Chun-Yan Hong

Silver Nanoparticles Covered with pH-Sensitive Camptothecin-Loaded Polymer Prodrugs: Switchable Fluorescence “Off” or “On” and Drug Delivery Dynamics in Living Cells

Co-reporter:Liang Qiu, Jia-Wei Li, Chun-Yan Hong, and Cai-Yuan Pan

ACS Applied Materials & Interfaces November 22, 2017 Volume 9(Issue 46) pp:40887-40887

Publication Date(Web):October 31, 2017

DOI:10.1021/acsami.7b14070

A unique drug delivery system, in which silver nanoparticles (AgNPs) are covered with camptothecin (CPT)-based polymer prodrug, has been developed, and the polymer prodrug, in which the CPT is linked to the polymer side chains via an acid-labile β-thiopropionate bond, is prepared by RAFT polymerization. For poly(2-(2-hydroxyethoxy)ethyl methacrylate-co-methacryloyloxy-3-thiahexanoyl-camptothecin)@AgNPs [P(HEO2MA-co-MACPT)@AgNPs], the polymer thickness on the AgNP surface is around 5.9 nm (TGA method). In vitro tests in buffer solutions at pH = 7.4 reveal that fluorescence of the CPT in the hybrid nanoparticles is quenched due to the nanoparticle surface energy transfer (NSET) effect, but under acidic conditions, the CPT fluorescence is gradually recovered with gradual release of the CPT molecules from the hybrid nanoparticles through cleavage of the acid-labile bond. The NSET “on” and “off” is induced by the CPT–AgNP distance change. This unique property makes it possible to track the CPT delivery and release process from the hybrid nanoparticles in the living cells in a real-time manner. The internalization and intracellular releasing tests of the hybrid nanoparticles in the HeLa cells demonstrate that the lysosome containing the hybrid nanoparticles displays CPT blue fluorescence due to release of the CPT under acidic conditions, and the drug-releasing kinetics shows fluorescence increase of the released CPT with incubation time. The cytotoxicity of hybrid nanoparticles is dependent on activity of the acid-labile bond. Therefore, this is a potential efficient drug delivery system in cancer therapy and a useful approach to study the mechanism of release process in the cells.Keywords: amphiphilic copolymer; drug release; fluorescence; pH-sensitive; silver nanoparticles;

Fabrication of PDEAEMA-Coated Mesoporous Silica Nanoparticles and pH-Responsive Controlled Release

Co-reporter:Chun-Yan Hong;Jiao-Tong Sun;Cai-Yuan Pan

The Journal of Physical Chemistry C July 29, 2010 Volume 114(Issue 29) pp:12481-12486

Publication Date(Web):Publication Date (Web): July 6, 2010

DOI:10.1021/jp103982a

Mesoporous silica nanoparticles (MSNs) are considered for potential scaffoldings in drug delivery due to their good biocompatibility and large pore volume, and it is the focus to find a suitable gatekeeper for the mesopores. In this paper, a reliable and versatile method of surface-initiated atom transfer radical polymerization (SI-ATRP) has been employed to prepare the hybrid poly(2-(diethylamino)ethyl methacrylate)-coated MSNs (MSN-PDEAEMA). The resultant hybrid nanoparticles with pH-sensitive polymer shell and MSN core were characterized by a series of techniques including high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, and nitrogen adsorption isotherms. The pH-responsive PDEAEMA brushes anchored on MSNs could serve as a switch to control the opening and closing of the pores. Release of guest molecules was conducted at different pHs, and the results showed rapid release in acidic aqueous solution but very little leakage in alkaline solution. By adjusting the pH of the solution repeatedly, the release of encapsulated molecules could be switched on and off at will. We envision that this nanosystem should have potential applications in sited release of anticancer drug and gene delivery.

Efficient Fabrication of Photosensitive Polymeric Nano-objects via an Ingenious Formulation of RAFT Dispersion Polymerization and Their Application for Drug Delivery

Co-reporter:Wen-Jian Zhang, Chun-Yan Hong, and Cai-Yuan Pan

Biomacromolecules April 10, 2017 Volume 18(Issue 4) pp:1210-1210

Publication Date(Web):March 13, 2017

DOI:10.1021/acs.biomac.6b01887

An ingenious formulation of RAFT dispersion polymerization based on photosensitive monomers of 2-nitrobenzyl methacrylate (NBMA) and 7-(2-methacryloyloxy-ethoxy)-4-methyl-coumarin (CMA) is reported herein. Various morphologies, such as spherical micelle, nanoworm, lamella, and vesicle, are fabricated at up to 20% solids content. Photoinduced cleavage of the NBMA moieties and dimerization of the coumarin moieties are simultaneously triggered upon UV (365 nm) irradiation. The former endows the cores of the nano-objects with abundant carboxyl groups, resulting in the transformation of the hydrophobic cores to hydrophilic ones. The latter induces the core-cross-linking of the nano-objects, which endows the nano-objects with enhanced structural stability and prevents the nanoparticle-to-unimer disassembly. The resultant nano-objects exhibit superior structural stability and excellent performances for drug delivery, including high drug loadings, pH-stimuli release, and high-efficient endosomal escape.

