Preparation and characterization of thermally responsive block copolymer micelles comprising poly(N-isopropylacrylamide-b-dl-lactide)

Kohori, Fukashi; Sakai, Kiyotaka; Aoyagi, Takaaki; Yokoyama, M.; Sakurai, Yasuhisa; Okano, Teruo

doi:10.1016/s0168-3659(98)00023-6

Cited by 271 publications

(199 citation statements)

References 22 publications

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“…68 Meanwhile, breathing water in a temperature-responsive 69 hydrogel is easier for nanoparticles because of shorter trans- 70 port distance, so their response to a temperature stimulus is 71 much faster than that of a bulk hydrogel. In addition, smaller 72 hybrid particles form more stable colloids and they circulate 73 better in the body; at the same time they can more easily 74 penetrate and accumulate in the leaky, defective archi- Table 2.…”

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confidence: 99%

Biomedical nanoparticle carriers with combined thermal and magnetic responses

et al. 2009

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Several biocompatible polymers are capable of large responses to small temperature changes around 37ºC. In water, their responses include shrinkage and swelling as well as transitions in wettability. These properties have been harnessed for biomedical applications such as tissue engineering scaffolds and drug delivery carriers. A soft material/hard material hybrid in which a magnetic metal or oxide is embedded in a temperatureresponsive polymer matrix can combine the thermal sensitivity with magnetic signatures. Importantly, nanosizing such construct brings about new desirable features of extremely fast thermal response time, small magnetic hysteresis and enhanced magnetic susceptibility. Remote magnetic maneuvering and heating of the hybrid nanocolloids makes possible such applications as high-throughput enzyme separation and cell screening. Robust drug release on demand may also be obtained using these colloids and nanoparticle-derived thin film devices of combined thermal magnetic sensitivity. • C. In water, their responses include shrinkage and swelling as well as transitions in wettability. These properties have been harnessed for biomedical applications such as tissue engineering scaffolds and drug delivery carriers. A soft material/hard material hybrid in which a magnetic metal or oxide is embedded in a temperature-responsive polymer matrix can combine the thermal sensitivity with magnetic signatures. Importantly, nanosizing such construct brings about new desirable features of extremely fast thermal response time, small magnetic hysteresis and enhanced magnetic susceptibility. Remote magnetic maneuvering and heating of the hybrid nanocolloids makes possible such applications as high-throughput enzyme separation and cell screening. Robust drug release on demand may also be obtained using these colloids and nanoparticle-derived thin film devices of combined thermal magnetic sensitivity. ARTICLE IN PRESS+Model NANTOD 7 1-14 Nano Today (2008) xxx, xxx-xxx 1 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a

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Biomedical nanoparticle carriers with combined thermal and magnetic responses

et al. 2009

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“…[29][30][31][32][33][34] When a unitary solvent, such as water, is used as a selective solvent to form star micelles, spherical micelles are obtained and other micellar shapes not formed within our knowledge. [1][2][3][4][5][6][7][8][9][10]31,32,[35][36][37][38] The PMG-Te possessed much longer hydrophilic blocks than hydrophobic blocks. Therefore, a spherical micelle would be formed by the aggregation of PMG-Te.…”

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confidence: 99%

“…Such micelles have attracted much attention in drug delivery systems because of their ability to solubilize hydrophobic molecules; nanoscale size; good thermodynamic solution stability; extended release of various drugs; and prevention of rapid clearance by the reticuloendothelial system. [1][2][3][4][5][6][7][8][9][10] One needs to use model polymers with well-controlled molecular weight, narrow molecular weight distribution, and low compositional heterogeneity for systematic studies of micellar properties. Living polymerization is eminently suitable to prepare block copolymers with these properties.…”

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Conventional Synthesis of Amphiphilic Block Copolymer Utilized for Polymeric Micelle by Mechanochemical Solid-State Polymerization

