• Title/Summary/Keyword: Polymer micelle

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Physical Characteristics of Hydrophobic Poly(sodium acrylate)s (소수성 성질을 갖는 Poly(sodium acrylate)s의 물리적 특성)

  • Ahn, Beom-Shu
    • Journal of the Korean Applied Science and Technology
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    • v.27 no.4
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    • pp.545-551
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    • 2010
  • Hydrophobically monoendcapped poly(sodium acrylate)s formed hydrophobic microdomains in water. This was concluded on poly(sodium acrylate)s with a linear $C_{12}$-alkyl chain attached specifically at the end of the polymer. There was no well defined CMC (critical micelle concentration), but rather a gradual transition from a micelle free solution to a micelle solution. Steady state fluorescence spectroscopy indicates that the micro domains are rather hydrophobic. At pH 5 in the abscence of salt and at pH 9 in the prescence of 1 M sodium citrate the CAC (critical aggregation concentration) was in the range of 0.1 to 2.4 mM. However at pH 5 there was a linear increase in the transition concentration with a head-group size due to an increase in steric and electrostatic repulsions between polymer main chains. At pH 9 in the abscence of salt the transition concentration was in the range of 1 to 80 mM. For the larger polymers there was a effect which consisted of a concentration gradient of sodium counterion toward the hydrophobic domain. The effect was larger for the larger polymers because of the higher total sodium concentration and the less steep counterion concentration gradient.

Small-Angle Neutron Scattering Study of the Structure of Micelles Formed by a Polystyrene-Poly(ethylene oxide) Diblock Copolymer in Aqueous Solution (수용액 내 폴리스티렌-폴리에틸옥사이드 이중블록공중합체 미셀 구조에 대한 소각중성자산란 연구)

  • Kang, Byoung-Yook;Choi, Mi-Ju;Hwang, Kyu-Hee;Lee, Kwang-Hee;Jin, Byoung-Suk
    • Polymer(Korea)
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    • v.33 no.5
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    • pp.485-489
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    • 2009
  • The temperature dependence of the structure of micelles formed by a deuterated polystyrene-poly(ethylene oxide) diblock copolymer (dPS-PEO) in heavy water were investigated with small-angle neutron scattering (SANS). SANS data were analyzed using the hard-sphere structure factor in combination with the form factor of a core-shell model. The micelle aggregation number and corona radius were obtained from the fits to the SANS data. The micelle aggregation numbers varied with temperature from 229 at $25^{\circ}C$ to 240 at $45^{\circ}C$, with a corresponding increase in the core radius. However, the shell thickness of micelles decreased with increasing temperature from 6.2 to 5.8 nm. These structural changes of micelles might be ascribed to the decrease in the hydration volume per hydrophilic group in the corona because of the increase in hydrophobicity of the PEO block with increasing temperature.

Quantitative Analysis of ″Polymer-Balls″ in Aqueous Solutions by Small-Angle Neutron Scattering

  • Shibayama, Mitsuhiro;Okabe, Satoshi;Nagao, Michihiro;Sugihara, Shinji;Aoshima, Sadahito;Harada, Tamotsu;Matsuoka, Hideki
    • Macromolecular Research
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    • v.10 no.6
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    • pp.311-317
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    • 2002
  • The quantitative analysis of polymer micelles consisting of amphiphilic block copolymers was carried out by small-angle neutron scattering (SANS). The block copolymers, made of poly(2-ethoxyethyl vinyl ether-b-2-hydroxyethyl vinyl ether)(poly(EOVE-b-HOVE)), exhibited a sharp morphological transition from a homogeneous solution to a micelle structure with increasing temperature. This transition is accompanied by a formation of spherical domains of poly(EOVE) with a radius around 200 $\AA$. The variations of the size and its distribution of the domains were investigated as a function of polymer concentration and temperature. The validity of SANS analysis, including the wavelength- and incident-beam-smearing effects of the SANS instrument, was examined with a pre-calibrated polystyrene latex.

Studies on Skin Permeation with Polymer Micelles and the Cell Penetrating Peptide of Pyrus Serotina Var Stem Extracts

