Tesis sobre el tema "Polyethylene glycol"
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Pathak, Shantanu Chaturvedi. "Characterization of plasma-polymerized polyethylene glycol-like films". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/31789.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Dr. Dennis W. Hess; Committee Member: Dr. Clifford L. Henderson; Committee Member: Dr. J. Carson Meredith; Committee Member: Dr. L. Andrew Lyon; Committee Member: Dr. Mark R. Prausnitz. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Malik, Farooq. "Construction and characterisation of polyethylene glycol modified cytokines". Thesis, Open University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308154.
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Turner, Kelly A. "Polyethylene glycol stationary phases for capillary gas chromatography". Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/44090.
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The chromatographic properties of various silicone stationary phases for capillary gas chromatography have been extensively studied, yet the properties of nonsilicone phases have not been so well investigated. The most popular nonsilicone phases are the high molecular weight polyethylene glycols (HMW PEG) which are commercially available in a wide range of molecular weights, crossâ linkable and uncross-linkable (Carbowax 2OM and 4OM, the Superox series, etc.). Their most outstanding features are their unique polarity and selectivity; for this reason these phases are widely used in the analysis of aqueous solutions, essential oils, and perfumes.
Unfortunately HMW-PEG's are very sensitive to slight differences in preparation and handling procedures which can cause analyses to differ with each laboratory, each column, and even each use. HMWâ PEG's also suffer from low temperature stability, a high minimum allowable operating temperature, and have lower diffusion coefficients than silicone phases.
This study examines the efficiency differences of eight columns differing only in immobilization procedure and added functional groups. Comparison is made using HETP versus u and separation number (TZ) versus u curves. These curves offer important information, in particular, the effect of carrier gas, u, column operating temperature, degree of crossâ linking, and cross-linking temperature on chromatographic efficiency and separation number. In addition, the contributions of the CL (resistance to mass transfer in the liquid phase) and DL (diffusion coefficient in the liquid phase) terms in the Golay equation are calculated [1]. Solids at room temperature, PEG stationary phases undergo a solid-liquid phase transition within their useful temperature range. The effect of this transition on the chromatographic properties is investigated using efficiency, separation number, capacity ratio, and retention index versus temperature curves. Four more columns, in addition to the eight mentioned above, demonstrate the influence of end-groups and the molecular weight of the stationary phase on the phase transition temperature range.Master of Science
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Zuo, Amy. "Cross-interactions of bovine chymotrypsinogen-A and polyethylene glycol". Connect to resource, 2010. http://hdl.handle.net/1811/45411.
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Naigamwalla, Dinaz. "Effects of polyethylene glycol on colon carcinogenesis in rodents". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0005/MQ46132.pdf.
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COLLAZOS, STEPHANIE ORTIZ. "LANGMUIR FILMS OF FATTY ACID ESTERS OF POLYETHYLENE GLYCOL". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29504@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Ésteres de polietilenoglicol derivados de ácidos graxos são surfactantes não iônicos biodegradáveis com aplicação em vários segmentos da indústria, em especial nas indústrias de óleo e gás, farmacêutica, de cosméticos e de alimentos. Ésteres de ácidos graxos naturais, tais como acido esteárico e palmítico, foram sintetizados e caracterizados, e os seus filmes de Langmuir foram obtidos. As propriedades viscoelásticas destes polímeros modificados hidrofobicamente foram investigadas na interface ar-água. Desta forma foi também possível avaliar a isoterma de Langmuir Pi-A e as propriedades mecânicas das monocamadas através do cálculo do módulo de compressão (Cs -1). A elasticidade superficial dilatacional e a tensão superficial dinâmica dos filmes adsorvidos foram analisadas pelo método da gota pendente em um goniômetro. Os módulos dinâmicos oscilatórios de armazenamento e perda do bulk da solução aquosa do tensioativo foram estudados em um reômetro de cisalhamento. Os estudos de tensão superficial dinâmica revelaram que a adsorção do surfactante na interface ar-água acontece de maneira rápida atingindo uma região de meso-equilíbrio em aproximadamente de 1 a 2 min. Foi demostrado o comportamento preferencialmente elástico destes polímeros modificados hidrofobicamente em duas e três dimensões (interface e bulk). Consequentemente, foi alcançada uma boa capacidade para estes polímeros atuarem como agentes coletores de petróleo na presença ou ausência de eletrólitos na subfase aquosa.
Fatty acid esters of polyethylene glycols are biodegradable non-ionic surfactants with application in many industrial segments such as oil and gas, pharmaceutical, cosmetics, and food. Esters of polyethylene glycols based on natural fatty acids such as stearic acid and palmitic acid, were synthesized and characterized, and their Langmuir films were obtained. The viscoelastic properties of these hydrophobically modified polymers at the air/water interface have been investigated. Thus it was also possible to evaluate the Langmuir isotherm (Pi-A) and mechanical properties of the monolayers by calculating the compression modulus (Cs-1). The surface dilatational elasticity and dynamic surface tension of the adsorbed films were analyzed by the pendant drop method with a goniometer apparatus. The oscillatory dynamic storage and loss modules of the bulk of the aqueous surfactant solution were studied in a shear rheometer. The dynamic surface tension studies show that the kinetics of the surfactant adsorption at the air-water interface is reasonably fast, reaching the meso-equilibrium region in approximately 1 to 2 min. It was demonstrated an elastic behavior of these hydrophobic modified polymers in two and three dimensions (interface and bulk). Consequently, it was achieved a good capacity for them to act as oil herding agents in presence or absence of electrolytes in the aqueous subphase.
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Houts, Frederick William. "Analysis of Methoxy-polyethylene Glycol-modified Human Serum Albumin". University of Toledo Health Science Campus / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=mco1149010508.
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Dancho, David M. "Analysis of Polyethylene Glycol in the α-Hemolysin Nanopore". VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/483.
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Nanopores have been shown to be a useful analytical tool for single molecule detection. They have been used to study the composition of DNA and other molecules of interest. These pores are usually α-hemolysin which is a toxin from Staphylococcus aureus or more recently nanoscale synthetic solid state pores. Now we are beginning to look at other molecules or proteins by sending them into the nanopores and measuring a characteristic partial current blockade. In this thesis we look at polyethylene glycol (PEG) as it enters and blocks current through a single alpha hemolysin pore. We report the effects of ionic strength, PEG size, and applied voltage on the depth and duration of the current blockades. We also apply autocorrelation analysis on the arrival times of PEG molecules to the pore see if we can identify if the PEG is translocating through the pore or escaping from the same side it enters. This suggests a new approach to current blockade analysis.
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Howard, Matthew A. Neau Steven H. "The application of polyethylene oxide (PolyOx®) and methoxypolyethylene glycol (Carbowax Sentry®) in the production of extruded-spheronized beads with a high drug load". Diss., UMK access, 2004.
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Thesis (Ph. D.)--School of Pharmacy and Dept. of Chemistry. University of Missouri--Kansas City, 2004."A dissertation in pharmaceutical sciences and chemistry." Advisor: Steven H. Neau. Typescript. Vita. Description based on contents viewed Feb. 24, 2006; title from "catalog record" of the print edition. Includes bibliographical references (leaves 129-141). Online version of the print edition.
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Schmidt, Kurt A. G. "Solubility of sulphur dioxide in mixed polyethylene glycol dimethyl ethers". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq22670.pdf.
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Fu, Guopeng. "Molecular Complexation and Phase Diagrams of Urea/Polyethylene Glycol Mixtures". University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366631616.
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Iza, Mustapha. "Caracterisations des proprietes interactionnelles, mecaniques et diffusionnelles d'hydrogels de polyethylene glycol". Paris 11, 1997. http://www.theses.fr/1997PA114853.
