The Experts below are selected from a list of 7512 Experts worldwide ranked by ideXlab platform

Shunai Che - One of the best experts on this subject based on the ideXlab platform.

Congcong Cui - One of the best experts on this subject based on the ideXlab platform.

Lei Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Folate-functionalized unimolecular micelles based on a degradable amphiphilic dendrimer-like Star Polymer for cancer cell-targeted drug delivery.
    Biomacromolecules, 2011
    Co-Authors: Weiqiang Cao, Alexander Mann, Yong Wang, Jing Zhou, Lei Zhu
    Abstract:

    A folate-functionalized degradable amphiphilic dendrimer-like Star Polymer (FA-DLSP) with a well-defined poly(l-lactide) (PLLA) Star Polymer core and six hydrophilic polyester dendrons based on 2,2-bis(hydroxymethyl) propionic acid was successfully synthesized to be used as a nanoscale carrier for cancer cell-targeted drug delivery. This FA-DLSP hybrid formed unimolecular micelles in the aqueous solution with a mean particle size of ca. 15 nm as determined by dynamic light scattering and transmission electron microscopy. To study the feasibility of FA-DLSP micelles as a potential nanocarrier for targeted drug delivery, we encapsulated a hydrophobic anticancer drug, doxorubicin (DOX), in the hydrophobic core, and the loading content was determined by UV–vis analysis to be 4 wt %. The DOX-loaded FA-DLSP micelles demonstrated a sustained release of DOX due to the hydrophobic interaction between the Polymer core and the drug molecules. The hydrolytic degradation in vitro was monitored by weight loss and proto...

  • folate functionalized unimolecular micelles based on a degradable amphiphilic dendrimer like Star Polymer for cancer cell targeted drug delivery
    Biomacromolecules, 2011
    Co-Authors: Weiqiang Cao, Alexander Mann, Yong Wang, Jing Zhou, Lei Zhu
    Abstract:

    A folate-functionalized degradable amphiphilic dendrimer-like Star Polymer (FA-DLSP) with a well-defined poly(L-lactide) (PLLA) Star Polymer core and six hydrophilic polyester dendrons based on 2,2-bis(hydroxymethyl) propionic acid was successfully synthesized to be used as a nanoscale carrier for cancer cell-targeted drug delivery. This FA-DLSP hybrid formed unimolecular micelles in the aqueous solution with a mean particle size of ca. 15 nm as determined by dynamic light scattering and transmission electron microscopy. To study the feasibility of FA-DLSP micelles as a potential nanocarrier for targeted drug delivery, we encapsulated a hydrophobic anticancer drug, doxorubicin (DOX), in the hydrophobic core, and the loading content was determined by UV-vis analysis to be 4 wt %. The DOX-loaded FA-DLSP micelles demonstrated a sustained release of DOX due to the hydrophobic interaction between the Polymer core and the drug molecules. The hydrolytic degradation in vitro was monitored by weight loss and proton nuclear magnetic resonance spectroscopy to gain insight into the degradation mechanism of the FA-DLSP micelles. It was found that the degradation was pH-dependent and Started from the hydrophilic shell gradually to the hydrophobic core. Flow cytometry and confocal microscope studies revealed that the cellular binding of the FA-DLSP hybrid against human KB cells with overexpressed folate-receptors was about twice that of the neat DLSP (without FA). The in vitro cellular cytotoxicity indicated that the FA-DLSP micelles (without DOX) had good biocompatibility with KB cells, whereas DOX-loaded micelles exhibited a similar degree of cytotoxicity against KB cells as that of free DOX. These results clearly showed that the FA-DLSP unimolecular micelles could be a promising nanosize anticancer drug carrier with excellent targeting property.

  • synthesis and unimolecular micelles of amphiphilic dendrimer like Star Polymer with various functional surface groups
    Macromolecules, 2011
    Co-Authors: Weiqiang Cao, Lei Zhu
    Abstract:

    We report the synthesis and functionalization of amphiphilic dendrimer-like Star Polymers (DLSPs) with a hydrophobic Star-shaped poly(l-lactide) (PLLA) core and a hydrophilic poly(amidoamine) (PAMAM) dendron shell. First, carboxylic acid-functionalized PLLA Star Polymer was synthesized by ring-opening Polymerization of l-lactide followed by functionalization with succinic anhydride. Second, 1-, 2-, and 3-generation PAMAM dendrons with a primary amine at the dendron root and benzyl ester protections at the periphery were prepared via a divergent method. By amide coupling between the carboxylic acid-terminated PLLA Star Polymer and six PAMAM dendrons, amphiphilic DLSPs were successfully synthesized. To enhance bioactivity and bioconjugation capability, the benzyl ester surface groups in these DLSPs were converted to carboxylic acid, primary amine, and triethylene glycol functional groups, respectively. Nuclear magnetic resonance spectroscopy and size-exclusion chromatography were used to confirm quantitativ...

