Cationic Polymeric Micelles Research Articles

The self-assembly of biodegradable cationic polymer micelles as vectors for gene transfection

Cationic micelles self-assembled from a biodegradable amphiphilic copolymer, poly{( N-methyldietheneamine sebacate)- co-[(cholesteryl oxocarbonylamido ethyl) methyl bis(ethylene) ammonium bromide] sebacate} (P(MDS- co-CES)) have recently been reported for efficient gene delivery and co-delivery of drug and nucleic acid. In this study, poly(ethylene glycol) (PEG) of various molecular weights ( M n=550, 1100 and 2000) was conjugated to P(MDS- co-CES) having different cholesterol grafting degrees to improve the stability of micelle/DNA complexes in the blood for systemic in vivo gene delivery. DNA binding ability, gene transfection efficiency and cytotoxicity of P(MDS- co-CES), PMDS, PEGylated PMDS and PEGylated P(MDS- co-CES) micelles were studied and compared. As with P(MDS- co-CES), PEG–P(MDS- co-CES) polymers could also self-assemble into stable micelles of small size. However, PMDS and PEG–PMDS without cholesterol could not form stable micelles but formed large particles. PEGylation of polymers significantly decreased their gene transfection efficiency in HEK293, HepG2, HeLa, MDA-MB-231 and 4T1 cells. However, increasing N/P ratio promoted gene transfection. An increased cholesterol grafting degree led to greater gene expression level possibly because of the more stable core–shell structure of the micelles. PEG550–P(MDS- co-CES) micelles induced high gene transfection level, comparable to that provided by P(MDS- co-CES) micelles. PEGylated polymers were much less cytotoxic than P(MDS- co-CES). PEGylated P(MDS- co-CES) micelles may provide a promising non-viral vector for systemic in vivo gene delivery.

Layer-by-layer Assembly of Poly(lactic-co-glycolic acid)-b-poly(l-lysine) Copolymer Micelles

Biocompatible, biodegradable polyionic micelles were used as a building component for layer-by-layer (LbL) assembly that can produce drug-loaded nanolayers. To prepare the polycationic micelles, poly(lactic-co-glycolic acid)-b-poly(l-lysine) [PLGA-b-P(Lys)] copolymers were synthesized. In an aqueous phase, PLGA-b-P(Lys) copolymers were self-assembled to form spherical micelles with the inner core of poly(lactic-co-glycolic acid) (PLGA) and the cationic outer shell of P(Lys). The micelles were characterized by zeta potential, dynamic light scattering, and nuclear magnetic resonance. PLGA-b-P(Lys) micelles showed the positive zeta potential values in a broad range of pH (3–11), indicating the high stability of the polyionic micelles with the outer shell of positive charges. Cationic polymeric micelles were coated on the surface via electrostatic interactions with the oppositely charged polyelectrolyte, poly(sodium 4-styrenesulfonate). Formation of multiple micelle layers was monitored using quartz crystal microbalance in situ, and the surface topology of the layers was characterized by atomic force microscopy ex situ, as the number of micelle layer was increased. The multiple micelle layers were stable, and the thickness of micelle layer grew as the number of LbL coating increased. The approach described in this work can be used for the development of the biocompatible, biodegradable, drug-loaded bioactive nanocoatings.

Graphoepitaxy Control of the Deposition of Cationic Polymer Micelles on SiO2 Surfaces

The concept of graphoepitaxy is applied to the deposition of cationic polymer micelles (formed from poly(styrene)-block-poly(2-vinylpyridine) in pH 1 aqueous solution) from the solution phase onto ...