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Chatham, Sarah Marianna. "Characterisation of molten filled hard gelatin capsules". Thesis, King's College London (University of London), 1985. https://kclpure.kcl.ac.uk/portal/en/theses/characterisation-of-molten-filled-hard-gelatin-capsules(5b2e73bf-b02c-4ecc-b00a-146fd90ec814).html.
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Bayard, Fabrice J. C. "Increasing drug retention in lung tissue through conjugation with polyethylene-glycol". Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13214/.
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The pulmonary delivery of drugs is an attractive route of administration because of the large surface area and high permeability of the airway epithelium. The large majority of inhaled drugs are used to manage asthma and Chronic Obstructive Pulmonary Disorder (COPD), such as inhaled corticosteroids and β2-adrenergic receptor agonists. Local delivery of small molecules often results in sub-optimal pharmacokinetics characterised by short absorption times (tmax) and high systemic concentrations (Cmax). Numerous drug delivery strategies have been attempted to increase lung retention time, including drug encapsulation in microspheres, the use of polymeric excipients, or the formation of low solubility drugs. So far, drug conjugation strategies have been limited to decreasing the prodrug solubility. The non-permanent conjugation of small molecules to a large hydrophilic polymer has not been studied for pulmonary delivery. The rationale behind such a strategy is that small molecules are mainly absorbed through the epithelium by passive diffusion, the absorption rates being positively correlated to the drug lipophilicity and molecular weight. This project has therefore been looking at the production, characterisation, in vitro and ex vivo evaluation of polyethylene glycol (PEG)-ester conjugates for the sustained delivery of drugs to the lung. This thesis presents the successful oxidation and subsequent esterification of PEG of various molecular weights with prednisolone (a corticosteroid) and salbutamol (a β2-adrenergic receptor agonist). This study illustrated the feasibility of a polymeric drug conjugate strategy for sustained release of drugs to the lung. The conjugates exhibited good in vitro stability which was translated into improved pharmacokinetics and longer residence time ex vivo in the isolated and perfused rat lung. Further studies must be conducted to fully assess the role of esterases in the pulmonary hydrolysis of the conjugates and in vivo experiments would be necessary to verify the safety of the conjugates and efficacy of the drug.
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Ruttenberg, David. "Intestinal permeability to polyethylene glycol 400 in patients with Crohn's disease". Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/25587.
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An altered small intestinal permeability has been proposed as an important aetiological factor in the pathogenesis of inflammatory bowel disease. The relevant literature was reviewed. Intestinal permeability to Polyethylene glycol 400 in patients with Crohn' s disease, their relatives and healthy controls was examined and the data compared with studies of small bowel permeability to other similar sized probes. A new technique of analysis of urinary Polythylene Glycol 400 by High Performance Liquid Chromatography was described and compared with a previously established HPLC method. No evidence of an altered bowel permeability could be found using Polyethylene glycol 400, but the possibility that this may have been related to probe size and characteristics can not be excluded .
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Qaderi, Kamran. "Polyethylene Glycol Diacrylate (PEGDA) Resin Development for 3D-Printed Microfluidic Devices". BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5555.
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In this thesis, the successful fabrication of 3D-printed microfluidic devices will be discussed. Fabrication is performed with a low-cost commercially available stereolithographic 3D printer utilizing a custom PEGDA resin formulation tailored for low non-specific protein adsorption based on my colleagues' work [Rogers et al., Anal. Chem. 83, 6418 (2011)]. Horizontal microfluidic channels with designed rectangular cross sectional dimensions as small as 300 um wide and 150 um tall are printed with 100% yield, as are cylindrical vertical microfluidic channels with 300 um designed (334 um actual) diameters. Moreover, two different resins developed by our group are utilized in the process of 3D-printing which is the novel aspect about this thesis since other groups have not done research on this aspect of 3D-printing.
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Keskin, Tugba. "Preparation Of Polyethylene Glycol Coated Magnetic Nanoparticles For Targeting Of Cancer Cells". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614089/index.pdf.
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Conventional cancer chemotherapies cannot differentiate between healthy and cancer cells, and lead to severe side effects and systemic toxicity. In the last decades, different kinds of controlled drug delivery systems have been developed to overcome these shortcomings of chemotherapeutics. Magnetic nanoparticles (MNP) are potentially important in cancer treatment since they can be targeted to tumor site by an externally applied magnetic field.
In this study, it is aimed to synthesize folic acid conjugatedpolyethylene glycol (PEG) coated magnetic nanoparticles with appropriate size, surface chemistry, magnetization and biocompatibility to be used in biomedical applications. First MNP were synthesized, then covered with oleic and PEG
and finally conjugated with folic acid. A detailed characterization of synthesized nanoparticles was done by TEM, XRD, FTIR, VSM and XTT analyses. MNP synthesized by the rapid addition of ammonium hydroxide exhibited more spherical nanoparticles with a narrower size distribution. Agglomeration tendency of naked nanoparticles was prevented by oleic acid addition during the synthesis. Both naked and surface treated MNP have been found to exhibit superparamagnetic behavior both at room temperature (23
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Kinsley, Chris. "Soybean peroxidase-catalysed treatment of phenol in the presence of polyethylene glycol". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44018.pdf.
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Yeom, Sin Hea. "TEMPERATURE-DEPENDENT TUNABLE PHOTOLUMINESCENCE PROPERTIES OF CARBON NANODOTS DERIVED FROM POLYETHYLENE GLYCOL". UKnowledge, 2014. http://uknowledge.uky.edu/chemistry_etds/46.
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Fluorescent carbon dots (C-dots) are well known for their low cell-cytotoxicity, biocompatibility, low preparation cost, excitation dependent photoluminescence, and excellent photostability. Typically, raw C-dots have low quantum efficiency and thus researchers have been utilizing biocompatible polymers such as polyethylene glycol (PEG) as a passivation agent in order to increase fluorescence signal. In this work, we report fluorescent self-passivated carbon nanodots (CNDs) synthesized from PEG by using it as a carbon source as well as a passivating agent. Importantly, the addition of graphene quantum dots (GQDs) during the synthesis of self-passivated CNDs can tune photoluminescence property. The results of bioimaging and cytotoxicity test of self-passivated CNDs hold promises for biomedicine applications.
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Gustafsson, Carla Astrid. "Modified polyethylene glycol hydrogels for growth factor delivery and controlled tissue invasion". Master's thesis, Faculty of Health Sciences, 2019. http://hdl.handle.net/11427/31068.
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The prevalence of cardiovascular disease and myocardial infarction-induced heart failure has risen significantly over recent years, emphasising the need for new, effective therapeutic strategies. A promising alternative approach is the cardiac delivery of potentially cardioprotective and regenerative growth factors from biomaterial scaffolds. One hydrogel system that has promise in this area is an injectable enzymatically degradable polyethylene glycol (PEG) hydrogel. Two modifications aimed at further optimising this system as a regenerative medicine scaffold were explored. Firstly, the covalent addition of heparin into the PEG backbone was assessed for its ability to stimulate angiogenesis by assessing the controlled release of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and placental growth factor 2 (PlGF-2), and also assaying endothelial cell sprouting in an in vitro 3D spheroid angiogenesis assay. The second modification involved overlaying an increasingly hydrolytic degradability on top of the enzymatically degradable background of the hydrogel. The potential of this modification to regulate the rate of hydrogel replacement by invading tissue was assessed in the 3D spheroid assay and a subcutaneous implant study in a rat model. The covalent coupling of heparin was found to substantially increase the rate of release of bFGF, VEGF and PlGF-2 over 20 days by 23%, 42% and 19%, respectively, relative to nonheparinised PEG hydrogels (p<0.01). A 3D spheroid-based angiogenesis assay was modified for use in quantifying endothelial cell sprouting in PEG hydrogels. bFGF and VEGF were shown to elicit a significant increase (2.3 – 2.4-fold increase) in average cumulative sprout lengths relative to that seen in the control spheroids (p<0.01). However, PlGF-2 did not stimulate a significant response (1.4-fold increase, p=NS). In follow up studies with heparinised hydrogels, it was found that the 3D angiogenesis was not rigorously established and ways forward are discussed. Enzymatically degradable PEG hydrogels that retained their enzymatic degradability with increasing levels of potential for hydrolysis were formed by increasing the proportion of PEGacrylate (PEG-Ac) and correspondingly decreasing the portion of PEG-vinyl sulfone (PEG-VS) monomers. PEG-Ac forms hydrolytically unstable bonds with the peptide crosslinker whilst 4 PEG-VS forms stable linkages. This approach was shown through swelling studies to be capable of generating a range of hydrolytic degradation rates. Sprouting of endothelial cells from PEG hydrogel embedded spheroids was shown to increase as the PEG-AC concentration increased. Importantly, the rate of tissue invasion in vivo was also shown to be positively correlated with the PEG-Ac concentration. The increased utility of these hydrogels to act as delivery vehicles for therapeutic agents, through covalent coupling of heparin, is promising for their use as regenerative medicine scaffolds. Additionally, so is the ability to finely tune tissue invasion by manipulating their hydrolytic degradability.