The photo-controlled polymerization-induced self-assembly and reorganization process for fabrication of polymeric nanomaterials

Co-reporter:Jiemei Zhou;Chunyan Hong;Caiyuan Pan

Materials Chemistry Frontiers 2017 vol. 1(Issue 6) pp:1200-1206

Publication Date(Web):2017/06/01

DOI:10.1039/C6QM00380J

A visible light mediated reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) is conducted in ethanol using poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) as a macro-chain transfer agent (macro-CTA), affording polymeric nanomaterials with various morphologies. Unlike the polymerization-induced self-assembly and reorganization (PISR) process initiated by thermal stimuli, the photo-controlled PISR can be performed under more mild conditions, such as visible light and room temperature. Photoredox catalysis is employed to regulate the polymerization via a photoinduced electron transfer (PET) process. It is observed that the polymerization can be affected by catalyst concentration and light intensity, and “ON/OFF” control over polymerization is also demonstrated.

Circularly polarized light triggered enantioselective thiol–ene polymerization reaction

Co-reporter:Guang Yang;Yang Y. Xu;Zi D. Zhang;Long H. Wang;Xue H. He;Qi J. Zhang;Chun Y. Hong;Gang Zou

Chemical Communications 2017 vol. 53(Issue 10) pp:1735-1738

Publication Date(Web):2017/01/31

DOI:10.1039/C6CC09256J

Herein, circularly polarized light is utilized to trigger an enantioselective polymerization reaction, resulting in the synthesis of an optically active polymer from racemic monomers in the absence of any chiral dopant or catalyst.

Asymmetric Michael addition in an aqueous environment with the assistance of optically active hyperbranched polymers

Co-reporter:Hongli Zhang;Qijin Zhang;Chunyan Hong;Gang Zou

Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 11) pp:1771-1777

Publication Date(Web):2017/03/14

DOI:10.1039/C7PY00036G

Herein, we report a novel category of optically active hyperbranched polymers (HBPs) that can serve as a recyclable chiral host platform to promote the asymmetric Michael addition reactions in aqueous environments. The chiral hydrophobic cavities within the HBPs provide a chiral microenvironment for the asymmetric Michael addition with a high product yield of up to 89% and satisfactory enantioselectivity. HBPs-6 (prepared with pure D-type chiral monomer) and quinine can work together in a synergistic way, which leads to an enhancement in catalytic stereoselectivity. However, for HBPs-1 (prepared with pure L-type chiral monomer), the catalytic stereoselectivity of quinine within the L-type chiral hydrophobic cavities is slightly suppressed since the quinine units are very likely to be shielded by the polymer chains. The present study not only provides a catalyst scaffold to achieve high yield and enantioselectivity for the asymmetric Michael addition in aqueous environments, but also is of great fundamental value for the rational design of artificial synthetic materials in approximating enzymes.

Template-Directed Fabrication of Anatase TiO2 Hollow Nanoparticles and Their Application in Photocatalytic Degradation of Methyl Orange

Co-reporter:Jie Chang;Wenjian Zhang;Chunyan Hong

Chinese Journal of Chemistry 2017 Volume 35(Issue 6) pp:1016-1022

Publication Date(Web):2017/06/01

DOI:10.1002/cjoc.201600890

Polymerization-induced self-assembly (PISA) was used to fabricate polymeric nanoparticles via reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) using diblock copolymer poly(glycerol monomethacrylate)-block-poly(2-dimethylaminoethyl methacrylate) (PGMMA- PDMAEMA-CTA) as the macro RAFT agent. The dispersion of polymeric nanoparticles with a final concentration of about 210 mg/g (solid content of 21%) was obtained via this efficient method (PISA). The resultant polymeric nanoparticles consisting of corona-shell-core three layers with weak polyelectrolyte PDMAEMA as the shell were used as sacrificial template to fabricate TiO2 hollow nanoparticles. The negatively charged titanium precursor was absorbed into the PDMAEMA shell via the electrostatic interaction, and hydrolyzed to form polymer/TiO2 hybrid nanoparticles. Anatase TiO2 hollow nanoparticles were formed after removing the polymeric templates by calcination at 550 °C. The experiments of photocatalytic degradation of methyl orange showed that the resultant anatase TiO2 hollow nanoparticles had high photocatalytic activity and good reusability.

Unimolecular micelles of camptothecin-bonded hyperbranched star copolymers via β-thiopropionate linkage: synthesis and drug delivery

Co-reporter:Liang Qiu, Qing Liu, Chun-Yan Hong and Cai-Yuan Pan

Journal of Materials Chemistry A 2016 vol. 4(Issue 1) pp:141-151

Publication Date(Web):02 Dec 2015

DOI:10.1039/C5TB01905B

In order to develop pH- and redox-responsive unimolecular micelles composed of camptothecin (CPT)-conjugated hyperbranched star copolymers via acid-labile β-thiopropionate linkage, a new monomer, methacryloyloxy-3-thiohexanoyl–CPT, is synthesized through conjugation of CPT with methacrylate via β-thiopropionate linkage, and then used in synthesis of the CPT-conjugated hyperbranched star copolymers by two steps of atom transfer radical polymerization (ATRP): self-condensation vinyl polymerization of the CPT-based monomer, 2-hydroxypropyl methacrylate and inimer, and subsequent ATRP of oligo(ethylene glycol) methacrylate using the obtained hyperbranched polymers as the macroinitiator. The obtained polymers dissolve in water to form unimolecular micelles, and their release of CPT in water at various pHs and their anticancer efficacy are studied. The CPT-loaded unimolecular micelles with diameters of 3.56–6.08 nm are quite stable under neutral environment, and are easily triggered by mild acidic pH, such as 6.0 and 5.0. They can be easily internalized by the tumor cells, releasing the CPT. The CPT-conjugated unimolecular micelles via acid-labile β-thiopropionate linkage have potential for application as tumor-targeted drug release systems.

