Recent reports indicate that modification of cell-free hemoglobin derivatives with multiple chains of polyethylene glycol (PEG) suppresses vasoactivity. Gladwin and co-workers observed that the nitrite reductase activity of hemoglobin serves as a major endogenous source of nitric oxide. If PEG conjugation leads to enhanced nitrite reductase activity, this could compensate for scavenged endogenous nitric oxide. To test this possibility, the rates of conversion of nitrite ion to nitric oxide by altered hemoglobins with and without PEG were measured at 25 degrees C. Fumaryl (alpha99-alpha99) cross-linked hemoglobin reacts with nitrite with a bimolecular rate constant of 0.52 M (-1) s (-1), which is comparable to that associated with native hemoglobin (0.25 M (-1) s (-1)). Addition of PEG chains to the cross-linked hemoglobin at beta-Cys93 (alphaalpha-Hb-PEG5K 2) results in a material that produces nitric oxide much more rapidly ( k = 1.41 M (-1) s (-1)). R-State-stabilized hemoglobins with multiple PEG chains (Hb-PEG5K 2 and Hb-PEG5K 6) react 10 times faster with nitrite to produce nitric oxide than does native hemoglobin ( k = 2.5 and 2.4 M (-1) s (-1), respectively). These results, showing enhanced production of nitric oxide resulting from an increased proportion of the protein residing in the R-state, are consistent with the decrease in vasoactivity associated with PEG conjugation.

  16. The Effect of Melatonin Adsorbed to Polyethylene Glycol Microspheres on the Survival of MCF-7 Cells.

    PubMed

    França, Eduardo Luzía; Honorio-França, Adenilda Cristina; Fernandes, Rubian Trindade da Silva; Marins, Camila Moreira Ferreira; Pereira, Claudia Cristina de Souza; Varotti, Fernando de Pilla

    2016-01-01

    Although melatonin exhibits oncostatic properties such as antiproliferative effects, the oral bioavailability of this hormone is less than 20%. Modified drug release systems have been used to improve the pharmacological efficiency of drugs. These systems can change the pharmacokinetics and biodistribution of the associated drugs. Thus, this study investigated the effect of melatonin adsorbed to polyethylene glycol (PEG) microspheres on MCF-7 human breast cancer cells. The MCF-7 cells were obtained from the American Type Culture Collection. MCF-7 cells were preincubated for 24 h with or without melatonin (100 ng/ml), PEG microspheres or melatonin adsorbed to PEG microspheres (100 ng/ml). Viability, intracellular calcium release and apoptosis in MCF-7 cells were determined by flow cytometry. MCF-7 cells incubated with melatonin adsorbed to PEG microspheres showed a lower viability rate (40.0 ± 8.3 with melatonin adsorbed to PEG microspheres compared to 54.1 ± 7.3 with melatonin; 81.8 ± 12.5 with PEG microsphere and 92.7 ± 4.1 with medium), increased spontaneous intracellular Ca2+ release (27.0 ± 8.6 with melatonin adsorbed to PEG microspheres compared to 21.5 ± 13.4 with melatonin; 10.1 ± 5.4 with PEG microsphere and 9.1 ± 5.6 with medium) and increased apoptosis index (51.2 ± 2.7 with melatonin adsorbed to PEG microspheres compared to 36.0 ± 2.1 with melatonin; 4.9 ± 0.5 with PEG microsphere and 3.1 ± 0.6 with medium). The results indicate that melatonin adsorbed to PEG microspheres exerts antitumor effects on human MCF-7 breast cancer cells. However, clinical tests must be performed to confirm the use of melatonin adsorbed to PEG microspheres as an alternative therapy against cancer.