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Muenyi, Clarisse Sornsay. "Cell Toxicology Study of RRR-Alpha-Tocopheryl Polyethylene Glycol 1000 Succinate (TPGS)". Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etd/1037.
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This research focused on the cytotoxic properties of RRR-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in transformed and cancerous cell lines. We used RAW264.7 macrophage and prostate cancer (LNCaP) cell lines in this study. TPGS caused cell death and decreased cell viability in a dose and time dependent manner. Cell death was evaluated fluorimetrically by employing the nucleic acid-binding fluorophore; propidium iodide. A colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. Cell death can occur through necrosis or apoptosis. Our results suggested that TPGS triggered apoptotic cell death. Induction of apoptosis, as measured by caspase 3 enzymatic activity, was dependent upon the TPGS dose and incubation time. Caspase 8 was activated before caspase 9, suggesting the importance of the death receptor pathway in apoptosis. Our results indicated that TPGS cytotoxicity could also be due to one of its products of hydrolysis, alpha-tocopheryl succinate.
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Perney, Pascal. "Etude prospective de la tolérance et de l'efficacité de trois préparations pour la coloscopie". Montpellier 1, 1992. http://www.theses.fr/1992MON11064.
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Samkange, Tendai. "Evaluation of the effect of polyethylene glycol incorporation on the performance of poly(lactic-co-glycolic acid) nanoparticles". University of the Western Cape, 2016. http://hdl.handle.net/11394/6112.
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Magister Scientiae - MSc (Pharmaceutical Chemistry)Nanoparticle drug delivery is challenged by the binding of proteins in blood which result in their rapid removal from the circulatory system. Nanoparticles engineered to delay protein binding have shown to have extended circulatory times. One such engineering technique is PEGylation, which is the coating of nanoparticles with polyethylene glycol (PEG). PEG shields the nanoparticle from adhesive interactions with proteins. However, the optimal PEG content required to impart this "stealth" property onto poly(lactic-co-glycolic acid) (PLGA) nanoparticles, is unknown. Moreover, the effect of PEGylation on drug release has not been thoroughly investigated.
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Balasubramanian, Shankar Ganesh Sokkalinga Simonian Aleksandr L. "Development of smart functional surfaces for biosensor applications". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/FALL/Materials_Engineering/Dissertation/Balasubramania_S%20G_2.pdf.
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Thesis (Ph. D.)--Auburn University, 2008.Abstract. Vita. The following patent resulted from the dissertation research: Davis, V., Simonian, A.L., Nepal, D., Balasubramanian, S, "Preparation of Precisely Controlled Thin Film Nanocomposites of Carbon Nanotubes and Biomaterials", U.S. Provisional Patent Application No. 61/000,938, filed on 30 October 2007. The following peer-reviewed publications resulted from the dissertation research: Dhriti Nepal, Shankar Balasubramanian, Aleksandr Simonian, and Virginia Davis, "Mechanically Strong Antibacterial Thin Film Based on Single-Walled Carbon Nanotubes Armored with Biopolymers", Nano Letters ASAP article, May 2008 (# equal contribution) -- Shankar Balasubramanian, Iryna B. Sorokulova, Vitaly J. Vodyanoy, and Aleksandr L. Simonian, "Lytic Phage as a Specific and Selective Probe For Detection of Staphylococcus Aureus: A Surface Plasmon Resonance Spectroscopic Study", Biosensors and Bioelectronics, 2007, 22, 948-955 -- Shankar Balasubramanian, Alexander Revzin, Aleksandr Simonian, "Electrochemical Desorption of Proteins from Gold Electrode Surface", Electroanalysis, 2006, 18, 1885-1892 (Invited article) -- Vishwaprakash Nanduri, Shankar Balasubramanian, Srinivas Sista, Vitaly J. Vodyanoy, and Aleksandr L. Simonian, "Highly Sensitive Phage-based Biosensor for the Detection of ß-galactosidase", Analytica Chimica Acta, 2007, 589, 166- 172 -- H. Luckarift, Shankar Balasubramanian, S. Paliwal, G. Johnson and A. Simonian, "Enzyme-Encapsulated Silica Monolayers For Rapid Functionalization of a Gold Surface", Colloids and Surfaces B: Biointerfaces, 2007, 58, 28-33 (Invited article) -- Dong Wei, Omar Oyarzabal, Tung-Shi Huang, Shankar Balasubramanian, Srinivas Sista, Aleksandr Simonian, "Development of Surface Plasmon Resonance Biosensor For The Identification of Campylobacter jejuni", Journal of Microbiological Methods, 2007, 69, 78-85. The following conferences presentations resulted from the dissertation research: Covalent Immobilization of Organophosphorus Hydrolase on Carbon Nanotubes for Biosensor Applications, accepted for oral presentation at 12th International Meeting on Chemical Sensors, Jul. 13-16, 2008, Columbus, OH -- Electrochemical characteristics of SWNT-biopolymer nanocomposites, accepted for 213th meeting of The Electrochemical Society, May 18-23, 2008, Phoenix, AR -- Mechanically Robust Antibacterial Thin Films Composed of Single-Walled Carbon Nanotubes and Biopolymers, 2008 AIChE Spring National Meeting, Apr. 6-10, New Orleans, LA -- Production and characterization of protein and DNA based single wall carbon nanocomposites by layer-by-layer assembly, MRS Fall Meeting, Nov. 26-30, 2007, Boston, MA -- Gold surface modified with enzyme-encapsulated silica monolayers for biosensor application, The 58th Southeast Regional Meeting of the American Chemical Society, Nov. 1-4, 2006, Augusta, GA -- Electrochemical modulation of biological interfaces, 209th meeting of The Electrochemical Society, May 7-12, 2006, Denver, CO -- SPR based biosensor using lytic phage as a specific and selective probe for staphylococcus aureus detection, 57th Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, Mar. 12-17, 2006, Orlando, FL -- Specific & selective detection of staphylococcus aureus by lytic phage using SPR biosensor, 57th Southeast / 61st Southwest Joint Regional Meeting of the American Chemical Society, Nov. 1-4, 2005, Memphis, TN -- Prevention of non-specific binding as a way to increase sensitivity of SPR-based sensors, 206th meeting of The Electrochemical Society, October 3-8, 2004, Honolulu, HI. Includes bibliographical references.
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Calmeyn, Timothy J. "Optimization of the melt-phase polyethylene terephthalate manufacturing process". Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179336415.
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Bejaoui, Mohamed. "Polyethylene glycol conditioning: An effective strategy to protect against liver ischemia reperfusion injury". Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/385612.