Fabrication of Functional Nano-objects through RAFT Dispersion Polymerization and Influences of Morphology on Drug Delivery

Co-reporter:Liang Qiu, Chao-Ran Xu, Feng Zhong, Chun-Yan Hong, and Cai-Yuan Pan

ACS Applied Materials & Interfaces 2016 Volume 8(Issue 28) pp:18347-18359

Publication Date(Web):July 11, 2016

DOI:10.1021/acsami.6b04693

To study the influence of self-assembled morphologies on drug delivery, four different nano-objects, spheres, nanorods, nanowires, and vesicles having aldehdye-based polymer as core, were successfully prepared via alcoholic RAFT dispersion polymerization of p-(methacryloxyethoxy)benzaldehyde (MAEBA) using poly((N,N′-dimethylamino)ethyl methacrylate) (PDMAEMA) as a macro chain transfer agent (macro-CTA) for the first time. The morphologies and sizes of the four nano-objects were characterized by TEM and DLS, and the spheres with average diameter (D) of 70 nm, the nanorods with D of 19 nm and length of 140 nm, and the vesicles with D of 137 nm were used in the subsequent cellular internalization, in vitro release, and intracellular release of the drug. The anticancer drug doxorubicin (DOX) was conjugated onto the core polymers of nano-objects through condensation reaction between aldehyde groups of the PMAEBA with primary amine groups in the DOX. Because the aromatic imine is stable under neutral conditions, but is decomposed in a weakly acidic solution, in vitro release of the DOX from the DOX-loaded nano-objects was investigated in the different acidic solutions. All of the block copolymer nano-objects show very low cytotoxicity to HeLa cells up to the concentration of 1.2 mg/mL, but the DOX-loaded nano-objects reveal different cell viability and their IC50s increase as the following order: nanorods-DOX < vesicles-DOX < spheres-DOX. The IC50 of nanowires-DOX is the biggest among the four nano-objects owing to their too large size to be internalized. Endocytosis tests demonstrate that the internalization of vesicles-DOX by the HeLa cells is faster than that of the nanorods-DOX, and the spheres-DOX are the slowest to internalize among the studied nano-objects. Relatively more nanorods localized in the acidic organelles of the HeLa cells lead to faster intracellular release of the DOX, so the IC50 of nanorods is lower than that of the vesicles-DOX.

Promotion of morphology transition of di-block copolymer nano-objects via RAFT dispersion copolymerization

Co-reporter:Jiemei Zhou, Wenjian Zhang, Chunyan Hong and Caiyuan Pan

Polymer Chemistry 2016 vol. 7(Issue 19) pp:3259-3267

Publication Date(Web):12 Apr 2016

DOI:10.1039/C6PY00164E

Reversible addition–fragmentation chain transfer (RAFT) dispersion copolymerization of styrene (St) and methyl methacrylate (MMA) is conducted in methanol using poly(2-hydroxyethyl acrylate) (PHEA) as a macro chain transfer agent (macro-CTA). Compared with the general macro-CTA mediated alcoholic dispersion polymerization of St, RAFT dispersion copolymerization of St and MMA can promote the morphology transition of di-block copolymer nano-objects. Three phase diagrams are constructed by changing the molar ratio of St/MMA to reflect the relationship between the degree of polymerization (DP) of P(St-co-MMA), solids concentration and morphology of obtained nano-materials, and it is found that the phase diagrams could be affected by the molar ratio of St/MMA. Ultra-sensitive differential scanning calorimetry (US-DSC) is employed to determine the glass transition temperature (Tg) of polymeric nano-objects in methanol, and the result shows that the Tg values decrease with the increase of the molar content of MMA units in copolymers. Introduction of MMA units into the solvophobic block can enhance its mobility in methanol, which is beneficial for the morphology transition of di-block copolymer nano-objects.

Au–polymer hybrid microgels easily prepared by thermo-induced self-crosslinking and in situ reduction

Co-reporter:Zhen Wu, Xiang Chen, Jiao-Yang Li, Cai-Yuan Pan and Chun-Yan Hong

RSC Advances 2016 vol. 6(Issue 54) pp:48927-48932

Publication Date(Web):09 May 2016

DOI:10.1039/C6RA07864H

This work presents a facile method to prepare Au–polymer hybrid microgels through thermo-induced self-crosslinking and in situ reduction of a gold precursor. Self-assembly of poly(2-dimethylaminoethyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate) (P(DMAEMA-co-TMSPMA)) produced particles by heating the P(DMAEMA-co-TMSPMA) solution above the lower critical solution temperature (LCST), which were subsequently cross-linked via the hydrolysis and condensation of the methoxysilyl groups to form microgels. The polymer microgels can be used as a reducing agent for in situ reduction of a gold precursor and a stabilizing agent of gold nanoparticles, leading to the formation of Au–polymer hybrid microgels. The size of the Au–polymer hybrid microgels can be adjusted by varying the concentration of the polymer solution. Furthermore, Au–polymer hybrid microgels were used as a catalyst for the reduction of 4-nitrophenol, which exhibited catalytic performance and reusability towards the reaction.

