The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Ya Xia - One of the best experts on this subject based on the ideXlab platform.

Jeffrey T. Koberstein - One of the best experts on this subject based on the ideXlab platform.

  • main chain polyacetal conjugates with hif 1 inhibitors temperature responsive ph degradable drug delivery vehicles
    Journal of Materials Chemistry B, 2018
    Co-Authors: Sanjoy Samanta, Chathuranga C De Silva, Porakrit Leophairatana, Jeffrey T. Koberstein
    Abstract:

    Main-chain polymer–drug conjugates are prepared from Polyacetals (PA) and three hydrophobic diol-based HIF-1 inhibitors. The new conjugates are temperature-responsive with lower critical solution temperature (LCST) behavior and are intrinsically pH-degradable. While soluble in plasma at room temperature, they lose solubility above a target temperature that can be adjusted to virtually any temperature of physicological interest, providing mechanisms for site-specific delivery by active thermal targeting or temperature-induced gelation. The reverse phase transition temperature can be precisely tuned by proper choice of four structural variables that characterize the amphiphilic diol and divinyl ether monomers used in the synthesis, or by adjusting the content of drug incorporated within the polymer. These main-chain PA–drug conjugates also allow for site-specific controlled release as they degrade in acidic microenvironments such as tumors. The degradation rates increase with decreasing pH, degradation products are neutral, and pristine drug is released, without any remnants of the conjugation chemistry.

  • Polyacetals: Water-Soluble, pH-Degradable Polymers with Extraordinary Temperature Response
    Macromolecules, 2016
    Co-Authors: Sanjoy Samanta, Danielle R. Bogdanowicz, Helen H. Lu, Jeffrey T. Koberstein
    Abstract:

    Temperature-responsive polymers exhibit a drastic change in solubility upon change in temperature, a property responsible for their increased use in a wide variety of emerging smart material applications. Here, we describe a flexible new family of Polyacetals with lower critical solution temperature (LCST) behavior, falling out of aqueous solution upon increase in temperature. These are the first synthetic LCST polymers to be intrinsically biodegradable, forming neutral degradation products in acidic environments. The temperature response of the Polyacetals is extraordinary. Their LCST cloud point temperatures can be predicted and tuned to high precision over a temperature range of ca. 6–80 °C as they are linearly dependent on the number of methylene and ethylene oxide units in the diol and divinyl ether monomers. We further demonstrate that the LCST temperatures are insensitive to salt and/or polymer concentration, properties that are important to in vivo applications, and that they are biocompatible.

Enjami R Elling - One of the best experts on this subject based on the ideXlab platform.

Sanjoy Samanta - One of the best experts on this subject based on the ideXlab platform.

  • main chain polyacetal conjugates with hif 1 inhibitors temperature responsive ph degradable drug delivery vehicles
    Journal of Materials Chemistry B, 2018
    Co-Authors: Sanjoy Samanta, Chathuranga C De Silva, Porakrit Leophairatana, Jeffrey T. Koberstein
    Abstract:

    Main-chain polymer–drug conjugates are prepared from Polyacetals (PA) and three hydrophobic diol-based HIF-1 inhibitors. The new conjugates are temperature-responsive with lower critical solution temperature (LCST) behavior and are intrinsically pH-degradable. While soluble in plasma at room temperature, they lose solubility above a target temperature that can be adjusted to virtually any temperature of physicological interest, providing mechanisms for site-specific delivery by active thermal targeting or temperature-induced gelation. The reverse phase transition temperature can be precisely tuned by proper choice of four structural variables that characterize the amphiphilic diol and divinyl ether monomers used in the synthesis, or by adjusting the content of drug incorporated within the polymer. These main-chain PA–drug conjugates also allow for site-specific controlled release as they degrade in acidic microenvironments such as tumors. The degradation rates increase with decreasing pH, degradation products are neutral, and pristine drug is released, without any remnants of the conjugation chemistry.