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Ischemia is defined by the arrest of blood flow in the organ cutting thus oxygen and metabolite supply indispensable for its survival and function. Restoration of blood flow in hypoxic tissue, called reperfusion, can paradoxically result in more destructive than beneficial effects. Ischemia reperfusion injury (IRI) is an inevitable problem in many clinical situation of liver surgery such as organ transplantation, trauma and liver resection. Therapeutic strategies against IRI have been developed during the last 60 years and great advance into the mechanisms responsible of injuries have been achieved. However, efficient therapy against IRI is still lacking and few clinical studies in phase III have proven their effectiveness. This could be due in part to the complexity of the mechanisms responsible of IRI and to the specific drugs activity and their potential adverse effects.
Polyethylene glycols (PEGs) are water soluble nontoxic polymers that have been employed in many biomedical applications such as gastrointestinal disorders and drugs pegylation. Besides its usefulness as oncotic agents in preservation solutions, it has been shown that PEGs molecules protect against cold injury and ischemic damage.
In contrast to the current pharmacological strategies used against IRI, PEG presents the advantages of being a multi-target strategy. In fact, IRI is a multifactorial disease including oxidative stress, inflammation, endoplasmic reticulum stress, mitochondrial damage, and cytoskeleton alterations which lead to cell death and organ dysfunction. PEG has been associated with the majority of these events as it has been shown that PEG reduces reactive oxygen species, prevents cell death, maintains mitochondrial integrity, and reduces inflammation and endoplasmic reticulum stress. From this perspective, it is reasonable to expect that PEG administration may be an effective therapeutic strategy against liver IRI.
The aim of this thesis was to investigate the beneficial effects of PEG 35 in different models of IRI that mimic clinical situation of liver surgery. In the first study, we investigated the impact of the administration of intravenous PEG 35 before liver warm IRI. In the second one, we investigated whether intravenously administrated PEG 35 could protect against cold IRI in steatotic rat livers. Finally, we developed a new washout solution containing PEG 35 to prevent reperfusion injury after prolonged cold preservation.
The results of the present thesis demonstrated that:
- Intravenous administration of PEG 35 at 10 mg/kg protects the liver in an experimental model of warm IRI in rats. The protective mechanisms are associated with the activation of the pro survival pathways Akt and AMPK and the inhibition of apoptosis. PEG 35 also protects the hepatocyte morphology by increasing F/G-actin ratio and activating p-p38.
- Intravenous administration of PEG 35 at 10 mg/kg protects steatotic livers in an experimental model of cold IRI in obese rats. The protective effects of PEG 35 are mediated by the preservation of mitochondrial status, the stabilisation of the cytoskeleton and the regulation of the cytoprotective AMPK and Akt signalling pathways.
- Liver graft washout with a PEG 35-containing rinse solution increases the protection against IRI in a model of isolated perfused rat liver. .Protection was due to the inhibition of metalloproteinases, the activation of cytoprotective AMPK and eNOS signalling pathways and the preservation of cytoskeleton integrity.La lesión por isquemia reperfusión (I/R) es un proceso complejo que tiene lugar cuando un órgano se ve privado del aporte sanguíneo (isquemia) y se manifiesta de forma predominante después del posterior restablecimiento del flujo sanguíneo (reperfusión). Existen numerosas situaciones en la práctica clínica en las que el hígado se ve sometido a una situación de I/R, entre ellas, la resección hepática y el trasplante hepático. Los polietilenglicoles (PEGs) son polímeros solubles en agua, no tóxicos y con diferentes pesos moleculares. Algunos de ellos, con un peso molecular de 20 kDa (PEG 20) y de 35 kDa (PEG 35) forman parte de la composición de soluciones de preservación de órganos (SCOT e IGL-1). Además, en varios modelos experimentales de in vivo e in vitro se ha reportado que varios PEGs ejercen efectos beneficiosos. Atendiendo a lo anteriormente expuesto, la utilización de PEGs puede constituir una excelente herramienta para prevenir el daño hepático por I/R. El objetivo de esta tesis es investigar los efectos beneficiosos del PEG 35 en diferentes modelos de lesión por I/R, que imitan una cirugía hepática. Nuestros resultados demuestran que: - EL PEG 35 administrado por vía intravenosa protege eficientemente el hígado de ratas contra la I/R caliente. Los mecanismos de protección están asociados con la activación de la supervivencia vía Akt y AMPK y la inhibición de la apoptosis. El PEG 35 también protege la morfología de los hepatocitos mediante el aumento de la F/G-actina y la activación de p-p38. - La administración intravenosa de PEG 35 protege los hígados esteatósicos en un modelo de I/R fría en ratas obesas. Los efectos protectores de PEG 35 están mediados por la preservación del estado mitocondrial, la estabilización del citoesqueleto y la regulación de las vías de señalización citoprotectoras AMPK y AKT. - La adición de PEG 35 a una nueva solucione de lavado aumenta la protección contra la lesión por I/R en un modelo de hígado de rata aislado y perfundido a través de la inhibición de las metaloproteinasas, la activación de vías de señalización citoprotectoras AMPK y eNOS y la preservación de la integridad del citoesqueleto.
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Scally, David James. "Novel polyethylene glycol based drug delivery systems : a calorimetric and QASAR based study". Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282425.
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Allehyani, S. H. A., R. Seoudi, D. A. Said, A. R. Lashin y A. Abouelsayed. "Synthesis, Characterization, and Size Control of Zinc Sulfide Nanoparticles Capped by Polyethylene Glycol". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42490.
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Zinc sulfide nanoparticles were synthesized with controllable size via chemical precipitation. highresolution transmission electron microscopy (HRTEM) and X-ray powder diffraction (XRD) showed that the samples were grown with the cubic phase; the particle size was varied by varying the molar ratios of zinc chloride and sodium sulfide in the presence of poly(ethylene glycol). The optical band gap was calculated on the basis of ultraviolet-visible spectroscopy (UV-VIS) and ranged from 4.13 eV to 4.31 eV depending on the particle size. Surface passivation and adsorption of poly(ethylene glycol) on the nanoparticles was explained on the basis of Fourier transform infrared measurements (FTIR).
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Ralph, J. "Chemical treatment of backsawn Tasmanian Oak with Polyethylene Glycol (PEG) prior to drying". Thesis, University of Tasmania Library, Special & Rare Materials Collections, 2006. https://eprints.utas.edu.au/1222/1/JRalphthesis_front.pdf.
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A series of experiments was conducted with the view of obtaining baseline information
on the use of polyethylene glycol (PEG) on Tasmanian Oak for the purpose of improving
the quality of the seasoned structural timber product. Tasmanian Oak is the marketing
name for a triad of Tasmanian-grown eucalypt species (E. delegatensis, E. obliqua, and E.
regnans). Incubation of freshly-milled timber in aqueous PEG solutions prior to
seasoning follows on from investigations in northern hemispheric timber species such as
hoop pine and spruce in the middle of the 20th Century.
PEG penetrates freshly sawn Tasmanian Oak in a manner which is considerate of
incubation time, temperature, PEG molecular weight/size and timber density.
Histological examination indicated that PEG penetrated completely throughout the
structure of the wood substance in three orientations (transverse, radial and tangential).
During air-drying of PEG soaked timber, further migration of PEG into Tasmanian Oak is
negligible. The rate of moisture content loss in Tasmanian Oak was shown to be retarded
by PEG pre-treatment although the ability to prevent moisture loss was not concomitant
with dimensional stability. An investigation to explain the change in rate of moisture loss
examined effects on the thermodynamic property, water activity. Results indicated that a
change in solution water activity could partly expain changes in the rate of moisture
content loss, but more research is required to better divine this relationship.
