Thermal characterization of poly(ethylene glycol)–poly(d,l-lactide) block copolymer micelles based on pyrene excimer formation

Jule, Eduardo; Yamamoto, Yuji; Thouvenin, Muriel; Nagasaki, Yukio; Kataoka, Kazunori

doi:10.1016/j.jconrel.2004.02.012

Cited by 8 publications

(9 citation statements)

References 22 publications

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“…Therefore the spectra produced gives compelling evidence for the excimer formation. This is further supported from previous work where similar peak shift had been reported 4, 27, 28. Similarly, at 2.5 and 10 mg ml −1 concentrations (above 2nd CAC value), peak shift was observed for Naphth self‐assemblies while no red shift was observed at 0.05 and 0.1 mg ml −1 (below first CAC) (Fig.…”

Section: Resultssupporting

confidence: 91%

“…Self‐assembling polymers are generally constructed from diverse amphiphilic polymer architectures and are known to form different types of supramolecular structures such as polymeric micelles,1–4 nanoparticles,5 vesicles,5, 6 rod‐shaped, or disk like structures7 in aqueous environment. The supramolecular structures formed are of great interest in the biomedical field especially in drug delivery application due to the ability of these nanostructures to encapsulate a variety of therapeutic agents such as hydrophobic drugs, proteins, and genes.…”

Section: Introductionmentioning

confidence: 99%

“…The nanoparticles formed have promising potential as chemosensors 23. Jule et al 4. also reported on the formation of polymeric micelles based on poly(ethylene glycol)‐poly( D , L ‐lactide) block copolymer conjugated with pyrene.…”

Section: Introductionmentioning

confidence: 99%

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Novel fluorescent amphiphilic poly(allylamine) and their supramacromolecular self‐assemblies in aqueous media

Hoskins

Lin

Tetley

et al. 2011

Polymers for Advanced Techs

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Fluorescent amphiphilic polymers were produced by grafting different types and levels of hydrophobic pendant groups with intrinsic fluorescent properties (fluorenylmethoxy carbonyl (Fmoc), dimethylamino-1-naphthalenesulfonyl (Dansyl), and naphthalene (Naphth) to a water soluble homopolymer backbone, polyallylamine (PAA). Non-fluorescent hydrophobic pendant group (cholesteryl moieties) were also grafted onto PAA. The polymers were characterized with elemental analysis, NMR and FTIR spectroscopy. All polymers formed self-assemblies by probe sonication in water with sizes ranging from 120 to 199 nm and TEM images showed the presence of spherical particles. The critical aggregation concentration (CAC) varied from 0.093 to 1.5 mg ml S1 depending on the type of hydrophobic pendant groups. The Cholesteryl and Dansyl polymers showed the presence of one CAC while the Fmoc and Naphth grafted polymers revealed the presence of two CACs. The first CAC observed was possibly due to intermolecular aggregation while the second CAC at the higher polymer concentration was the result of excimer formation revealed by their fluorescent spectra. We reasoned that Naphth and Fmoc aromatic pendant groups possess a flat stereochemistry, thus allowing p-p stacking at higher concentrations. The presence of the N-dimethylamino group in the Dansyl moiety gives rise to a 3D structure, thus hindering any stacking. The understanding of the supramolecular assemblies formed by these fluorescent amphiphilic polymers will aid in the engineering of advanced materials with superior functionality for biomedical applications.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Novel fluorescent amphiphilic poly(allylamine) and their supramacromolecular self‐assemblies in aqueous media

Hoskins

Lin

Tetley

et al. 2011

Polymers for Advanced Techs

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“…The micelle formation of the block copolymer in an aqueous phase was confirmed by fluorescence spectroscopy and dynamic light scattering. − The amphiphilic Py-PCL- b -poly(carboxylic acid) copolymer is expected to self-associate in water to form polymer micelles of the hydrophobic PCL inner core and the hydrated poly(carboxylic acid) outer shell. Upon micellization in water, pyrene moieties labeled at the PCL termini preferably locate inside the hydrophobic microdomain of micelles, and thus consequently, they come into close contact to generate the excimers . Figure shows the fluorescence emission spectra of Py-PCL- b -PMAA aqueous solutions at various concentrations.…”