  • An, Gyu Min;Park, Su In;Kim, Min Gi;Heo, Soo Hyeon;Shin, Moon Sam
    • Korean Chemical Engineering Research
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    • v.58 no.1
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    • pp.21-28
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    • 2020
  • The stem extract from Pyrus serotina var has natural antioxidant ability, but the extraction method does not result in a soluble compound in cosmetic formulations. This study investigated the cosmetic efficacy of the Pyrus serotina var stem extract and its epidermis permeation ability when combined with polymer micelles and a cell penetrating peptide. The total concentration of polyphenol compounds was determined to be 103.1644 ± 1.38 mg/g in the ethanol extract and 78.97 ± 1.45 mg/g in the hydrothermal extract. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effects were 55.94 ± 0.22% in the ethanol extract at 1,000 mg/L. Superoxide dismutase (SOD) activity rates were 104.05 ± 3.28% in the ethanol extract at 62.5 mg/L. The elastase inhibition rate was 67.21 ± 2.72% in the ethanol extract at 1,000 mg/L. An antimicrobial effect was observed in the Propionibacterium acnes strain. In the epidermal permeability experiment, it was confirmed that formulation of the polymer micelle containing the Pyrus serotina var stem extract and cell penetrating peptide (R6, hexa-D-arginine) showed small particle size and much better skin permeability. The cumulative amount of total Pyrus serotina var stem extract that penetrated to the skin over time increased over 24 hours in three formulations. The three formulations showed 51.61 ㎍/㎠ (Formulation 0), 75.97 ㎍/㎠ (Formulation 1) and 95.23 ㎍/㎠ (Formulation 2) skin penetration, respectively. Therefore, it was confirmed that the ethanol extracts of Pyrus serotina var stem showed good cosmetic efficacy and excellent epidermis permeation ability when combined with a polymer micelle and cell penetrating peptide. Thus, this extract has the potential to be used as a safe and natural cosmetic material in the future.

Characterizations and Release Behavior of Poly [(R)-3-hydroxy butyrate]-co-Methoxy Poly(ethylene glycol) with Various Block Ratios

  • Jeong, Kwan-Ho;Kwon, Seung-Ho;Kim, Young-Jin
    • Macromolecular Research
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    • v.16 no.5
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    • pp.418-423
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    • 2008
  • Poly[(R)-3-hydroxy butyrate] (PHB) and methoxy poly(ethylene glycol) (mPEG) were conjugated by the transesterification reaction with tin(II)-ethylhexanoate (Sn(Oct)-II) as a catalyst. Hydrophobic PHB and hydrophilic mPEG formed an amphiphilic block copolymer which was formed with the self-assembled polymeric micelle in aqueous solution. In this study, we tried to determine the optimum ratio of hydrophobic/hydrophilic segments for controlled drug delivery. The particle size and shape of the polymeric micelle were measured by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Their size were 61-102 nm with various block ratios. Griseofulvin was loaded in the polymeric micelle as a hydrophobic model drug. The loading efficiency and release profile were measured by high performance liquid chromatography (HPLC). The model drug in our system was constantly released for 48 h.

Drug Release Behavior of Poly($\varepsilon$-caprolactone )-b-Poly( acrylic acid) Shell Crosslinked Micelles below the Critical Micelle Concentration

  • Hong Sung Woo;Kim Keon Hyeong;Huh June;Ahn Cheol-Hee;Jo Won Ho
    • Macromolecular Research
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    • v.13 no.5
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    • pp.397-402
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    • 2005
  • To explore the potential of shell crosslinked micelle (SCM) as a drug carrier, the drug release behavior of poly($\varepsilon$-caprolactone)-b-poly(acrylic acid) (PCL-b-PAA) SCMs was investigated. PCL-b-PAA was synthesized by ring opening polymerization of $\varepsilon$-caprolactone and atom transfer radical polymerization of tert-butyl acrylate, followed by selective hydrolysis of tert-butyl ester groups to acrylic acid groups. The resulting amphiphilic polymer was used to prepare SCMs by crosslinking of PAA corona via amidation chemistry. The drug release behavior of the SCMs was studied, using pyrene as a model drug, and was compared with that of non-crosslinked micelles, especially below the critical micelle concentration (CMC). When the shell layers were crosslinked, the drug release behavior of the SCMs was successfully modulated at a controlled rate compared with that of the non-crosslinked micelles, which showed a burst release of drug within a short time.

Encapsulation of CdSe/ZnS Quantum Dots in Poly(ethylene glycol)-Poly(D,L-lactide) Micelle for Biomedical Imaging and Detection

  • Lee, Yong-Kyu;Hong, Suk-Min;Kim, Jin-Su;Im, Jeong-Hyuk;Min, Hyun-Su;Subramanyam, Elango;Huh, Kang-Moo;Park, Sung-Woo
    • Macromolecular Research
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    • v.15 no.4
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    • pp.330-336
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    • 2007
  • Luminescent CdSe/ZnS QDs, with emission in the red region of the spectrum, were synthesized and encapsulated in poly(ethylene glycol)-poly(D,L-lactide) diblock copolymer micelles, to prepare water-soluble, bio-compatible QD micelles. PEG-PLA diblock copolymers were synthesized by ring opening polymerization of D,L-lactide, in the presence of methoxy PEG as a macro initiator. QDs were encapsulated with PEG-PLA polymers using a solid dispersion method in chloroform. The resultant polymer micelles, with encapsulated QDs, were characterized using various analytical techniques, such as UV- Vis measurement, light scattering, fluorescence spectroscopy, transmission electron microscopy (TEM) and atomic forced microscopy (AFM). The polymer micelles, with encapsulated QDs, were spherical and showed diameters in the range of 20-150 nm. The encapsulated QDs were highly luminescent, and have high potential for applications in biomedical imaging and detection.