Shrinkage in Tasmanian Oak was reduced after treatment with aqueous PEG 400
solutions at or above 30% (v/v), with a greater percentage reduction in tangential
shrinkage compared to reduction in radial shrinkage. This is significant as backsawn (a.k.a. flatsawn) timber, with its broader tangential face, was in particular focus. The
reduction in shrinkage was consistent with PEG concentration in the incubating medium.
A decrease in the formation of drying defect, such as surface and internal checking
accompanied the improvement in keeping sawn dimensions.
Backsawn Tasmanian Oak obtained from young trees (less than 20 years) from plantation
resource presents a challenging profile for commercial timber drying and will become
more prevalent as the logging of old-growth forests is phased out. Timber seasoners may
be faced with options of longer drying times or lower yields due to drying defect unless a
method can be developed to provide added protection to the sawn timber product during
drying. At this stage, pre-treatment of Tasmanian Oak with PEG shows the hallmarks of
providing a solution to this emerging dilemma.
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Dumetz, André C. "Measurement of protein-protein interactions applied to protein crystallization in salt and polyethylene glycol solutions". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 1.40Mb., 130 p, 2005. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1428182.
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Perrier, SeÌbastien. "Synthesis of novel surface active agents via copper mediated living radical polymerisation : synthetic and mechanistic study". Thesis, University of Warwick, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246763.
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Daugherty, Megen Aileen. "The Safety and Efficacy of Oral Low-Volume Sodium Phosphate Bowel Preparation for Colonoscopy in Dogs". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/34080.
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Sodium phosphate (NaP) is a low-volume, hyperosmolar laxative that has been shown to be an effective bowel cleansing agent in people. The purposes of this study were to evaluate the safety and efficacy of oral NaP in dogs. Standard (NaP and enemas; NaP1) and control preparations (polyethylene glycol [PEG] and enemas) were compared in a crossover design to determine safety and efficacy of NaP. Serial clinical and serum analytical evaluations were used to determine the safety of NaP. The efficacy of the NaP1 preparation was compared to 3 NaP variations which excluded enema or included bisacodyl, with or without enemas in a crossover design. Eight dogs received each of 6 bowel preparations prior to colonoscopy performed one time per week. An observer blinded to the bowel preparation assigned a score of 1-4 (1 clean colon and ≥3 unacceptable preparation) to each of 5 regions of the colon. Mean total colon cleansing score (TCS), defined as the sum of scores from each region, of the control (9.4) was less than NaP1 (13.6) (p<0.05). There were no significant differences in regional or TCS for the remaining 4 NaP preparations. NaP1 resulted in moderate, but clinically occult, hyperphosphatemia and hypocalcemia, which resolved within 24 hours of initial administration. Despite the safety and ease of administration of the NaP preparations, the NaP bowel cleansing preparations used in this study cannot be recommended for routine clinical use due to the inadequate quality of bowel preparation compared to the PEG containing bowel cleansing protocol evaluated.Master of Science
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Farbod, Kambiz. "Uv and spontaneously cured polyethylene glycol-based hydrogels for soft and hard tissue scaffolds". Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32940.
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UV-curing is one of the most commonly used methods for producing hydrogels for soft and hard tissue scaffolds. Spontaneous curing is an alternative method which possesses some advantages in comparison to the conventional UV-curing methods; for example, in situ crosslinking and excluding initiators. The main objective of this study was to investigate promising materials for producing UV and spontaneously cured hydrogels, and subsequently to perform a comparison between the produced hydrogels with regard to their different mechanical and physical properties.Seventeen different hydrogels including five UV-cured and twelve spontaneously cured hydrogels were produced by applying thiol-ene chemistry and by varying precursor materials. Hydrogel systems including di- and tetra- functional PEGs of different lengths (2 kDa and 6 kDa) and two different thiol-crosslinkers (ETTMP 1300 Da and DTT) were subsequently characterized and evaluated. The evaluation tests applied in this study were Raman spectroscopy, weight and volumetric swelling test, leaching test, tensile test, and rheology test. Between all the systems, tetra-acrylated PEG (6 kDa) BisMPA was found to be the most promising system. The pH level of the applied solvent (PBS) for spontaneously cured hydrogels was varied from the physiologically relevant level of 7.4 to 7.0 and 7.8 in order to investigate the dependency of physical and mechanical properties of the hydrogels to this parameter.Spontaneous curing of tetra-acrylated PEG (6 kDa) BisMPA with ETTMP 1300 Da as the thiol-crosslinker, was accomplished within 3½ min in PBS with a pH level of 7.4; and it came out to be the fastest spontaneously cured system between all the tested hydrogels. Increasing the PBS pH level resulted in a faster curing process (accomplished in 1½ min). Spontaneously cured hydrogels generally showed decreased mechanical properties, but improved swelling behavior compared to UV-cured hydrogels. Nevertheless, the discussed system still possessed 50% of the elastic modulus in the tensile test in comparison to the UV-cured state; and showed the highest elastic modulus in comparison to other spontaneously cured systems. The storage modulus of the mentioned hydrogel in the spontaneously cured state was very close to the same parameter in the UV-cured hydrogel based on the same precursors. It also possessed the highest storage modulus between all the spontaneously cured hydrogels. Although the obtained swelling properties of this system were not the highest between all the tested hydrogels, these parameters were still in an acceptable range as for a hydrogel proposed for tissue scaffold application (swelling ratio: 9.72, water content: 89.71%, volumetric swelling ratio: 9.05). Furthermore, the system had the lowest weight loss ratio between all the acrylate-based hydrogels (including both UV and spontaneously cured systems), which along with the Raman spectroscopy results shows the high crosslinking efficiency of the system.
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Codoni, D. "Development and physical characterisation of polyethylene glycol glycerides-based gel formulations for macromolecule delivery". Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/48764/.
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Lipid-based delivery systems offer many advantages on enhancing the bioavailability of protein/peptides. Gelucire 50/13 is a complex mixture of glycerides and PEG. It is mainly used in solid oral formulations for delivering small molecular weight drugs. The purpose of this project was to develop novel uses of Gelucire as a liquid crystalline-based gel-forming material for protein/peptide delivery. A thorough physical and mechanical characterisation of the gels (with and without lysozyme as a model protein) was conducted using a combination of analytical techniques including ATR-FTIR, DSC, relaxometry NMR, rheological and texture analyser, and imaging analyses (SEM, AFM, and cryo-TEM). The results demonstrated the sophisticated microstructures of the gels due to the formation of various liquid crystalline phases that change with the gel water content. The gels with low water contents are characterised by highly restricted diffusion of water molecules in the gels, while water-rich and lipid-rich phases are present in the gels with medium to high water contents. The ordered liquid crystalline structures with lipid-rich and water-rich domains provide excellent carrier properties for hosting proteins/peptides. The effect of water content on the microstructure, physical properties and in vitro performance of the gels prevails on other effects such as gel preparation method and protein incorporation. The wide range of microstructures of the gels enables the mucoadhesive properties and release profiles of lysozyme from the gels to be controlled. Highly stable disc-shaped nanoparticles were produced from the Gelucire gels using a single-step and solvent-free method without the addition of stabilisers. In vitro cell culture studies revealed high tolerance to and rapid uptake of the gel nanoparticles by Caco-2 cells. The good protein encapsulation efficiency and the retained biological activity of lysozyme indicates considerable potential for these nanoparticles to be a new class of safe, low-cost and effective carriers for protein/peptide delivery.
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Aljaeid, Bader Mubarak. "Formulation of novel cross-linked sterically stabilised polyplexes with polyethylene glycol for DNA delivery". Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.588065.