Kondo

Mori

Sasai

et al. 2007

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Considerable attention has been paid to the use of polymeric micelles in drug delivery systems because of their ability to solubilize hydrophobic molecules and their nanoscale size, good thermodynamic stability in solution, capacity for extended release of various drugs, and their resistance to rapid clearance by the reticuloendothelial system. [1][2][3][4][5][6][7][8][9] Stimulus-responsive polymeric micelles have recently emerged as a novel controlled-release system in which drugs can be released by applying an appropriate stimulus, such as a specific temperature, pH, or ultrasound. A pHsensitive polymeric micelle would be particularly useful for targeting tumor tissues, endosomes, and lysosomes because these sites are more acidic than other parts of the body, such as the blood.…”

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Novel pH-Responsive Polymeric Micelles Prepared through Self-assembly of Amphiphilic Block Copolymer with Poly-4-vinylpyridine Block Synthesized by Mechanochemical Solid-State Polymerization

Kondo

Asano

Koizumi

et al. 2015

CHEMICAL & PHARMACEUTICAL BULLETIN

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We fabricated polymeric micelles containing 5-fluorouracil (5-FU) or fluorescein using the amphiphilic block copolymer, poly-4-vinylpyridine-b-6-O-methacryloyl galactopyranose. Although the polymeric micelles were stable at pH 7.4, they readily decomposed at pH 5, resulting in near complete release of 5-FU. Uptake of polymeric micelles containing fluorescein by HepG2 and HCT116 cells was also investigated. With both cell types, strong fluorescence was observed after a 12-h incubation, but the fluorescence weakened after 24 h of incubation. The fluorescein incorporated into the polymeric micelles was released into acidic organelles (endosome and/or lysosome), from which it diffused throughout the cell. The cytotoxicity of polymeric micelles containing 5-FU was evaluated against HepG2 cells using a CCK-8 assay. The results suggest that polymeric micelles containing 5-FU are more cytotoxic to HepG2 cells than free 5-FU.Key words pH responsiveness; polymeric micelle; mechanochemical solid-state polymerization; amphiphilic block copolymer Polymeric micelles formed from amphiphilic block copolymers (which consist of hydrophilic and hydrophobic blocks) have been extensively studied for their potential use as nanocarriers in aqueous solutions. Considerable attention has been paid to the use of polymeric micelles in drug delivery systems because of their ability to solubilize hydrophobic molecules and their nanoscale size, good thermodynamic stability in solution, capacity for extended release of various drugs, and their resistance to rapid clearance by the reticuloendothelial system. 1-9) Stimulus-responsive polymeric micelles have recently emerged as a novel controlled-release system in which drugs can be released by applying an appropriate stimulus, such as a specific temperature, pH, or ultrasound. A pHsensitive polymeric micelle would be particularly useful for targeting tumor tissues, endosomes, and lysosomes because these sites are more acidic than other parts of the body, such as the blood. Several reports describe the use of various types of pH-sensitive polymeric micelles for acidic pH-triggered drug release of drugs at tumor sites. [10][11][12][13] We previously reported the synthesis and drug release profiles of various polymeric prodrugs prepared by mechanochemical solid-state polymerization carried out through vibratory ball-milling of solid monomers in a metallic vessel under anaerobic conditions. 14-26) A series of studies revealed that this method is applicable to the preparation of a wide variety of vinyl monomers of important classes of bioactive compounds with different physicochemical properties. The method also provides a simple, novel means of synthesizing functionalized polymers in a totally dry process.19) The mechanochemical solid-state polymerization method we reported has several features: the resulting polymeric prodrugs have a narrow molecular weight distribution, represented by M w /M n , where M w represents the weight average molecular weight and M n the number average molecular weight; b...

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Preparation and characterization of thermally responsive block copolymer micelles comprising poly(N-isopropylacrylamide-b-dl-lactide)

Cited by 271 publications

References 22 publications

Biomedical nanoparticle carriers with combined thermal and magnetic responses

Biomedical nanoparticle carriers with combined thermal and magnetic responses

Conventional Synthesis of Amphiphilic Block Copolymer Utilized for Polymeric Micelle by Mechanochemical Solid-State Polymerization

Novel pH-Responsive Polymeric Micelles Prepared through Self-assembly of Amphiphilic Block Copolymer with Poly-4-vinylpyridine Block Synthesized by Mechanochemical Solid-State Polymerization

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