Cross-Linked Nano-Objects Containing Aldehyde Groups: Synthesis via RAFT Dispersion Polymerization and Application

Co-reporter:Liang Qiu;Chao-Ran Xu;Feng Zhong;Cai-Yuan Pan

Macromolecular Chemistry and Physics 2016 Volume 217( Issue 9) pp:1047-1056

Publication Date(Web):

DOI:10.1002/macp.201500443

Fabrication of Reductive-Responsive Prodrug Nanoparticles with Superior Structural Stability by Polymerization-Induced Self-Assembly and Functional Nanoscopic Platform for Drug Delivery

Co-reporter:Wen-Jian Zhang, Chun-Yan Hong, and Cai-Yuan Pan

Biomacromolecules 2016 Volume 17(Issue 9) pp:2992

Publication Date(Web):August 22, 2016

DOI:10.1021/acs.biomac.6b00819

A highly efficient strategy, polymerization-induced self-assembly (PISA) for fabrication of the polymeric drug delivery systems in cancer chemotherapy is reported. Diblock prodrug copolymer, PEG-b-P(MEO2MA-co-CPTM) was used as the macro-RAFT agent to fabricate prodrug nanoparticles through PISA. The advantages of fabricating intelligent drug delivery system via this approach are as following: (1) Simultaneous fulfillment of polymerization, self-assembly, and drug encapsulation in one-pot at relatively high concentration (100 mg/mL); (2) Almost complete monomer conversion allows direct application of the resultant prodrug nanoparticles without further purification; (3) Robust structures of the resultant prodrug nanoparticles, because the cross-linker was used as the comonomer, resulted in core-cross-linking simultaneously with the formation of the prodrug nanoparticles; (4) The drug content in the resultant prodrug nanoparticles can be accurately modulated just via adjusting the feed molar ratio of MEO2MA/CPTM in the synthesis of PEG-b-P(MEO2MA-co-CPTM). The prodrug nanoparticles with similar diameters but various drug contents were obtained using different prodrug macro-CTA. In consideration of the long-term biological toxicity, the prodrug nanoparticles with higher drug content exhibit more excellent anticancer efficiency due to that lower dosage of them are enough for effectively killing HeLa cells.

Silica Nanotubes Decorated by pH-Responsive Diblock Copolymers for Controlled Drug Release

Co-reporter:Jiemei Zhou, Wenjian Zhang, Chunyan Hong, and Caiyuan Pan

ACS Applied Materials & Interfaces 2015 Volume 7(Issue 6) pp:3618

Publication Date(Web):January 27, 2015

DOI:10.1021/am507832n

A novel nanocontainer, which has silica nanotube (SNT) core and pH-sensitive polymer shell attaching on the exterior surface of silica nanotube, is presented in this paper. Polymer nanorods, which are conveniently fabricated though polymerization-induced self-assembly and reorganization method, are used as templates for the deposition of silica to fabricate hybrid nanorods. Calcination of as-synthesized silica hybrid nanorods leads to hollow SNTs. SNTs are functionalized with reversible addition–fragmentation chain transfer (RAFT) agent, then surface RAFT polymerization is conducted to get poly(2-(diethylamino)ethyl methacrylate)-b-poly(oligo(ethylene glycol) methacrylate)-coated SNTs (SNT-PDEAEMA-b-POEGMA). Doxorubicin (DOX) can be encapsulated in SNT-PDEAEMA-b-POEGMA, and controlled release of loaded DOX is achieved by adjusting pH of the medium. In vitro cell viability and cellular internalization study confirm the potential application of this nanocontainer in drug and gene delivery.Keywords: controlled release; nanocontainer; RAFT polymerization; silica nanotubes

A facile synthesis of thermo-responsive Au–polymer hybrid microgels through temperature-induced co-aggregation and self-crosslinking

Co-reporter:Xiang Chen, Jiao-Tong Sun, Cai-Yuan Pan and Chun-Yan Hong

Polymer Chemistry 2015 vol. 6(Issue 33) pp:5989-5992

Publication Date(Web):25 Jun 2015

DOI:10.1039/C5PY00774G

Thermo-responsive Au–polymer hybrid microgels were prepared by a facile temperature-induced co-aggregation and self-crosslinking (TICASC) method, needing no complex operations such as preforming of microgels or prior modification of GNPs. The hybrid microgels were utilized as catalysts for the reduction of 4-nitrophenol, which exhibited good activity and recyclability.