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Linear poly(amidoamine) (PAA) cationic polymers complexed with DNA have potential as non-viral nucleic acid delivery systems. However, they have poor in vivo biodistribution and a tendency to aggregate. PEGylation polymers are a potential solution for these problems but previous work shows that they do not always form compact complexes. This might be overcome by using mixtures of homopolymer and PEGylated copolymer to form complexes. However, the complexes are unstable in the presence of serum. Therefore, the aim of this study was to improve stability and to allow release of DNA by incorporating a novel cross-linking system. A disulphide-based cross-linker was suggested for this work. Formulation and screening studies for the best homopolymer to copolymer ratio of cross-linked (XL) DNA delivery systems in comparison to non-cross-linked (non- XL) complexes were investigated. The formation of cross-linked complexes was carried out using mixtures of homopolymer (HP) and triblock copolymer (CP), based on the most promising P AA candidate from these aforementioned studies. In this study, we have used three different molecular weights of PEG (655, 1700 and 4600 Da). HP:CP at 1: 1 ratio proved to have the best collective physicochemical characteristics among all of the investigated ratios. The findings from biological evaluation of PEG655-PAA systems revealed that transfection efficiency of cross-linked and non-cross-linked complexes at all HP:CP ratios was similar to PAA in serum-free medium. Transfection of cross- linked complexes at 1: 1 HP:CP ratio did not show a significant difference in serum-free and serum-supplemented media, the transfection of all other formulations, lipofectAMINE and P AA were remarkably reduced in the presence of serum. The results also showed the ability of PEG 1700-P AA-XL complexes to improve the transfection 100 times relative to non-cross-linked complexes. Again, no significant difference could be observed for the gene expression of PEG 1700- P AA systems at 1: 1 HP:CP ratio, whereas the transfection of other systems dramatically reduced in the presence of 10% serum. The same pattern was seen with PEG4600-PAA systems. In vivo assessment of the cross-linked complexes showed that PEG655-PAA-XL complexes provided strikingly higher luciferase activity in the liver, whereas PEG4600-PAA-XL complexes showed the best transfection in non-reticuloendothelial system organs expected to benefit from a longer circulation time. PEG 1700-P AA-XL complexes showed similar transfection in all organs. Therefore, the disulphide-based cross-link was validated as a suitable DNA delivery system for in vivo application.
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Gunbas, Ismail Dogan. "Preparation And Characterization Of Chitosanpolyethylene Glycol Microspheres And Films For Biomedical Applications". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/2/12608817/index.pdf.
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In recent years, biodegradable polymeric systems have gained importance for design of surgical devices, artificial organs, drug delivery systems with different routes of administration, carriers of immobilized enzymes and cells, biosensors,
ocular inserts, and materials for orthopedic applications. Polysaccharide-based polymers represent a major class of biomaterials, which includes agarose, alginate, dextran, and chitosan. Chitosan has found many biomedical applications, including tissue engineering, owing to its biocompatibility, low
toxicity, and degradation in the body, which has opened up avenues for modulating drug release in vivo in the treatment of various diseases. These chitosan-based delivery systems range from microparticles to nanoparticles and from gels to films.
In this study, chitosan (CH) and chitosan-polyethylene glycol (CH-PEG) microspheres with different compositions were prepared by oil/water emulsion method and crosslinked with gluteraldehyde. Some microspheres were loaded
with a model chemotherapeutic drug, methotrexate (MTX). SEM, particle size and in vitro release analysis were performed. In vitro drug release studies showed that the release of MTX from CH-PEG microspheres was faster compared to CH microspheres.
In the second part, CH-PEG microspheres were conjugated with a monoclonal antibody which is immunoglobulin G (IgG). The cytotoxicity efficiencies of entrapped drug were determined by using MCF-7 and MCF-7/MDA-MB breast
cancer cell lines.
In the third part, CHF-PEG films with the same compositions as in microspheres were prepared by solvent casting method. IR, DSC, mechanical and surface analysis were performed. The mechanical properties of films were improved by
the presence of proper amount of PEG but higher amounts of PEG caused the deteriotion in the properties.
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Bali, Sinazo. "Polyethylene glycol (PEG) induced water stress alters the physiological and molecular responses of chia plants". The University of the Western Cape, 2017. http://hdl.handle.net/11394/5787.
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Magister Scientiae - MSc (Biotechnology)Water deficit is known to be one of the most detrimental environmental factors to affect crop production and growth in South Africa. This factor has become more apparent with increasing cases of drought in the country.
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Tuesca, Anthony D. Lowman Anthony M. "Synthesis, characterization, and application of polyethylene glycol modified insulin for oral delivery using complexation hydrogels /". Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2715.
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Dalton, Dustin. "Assessing the Role of Polyethylene Glycol (PEG) in Improving Functional Recovery Following Spinal Cord Injury". VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2543.
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Injury to the spinal cord results in the disruption of signal transmission between the brain and distal targets. It often presents with the loss of motor function and sensory perception below the level of injury. There are many obstacles following injury that must be overcome in order to encourage axon regeneration and improve functional recovery. A combinatorial approach is necessary to combat physical and chemical barriers to recovery. The fluid filled cyst that forms in the majority of spinal cord injuries presents a physical barrier that we treat with our electrospun bridges. We implanted our bridges into female Long Evans Hooded rats following a complete transection. Using a molecular fusogen, polyethylene glycol, known to seal damaged membranes in conjunction with our bridges, we were able to increase functional recovery compared to animals treated with a bridge and saline. In Chapter 1, we introduce spinal cord anatomy, the pathological classifications, axon pathology, and our therapeutic strategy. Chapter 2 details the materials and methods. Chapter 3 examines previous uses of polyethylene glycol as a molecular fusogen, previous studies utilizing it in spinal cord injury, and our strategy of fusing damaged axons to improve functional recovery. Finally in Chapter 4, I discuss our behavioral results, compare histology, and detail the future of our research including protocol improvements and future combination therapies that include PEG to improve outcome.
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Requardt, Hendrik [Verfasser]. "Polyethylene Glycol functionalized Multi Walled Carbon Nanotubes for Nanomedical application as Drug Carriers / Hendrik Requardt". Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2017. http://d-nb.info/115034105X/34.
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Rogers, Chad. "Optimization of Nonadsorptive Polymerized Polyethylene Glycol Diacrylate as a Material for Microfluidics and Sensor Integration". BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5310.
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Microfluidics is a continually growing field covering a wide range of applications, such as cellular analysis, biomarker quantification, and drug discovery; but in spite of this, the field of microfluidics remains predominately academic. New materials are pivotal in providing tailored properties to improve device integration and decrease prototype turnaround times. In biosensing, nonspecific adsorption in microfluidic systems can deplete target molecules in solution and prevent analytes, especially those at low concentrations, from reaching the detector. Polyethylene glycol diacrylate (PEGDA) mixed with photoinitiator forms, on exposure to ultraviolet (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 makes polydimethylsiloxane (PDMS) a widely used material for microfluidics. 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. Pneumatically actuated, non-elastomeric membrane valves fabricated from poly-PEGDA have been characterized for temporal response, valve closure, and long-term durability. A ∼100 ms valve opening time and a ∼20 ms closure time offer valve operation as fast as 8 Hz with potential for further improvement. Comparison of circular and rectangular valve geometries indicates that the surface area for membrane interaction in the valve region is important for valve performance. After initial fabrication, the fluid pressure required to open a closed circular valve is ∼50 kPa higher than the control pressure holding the valve closed. However, after ∼1000 actuations to reconfigure polymer chains and increase elasticity in the membrane, the fluid pressure required to open a valve becomes the same as the control pressure holding the valve closed. After these initial conditioning actuations, poly-PEGDA valves show considerable robustness with no change in effective operation after 115,000 actuations.Often, localized areas of surface functionalization are desired in biosensing, necessitating site-specific derivatization. Integration of poly-PEGDA with different substrates, such as glass, silicon, or electrode-patterned materials, allows for broad application in biosensing and microfluidic devices. Deposition of 3-(trimethoxysilyl) propyl methacrylate or (3-acryloxypropyl) dimethylmethoxysilane onto these substrates makes bonding to poly-PEGDA possible under UV exposure. Primary deposition of (3-acryloxypropyl) dimethylmethoxysilane, followed by photolithographic patterning, allows for silane removal through HF surface etching in the exposed areas and subsequent deposition of 3 aminopropyldiisopropylethoxysilane on the etched regions. Fluorescent probes are used to evaluate surface attachment methods. Primary attachment via reaction of Alexa Fluor 488 TFP ester to the patterned aminosilane demonstrates excellent fluorescent signal. Initial results with glutaraldehyde were demonstrated but require more optimization before this method for secondary attachment is viable. Fabrication of 3D printed microfluidic devices with integrated membrane-based valves is performed with a low-cost, commercially available stereolithographic 3D printer and a custom PEGDA resin formulation tailored for low non-specific protein adsorption. Horizontal microfluidic channels with designed rectangular cross sectional dimensions as small as 350 µm wide and 250 µm tall are printed with 100% yield, as are cylindrical vertical microfluidic channels with 350 µm designed (210 µm actual) diameters. Valves are fabricated with a membrane consisting of a single build layer. The fluid pressure required to open a closed valve is the same as the control pressure holding the valve closed. 3D printed valves are successfully demonstrated for up to 800 actuations. Poly-PEGDA is a versatile material for microfluidic applications ranging from electrophoretic separations, valve implementation, and heterogeneous material integration. Further improvements in PEGDA resin formulation, in combination with a UV source 3D printer, will provide poly-PEGDA devices that are not only rapidly fabricated (<40 min per device), but that also include pumps and valves and are usable with a variety of detection methods, such as laser-induced fluorescence and immunoassays, for broad application in biosensing.