Synthesis and pH-Dependent Micellization of Sulfonamide-Modified Diblock Copolymer

  • Pal Ravindra R.;Kim Min Sang;Lee Doo Sung
    • Macromolecular Research
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    • v.13 no.6
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    • pp.467-476
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    • 2005
  • The main objective of this study was to develop and characterize pH-sensitive biodegradable polymeric materials. For pH-sensitivity, we employed three kinds of moieties: 2-amino-3-(lH-imidazol-4-yl)-propionic acid (H), N-[4-( 4,6-dimethyl-pyrimidin-2ylsulfamoyl)-phenyl]succinamic acid (SM), and 2- {3-[ 4-( 4,6-dimethyl-pyrim­idin- 2-ylsulfamoyl)-phenylcarbamoyl]-propionylamino} -3-(3 H - imidazol-4-yl)-propionic acid (SH). The pH -sensitive diblock copolymers were synthesized by ring opening polymerization and coupling reaction from poly(ethylene glycol) (MPEG), $\varepsilon$-caprolactone (CL), D,L-lactide (LA) and pH-sensitive moieties. The pH-sensitive SH molecule was synthesized in a two-step reaction. The first step involved the synthesis of SHM, a methyl ester derivative of SH, by coupling reaction of SM and L-histidine methyl ester dihydrochloride, whereas the second step involved the hydrolysis of the same. The synthesized SM, SHM and SH molecules were characterized by FTIR, $^{1}H$-NMR and $^{13}C$-NMR spectroscopy, whereas diblock copolymers and pH-sensitive diblock copolymer were characterized by $^{1}H$-NMR and GPC analysis. The critical micelle concentrations were determined at various pH conditions by fluorescence technique using pyrene as a probe. The micellization and demicellization studies of pH-sensitive diblock copolymers were also done at different pH conditions. The pH-sensitivity was further established by acid-based titration and DLS analysis.

Synthesis and Characterization of Poly(ethylene glycol) Grafted Polysuccinimide (폴리(에틸렌 글리콜)이 결합된 Polysuccinimide의 합성과 특성)

  • Lim, Nak-Hyun;Lee, Ha-Young;Kim, Moon-Suk;Khang, Gil-Son;Lee, Hai-Bang;Cho, Sun-Hang
    • Polymer(Korea)
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    • v.29 no.1
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    • pp.36-40
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    • 2005
  • Poly(amino acid) derivatives have been widely investigated as a drug carrier in drug delivery system. Particularly,polysuccinimide (PSI) is one of the most promising drug carriers since it possesses suitable physicochemical characteristics for development of macromolecular prodrugs, due to biocompatibility and biodegradability. In this study, we deal with the synthesis of polyaspartamide having various functional groups such as methoxy-poly(ethylene glycol) (MPEG) via ring closing of PSI. PSI was synthesized by polyonensation polymerization of spartic acid. The variety of average molecular weight was confirmed with reacion time and catalyst content to observe the optimum condition of synthesis. MPEG, hydrophilic chain, was bonded to fabricate polymeric micell composed of hydrophilic and hydrophobic polymer. All materials were characterized by 1H-NMR, FT-IR and GPC. In addition, the formation of nanoparticle micelle as drug carrier were also examined. Micelle size was measured by ELS and AFM. The functionalized polysparamide formed nanoparticle micelle whose size ranged from 90 to 130 nm. In conclusion, we prepared polyaspartamide functionalized with PEG examined the possibility as drug carriers.

Preparation and Characterization of PEG-PLA(PLGA) Micelles for Solubilization of Rosiglitazone (Rosiglitazone 가용화를 위한 PEG-PLA(PLGA) 고분자 미셀의 제조 및 특성분석)

  • Kim, Yon-Hwan;Im, Jeong-Hyuk;Min, Hyun-Su;Kim, Jun-Ki;Lee, Yong-Kyu;Park, Go-Eun;Cho, Kwang-Jae;Huh, Kang-Moo
    • Polymer(Korea)
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    • v.34 no.3
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    • pp.274-281
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    • 2010
  • In this study, PEG-PLA(or PLGA) amphiphilic di-block copolymers were synthesized by ring opening polymerization of D,L-lactide(or glycolide) and applied to polymeric micelle system for solubilization of a rosiglitazone as diabetes drug. The drug could be efficiently loaded into the polymer micelle by solid dispersion technique, and the drug-loaded micelles were characterized and evaluated as a drug delivery carrier by fluorescence spectrometer, DSC, and DLS measurements. The colloidal stability of drug loaded micelles in aqueous media could be enhanced by addition of 2-hydroxy-N-picolylnitinamide as a hydrotropic agent. The polymer micelles also showed biocompatible and nontoxic properties in vitro cell viability using MTT assay, and the drug loaded micelles were observed to be more effective than free drug for decreasing glucose in blood of rats.