Observation of Massive Overcompensation in the Complexation of Sodium Poly(styrenesulfonate) with Cationic Polymer Micelles

Complex particles have been formed by the electrostatic association of protonated polystyrene-b-poly(2-vinylpyridine) (PS-b-PVPH+) micelles with sodium poly(styrenesulfonate) (PSS-Na+), all at pH 1. Light scattering demonstrates that there is a large mass excess of PSS- associated with each PS-b-PVPH+ micelle (the molecular weight increases by factors of 5−6), even in the limit that the weight ratio of the micelle to PSS-Na+ is very low, thereby avoiding bridged structures. This system is an example of charge and mass overcompensation, but to a much greater extent than usual. Surprisingly the effect of the molecular weight of the PSS-Na+ is minor. We believe that it is the flexible polymer micelle corona that permits such a large degree of mass and charge overcompensation because the linear PSS-Na+ can penetrate the micelle corona and adopt a convoluted local conformation with many loops or points of grafting attachment. While these particles are stable with respect to storage, they do not seem to be stab...

Adsorption of Cationic Polymer Micelles on Polyelectrolyte-Modified Surfaces

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTAdsorption of Cationic Polymer Micelles on Polyelectrolyte-Modified SurfacesMaria Ruela Talingting, Yanhui Ma, Chris Simmons, and S. E. WebberView Author Information Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712 Cite this: Langmuir 2000, 16, 2, 862–865Publication Date (Web):October 7, 1999Publication History Received2 February 1999Revised1 September 1999Published online7 October 1999Published inissue 1 January 2000https://doi.org/10.1021/la9901027Copyright © 2000 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views314Altmetric-Citations37LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (333 KB) Get e-AlertsSUBJECTS:Adsorption,Deposition,Electrostatics,Micelles,Polymers Get e-Alerts

Catalyses by polymer complexes. Part 3. Polymer micellar catalysis of isoalloxazine (flavin) oxidation of thiols

The effect of cationic polymer micelles on the isoalloxazine (flavin) oxidation of thiols is reported: the polymers employed were poly-(2-ethyl-1-vinylimidazole) quaternized with ethyl bromide and lauryl bromide [lauryl group content: 8.8 mol %(L-9), 28.9 mol %(L-29), and 40.9 mol %(L-41)]. Addition of L-29 and L-41 polymers caused a red shift of the u.v. absorption maximum of thiophenoxide ion and an increase in its acid dissociation constant, while L-9 polymer scarcely affected these values. Under anaerobic conditions, the oxidation of thiophenol and 2-mercaptoethanol by 10-ethyl-3-methylisoalloxazine in the presence of micelle-like polymers (L-29 and L-41) was 102–105 times faster than the corresponding reaction in a non-polymeric system, whereas L-9, a polyelectrolyte-like polymer, produced almost no acceleration. The thiolate anion bound to the polymer domain is activated probably due to the formation of a hydrophobic ion pair. On the other hand, the oxidation of butane-1,4-dithiol was not much affected by the polymer micelle. The difference in mechanism of dithiol oxidation is discussed in connection with the microenvironmental effect.

Catalyses by polymer complexes. VII. Enhanced esterolytic reactivity of polymer-coenzyme A, glutathione complexes.

AbstractThe association of coenzyme A(CoASH) and glutathione (GSH) with the water‐soluble polymers and their esterolytic reactivities were evaluated through the reaction with p‐nitrophenyl acetate in the presence of cationic polymer micelles: partially laurylated poly(2‐ethyl‐1‐vinylimidazole) and poly(4‐vinylpyridine). The polymer micelles with high lauryl‐group content (more than 12 mol%) markedly accelerated the reaction at very low concentrations of the polymer. Other polymers with no or small lauryl‐group content only slightly enhanced the association and the reaction rate. From the rate‐polymer concentration profiles, the association constants (K) and the rate constants for thiol coenzymes bound to the polymer (k′a,bound) were determined: for polymers with more than 12 mol % lauryl‐group content, KCoASH = 1110–2270 M−1, KGSH = 170–503M−1, k′a,bound at pH 8.65 = 142–341M−1 sec−1. k′a,bound were 20–340 times larger than that observed in the absence of the polymer. The logarithm of k′a,bound was found to be correlated well with the polymer hydrophobicity, indicating that the hydrophobic environment of the polymer activated the bound thiol anions. On the other hand, the polymer hydrophobicity did not correlate with the association constant.