  • Polyacetals: Water-Soluble, pH-Degradable Polymers with Extraordinary Temperature Response
    Macromolecules, 2016
    Co-Authors: Sanjoy Samanta, Danielle R. Bogdanowicz, Helen H. Lu, Jeffrey T. Koberstein
    Abstract:

    Temperature-responsive polymers exhibit a drastic change in solubility upon change in temperature, a property responsible for their increased use in a wide variety of emerging smart material applications. Here, we describe a flexible new family of Polyacetals with lower critical solution temperature (LCST) behavior, falling out of aqueous solution upon increase in temperature. These are the first synthetic LCST polymers to be intrinsically biodegradable, forming neutral degradation products in acidic environments. The temperature response of the Polyacetals is extraordinary. Their LCST cloud point temperatures can be predicted and tuned to high precision over a temperature range of ca. 6–80 °C as they are linearly dependent on the number of methylene and ethylene oxide units in the diol and divinyl ether monomers. We further demonstrate that the LCST temperatures are insensitive to salt and/or polymer concentration, properties that are important to in vivo applications, and that they are biocompatible.

  • Polyacetals: Water-Soluble, pH-Degradable Polymers with Extraordinary Temperature Response
    2016
    Co-Authors: Sanjoy Samanta, Danielle R. Ogdanowicz, Jeffrey T. Koberstei
    Abstract:

    Temperature-responsive polymers exhibit a drastic change in solubility upon change in temperature, a property responsible for their increased use in a wide variety of emerging smart material applications. Here, we describe a flexible new family of Polyacetals with lower critical solution temperature (LCST) behavior, falling out of aqueous solution upon increase in temperature. These are the first synthetic LCST polymers to be intrinsically biodegradable, forming neutral degradation products in acidic environments. The temperature response of the Polyacetals is extraordinary. Their LCST cloud point temperatures can be predicted and tuned to high precision over a temperature range of ca. 6–80 °C as they are linearly dependent on the number of methylene and ethylene oxide units in the diol and divinyl ether monomers. We further demonstrate that the LCST temperatures are insensitive to salt and/or polymer concentration, properties that are important to in vivo applications, and that they are biocompatible

Kazuo Hokkirigawa - One of the best experts on this subject based on the ideXlab platform.

  • tribological behavior of polyacetal composite lubricated in sodium hypochlorite solution
    Wear, 2019
    Co-Authors: Kei Shibata, Keigo Toyabe, Ryota Araki, Takeshi Yamaguchi, Masahiko Kawabata, Kazuo Hokkirigawa
    Abstract:

    Abstract Sodium hypochlorite (NaClO) solution is the most widely used disinfectant in the food industry. If NaClO solution can be used as a lubricant, the maintenance cost is reduced and the food safety is warrantied. Hypothetically, the concentration of the available chlorine in the solution affects the tribological behaviors. In this study, we investigated the tribological behavior of a composite of polyacetal (POM) resin and rice bran ceramics (RBC) in a lubricating solution of NaClO with two concentrations. The mean friction coefficient was higher in NaClO solution with 25 mg/L available chlorine than in purified water and in NaClO with 2500 mg/L available chlorine. The wear resistance of the composite was also degraded in the presence of 25 mg/L available chlorine. From the investigations of the tribological behavior of an RBC disk, the wear in the lower available chlorine was considered to be affected by degradation of the carbon parts. Although we should improve the tribological properties in the presence of 25 mg/L available chlorine, the POM/RBC composite had a sufficient potential to use in NaClO solution as a tribomaterial.

  • tribological behavior of polyacetal composite filled with rice bran ceramics particles under water lubrication
    Journal of Composite Materials, 2018
    Co-Authors: Kei Shibata, Takeshi Yamaguchi, Kazuo Hokkirigawa
    Abstract:

    We investigated the tribological behavior of polyacetal polyoxymethylenecomposite filled with rice bran ceramics particles under water lubrication, compared to those of polyoxymethylene composites filled with glass beads and glass fibers. Furthermore, the local contact pressure between a particle and the paired ball was calculated based on a simple contact model. The polyoxymethylene/rice bran ceramics composite showed low wear (ws < 10−8 mm2/N) and low friction (μ < 0.10) under water lubrication, irrespective of the normal load and sliding velocity. On a Stribeck curve, the lubrication condition of the polyoxymethylene/rice bran ceramics composite appeared to be near hydrodynamic lubrication. The specific wear rates of the polyoxymethylene/rice bran ceramics composite were the lowest of the composites, regardless of the bearing characteristic number. A smooth worn surface was observed for both the polyoxymethylene/rice bran ceramics composite and the paired ball. The dimensionless roughness parameters of...