  17. Blood compatibility evaluations of poly(ethylene glycol)-poly(lactic acid) copolymers.

    PubMed

    Li, Chenghua; Ma, Chengyan; Zhang, Yi; Liu, Zonghua; Xue, Wei

    2016-05-01

    Poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) copolymers have been widely used for various biomedical applications. However, their hemocompatibility has not been clarified, which would lag their developments and clinical applications. In this work, we studied the effect of PEG-PLA copolymers on key human blood components in terms of their structure and bio-functions, including morphology and lysis of red blood cells, fibrinogen structure and conformation, and plasma and blood coagulation. To elucidate a structure-activity relationship, we used diblock PEG-PLA copolymers with different molecular weight, PEG(5 kDa)-PLA(25 kDa) and PEG(2 kDa)-PLA(2 kDa), abbreviated as PEG5k-PLA25k and PEG2k-PLA2k, respectively. The results show that the PEG-PLA copolymers at the concentration range studied in this work neither caused morphological alteration and lysis of red blood cells nor affected the oxygen delivery function and fibrinogen conformation. PEG5k-PLA25k from 10 to 100 mg/mL and PEG2k-PLA2k from 1.5 to 5 mg/mL disturbed the local microenvironments of fibrinogen molecules. PEG5k-PLA25k at up to 0.1 mg/mL did not interfere in the coagulation process of plasma or whole blood, while PEG2k-PLA2k from 0.1 mg/mL significantly interfered in the intrinsic plasma coagulation pathway and impaired whole blood coagulation. The results provide important information for the molecular design and clinical applications of PEG-PLA copolymers.

  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. Liposomal Cu-64 labeling method using bifunctional chelators: poly(ethylene glycol) spacer and chelator effects.

    PubMed

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

    2010-07-21

    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 (64)Cu-TETA, (64)Cu-TETA-PEG2k, and (64)Cu-CB-TE2A-PEG2k liposomes showed that more than 86% of the radioactivity remains associated with the liposomal fraction after 48 h of incubation with mouse serum. The in vivo time activity curves (TAC) for the three liposomal formulations showed that approximately 50% of the radioactivity cleared from the blood pool in 16-18 h. As expected, the in vivo biodistribution and TAC data obtained at 48 h demonstrate that the clearance of radioactivity from the liver slows with the incorporation of a poly(ethylene glycol)-2k (PEG2k) brush. Our data suggest that (64)Cu-TETA and (64)Cu-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 (64)Cu-TETA-chelated liposomes rather than (64)Cu-CB-TE2A-chelated liposomes.

  20. 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

  1. Solute retention and the states of water in polyethylene glycol and poly(vinyl alcohol) gels.

    PubMed

    Baba, Takayuki; Sakamoto, Ryosaku; Shibukawa, Masami; Oguma, Koichi

    2004-06-18

    The states of water sorbed in a cross-linked polyethylene glycol (PEG) gel, TSKgel Ether-250, and cross-linked poly(vinyl alcohol) (PVA) gels of different pore sizes, TSKgel Toyopearl HW-40S, 50S, 55S and 75S, were investigated by means of differential scanning calorimetry (DSC). It was found that there were three types of water in these hydrogels, non-freezing water, freezable bound water and free water. The amount of water that functions as the stationary phase in the column packed with the each gel was also estimated by a liquid chromatographic method. The estimated amount of the stationary phase water is in good agreement with the sum of the amount of non-freezing water and that of freezable bound water for HW-40S, 50S and 55S, while it agrees with the amount of only non-freezing water for HW-75S and Ether-250. This means that the stationary phase water consists of non-freezing water and freezable bound water for HW-40S, 50S and 55S, while only non-freezing water functions as the stationary phase in HW-75S and Ether-250 gels. This result can be attributed to the difference in the structure of the gels; the PVA gels containing PVA at relatively high concentrations, HW-40S, 50S and 55S, have a homogeneous gel phase, whereas HW-75S and Ether-250 have a heterogeneous gel phase consisting hydrated polymer domains and macropores with relatively hydrophobic surface. The freezable bound water in Toyopearl HW-40S, 50S and 55S can be regarded as a component of a homogeneous PVA solution phase, while that in HW-75S and Ether-250 may be water isolated in small pores of the hydrophobic domains. The results obtained by the investigation on the retention selectivity of these hydrogels in aqueous solutions supported our postulated view on the structures of the hydrogels.