Sequential Michael addition thiol–ene and radical-mediated thiol–ene reactions in one-pot produced sequence-ordered polymers

Co-reporter:Lei Yu, Long-Hai Wang, Zong-Tao Hu, Ye-Zi You, De-Cheng Wu and Chun-Yan Hong

Polymer Chemistry 2015 vol. 6(Issue 9) pp:1527-1532

Publication Date(Web):04 Dec 2014

DOI:10.1039/C4PY01363H

Sequential Michael addition-based thiol–ene and free radical mediated thiol–ene reactions for preparing sequence-ordered polymers are reported for the first time. The thiols are produced in situ via the ring-opening of thiolactones, and they can readily react with the electron-deficient carbon–carbon double bond of allyl methacrylate via Michael addition-based thiol–ene, but they are unable to react with the electron-rich carbon–carbon double bond of allyl methacrylate without radicals, and intermediates with thiol and alkene units are formed. After the Michael addition thiol–ene and ring-opening reactions are complete, the thiol is activated by UV irradiation, enabling reaction with the electron-rich carbon–carbon double bond via a free radical-mediated thiol–ene reaction, to form sequence-ordered polymers of high molecular weights.

Formation of Hexagonally Packed Hollow Hoops and Morphology Transition in RAFT Ethanol Dispersion Polymerization

Co-reporter:Wen-Jian Zhang;Cai-Yuan Pan

Macromolecular Rapid Communications 2015 Volume 36( Issue 15) pp:1428-1436

Publication Date(Web):

DOI:10.1002/marc.201500122

Synthesis and Characterization of Coumarin-Containing Cyclic Polymer and Its Photoinduced Coupling/Dissociation

Co-reporter:Min Li;Wei Fan;Chunyan Hong;Caiyuan Pan

Macromolecular Rapid Communications 2015 Volume 36( Issue 24) pp:2192-2197

Publication Date(Web):

DOI:10.1002/marc.201500494

A unique fabrication strategy of hierarchical morphologies: combination of multi-step self-assembling and morphology transition

Co-reporter:Wen-Jian Zhang, Chun-Yan Hong and Cai-Yuan Pan

RSC Advances 2015 vol. 5(Issue 53) pp:42637-42644

Publication Date(Web):12 May 2015

DOI:10.1039/C5RA05105C

Multi-compartmental cylindrical microstructures with lots of nanotubes on their surface, whose shape resembles a sea cucumber, have been fabricated for the first time. This hierarchical morphology is formed through transitions of vesicles to large compound vesicles, to sea cucumber-like hierarchical microstructures. Along with the morphology transitions, aggregation of the residual polymer chains in the solution occurs, which is called multi-step self-assembling. The driving force of the phase transitions and the multistep self-assembling is polymerization because with the progress of the polymerization, the chain length ratio of PS to P4VP increases, which induces self-assembling and morphology transitions. The requisite for multi-step self-assembling is a high concentration of the P4VP-PS chains remaining in the solution after formation of the nascent assemblies. The concentration of the residual block chains can be controlled by varying the recipe and content of the ethanol. Thus, this study provides a unique strategy to fabricate useful hierarchical assemblies.

Syntheses of Sequence-Controlled Polymers via Consecutive Multicomponent Reactions

Co-reporter:Ze Zhang, Ye-Zi You, De-Cheng Wu, and Chun-Yan Hong

Macromolecules 2015 Volume 48(Issue 11) pp:3414-3421

Publication Date(Web):May 20, 2015

DOI:10.1021/acs.macromol.5b00463

Multicomponent reactions have recently attracted a great deal of attention as they are considered as a powerful tool for constructing sequence-controlled polymers. Although new examples are constantly flourishing in the literature, the process that allows two or more consecutive multicomponent-reactions to react in a single operation for the syntheses of sequence-controlled polymers has not been developed until now. Here, we propose a new strategy combining multicomponent reaction of amine, thiol, and alkene conjugating and multicomponent polymerization of diyne, azide, and diamine coupling in one-pot for the synthesis of sequence-controlled polymer.

Synthesis of graft copolymer with pendant macrocycles via combination of ATRP and click chemistry

Co-reporter:Min Li, Chao Liu, Chun-Yan Hong, Cai-Yuan Pan

Polymer 2015 Volume 71() pp:23-30

Publication Date(Web):5 August 2015

DOI:10.1016/j.polymer.2015.06.046

•Graft copolymers with pendant macrocyclic polystyrene were prepared via “graft onto” method.•A maximal grafting density of 20% was observed in the grafting reaction.•Graft copolymer exhibit higher Tg than those of linear and cyclic polystyrene.Graft copolymers with pendant macrocycles were synthesized via “graft onto” method. First, cyclic polystyrene (PS) was achieved by the combination of atom transfer radical polymerization (ATRP) and Cu-catalyzed azide–alkyne cycloaddition (CuAAc), and then an alkynyl group was introduced to cyclic PS. Meanwhile, poly(3-azide-2-hydroxypropyl methacrylate) (PGMA-N3) was synthesized by ATRP of glycidyl methacrylate (GMA) and successive ring-opening of pendant epoxide ring with NaN3. The graft copolymer was achieved by the following click reaction between PGMA-N3 and alkynyl-containing cyclic PS. GPC and 1H NMR were utilized to characterize the obtained graft copolymers, and a maximal grafting density of 20% was observed. Thermal behaviors of linear PS, cyclic PS and PGMA grafted with cyclic PS (PGMA-g-cPS) were investigated by differential scanning calorimeter (DSC), and Tg of PGMA-g-cPS is higher than those of linear and cyclic PS.