Section: Resultsmentioning

confidence: 99%

pH-Controlled, Polymer-Mediated Assembly of Polymer Micelle Nanoparticles

Lee

2006

Langmuir

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We describe pH-controlled, polymer-mediated assembly of polymer micelles in aqueous media based on reversible complexation between the micelles of pyrene-labeled poly(epsilon-caprolactone)-b-poly(carboxylic acid) copolymers and proton-accepting water-soluble polymers such as poly(ethylene glycol) (PEG), poly(2-ethyl-2-oxazoline) (PEtOz), and poly(1-vinylpyrrolidone) (PVP). The key factor determining assembly phenomena was identified as the modulation of hydrogen-bonding interaction between ionizable anionic micellar shells and the proton-accepting polymers by the pH control. As pH decreased from 7.4 to 2.0, the mixture of the polymer micelles and polymers underwent assembly and formed solid hybrids at specific pH values. The micelles assembled in the hybrid could be reversibly dispersed as micelles above specific pH ranges. The assembly/disassembly behavior as well as phase transitions of the micelle/proton-accepting polymer could be precisely controlled by adjusting pH. This assembling behavior depended on the rationally designed parameters such as the chemical structure and length of micellar shell-forming poly(carboxylic acid)s and the class of proton-accepting polymers.

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“…Indeed, a hydrophobic solvatochromic dye added to an aqueous solution containing aggregates tends to diffuse from the solution to the hydrophobic aggregate core. For instance, pyrene is one of the most widely used fluorescent probes, as its unique fluorescent emission spectrum varies according to the media that surrounds it and according to its concentration 29–32. Of great interest, and perhaps less known from polymer chemists, is 2,6‐diphenyl‐4‐(2,4,6‐triphenyl‐ N ‐pyridino) phenolate, a zwitterionic compound, known as Reichardt's betaine dye (Scheme ), which exhibits the largest observed solvatochromic effects of any known organic molecules 29.…”

Section: Resultsmentioning

confidence: 99%

Thermoresponsive micelles from well‐defined block copolymers synthesized via reversible addition–fragmentation chain transfer polymerization

Liu

Perrier

2005

J. Polym. Sci. A Polym. Chem.

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Poly(N-isopropylacrylamide) (PNIPAAm) homopolymers synthesized by reversible addition-fragmentation chain transfer polymerization were used as macrochain-transfer agents to synthesize smart amphiphilic block copolymers with a switchable hydrophilic-hydrophobic block of PNIPAAm and a hydrophilic block of poly(N-dimethylacrylamide). All polymers were characterized by gel permeation chromatography, 1 H NMR, and differential scanning calorimetry. The reversible micelles formed by the block copolymers of various compositions in aqueous solutions were characterized by 1 H NMR, dynamic light scattering, and tensiometry. Micelles were observed in the aqueous solutions when the temperature was increased to 40 8C because of the collapse of the PNIPAAm structure, which led to a PNIPAAm hydrophobic block. The drug loading capacity was illustrated with the use of the solvatochromic Reichardt's dye and measured by ultraviolet-visible. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3643-3654, 2005

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Thermal characterization of poly(ethylene glycol)–poly(d,l-lactide) block copolymer micelles based on pyrene excimer formation

Cited by 8 publications

References 22 publications

Novel fluorescent amphiphilic poly(allylamine) and their supramacromolecular self‐assemblies in aqueous media

Novel fluorescent amphiphilic poly(allylamine) and their supramacromolecular self‐assemblies in aqueous media

pH-Controlled, Polymer-Mediated Assembly of Polymer Micelle Nanoparticles

Thermoresponsive micelles from well‐defined block copolymers synthesized via reversible addition–fragmentation chain transfer polymerization

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