  2. Polyethylene glycol-based protein nanocapsules for functional delivery of a differentiation transcription factor.

    PubMed

    Biswas, Anuradha; Liu, Ying; Liu, Tianfei; Fan, Guoping; Tang, Yi

    2012-07-01

    Transcription factors (TFs) can direct cell fate by binding to DNA and regulating gene transcription. Controlling the intracellular levels of specific TFs can therefore enable reprogramming of cellular function and differentiation. Direct delivery of recombinant TFs to target cells can thus have widespread therapeutic value, but has remained challenging due to structural fragility of TFs and inefficient membrane transduction. Here we describe the functional delivery of TFs using degradable polymeric nanocapsules to drive cellular differentiation. The nanocapsules were synthesized with poly(ethylene) glycol (PEG)-based monomers and intracellularly-degradable crosslinkers. Physical properties and release kinetics of the nanocapsules were optimized through tuning of monomer and crosslinker ratios to achieve enhanced delivery of cargo destined for the nuclei. The nanocapsules did not display cytotoxicity in primary cell lines up to concentrations of 5 μm. A recombinant myogenic transcription factor, MyoD, was delivered to the nuclei of myoblast cells using degradable nanocapsules to induce myogenic differentiation. MyoD was confirmed to be delivered to the nuclei of myoblasts using confocal microscopy and was demonstrated to be active in transcription through a luciferase-based reporter assay. More importantly, delivered MyoD was able to drive myoblast differentiation as evidenced by the hallmark elongated and multinuclear morphology of myotubes. The activation of downstream cascade was also confirmed through immunostaining of late myogenic markers myogenin and My-HC. The efficiency of differentiation achieved via nanocapsule delivery is significantly higher than that of native MyoD, and is comparable to that of plasmid transfection. The encapsulated MyoD can also withstand prolonged protease treatment and remain functional. The ease of preparation, biocompatibility and effective cargo delivery make the polymeric nanocapsule a useful tool to deliver a variety of

  3. 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.

  4. The effect of polyethylene glycol on intake of Mediterranean shrubs by sheep and goats.

    PubMed

    Rogosic, J; Pfister, J A; Provenza, F D; Pavlicevic, J

    2008-12-01

    Poor nutritional quality and increased content of secondary compounds can reduce consumption of Mediterranean shrubs by herbivores. In 2 sequential trials, we examined the effect of polyethylene glycol (PEG) and number of shrub species offered on daily intake of Mediterranean shrubs by 12 sheep and 12 goats. The PEG (25 g) was fed to experimental animals with barley. In trial 1 (6 shrubs), goats ate more (P = 0.0008) daily total shrub biomass than did sheep (60.7 vs. 45.9 +/- 2.6 g/kg of BW). There was a trend (P = 0.08) toward a positive PEG effect on total shrub intake, with PEG-supplemented animals consuming more total shrubs than controls (56.7 vs. 50.0 +/- 2.6 g/kg of BW). Trial 2 (using 3 shrubs) was a continuation of trial 1, except that animals were given less barley and treatment animals were given more PEG (50 g). Both sheep and goats showed a numerical decrease in total shrub intake from trial 1 to trial 2. Sheep receiving PEG ate more (P = 0.002) total shrubs than did controls, but no PEG effect was found for goats. Thus, PEG had a greater influence on sheep than goats when only 3 shrubs were offered, a result that may be related to the fact that fewer shrubs with complementary secondary compounds were offered and that goats appear to have a greater ability to consume and detoxify secondary compounds from Mediterranean shrubs. Overall, as the number and diversity of shrubs offered increased, supplemental PEG had less effect on increasing intake for both goats and sheep.