A novel multicomponent reaction and its application in sequence-ordered functional polymer synthesis

Co-reporter:Ze Zhang, Ye-Zi You, De-Cheng Wu, Chun-Yan Hong

Polymer 2015 Volume 64() pp:221-226

Publication Date(Web):1 May 2015

DOI:10.1016/j.polymer.2014.12.012

•We propose a new reactant-synergistically catalyzed multicomponent reaction.•The units coming from the reactant can synergistically catalyze the two reactions at the same time.•This multicomponent reaction can be extended to multicomponent polymerization.•It is a very promising method for the preparation of sequence-ordered functional polymers with high molecular weights.•Functional side groups could be easily introduced to the polymers by effective post-modification.Multicomponent reactions are of substantial significance not only for organic synthesis but also for polymer synthesis due to their more bond-forming events per synthetic operation. Generally due to that there are two or more reactions in one multicomponent reaction system, synergistic catalysis, in which the two or more reactions are activated by two or more different catalysts at the same time, is very important for achieving high-efficiency transformations. However, achieving synergistic catalysis via using two or more different catalyst simultaneously is a great challenge. Here, we propose a new reactant-synergistically catalyzed multicomponent reaction, in which the units coming from the reactant can synergistically catalyze the two reactions at the same time. Moreover, this multicomponent reaction can be extended to multicomponent polymerization, which is a very promising method for the preparation of functional polymers with defined-sequence.

Two tandem multicomponent reactions for the synthesis of sequence-defined polymers

Co-reporter:Lu Yang;Ze Zhang;Bofei Cheng;Yezi You;Decheng Wu

Science China Chemistry 2015 Volume 58( Issue 11) pp:1734-1740

Publication Date(Web):2015 November

DOI:10.1007/s11426-015-5448-0

Multicomponent polymerizations have become powerful tools for the construction of sequence-defined polymers. Although the Passerini multicomponent reaction has been widely used in the synthesis of sequence-defined polymers, the tandem usage of the Passerini multicomponent reaction and other multicomponent reactions in one-pot for the synthesis of sequence-defined polymers has not been developed until now. In this contribution, we report the tandem usage of the Passerini three-component reaction and the three-component amine-thiol-ene conjugation reaction in one pot for the synthesis of sequence-defined polymers. The Passerini reaction between methacrylic acid, adipaldehyde, and 2-isocyanobutanoate was carried out, affording a new molecule containing two alkene units. Subsequently, an amine and a thiolactone were added to the reaction system, whereupon the three-component amine-thiol-ene conjugating reaction occurred to yield a sequence-defined polymer. This method offers more rapid access to sequence-defined polymers with high molecular diversity and complexity.

Fabrication and characterization of silica nanotubes with controlled dimensions

Co-reporter:Wen-Jian Zhang, Chun-Yan Hong and Cai-Yuan Pan

Journal of Materials Chemistry A 2014 vol. 2(Issue 21) pp:7819-7828

Publication Date(Web):15 Apr 2014

DOI:10.1039/C4TA00465E

Silica nanotubes with controlled diameters and lengths were fabricated by a template-directed method. Nanowires composed of poly(2-dimethylaminoethyl methacrylate)-block-polystyrene (PDMAEMA–PS), which were fabricated by RAFT dispersion polymerization of styrene in methanol using PDMAEMA as a macro-RAFT agent, were used as sacrificial templates. The diameter of the polymeric nanowires can be adjusted by changing the degree of polymerization (DP) of the hydrophilic PDMAEMA block. As the chain length of the hydrophilic PDMAEMA block increases, the DP of the PS block for formation of the nanowires increases, leading to the diameter increase of the corresponding nanowires. Moreover, the polymeric nanowires with controlled lengths and diameters of the core and the shell can be fabricated on a large scale through polymerization-induced self-assembly and reorganization, conveniently. The weak polyelectrolyte, PDMAEMA shell, is an ideal nanoreactor for deposition of silica to form hybrid nanowires. Silica nanotubes were prepared by calcination of the hybrid nanowires.

Fabrication of Spaced Concentric Vesicles and Polymerizations in RAFT Dispersion Polymerization

Co-reporter:Wen-Jian Zhang, Chun-Yan Hong, and Cai-Yuan Pan

Macromolecules 2014 Volume 47(Issue 5) pp:1664-1671

Publication Date(Web):February 19, 2014

DOI:10.1021/ma402497y

Different from concentric vesicles without spacing between the walls, the concentric vesicles with uniform spacing between the walls were rarely fabricated. We successfully fabricate the spaced concentric vesicles (SCVs) via RAFT dispersion polymerization, and continuous propagation of the residual polymer chains inside the large vesicles induces self-assembling to form SCVs. Concentration of the residual polymer chains in the solution of the nascent-formed vesicles is the determining factor for formation of SCVs, and continuous propagation of less or too more residual polymer chains will not form SCVs but form other morphologies. Generally, the concentration of the residual polymer chains after formation of vesicles is too low to self-assemble, so formation of SCVs is impossible. By adjusting the ratio of St/methanol or macro-RAFT agent P4VP-b-PS/P4VP, the concentration of residual polymer chains can be controlled, and further control of the morphologies is achieved. Formation of the inner vesicles by self-assembling inside the large vesicles requires high molecular weight of the polymer chains due to their very low concentration. The polymers of inner vesicles possess very high molecular weight (×106 g/mol) in comparison with the polymer of outmost vesicles (×105 g/mol). Polymerization kinetic study reveals very high increasing rate of the molecular weight inside the vesicles probably owing to long duration of the chain radicals, and the polymerization rate (Rp) inside the vesicles is faster than the Rp in the outmost vesicles, but both rates are in the same order.