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Fishman, Alexander. "Synthesis, characterization and applications of novel polyethylene glycols in organic chemistry /". 2004. http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99168.
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Thesis (Ph.D.)--York University, 2004. Graduate Programme in Chemistry.Typescript. Includes bibliographical references (leaves 160-172). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99168
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Chao, Yin-chun y 趙尹淳. "Synthesis and Application of polyethylene glycol Copolymers". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/94875719877313156470.
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博士國立臺灣科技大學
材料科學與工程系
100
In this study, a series of polyethylene glycol copolymers were prepared by the reaction of combining polyethylene glycol (PEG), Vinyltriethoxy silane (VTES) and N-Vinylpyrrolidone (NVP). One of these polyethylene glycol copolymers is PEG/VTES copolymers, and the other is PEG/PVP copolymers. PEG/VTES copolymers exhibited excellent surface activities, wetting power, as well as low foaming. Consequently, the application of a series of PEG/VTES copolymers can make cotton fabrics stain-resistant. PEG/PVP copolymers are products of biodegradable material polymerizations. The addition of copolymers reduced the overall Zeta potential of the dye and increased the particle sizes. The series of polyethylene glycol copolymers and dyes interacted, as the copolymer enabled shifts of the dyesλmax of UV, reduces the absorbance, which proofs that polyethylene glycol copolymers and dyes can be interactive and foams complex with dye-decolorization function.
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Munoz, Pinto Dany 1981. "Hybrid Polyethylene Glycol Hydrogels for Tissue Engineering Applications". Thesis, 2011. http://hdl.handle.net/1969.1/149213.
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Currently, organ transplant procedures are insufficient to address the needs of the number of patients that suffer of organ failure related disease. In the United States alone, only around 19% of the patients are able to get an organ transplant surgery and 25% die while waiting for a suitable donor. Tissue engineering (TE) has emerged as an alternative to organ transplant; thus, the aim of the present study was to validate a poly(ethylene glycol) diacrylate (PEG-DA) hydrogel system as a model for material scaffolding in TE applications.
This work explores the influence of scaffold material properties on cell behavior. Specifically, scaffold modulus, mesh size, and biochemical stimuli were characterized and their influence on cell response was analyzed at the biochemical, histological and microenvironmental levels. Three different TE targets were evaluated: vocal fold restoration, vascular grafts and osteochondral applications.
Vocal fold fibroblast (VFF) phenotype and extracellular matrix (ECM) production were impacted by initial scaffold mesh size and modulus. The results showed increasing levels of SM-α-actin and collagen production with decreasing initial mesh size/increasing initial modulus, which indicated that VFFs were induced to take an undesirable myofibroblast-like phenotype. In addition, it was possible to preserve VFF phenotype in long-term cultured hydrogels containing high molecular weight hyaluronan (HAHMW). On the other hand, regarding vascular graft applications, smooth muscle cell (SMC) phenotype was enhanced by increasing scaffold mesh size and modulus. Finally, the effect of scaffold inorganic content (siloxane) on rat osteoblasts and mouse mesenchymal stem cells was evaluated. Interestingly, the impact of inorganic content on cell differentiation seemed to be highly dependent on the initial cell state. Specifically, mature osteoblasts underwent transdifferentiation into chondrocyte-like cells with increasing inorganic content. However, Mesenchymal stem cells appeared to be preferentially driven toward osteoblast-like cells with an associated increase in osteocalcin and collagen type I production.
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Hsiao, Sheng-Wen y 蕭勝文. "Generation and cloning of anti-polyethylene glycol antibody". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/72993943881333776458.
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碩士高雄醫學大學
醫學研究所碩士班
93
The covalent bond the polyethylene glycol (polyethylene glycol, PEG) to protein improves its safety and the efficacy. PEG is one kind of water-solubility polymer. The matters after PEG modification for example: protein, hormone, and enzyme and cause to change the water solubility, reduces immunogenicity, increase the half-life, and change biodistribution. PEG modification drugs at present already had PEG-Intron (PEG-interferon alpha 2b), pegasys (PEG-IFN alpha 2a), PEG-Neupogen (PEG-G-CSF) and PEGV isomant (PEG-hGHra)that have been approved by the food and drug administration(FDA) and enter the clinical treatment or the experimental stage. Therefore qualitative and quantitative analysis PEG derivative member has its importance regarding the medicine development and the clinical practice. We have formerly made anti- PEG monoclonal antibody IgM —AGP3. Now we establish one kind of new anti-PEG monoclonal antibody IgG-E11. This project confirm E11 and AGP3 being able to bind on the PEG glycol skeleton and its length using western blot, ELISA and flow cytometry. Detection sensitivity increased with PEG length by sandwich ELISA includes the protein or the free state PEG.Accelerated clearance PEG modified protein in vivo, then will present used gene cloning technology to clone E11 and discuss as reporter gene or improve affinity.
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Chen, Ting-Yu y 陳挺宇. "The biomedical applications of anti-polyethylene glycol antibody". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/96055352430359384535.
