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Zou H.,Tongji University | Guo W.,Tongji University | Yuan W.,Tongji University | Yuan W.,Key Laboratory of Advanced Civil Materials
Journal of Materials Chemistry B | Year: 2013

An amphiphilic Py-PCL-b-POEGMA copolymer was prepared by the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Based on the host-guest inclusion complexation of α-CD with densely grafted chains of the POEGMA shell in Py-PCL-b-POEGMA micelles, supramolecular micellar hydrogels were obtained by adding α-CD into Py-PCL-b-POEGMA micellar solutions. Resulting from the dissociation of α-CD from the ICs upon heating, the Py-PCL-b-POEGMA IC-based supramolecular hydrogels presented thermo-responsive properties. As they were heated, the IC-based hydrogels underwent gel-sol transformation because of the breakage of the physical cross-links. Benefiting from the fluorescent pyrene group in the Py-PCL-b-POEGMA copolymer, the system showed fluorescent properties. And the fluorescent intensity decreased obviously and regularly during the sol-gel transformation process, which makes it possible to detect the sol-gel transformation through sensing the fluorescent intensity of the system. Due to the biodegradable and biocompatible properties, the IC-based hydrogels were used as carriers for delivery systems. The hydrogels showed good properties for controlled release, and the release rate and level can be controlled by temperature. This journal is © The Royal Society of Chemistry. Source


Zou H.,Tongji University | Yuan W.,Tongji University | Yuan W.,Key Laboratory of Advanced Civil Materials
Polymer Chemistry | Year: 2015

The amidine- and dimethylaminoethyl-containing block copolymer PADS-b-PDMAEMA was prepared by the combination of reversible addition-fragmentation chain transfer polymerization and click chemistry. Benefitting from its amphiphilic nature, the PADS-b-PDMAEMA copolymer could spontaneously form vesicles in water when the concentration was above the critical aggregation concentration. As the amidine and dimethylamino units in the copolymer are both typical CO2 responsive chemical groups, the PADS-b-PDMAEMA copolymer vesicles presented unique dual CO2 responses. Moreover, the vesicles also showed thermo-responsive behaviours due to the thermal response of the PDMAEMA block. The lower critical solution temperature (LCST) of the copolymer in aqueous solution was 42.8°C. The size and morphologies of these vesicles can be adjusted by controlling the protonation/deprotonation of amidine and dimethylamino species through bubbling with CO2 or Ar. Alternating treatment with CO2 and Ar could realize a reversible expansion-contraction transformation of these vesicles. Moreover, the reversible vesicles-micelles transition could also be achieved through stimuli of temperature and gas. Due to its CO2- and thermo-responsive properties, the PADS-b-PDMAEMA vesicles were used as a carrier for drug delivery systems. Doxorubicin (DOX), an anticancer drug, was used as a model drug and loaded into the vesicles. The vesicles presented good controlled release behaviour. The release rate and level could be controlled through bubbling with CO2 and by changing the temperature. This journal is © 2015 The Royal Society of Chemistry. Source


Zou H.,Tongji University | Yuan W.,Tongji University | Yuan W.,Key Laboratory of Advanced Civil Materials
Journal of Materials Chemistry B | Year: 2015

An amphiphilic PCL-SS-PDMAEMA copolymer was synthesized by the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) using a new disulfide functionalized double-head initiator with both terminal hydroxyl and bromine groups. Based on the self-assembly of the PCL-SS-PDMAEMA copolymer with oleic acid modified Fe3O4 nanoparticles in aqueous solutions, magnetic PCL-SS-PDMAEMA/Fe3O4 complex micelles with a saturation magnetization of 10.20 emu g-1 were prepared. The investigation of magnetothermal properties of the magnetic complex micelles showed that the temperature of the magnetic micellar systems increased in the alternating magnetic field (AMF) and the increasing rate and steady-state temperature could be adjusted through altering the magnetic flux density. Benefitting from the thermal response of PDMAEMA and redox response of the disulfide bond, the magnetic complex micelles presented obvious temperature- and redox-responsive properties. The Rh of the magnetic complex micelles would decrease when the micellar solutions were heated. And when DTT was added into the magnetic micellar systems, the distributions of Rh broadened with the emergence of aggregates. Due to the magnetic, magnetothermal, temperature- and redox-responsive properties, the magnetic complex micelles were used as a carrier for drug delivery systems. Doxorubicin (DOX), an anticancer drug, was used as a model drug and loaded into the magnetic complex micelles. The magnetic complex micelles presented good properties for controlled release. The release rate and level could be controlled by adding an external AMF and altering the DTT concentration. © 2015 The Royal Society of Chemistry. Source


Yuan W.,Tongji University | Yuan W.,Key Laboratory of Advanced Civil Materials | Guo W.,Tongji University
Polymer Chemistry | Year: 2014

Novel ultraviolet (UV) light-breakable and tunable thermoresponsive amphiphilic block copolymers were synthesized by atom transfer radical polymerization (ATRP). These amphiphilic copolymers can self-assemble into micelles in water. The lower critical solution temperature (LCST) and size of the micelles were adjusted by altering the ratio of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA). Upon UV light irradiation, 2-nitrobenzyl moieties were detached from polymer chains and the micelles were dissociated. When the solutions were heated above LCST, the micelles can be re-self-assembled. Investigation revealed that the Nile red molecules which were encapsulated in micelles can be controllably released through changing temperature and undergoing UV light irradiation of micelle solutions. © 2014 the Partner Organisations. Source


Yuan W.,Tongji University | Yuan W.,Key Laboratory of Advanced Civil Materials | Shen T.,Tongji University | Wang J.,Tongji University | Zou H.,Tongji University
Polymer Chemistry | Year: 2014

An amphiphilic copolymer containing PEO and PAPBA linked by a disulfide bond (PEO-SS-PAPBA) was synthesized by RAFT. The micelles with a PEO shell and a PAPBA core presented glucose, pH and redox triple responses. The controlled release of insulin could be achieved through adding glucose or GSH. This journal is © 2014 the Partner Organisations. Source

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