A Responsive Hyperbranched Polymer Not Only Can Self-Immolate but Also Can Self-Cross-Link

Co-reporter:Zhi-Qiang Yu, Xiao-Man Xu, Chun-Yan Hong, De-Cheng Wu, and Ye-Zi You

Macromolecules 2014 Volume 47(Issue 13) pp:4136-4143

Publication Date(Web):June 23, 2014

DOI:10.1021/ma5009012

Though many responsive polymers have been prepared, none of them can both self-immolate and self-cross-link via responding to the changes of the environment. Here, we introduce a new responsive hyperbranched polymer, which not only can self-immolate but also can self-cross-link via responding to the external stimuli. Moreover, the obtained polymer can form a bioreducible nanogel in its aqueous solution simply via heating, and the formed nanogel can self-immolate via UV irradiation.

In situ generation of bioreducible and acid labile nanogels/microgels simply via adding water into the polymerization system

Co-reporter:Zhong-Kai Wang, Long-Hai Wang, Jiao-Tong Sun, Li-Fen Han and Chun-Yan Hong

Polymer Chemistry 2013 vol. 4(Issue 5) pp:1694-1699

Publication Date(Web):19 Dec 2012

DOI:10.1039/C2PY21058D

A novel and versatile method for one-pot and in situ generation of bioreducible and acid labile nanogels/microgels simply via adding water into the polymerization system is reported. The produced polymers in the polymerization system become temperature-sensitive and less soluble after adding water, and hence they collapse together, forming nanoparticles. Subsequently, the disulfides inside the nanoparticle undergo intermolecular disulfide exchange to crosslink the nanoparticle into a bioreducible and acid labile nanogel/microgel. The size of the nanogel/microgel can be easily controlled by the polymerization time and the amount of water added. The formed nanogel/microgel is redox and pH responsive, and biocompatible.

Recent advances in RAFT dispersion polymerization for preparation of block copolymer aggregates

Co-reporter:Jiao-Tong Sun, Chun-Yan Hong and Cai-Yuan Pan

Polymer Chemistry 2013 vol. 4(Issue 4) pp:873-881

Publication Date(Web):03 Sep 2012

DOI:10.1039/C2PY20612A

Differently from bulk, solution, suspension, emulsion, and miniemulsion polymerizations, the controlled radical dispersion polymerization (CRDP) demonstrates self-assembly of the block copolymers formed in the homogeneous system, forming various kinds of micelles or vesicles. Thus, this technology can prepare both the block copolymers and the polymeric aggregates directly. Among CRDP, the reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization has been studied in relative detail and has been successfully developed to prepare a diverse range of assemblies. Several typical systems for RAFT dispersion polymerization are presented in detail and the factors influencing the polymerization and the in situ self-assembly are also highlighted in this minireview.

One-Pot Synthesis of Redox-Responsive Polymers-Coated Mesoporous Silica Nanoparticles and Their Controlled Drug Release

Co-reporter:Jiao-Tong Sun;Ji-Gang Piao;Long-Hai Wang;Mohsin Javed;Cai-Yuan Pan

Macromolecular Rapid Communications 2013 Volume 34( Issue 17) pp:1387-1394

Publication Date(Web):

DOI:10.1002/marc.201300477

Fabrication of Electrospinning Fibers from Spiropyran-Based Polymeric Nanowires and their Photochromic Properties

Co-reporter:Wen-Jian Zhang;Cai-Yuan Pan

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 21) pp:2445-2453

Publication Date(Web):

DOI:10.1002/macp.201300428

Galactose-Based Amphiphilic Block Copolymers: Synthesis, Micellization, and Bioapplication

Co-reporter:Ying Wang, Chun-Yan Hong, and Cai-Yuan Pan

Biomacromolecules 2013 Volume 14(Issue 5) pp:

Publication Date(Web):April 4, 2013

DOI:10.1021/bm4003078

Redox-responsive amphiphilic diblock copolymers, poly(6-O-methacryloyl-d-galactopyranose-co-2-(N,N-dimethylaminoethyl) methacrylate)-b-poly(pyridyl disulfide ethyl methylacrylate) (P(MAGP-co-DMAEMA)-b-PPDSMA) were obtained by deprotection of poly((6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-d-galactopyranose)-co-DMAEMA)-b-PPDSMA [P(MAlpGP-co-DMAEMA)-b-PPDSMA], which were prepared via reversible addition–fragmentation chain transfer (RAFT) polymerization of PDSMA using P(MAlpGP-co-DMAEMA) as macro-RAFT agent. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) studies showed that diblock copolymers P(MAGP-co-DMAEMA)-b-PPDSMA can self-assemble into micelles. Doxorubicin (DOX) could be encapsulated by P(MAGP-co-DMAEMA)-b-PPDSMA upon micellization and released upon adding glutathione (GSH) into the micelle solution. The galactose functional groups in the PMAGP block had specific interaction with HepG2 cells, and P(MAGP-co-DMAEMA)-b-PPDSMA can act as gene delivery vehicle. So, this kind of polymer has potential applications in hepatoma-targeting drug and gene delivery and biodetection.

