Random Copolymer

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Lin Mei - One of the best experts on this subject based on the ideXlab platform.

  • nanoparticle formulation of poly ɛ caprolactone co lactide d α tocopheryl polyethylene glycol 1000 succinate Random Copolymer for cervical cancer treatment
    Polymer, 2010
    Co-Authors: Laiqiang Huang, Cunxian Song, Xiaowei Zeng, Gan Liu, Lin Mei
    Abstract:

    Cervical cancer remains a critical problem that is second only to breast cancer affecting women worldwide. The objective of this study was to develop formulation of docetaxel-loaded biodegradable poly(ɛ-caprolactone-co-lactide)-d-α-tocopheryl polyethylene glycol 1000 succinate (PCL-PLA-TPGS) nanoparticles for cervical cancer chemotherapy. A novel Random Copolymer, PCL-PLA-TPGS, was synthesized from ɛ-caprolactone, lactide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization. The obtained polymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded PCL-PLA-TPGS nanoparticles were prepared by a modified solvent extraction/evaporation technique and characterized in terms of size and size distribution, morphology, surface charge and physical state of encapsulated docetaxel. Cellular uptake and in vitro cytotoxicity of nanoparticle formulations were done in comparison with commercial formulation Taxotere® to investigate the efficacy of PCL-PLA-TPGS nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated with CLSM, demonstrating the coumarin 6-loaded PCL-PLA-TPGS nanoparticles could be internalized by Hela cells. In vitro cancer cell viability experiment showed that judged by IC50, the PCL-PLA-TPGS nanoparticle formulation was found to be more effective in cell number reduction than the Taxotere® after 48 h (p < 0.05), 72 h (p < 0.05) treatment. In conclusion, the PCL-PLA-TPGS Copolymer could be acted as a novel and promising biologically active polymeric matrix material for nanoparticle formulation in cervical cancer treatment.

  • nanoparticles of poly lactide co glycolide d a tocopheryl polyethylene glycol 1000 succinate Random Copolymer for cancer treatment
    Nanoscale Research Letters, 2010
    Co-Authors: Yi Zheng, Kexin Liu, Ge Tian, Yan Tian, Feifei Yan, Laiqiang Huang, Lin Mei
    Abstract:

    Cancer is the leading cause of death worldwide. Nanomaterials and nanotechnologies could provide potential solutions. In this research, a novel biodegradable poly(lactide-co-glycolide)-d-a-tocopheryl polyethylene glycol 1000 succinate (PLGA-TPGS) Random Copolymer was synthesized from lactide, glycolide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization using stannous octoate as catalyst. The obtained Random Copolymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded nanoparticles made of PLGA-TPGS Copolymer were prepared by a modified solvent extraction/evaporation method. The nanoparticles were then characterized by various state-of-the-art techniques. The results revealed that the size of PLGA-TPGS nanoparticles was around 250 nm. The docetaxel-loaded PLGA-TPGS nanoparticles could achieve much faster drug release in comparison with PLGA nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated by CLSM, demonstrating the fluorescence PLGA-TPGS nanoparticles could be internalized by human cervix carcinoma cells (HeLa). The results also indicated that PLGA-TPGS-based nanoparticles were biocompatible, and the docetaxel-loaded PLGA-TPGS nanoparticles had significant cytotoxicity against Hela cells. The cytotoxicity against HeLa cells for PLGA-TPGS nanoparticles was in time- and concentration-dependent manner. In conclusion, PLGA-TPGS Random Copolymer could be acted as a novel and promising biocompatible polymeric matrix material applicable to nanoparticle-based drug delivery system for cancer chemotherapy.

Laiqiang Huang - One of the best experts on this subject based on the ideXlab platform.

  • nanoparticle formulation of poly ɛ caprolactone co lactide d α tocopheryl polyethylene glycol 1000 succinate Random Copolymer for cervical cancer treatment
    Polymer, 2010
    Co-Authors: Laiqiang Huang, Cunxian Song, Xiaowei Zeng, Gan Liu, Lin Mei
    Abstract:

    Cervical cancer remains a critical problem that is second only to breast cancer affecting women worldwide. The objective of this study was to develop formulation of docetaxel-loaded biodegradable poly(ɛ-caprolactone-co-lactide)-d-α-tocopheryl polyethylene glycol 1000 succinate (PCL-PLA-TPGS) nanoparticles for cervical cancer chemotherapy. A novel Random Copolymer, PCL-PLA-TPGS, was synthesized from ɛ-caprolactone, lactide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization. The obtained polymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded PCL-PLA-TPGS nanoparticles were prepared by a modified solvent extraction/evaporation technique and characterized in terms of size and size distribution, morphology, surface charge and physical state of encapsulated docetaxel. Cellular uptake and in vitro cytotoxicity of nanoparticle formulations were done in comparison with commercial formulation Taxotere® to investigate the efficacy of PCL-PLA-TPGS nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated with CLSM, demonstrating the coumarin 6-loaded PCL-PLA-TPGS nanoparticles could be internalized by Hela cells. In vitro cancer cell viability experiment showed that judged by IC50, the PCL-PLA-TPGS nanoparticle formulation was found to be more effective in cell number reduction than the Taxotere® after 48 h (p < 0.05), 72 h (p < 0.05) treatment. In conclusion, the PCL-PLA-TPGS Copolymer could be acted as a novel and promising biologically active polymeric matrix material for nanoparticle formulation in cervical cancer treatment.