  5. 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

  6. The in vitro and in vivo response to MMP-sensitive poly(ethylene glycol) hydrogels

    PubMed Central

    Amer, Luke D.; Bryant, Stephanie J.

    2017-01-01

    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 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 foreign body response 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 foreign body response 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 foreign body response. 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

  7. 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.

  8. 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.

  9. Diels-Alder mediated controlled release from a poly(ethylene glycol) based hydrogel.

    PubMed

    Koehler, Kenneth Christopher; Anseth, Kristi S; Bowman, Christopher N

    2013-02-11

    A synthetic amino acid bearing a furan functionality was developed and incorporated into peptide sequences using solid phase synthesis. Peptides expressing the furan moiety were attached to poly(ethylene glycol) (PEG) hydrogels through a thermally reversible covalent bond formed by a Diels-Alder reaction. Reactions of thiol and maleimide PEG macromers in an off-stoichiometric Michael addition were performed, such that the maleimide moiety was in excess, to create hydrogel networks with pendant Diels-Alder compatible tethering sites, that is, the maleimide. By making use of the Diels-Alder reaction, it was possible to control the release rate of reversibly bound moieties from the hydrogel by changing the temperature; higher temperatures favor a faster retro-Diels-Alder reaction and, therefore, a faster release from the polymer network. This concept was demonstrated by incorporating a fluorescently labeled furan-RGDS sequence into a hydrogel possessing excess maleimide functionalities and monitoring the subsequent liberation of RGDS at various temperatures, illustrating a Diels-Alder mediated release mechanism. The release profile was quantified at temperatures ranging from physiological (37 °C) to 80 °C. By changing the temperature, varying extents of release were attained over the time course of several days, ranging from 40% release for lower temperatures to complete release for the highest temperature considered. Further confirmation of a reaction-diffusion controlled release mechanism was obtained through comparison of experimental release data to a reaction-diffusion model of the release. In addition to thermal modulation, tuning of the release rate was accomplished by altering the number of possible Diels-Alder tethering sites present in the hydrogel. Increasing the amount of free maleimide and, therefore, the number of potential Diels-Alder reaction sites, effectively slowed the release of peptide from the polymer. For instance, doubling the amount of

  10. A Comprehensive Study of Photorefractive Properties in Poly(ethylene glycol) Dimethacrylate— Ionic Liquid Composites

    PubMed Central

    Ellabban, Mostafa A.; Glavan, Gašper; Klepp, Jürgen; Fally, Martin

    2016-01-01

    A detailed investigation of the recording, as well as the readout of transmission gratings in composites of poly(ethylene glycol) dimethacrylate (PEGDMA) and ionic liquids is presented. Gratings with a period of about 5.8 micrometers were recorded using a two-wave mixing technique with a coherent laser beam of a 355-nm wavelength. A series of samples with grating thicknesses d0=10…150 micrometers, each for two different exposure times, was prepared. The recording kinetics, as well as the post-exposure properties of the gratings were monitored by diffracting a low intensity probe beam at a wavelength of 633 nm for Bragg incidence. To obtain a complete characterization, two-beam coupling experiments were conducted to clarify the type and the strength of the recorded gratings. Finally, the diffraction efficiency was measured as a function of the readout angle at different post-exposure times. We found that, depending on the parameters, different grating types (pure phase and/or mixed) are generated, and at elevated thicknesses, strong light-induced scattering develops. The measured angular dependence of the diffraction efficiency can be fitted using a five-wave coupling theory assuming an attenuation of the gratings along the thickness. For grating thicknesses larger than 85 microns, light-induced scattering becomes increasingly important. The latter is an obstacle for recording thicker holograms, as it destroys the recording interference pattern with increasing sample depth. The obtained results are valuable in particular when considering PEGDMA-ionic liquid composites in the synthesis of advanced polymer composites for applications, such as biomaterials, conductive polymers and holographic storage materials. PMID:28772368

  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. Citrus reticulata peel improves patient tolerance of low-volume polyethylene glycol for colonoscopy preparation.

