A well-defined coil–comb polycationic brush with “star polymers” as side chains for gene delivery

2014 ◽  
Vol 5 (16) ◽  
pp. 4670-4678 ◽  
Author(s):  
Mingming Zhang ◽  
Qingqing Xiong ◽  
Yinsong Wang ◽  
Zhibao Zhang ◽  
Wei Shen ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Star Polymers ◽  
Star Polymer ◽  
Side Chains ◽  
Single Star ◽  
Grafting Density

The well-defined polycationic brush with super-high grafting density of PDMAEMA showed higher transfection capability than the single star polymer and PEI25K.

EXTENSIVE STUDY OF INTERACTION FORCE BETWEEN SPHERICAL COLLOIDS AND STAR POLYMERS

2012 ◽  
Vol 26 (17) ◽  
pp. 1250105
Author(s):  
MUSTAPHA HIMMI ◽  
LAILA MOHAMMADI
Keyword(s):  
Colloidal Particles ◽  
Star Polymers ◽  
Interaction Force ◽  
Extensive Study ◽  
Star Polymer ◽  
Polymerization Degree ◽  
Small Molecular Weight ◽  
Effective Force ◽  
Flexible Polymer ◽  
Grafting Density

We consider a system consisting of very small colloidal particles clothed each by f end-grafted flexible polymer chains we regarded as star polymers, and hard spherical colloidal particles in a good solvent. Our main objective is to determine the expression of the interaction force between a spherical colloid and a star polymer as a function of distance between them. We limit ourselves to the case where the star polymer is smaller than the colloid. In the first part, the system is dissolved in a melt of short linear chains of polymerization degree P<N, where N denotes the polymerization degree of grafted chains. To compute the expected force, we consider two regimes: (1) high-grafting density [Formula: see text] and (2) small-grafting density (f < f*). For (f > f*), we show that the expression of the expected force coincides exactly with that of the case of a small molecular weight solvent. For (f < f*), we show that there is a change in behavior. In the second part, we assume that the lengths of the f grafted chains were randomly distributed and there is talk of a polydisperse star polymer. We show that the computation of the expected force depends on the relative values of the polymerization degree of longest grafted chain, N, when it is compared to the typical one Nc ~ f1/(α-1). Here α is the polydispersity exponent. We distinguish two regimes depending on whether N < Nc or N > Nc. For the regime with N < Nc, and comparing the expression of the force obtained for the monodisperse case, we can say that the polydispersity of grafted chains induce a drastic change of the force expression. For the regime with N > Nc, we found the existence of two distance-ranges. For small distances, the effective force expression is identical to that relative to the above case (N < Nc). But for high distances, the effective force expression is similar to the monodisperse case.

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

Brushes and lamellar mesophases of comb-shaped (co)polymers: a self-consistent field theory

2020 ◽  
Vol 22 (40) ◽  
pp. 23385-23398
Author(s):  
Ivan V. Mikhailov ◽  
Ekaterina B. Zhulina ◽  
Oleg V. Borisov
Keyword(s):  
Field Theory ◽  
Main Chain ◽  
Side Chains ◽  
Comb Polymers ◽  
Grafting Density ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Self Consistent Field Theory

Superimposed distributions of main chain ends in brush of comb polymers with different length and grafting density of side chains.

High Performance Gene Delivery Polymeric Vector: Nano-Structured Cationic Star Polymers (Star Vectors)

2005 ◽  
Vol 2 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Yasuhide Nakayama ◽  
Takeshi Masuda ◽  
Makoto Nagaishi ◽  
Michiko Hayashi ◽  
Moto Ohira ◽  
...  
Keyword(s):  
Gene Delivery ◽  
High Performance ◽  
Star Polymers

Synthesis and characterization of novel brush copolymers with biodegradable polyphosphoester side chains for gene delivery

2013 ◽  
Vol 51 (10) ◽  
pp. 2150-2160 ◽  
Author(s):  
Ying Hao ◽  
Jinlin He ◽  
Mingzu Zhang ◽  
Yunfeng Tao ◽  
Jian Liu ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Synthesis And Characterization ◽  
Side Chains

Evaluating the Effect of Termination by Chain - Chain Coupling in Living Free-Radical Polymerizations

2003 ◽  
Vol 56 (8) ◽  
pp. 775 ◽  
Author(s):  
Jeffrey Pyun ◽  
Ian Rees ◽  
Jean M. J. Fréchet ◽  
Craig J. Hawker
Keyword(s):  
Free Radical ◽  
Star Polymers ◽  
Star Polymer ◽  
Direct Result ◽  
Vinyl Monomers ◽  
Linear Polymers ◽  
Radical Coupling ◽  
Novel Approach ◽  
Vis Spectroscopy ◽  
Radical Polymerizations

A novel approach based on the reaction of multifunctional star polymers with chromophore-labelled linear polymers is presented for evaluating the extent of termination by chain–chain coupling during living free-radical polymerizations. A mixed initiating system consisting of an unlabelled, multifunctional initiator and an excess of a monofunctional alkoxyamine initiator containing a chromophore, such as pyrene, is used to initiate the living polymerization of vinyl monomers leading to a mixture of star and linear polymers. The occurrence of chain–chain coupling is readily identified and quantified by isolating the star polymer that is obtained and elucidating the level of incorporation of pyrene units by UV/vis spectroscopy. This allows the level of chain–chain coupling to be determined since the inclusion of pyrene into the star structure is a direct result of termination by radical coupling.

Electrophoretic Deposition of Star Polymer-Europium Chalcogenide Nanocomposite Films

2009 ◽  
Vol 412 ◽  
pp. 113-118
Author(s):  
Suseela Somarajan ◽  
Saad A. Hasan ◽  
Melissa A. Harrison ◽  
Sameer V. Mahajan ◽  
Chinessa T. Adkins ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Colloidal Suspension ◽  
Star Polymers ◽  
Optical Switches ◽  
Nanocomposite Films ◽  
Star Polymer ◽  
Liquid Suspension ◽  
Nanocrystal Films ◽  
Optical Isolators ◽  
Stratified Liquid

The electrophoretic deposition of polystyrene/divinylbenzene (PS/DVB) star polymer-europium sulphide (EuS) nanocomposite films from a colloidal suspension is reported. Liquid suspension, containing both the PS/DVB star polymer and EuS nanocrystals were prepared by separately injecting dichloromethane (DCM) based solutions of EuS nanocrystals and of the star polymers, respectively, into a stratified liquid combination of hexane and DCM. Scanning electron microscopy illustrates images of the dependence of surface morphology on nanocrystal concentration of the PS/DVB-EuS star polymer film. These polymer-encased nanocrystal films may be a more practical option for the fabrication of magneto-optical thin film devices, such as optical switches, optical isolators, and optical memories.

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