  • nanoparticles of poly lactide co glycolide d a tocopheryl polyethylene glycol 1000 succinate Random Copolymer for cancer treatment
    Nanoscale Research Letters, 2010
    Co-Authors: Yi Zheng, Kexin Liu, Ge Tian, Yan Tian, Feifei Yan, Laiqiang Huang, Lin Mei
    Abstract:

    Cancer is the leading cause of death worldwide. Nanomaterials and nanotechnologies could provide potential solutions. In this research, a novel biodegradable poly(lactide-co-glycolide)-d-a-tocopheryl polyethylene glycol 1000 succinate (PLGA-TPGS) Random Copolymer was synthesized from lactide, glycolide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization using stannous octoate as catalyst. The obtained Random Copolymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded nanoparticles made of PLGA-TPGS Copolymer were prepared by a modified solvent extraction/evaporation method. The nanoparticles were then characterized by various state-of-the-art techniques. The results revealed that the size of PLGA-TPGS nanoparticles was around 250 nm. The docetaxel-loaded PLGA-TPGS nanoparticles could achieve much faster drug release in comparison with PLGA nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated by CLSM, demonstrating the fluorescence PLGA-TPGS nanoparticles could be internalized by human cervix carcinoma cells (HeLa). The results also indicated that PLGA-TPGS-based nanoparticles were biocompatible, and the docetaxel-loaded PLGA-TPGS nanoparticles had significant cytotoxicity against Hela cells. The cytotoxicity against HeLa cells for PLGA-TPGS nanoparticles was in time- and concentration-dependent manner. In conclusion, PLGA-TPGS Random Copolymer could be acted as a novel and promising biocompatible polymeric matrix material applicable to nanoparticle-based drug delivery system for cancer chemotherapy.

Andy H Tsou - One of the best experts on this subject based on the ideXlab platform.

  • 2d waxs saxs study on isotactic propylene 1 butylene Random Copolymer subjected to uniaxial stretching the influence of temperature
    Polymer, 2013
    Co-Authors: Yimin Mao, Christian Burger, Benjamin S Hsiao, Andy H Tsou
    Abstract:

    Abstract The influence of temperature on the crystallization process of isotactic propylene-1-butylene (P–B) Random Copolymer with low comonomer concentration subjected to uniaxial tensile force was studied in-situ by using synchrotron-based wide- and small-angle X-ray scattering techniques (WAXS/SAXS). Data analysis was performed on the whole-pattern base. P–B Copolymer was stretched at three temperatures, i.e., 100 °C, 60 °C and 25 °C. Before stretching, the static sample contained both γ- and α-phase of isotactic polypropylene (iPP) homopolymer, with the γ-phase being the dominant crystal modification. When subjected to uniaxial stretching, γ-phase adopted a tilted cross-β configuration, with the c -axis forming a tilting angle with respect to the fiber axis at all temperatures. At 100 °C and 60 °C, γ-phase was transformed to α-phase with parallel orientation of polymer chains. Daughter lamellae of the α-phase were observed at 100 °C but not at 60 °C. At room temperature, large lamellar crystals could not be formed due to strong tensile force applied to the polymer network. Low temperature stretching was featured with the formation of mesomorphic phase which was composed of tiny β-form crystals and of about 50% of oriented amorphous phase. The c -axis of the β-form crystal was in parallel to the fiber axis. The crystals were so small that no ordered texture was observed at the length scale of nanometers.

  • wide angle x ray scattering study on shear induced crystallization of propylene 1 butylene Random Copolymer experiment and diffraction pattern simulation
    Macromolecules, 2011
    Co-Authors: Yimin Mao, Christian Burger, Feng Zuo, Benjamin S Hsiao, Aspy K Mehta, Cynthia A Mitchell, Andy H Tsou
    Abstract:

    Shear-induced crystallization of a propylene-1-butylene Random Copolymer with low butylene content (5.7 mol %) was studied using time-resolved wide-angle X-ray scattering (WAXS) techniques. Polymor...

Kiyokazu Imai - One of the best experts on this subject based on the ideXlab platform.

