The Experts below are selected from a list of 18876 Experts worldwide ranked by ideXlab platform

Thomas P. Davis - One of the best experts on this subject based on the ideXlab platform.

Arthi Jayaraman - One of the best experts on this subject based on the ideXlab platform.

  • Molecular dynamics simulation study of linear, bottlebrush, and star-like amphiphilic block Polymer assembly in solution
    Soft matter, 2019
    Co-Authors: Michiel G. Wessels, Arthi Jayaraman
    Abstract:

    In this study we investigate the effect of varying branched Polymer Architectures on the assembly of amphiphilic block Polymers in solution using coarse-grained molecular dynamics simulations. We quantify assembly structure (e.g., aggregation number, assembly morphology, and micelle core size) and thermodynamics (e.g., unimer to micelle transition conditions) as a function of increasing solvophobicity of the solvophobic block in the coPolymer for three broad categories of Polymer Architectures: linear, ‘bottlebrush’ (with many short side chains on a long backbone), and ‘star-like’ (with few long side chains on a short backbone). Keeping the total number of coarse-grained beads in each Polymer (or Polymer molecular weight) constant, as we go from either linear or ‘star-like’ to ‘bottlebrush’ Polymer Architectures, the micelle aggregation number and micelle core size decrease, and the solvophobicity required for assembly (i.e., transition solvophobicity) increases. This trend is linked to the topological/steric hinderance for making solvophobic bead contacts between neighboring Polymers for the ‘bottlebrush’ Polymer Architecture compared to the linear or ‘star-like’ Architectures. We are able to identify some universal trends in assembly by plotting the assembly structure and thermodynamics data as a function of branching parameter defined as the ratio of the branched chain to the linear chain radius of gyration in the unimer state, and the relative lengths of the backbone versus side chain. The results in this paper guide how one could manipulate the amphiphilic block Polymer assembly structure and thermodynamics by choosing appropriate Polymer Architecture, block sequence, and composition.

  • Effect of Polymer Architecture on the Structure and Interactions of Polymer Grafted Particles: Theory and Simulations
    Macromolecules, 2017
    Co-Authors: Kevin J. Modica, Tyler B. Martin, Arthi Jayaraman
    Abstract:

    We use Langevin dynamics simulations and Polymer Reference Interaction Site Model (PRISM) theory to study Polymer grafted nanoparticles specifically to explain the impact of comb Polymer Architecture on the grafted layer structure and effective interparticle interactions in solvent and in matrix Polymer. First, we use simulations to study a single particle grafted with comb Polymers with varying comb Polymer design (i.e., spacing and length of side chains along the comb Polymer backbone), grafting density (i.e., Polymer chains/particle surface area), and particle curvature in implicit solvent at the athermal limit. We find that increasing side chain length or decreasing side chain spacing along the comb Polymer effectively swells and extends the Polymer backbone due to the increasing side chain monomer crowding. For particles at finite curvature with increasing side chain monomer crowding, the monomer concentration profile of the comb Polymer backbone at short distances from the surface resembles the conc...

Jordan P. Page - One of the best experts on this subject based on the ideXlab platform.

  • Polymer Architecture: Does It Influence Shear Stability?
    Industrial & Engineering Chemistry Research, 2018
    Co-Authors: Jordan P. Page
    Abstract:

    Hyperbranched and linear poly(alkyl methacrylate)s with and without polycaprolactone segments were designed and prepared via a core-first strategy, and then evaluated with respect to their rheology and shear stability performance. The focus of this work was to study the effect of Architecture on mechanical shear stability, as it relates to lubricant performance. The Polymers were prepared from functionalized macroinitiators subsequently subjected to atom transfer radical Polymerization (ATRP)/activators regenerated by electron transfer atom transfer radical Polymerization (ARGET ATRP) conditions with dodecyl methacrylate and 2-ethylhexyl methacrylate mixtures. As expected, most compounds displayed an increased viscosity index along with increasing molecular weight. The inclusion of polycaprolactone appears to have enhanced the viscosity index in select samples. Although the hyperbranched Polymers studied here varied in the number of arms from about 20 to 1 (linear), the data presented supports the empiric...

Martina H. Stenzel - One of the best experts on this subject based on the ideXlab platform.

Won Jong Kim - One of the best experts on this subject based on the ideXlab platform.

  • A Pt(iv)-mediated Polymer Architecture for facile and stimuli-responsive intracellular gene silencing with chemotherapy.
    Biomaterials science, 2018
    Co-Authors: Sungjin Jung, Jinhwan Kim, Swapan Pramanick, Hyeongmok Park, Hyori Lee, Junseok Lee, Won Jong Kim
    Abstract:

    Conventional chemotherapy has been impeded by the inherent characteristics of cancer including fast mutagenesis and drug resistance; thus a combination therapy consisting of multiple therapeutic strategies has attracted much attention. However, the loading processes of multiple therapeutic molecules affect each other; thus the development of a nanocarrier that enables independent loading of the cargo molecules has been demanded. Herein, we report an ingeniously designed Pt(IV)-mediated Polymeric Architecture (Pt-PA) for combinatorial gene and chemotherapy to address the issue, prepared by crosslinking a cationic Polymer (polyethylenimine, PEI) with a Pt(IV) prodrug. Therapeutic siRNA (anti-BCL2) was simply loaded by electrostatic interaction to form a stable nanocomplex. In the cellular study, the simultaneous release of both the active Pt(II) drug and siRNA was monitored under the intracellular reducing environment, driven by dissociation of the Polymer Architecture due to an inherent characteristic of the Pt(IV) crosslinker. Therefore, an enhanced gene silencing effect and an anticancer effect were observed. Furthermore, in the animal study, an improved therapeutic effect of the nanocomplex was observed, which can be explained by tumor targeting via the EPR effect, and enhanced drug and siRNA release at the intracellular environment simultaneously. Taken together, the overall results from in vitro and in vivo studies strongly suggest the therapeutic potential of our precisely designed Pt(IV)-mediated Polymer Architecture.

  • Phenylboronic acid-sugar grafted Polymer Architecture as a dual stimuli-responsive gene carrier for targeted anti-angiogenic tumor therapy.
    Biomaterials, 2015
    Co-Authors: Jinhwan Kim, Yeong Mi Lee, Hyunwoo Kim, Dongsik Park, Ji-hoon Kim, Won Jong Kim
    Abstract:

    We present a cationic Polymer Architecture composed of phenylboronic acid (PBA), sugar-installed polyethylenimine (PEI), and polyethylene glycol (PEG). The chemical bonding of PBA with the diol in the sugar enabled the crosslinking of low-molecular-weight (MW) PEI to form high-MW PEI, resulting in strong interaction with anionic DNA for gene delivery. Inside the cell, the binding of PBA and sugar was disrupted by either acidic endosomal pH or intracellular ATP, so gene payloads were released effectively. This dual stimuli-responsive gene release drove the Polymer to deliver DNA for high transfection efficiency with low cytotoxicity. In addition, PBA moiety with PEGylation facilitated the binding of Polymer/DNA polyplexes to sialylated glycoprotein which is overexpressed on the tumor cell membrane, and thus provided high tumor targeting ability. Therapeutic application of our Polymer was demonstrated as an anti-angiogenic gene delivery agent for tumor growth inhibition. Our judicious designed Polymer structure based on PBA provides enormous potential as a gene delivery agent for effective gene therapy by stimuli-responsiveness and tumor targeting.