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碩士高雄醫學大學
醫學檢驗生物技術學研究所
99
PEGylation of protein drugs are increasingly popular for improving clinical pharmacokinetics. However, quantification of PEGylated proteins with protein-specific sandwich enzyme-linked immunosorbent assay (ELISA) is not sensitivity due to the shielding effect of PEG that prevents the binding of protein-specific antibody. To overcome this problem, an optimized anti-PEG sandwich ELISA developed with anti-PEG antibodies (AGP4 and biotinylated 3.3) was used to measure PEGylated protein drugs as well as PEG (12kDa)–interferon α-2b (PEG-IntronR) and PEG (40kDa)–interferon α-2a (PegasysR) that are current interferon (IFN) drugs for hepatitis B and C treatment. The anti-PEG sandwich ELISA showed a higher sensitivity while measuring interferon (IFN) conjugated with higher molecular weight PEG, contrary to a commercial IFN-specific (anti-IFN) sandwich ELISA kit. The present of human or murine serum in sample has no effect on the detection of the anti-PEG sandwich ELISA. In a pharmacokinetic study in mice, the quantification of 131I-PegasysR in serum by the anti-PEG sandwich ELISA was comparable to that by the anti-INF sandwich ELISA and radioassay. This anti-PEG sandwich ELISA may be a better choice than traditional methods for quantitative analysis of PEGylated protein drugs sensitively and conveniently. Reporter gene imaging plays an important role in assessment of gene therapy or stem cell therapy; however, the current reporter genes are not suitable for human due to low specificity or high immunogenicity. To establish a reporter gene system for clinical imaging, we developed an h-αPEG reporter for in vivo imaging with PEGylated imaging agents, which was expressing a Fab fragment of a humanized anti-polyethylene glycol (PEG) antibody. According to multiple sequence alignment, the variable region of the humanized anti-PEG antibody exhibited almost 88 % identity to human immunoglobulin germline V genes. Through the transduction of reporter gene-carrying retrovirus, h-αPEG reporter anchored on cell surface stably, and trapped PEGylated imaging agent proved by flow cytometry. In the experiment of in vitro and in vivo images, PEGylated probes (PEG-NIR797 for optical Imaging and 124I-PEG-SHPP for micro-PET) were specifically accumulated on h-αPEG reporter–expressing cells or subcutaneous tumor. Furthermore, h-αPEG reporter also revealed the in vivo distribution of metastatic tumor in lung by non-invasive optical imaging. Together, h-αPEG reporter combining with PEGylated imaging agents may proves a powerful monitoring tools to evaluate the safety and clinical efficacy of gene therapy or stem cell therapy in human object.
47
CHOU, joyce y 周俊利. "Polystyrene-(Polyethylene glycol) block copolymer,synthesize and structure identification". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/97856856302162136078.
Texto completoResumen
碩士國立成功大學
化學工程學系
86
Abstract We attempted to synthesize a series block copolymers of Polystyrene-(Polyethylene glycol) by two methods：One is iniferter system and the other is macroazoinitiator system. Block copolymers involved different PEG''s molecular weights ,600、2000、4000, in the polymer chains. The prepared polymers thus contained 34∼89 wt% of PS hard segments obtaining from elemental analysis (EA). Gel permeation chromatography (GPC) was used to determine the average molecular weight of PS segments after hydrolysis. The polymers showed an absorbance at 1110㎝-1 corresponding to the ether groups in PEG segments by Fourier transform infrared Spectrophotometer (FTIR). From the thermal properties of the block copolymers studied by differential scanning calorimeter (DSC) , we knew that PS and PEG blocks existe two phases. Therefore , some investigations regarding the compositions dependent of the PS blocks was studied. In order to understand the shapes and sizes of microdomains , we took some pictures from transmission electron microscope (TEM) and got three microphases ：one was rodlike domain of PEG； another was PEG vesicles；the rest was spherical PS domains. At the last , we compared the sizes of microdomain from the pictures with the help of molecular structure modeling .
48
Francisco, Aubrey Therese. "Laminin-Functionalized Polyethylene Glycol Hydrogels for Nucleus Pulposus Regeneration". Diss., 2013. http://hdl.handle.net/10161/8204.
Texto completoResumen
Intervertebral disc (IVD) disorders and age-related degeneration are believed to contribute to low back pain. There is significant interest in cell-based strategies for regenerating the nucleus pulposus (NP) region of the disc; however, few scaffolds have been evaluated for their ability to promote or maintain an immature NP cell phenotype. Additionally, while cell delivery to the pathological IVD has significant therapeutic potential for enhancing NP regeneration, the development of injectable biomaterials that retain delivered cells, promote cell survival, and maintain or promote an NP cell phenotype in vivo remains a significant challenge. Previous studies have demonstrated NP cell - laminin interactions in the NP region of the IVD that promote cell attachment and biosynthesis. These findings suggest that incorporating laminin ligands into biomaterial scaffolds for NP tissue engineering or cell delivery to the disc may be beneficial for promoting NP cell survival and phenotype. In this dissertation, laminin-111 (LM111) functionalized poly(ethylene glycol) (PEG) hydrogels were developed and evaluated as biomaterial scaffolds for cell-based NP regeneration.
Here, PEG-LM111 conjugates with functional acrylate groups for crosslinking were synthesized and characterized to allow for protein coupling to both photocrosslinkable and injectable PEG-based biomaterial scaffolds. PEG-LM111 conjugates synthesized using low ratios of PEG to LM111 were found support NP cell attachment and signaling in a manner similar to unmodified LM111. A single PEG-LM111 conjugate was conjugated to photocrosslinkable PEG-LM111 hydrogels, and studies were performed to evaluate the effects of hydrogel formulation on immature NP cell phenotype in vitro. When primary immature porcine NP cells were seeded onto PEG-LM111 hydrogels of varying stiffnesses, softer LM111 presenting hydrogels were found to promote cell clustering and increased levels of sGAG production as compared to stiffer LM111 presenting and PEG-only gels. When cells were encapsulated in 3D gels, hydrogel formulation was found to influence NP cell metabolism and expression of proposed NP phenotypic markers, with higher expression of N-cadherin and cytokeratin 8 observed for cells cultured in softer (<1 kPa) PEG-LM111 hydrogels.
A novel, injectable PEG-LM111 hydrogel was developed as a biomaterial carrier for cell delivery to the IVD. PEG-LM111 conjugates were crosslinked via a Michael-type addition reaction upon the addition of PEG-octoacrylate and PEG-dithiol. Injectable PEG-LM111 hydrogel gelation time, mechanical properties, and ability to retain delivered cells in the IVD space were evaluated. Gelation occurred in approximately 20 minutes without an initiator, with dynamic shear moduli in the range of 0.9 - 1.4 kPa. Primary NP cell retention in cultured IVD explants was significantly higher over 14 days when cells were delivered within a PEG-LM111 hydrogel carrier, as compared to cells in liquid suspension.
The studies presented in this dissertation demonstrate that soft, LM111 functionalized hydrogels may promote or maintain the expression of specific markers and cell-cell interactions characteristic of an immature NP cell phenotype. Furthermore, these findings suggest that this novel, injectable laminin-functionalized biomaterial may be an easy to use and biocompatible carrier for delivering cells to the IVD.
Dissertation
49
Yang, Hsiang-yun y 楊翔雲. "Synthesis and Optimization of Sulfated Monooleate Polyethylene Glycol Polyester". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/93vu35.
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碩士國立臺北科技大學
有機高分子研究所
105
Sulfated monooleate polyethylene glycol polyester is an anionic surfactant, which can be produced by the reaction of monooleate polyethylene glycol (PEG300MO) with sulfamic acid. The sulfation efficiency is usually influenced by the water content of PEG300MO, as well as the mole ratio of reactants. Theoretically, the lower the water content and the higher the sulfamic acid, the better the sulfation efficiency. However, it takes a lot of energy and time to obtain low-moisture PEG300MO in an industrial scale. Using a high proportion of sulfamic acid also increases the material cost. To strike a balance between the sulfation efficiency and the material cost, the effects of PEG300MO water content and the reactant ratio on the sulfation of PEG300MO were investigated. PEG300MO samples with three different water contents (500 ppm、1500 ppm、2500 ppm) were used, and the sulfamic acid-to-PEG300MO mole ratio was varied from 1.2 to 1.8. The sulfation efficiency was evaluated in terms of SO3% according to CNS4986. The results show that the lower the water content of PEG300MO, the higher the sulfation efficiency. The sulfation efficiency also increased with increasing proportion of sulfamic acid, but the improvement in SO3% gradually leveled off when the mole ratio of sulfamic acid exceeded 1.4.
50
Jebrail, Mais J. "Effect of aliphatic chain length on the stability of poly(ethylene glycol)-grafted phospholipid mixed monolayers at the air/water interface /". 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR32003.
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Thesis (M.Sc.)--York University, 2007. Graduate Programme in Chemistry.Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR32003