  • application of equation of state theory to Random Copolymer blends with upper critical solution temperature type miscibility
    Macromolecules, 1996
    Co-Authors: Tsukasa Sato, Masao Tohyama, Masato Suzuki, And Tomoo Shiomi, Kiyokazu Imai
    Abstract:

    The Flory interaction parameters χ for blends of Random Copolymers consisting of binary combinations of methyl methacrylate (MMA), n-butyl methacrylate (nBMA), and isobutyl methacrylate (iBMA) monomers were calculated using the Flory equation-of-state theory with modified combining rules extended to Random Copolymer systems. In order to determine the intersegmental or intermolecular parameters necessary for the calculation of χ for the blends, osmotic pressures, heats of mixing at infinite dilution, and excess volumes of mixing for solutions of the methacrylate Random Copolymers in cyclohexanone were measured, and the equation-of-state theory was applied to these solutions. Using the intersegmental parameters thereby determined, the theory gives U-shaped curves for the temperature dependence of χ for the blends. Namely, the theory shows that miscibility of these polymer blends is of the upper critical solution temperature type, which is consistent with the miscibility results obtained experimentally in ou...

  • a consideration on miscibility behaviour in Random Copolymer blends based on the equation of state theory
    Polymer, 1991
    Co-Authors: Tomoo Shiomi, Kiyokazu Imai
    Abstract:

    Abstract So-called miscibility and immiscibility windows in Random Copolymer blends are terms that describe the variation in miscibility with Copolymer composition, i.e. immiscible → miscible → immiscible and miscible → immiscible → miscible, respectively. The miscibility has been explained by the change of sign of the intermolecular interaction parameter χ expressed in terms of the intersegmental interaction parameters. For the former and the latter windows the sign of the intermolecular parameter χ changes with Copolymer composition from positive → negative → positive and negative → positive → negative, respectively. However, the changing pattern of the sign of χ may depend on temperature because the Flory-Huggins interaction parameter χ depends on temperature. Flory's equation-of-state theory gives two kinds of temperature dependence of χ: (a) a U-shaped curve, which is always positive, and (b) a function increasing monotonically from negative to positive. In this report we discuss, on the basis of Flory's equation-of-state theory, how the pattern of the temperature dependence of χ changes with Copolymer composition for Copolymer blends. In consequence, even though the sign of χ changes with Copolymer composition from positive → negative → positive in a limited temperature range, there were two types of dependences of temperature versus χ curve on Copolymer composition: (1) (b) regardless of the Copolymer composition as well as (2) (a) → (b) → (a) with Copolymer composition predicted by theory. Also, for the blends in which χ changes from negative → positive → negative at a certain temperature, two types were obtained: (3) (b) regardless of the Copolymer composition as well as (4) (b) → (a) → (b) with Copolymer composition. U-shaped curves can be found only in types (2) and (4); namely in these two types there exists a Copolymer composition range where the two polymers are immiscible regardless of temperature. Therefore, it was concluded that so-called miscibility and immiscibility windows should be defined by types (2) and (4), respectively, even though the miscibility change is observed to be immiscible → miscible → immiscible or miscible → immiscible → miscible with Copolymer composition in a limited range of temperature.

Jimmy W Mays - One of the best experts on this subject based on the ideXlab platform.

  • using surface active Random Copolymers to control the domain orientation in diblock Copolymer thin films
    Macromolecules, 1998
    Co-Authors: Elbert E. Huang, Thomas P. Russell, Craig J. Hawker, Christopher Harrison, P M Chaikin, Richard A Register, Jimmy W Mays
    Abstract:

    The structure of thin films of a symmetric diblock Copolymer, P(dS-b-MMA) (dS = perdeuterated styrene, MMA = methyl methacrylate), was investigated near preferential and nonpreferential (neutral) surfaces. Neutral surfaces were achieved at the substrate and air interfaces by localizing Random Copolymer, P(S-r-MMA), having a styrene fraction of 0.60, to each of these interfaces. This was performed by chemically grafting the Random Copolymer to the substrate and anchoring a surface active Random Copolymer having a perfluorinated end group to the air interface, respectively. Neutron reflectivity and small-angle neutron scattering were used to determine the orientation of the lamellar microdomains for films having various boundary conditions. Successive steps of CF4 reactive ion etching followed by field emission scanning electron microscopy were used to ascertain the orientation of the microdomains as a function of film depth. For films confined between two continuous neutral surfaces, the orientation of the...

  • ordered diblock Copolymer films on Random Copolymer brushes
    Macromolecules, 1997
    Co-Authors: Paul Mansky, Thomas P. Russell, Craig J. Hawker, Marinos Pitsikalis, Jimmy W Mays
    Abstract:

    Optical microscopy, neutron reflectivity, and small angle neutron scattering studies were used to investigate the structure of thin films of symmetric diblock Copolymers of P(dS-b-MMA) as the interactions between the Copolymer and the substrate were changed in a systematic manner. In cases where there was a strong preferential segregation of one of the components to the substrate, the lamellar microdomains were oriented parallel to the film surface. However, on a nearly neutral substrate, a mixed morphology was found where the lamellae adjacent to the free surface are oriented parallel to the plane of the film, while the lamellae adjacent to the substrate are oriented normal to the plane of the film.