Christos N. Likos - One of the best experts on this subject based on the ideXlab platform.

  • Coarse graining of Star-Polymer--colloid nanocomposites.
    The Journal of chemical physics, 2012
    Co-Authors: Daniela Marzi, Christos N. Likos, Barbara Capone
    Abstract:

    We consider mixtures of self-avoiding multiarm Star Polymers with hard colloids that are smaller than the Star Polymer size. By employing computer simulations, and by extending previous theoretical approaches, developed for the opposite limit of small Star Polymers [A. Jusufi et al., J. Phys.: Condens. Matter 13, 6177 (2001)10.1088/0953-8984/13/28/303], we coarse-grain the mixture by deriving an effective cross-interaction between the unlike species. The excellent agreement between theory and simulation for all size ratios examined demonstrates that the theoretical approaches developed for the colloidal limit can be successfully modified to maintain their validity also for the present case of the protein limit, in contrast to the situation for mixtures of colloids and linear Polymers. We further analyze, on the basis of the derived interactions, the non-additivity parameter of the mixture as a function of size ratio and Star functionality and delineate the regions in which we expect mixing as opposed to d...

  • Structural arrest in dense Star-Polymer solutions.
    Physical review letters, 2003
    Co-Authors: Giuseppe Foffi, Francesco Sciortino, Piero Tartaglia, Emanuela Zaccarelli, F. Lo Verso, Luciano Reatto, Kenneth A. Dawson, Christos N. Likos
    Abstract:

    The dynamics of Star Polymers is investigated via extensive molecular and Brownian dynamics simulations for a large range of functionality f and packing fraction eta. The calculated isodiffusivity curves display both minima and maxima as a function of eta and minima as a function of f. Simulation results are compared with theoretical predictions based on different approximations for the structure factor. In particular, the ideal glass transition line predicted by mode-coupling theory is shown to exactly track the isodiffusivity curves, offering a theoretical understanding for the observation of disordered arrested states in Star-Polymer solutions.

  • Phase separation in Star-Polymer-colloid mixtures.
    Physical Review E, 2001
    Co-Authors: Joachim Dzubiella, A. Jusufi, Christos N. Likos, C. Von Ferber, Hartmut Löwen, J Stellbrink, Jürgen Allgaier, Dieter Richter, Andrew B. Schofield, P A Smith
    Abstract:

    We examine the demixing transition in Star-Polymer-colloid mixtures for Star arm numbers f=2,6,16,32 and different Star-Polymer-colloid size ratios 0.18< or =q< or =0.50. Theoretically, we solve the thermodynamically self-consistent Rogers-Young integral equations for binary mixtures using three effective pair potentials obtained from direct molecular computer simulations. The numerical results show a spinodal instability. The demixing binodals are approximately calculated and found to be consistent with experimental observations.

  • Phase transitions in colloidal suspensions and Star Polymer solutions
    Journal of Physics: Condensed Matter, 2000
    Co-Authors: Hartmut Löwen, A. Jusufi, Christos N. Likos, M. Watzlawek, Matthias Schmidt, Alan R. Denton
    Abstract:

    Possibilities of fluid-solid and solid-solid phase transformations in colloidal suspensions and Star Polymer solutions are reviewed. We Start from given interparticle pair potentials and predict the corresponding phase diagrams using computer simulations and density functional theory. When possible, the results are compared with experimental data. In particular, we discuss a cascade of freezing transitions for confined colloids and re-entrant melting and anisotropic solid phases for Star Polymer solutions.

  • phase diagram of Star Polymer solutions
    Physical Review Letters, 1999
    Co-Authors: M. Watzlawek, Christos N. Likos, Hartmut Löwen
    Abstract:

    The phase diagram of Star Polymer solutions in a good solvent is obtained over a wide range of densities and arm numbers by Monte Carlo simulations. The effective interaction between the Stars is modeled by an ultrasoft pair potential which is logarithmic in the core-core distance. Among the stable phases are a fluid as well as body-centered cubic, face-centered cubic, body-centered orthogonal, and diamond crystals. In a limited range of arm numbers, reentrant melting and reentrant freezing transitions occur for increasing density.

Lu Han - One of the best experts on this subject based on the ideXlab platform.