    PubMed

    Lan, Hung-Chieh; Liang, Ying; Hsu, Hsiu-Chuan; Shu, Jiah-Hwang; Su, Chien-Wei; Hung, Hung-Hsu; Hou, Ming-Chih; Lin, Han-Chieh; Lee, Shou-Dong; Wang, Yuan-Jen

    2012-09-01

    Adequate adjuncts help to reduce the volume of polyethylene glycol-electrolyte lavage solution (PEG-ELS) needed, to ameliorate patient discomfort, and to improve colonic visibility during colonoscopy. This study aimed to assess the effect of Citrus reticulata peel (CRP) as an adjunct to low-volume PEG for colonic preparation. A total of 1092 health examination examinees received colonoscopy during the study period. After excluding those who refused to participate and those who did not meet our criteria, 212 examinees were enrolled into this study. They were divided into the PEG group and the PEG + CRP group according to their date of examination. All examinees received 2 L of PEG-ELS one day before colonoscopy. The PEG + CRP group also received additional CRP in the form of a "buccal tablet" between drinks. Tolerance and adverse events were assessed by questionnaire, while the quality of bowel preparation for colonoscopy was scored by an endoscopist. There were 107 examinees in the PEG group and 105 examinees in the PEG + CRP group. The demographic characteristics of the examinees were comparable between these two groups. Examinees in the PEG + CRP group had a trend of better colonic visibility than those in the PEG group (p = 0.056). Moreover, examinees in the PEG + CRP group had higher rate of acceptable taste (p = 0.015) and lower rate of difficulty swallowing (p = 0.001). The incidences of adverse events including vomiting (p = 0.045), bloating (p = 0.035), and difficulty sleeping (p < 0.001) were also significantly lower in the PEG + CRP group. Compared with conventional colonic preparation, the application of CRP as an adjunct could improve examinees' tolerance, decrease the incidence of adverse events, and maintain the quality of colonic cleansing. 2012 Published by Elsevier B.V

  13. Modification and patterning of nanometer-thin poly(ethylene glycol) films by electron irradiation.

    PubMed

    Meyerbröker, Nikolaus; Zharnikov, Michael

    2013-06-12

    In this study, we analyzed the effect of electron irradiation on highly cross-linked and nanometer-thin poly(ethylene glycol) (PEG) films and, in combination with electron beam lithography (EBL), tested the possibility to prepare different patterns on their basis. Using several complementary spectroscopic techniques, we demonstrated that electron irradiation results in significant chemical modification and partial desorption of the PEG material. The initially well-defined films were progressively transformed in carbon-enriched and oxygen-depleted aliphatic layers with, presumably, still a high percentage of intermolecular cross-linking bonds. The modification of the films occurred very rapidly at low doses, slowed down at moderate doses, and exhibited a leveling off behavior at higher doses. On the basis of these results, we demonstrated the fabrication of wettability patterns and sculpturing complex 3D microstructures on the PEG basis. The swelling behavior of such morphological patterns was studied in detail, and it was shown that, in contrast to the pristine material, irradiated areas of the PEG films reveal an almost complete absence of the hydrogel-typical swelling behavior. The associated sealing of the irradiated areas allows a controlled deposition of objects dissolved in water, such as metal nanoparticles or fluorophores, into the surrounding, pristine areas, resulting in the formation of nanocomposite patterns. In contrast, due to the distinct protein-repelling properties of the PEG films, proteins are exclusively adsorbed onto the irradiated areas. This makes such films a suitable platform to prepare protein-affinity patterns in a protein-repelling background.

  14. Need and utility of a polyethylene glycol marker to ensure against urine falsification among heroin users.

    PubMed

    Jones, Jermaine D; Atchison, Jared J; Madera, Gabriela; Metz, Verena E; Comer, Sandra D

    2015-08-01

    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. 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). 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. 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. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. 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.

  16. Polyethylene glycol reduces early and long-term cold ischemia-reperfusion and renal medulla injury.

    PubMed

    Faure, Jean Pierre; Hauet, Thierry; Han, Zeqiu; Goujon, Jean Michel; Petit, Isabelle; Mauco, Gerard; Eugene, Michel; Carretier, Michel; Papadopoulos, Vassilios

    2002-09-01

    Ischemia-reperfusion injury (IRI) after transplantation is a major cause of delayed graft function, which has a negative impact on early and late graft function and improve acute rejection. We have previously shown that polyethylene glycol (PEG) and particularly PEG 20M has a protective effect against cold ischemia and reperfusion injury in an isolated perfused pig and rat kidney model. We extended those observations to investigate the role of PEG using different doses (30g or 50g/l) added (ICPEG30 or ICPEG50) or not (IC) to a simplified preservation solution to reduce IRI after prolonged cold storage (48-h) of pig kidneys when compared with Euro-Collins and University of Wisconsin solutions. The study of renal function and medulla injury was performed with biochemical methods and proton NMR spectroscopy. Histological and inflammatory cell studies were performed after reperfusion (30-40 min) and on days 7 and 14 and weeks 4, 8, and 12. Peripheral-type benzodiazepine receptor (PBR), a mitochondrial protein involved in cholesterol homeostasis, was also studied. The results demonstrated that ICPEG30 improved renal function and reduced medulla injury. ICPEG30 also improved tubular function and strongly protect mitochondrial integrity. Post-IRI inflammation was strongly reduced in this group, particularly lymphocytes TCD4(+), PBR expression was influenced by IRI in the early period and during the development of chronic dysfunction. This study clearly shows that PEG has a beneficial effect in renal preservation and suggests a role of PBR as a marker IRI and repair processes.

  17. 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.

  18. 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.

  19. Coatings of polyethylene glycol for suppressing adhesion between solid microspheres and flat surfaces.

    PubMed

    Upadhyayula, Srigokul; Quinata, Timothy; Bishop, Stephen; Gupta, Sharad; Johnson, Noah Ray; Bahmani, Baharak; Bozhilov, Kliment; Stubbs, Jeremy; Jreij, Pamela; Nallagatla, Pratima; Vullev, Valentine I

    2012-03-20

    This article describes the development and the examination of surface coatings that suppress the adhesion between glass surfaces and polymer microspheres. Superparamagnetic doping allowed for exerting magnetic forces on the microbeads. The carboxyl functionalization of the polymer provided the means for coating the beads with polyethylene glycol (PEG) with different molecular weight. Under gravitational force, the microbeads settled on glass surfaces with similar polymer coatings. We examined the efficacy of removing the beads from the glass surfaces by applying a pulling force of ~1.2 pN. The percent beads remaining on the surface after applying the pulling force for approximately 5 s served as an indication of the adhesion propensity. Coating of PEG with molecular weight ranging between 3 and 10 kDa was essential for suppressing the adhesion. For the particular substrates, surface chemistry and aqueous media we used, coatings of 5 kDa manifested optimal suppression of adhesion: that is, only 3% of the microbeads remained on the surface after applying the pulling magnetic force. When either the glass or the beads were not PEGylated, the adhesion between them was substantial. Addition of a noncharged surfactant, TWEEN, above its critical micelle concentrations (CMCs) suppressed the adhesion between noncoated substrates. The extent of this surfactant-induced improvement of the adhesion suppression, however, did not exceed the quality of preventing the adhesion that we attained by PEGylating both substrates. In addition, the use of surfactants did not significantly improve the suppression of bead-surface adhesion when both substrates were PEGylated. These findings suggest that such surfactant additives tend to be redundant and that covalently grafted coatings of PEGs with selected chain lengths provide sufficient suppression of nonspecific interfacial interactions.

  20. 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