Polymerizing Nonfluorescent Monomers without Incorporating any Fluorescent Agent Produces Strong Fluorescent Polymers

Co-reporter:Jun-Jie Yan;Zhong-Kai Wang;Xiang-Song Lin;Hao-Jun Liang;Cai-Yuan Pan ;Ye-Zi You

Advanced Materials 2012 Volume 24( Issue 41) pp:5617-5624

Publication Date(Web):

DOI:10.1002/adma.201202201

Bioreducible nanogels/microgels easily prepared via temperature induced self-assembly and self-crosslinking

Co-reporter:Zhi-Qiang Yu, Jiao-Tong Sun, Cai-Yuan Pan and Chun-Yan Hong

Chemical Communications 2012 vol. 48(Issue 45) pp:5623-5625

Publication Date(Web):29 Mar 2012

DOI:10.1039/C2CC30908D

A facile temperature induced self-assembly and self-crosslinking method has been developed for preparing bioreducible nanogels/microgels without need of any stabilizer, catalyst or additional crosslinking agent. The size of formed nanogels/microgels can be easily tuned via the polymer concentration.

Biocompatible Zwitterionic Sulfobetaine Copolymer-Coated Mesoporous Silica Nanoparticles for Temperature-Responsive Drug Release

Co-reporter:Jiao-Tong Sun;Zhi-Qiang Yu;Cai-Yuan Pan

Macromolecular Rapid Communications 2012 Volume 33( Issue 9) pp:811-818

Publication Date(Web):

DOI:10.1002/marc.201100876

Abstract

A novel nanocontainer, which could regulate the release of payloads, has been successfully fabricated by attaching zwitterionic sulfobetaine copolymer onto the mesoporous silica nanoparticles (MSNs). RAFT polymerization is employed to prepare the hybrid poly(2-(dimethylamino)ethyl methacrylate)-coated MSNs (MSN-PDMAEMA). Subsequently, the tertiary amine groups in PDMAEMA are quaternized with 1,3-propanesultone to get poly(DMAEMA-co-3-dimethyl(methacryloyloxyethyl)ammonium propanesulfonate)-coated MSNs [MSN-Poly(DMAEMA-co-DMAPS)]. The zwitterionic PDMAPS component endows the nanocarrier with biocompatibility, and the PDMAEMA component makes the copolymer shell temperature-responsive. Controlled release of loaded rhodamine B has been achieved in the saline solutions.

Formation of the block copolymer aggregates via polymerization-induced self-assembly and reorganization

Co-reporter:Jiao-Tong Sun, Chun-Yan Hong and Cai-Yuan Pan

Soft Matter 2012 vol. 8(Issue 30) pp:7753-7767

Publication Date(Web):01 Jun 2012

DOI:10.1039/C2SM25537E

The self-assembly of block copolymers attracts wide interest due to many potential applications of the polymeric aggregates. Great effort has been made to realize the convenient fabrication of abundant polymeric materials with well-defined nanostructures. This review introduces the development of the in situ preparation of block copolymer aggregates by heterogeneous polymerization. Great emphasis is put on discussing the formation mechanism of aggregates with different morphologies. Some important factors that influence the morphologies are illustrated when different polymerization methods are employed. By demonstrating some recent advances and existing problems in this area, more attention and effort should be paid to this field to facilitate its further progress.

Spiropyran-Based Hyperbranched Star Copolymer: Synthesis, Phototropy, FRET, and Bioapplication

Co-reporter:Ying Wang, Chun-Yan Hong, and Cai-Yuan Pan

Biomacromolecules 2012 Volume 13(Issue 8) pp:

Publication Date(Web):July 3, 2012

DOI:10.1021/bm3008346

Photo- and pH-responsive amphiphilic hyperbranched star copolymers, poly(6-O-methacryloyl-1,2;3,4-di-O-isopropylidene-d-galactopyranose)[poly(2-(N,N-dimethylaminoethyl) methacrylate)-co-poly(1′-(2-methacryloxyethyl)-3′,3′-dimethyl-6-nitro-spiro(2H-1-benzo-pyran-2,2′-indoline))]ns [HPMAlpGP(PDMAEMA-co-PSPMA)n], were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization of the DMAEMA and the SPMA using hyperbranched PMAlpGP as a macro RAFT agent. In aqueous solution, the copolymers self-assembled to form core–shell micelles with HPMAlpGP core and PDMAEMA-co-PSPMA shell. The hydrophobic fluorescent dye nitrobenzoxadiazolyl derivative (NBD) was loaded into the spiropyran-containing micelles. The obtained micelles not only have the photochromic properties, but also modulate the fluorescence of NBD through fluorescence resonance energy transfer (FRET), which was also observed in living cells. Slight fluorescence intensity decrease of the spiropyran in merocyanine (ME) form was observed after five UV–visible light irradiation cycles. The cytotoxicity of the HPMAlpGP(PDMAEMA-co-PSPMA)n micelles was lower than that of 25k PEI. All the results revealed that these photoresponsive nanoparticles are a good candidate for cell imaging and may find broad applications in biological areas such as biological diagnosis, imaging, and detection.

Selective Diels–Alder cycloaddition on semiconducting single-walled carbon nanotubes for potential separation application

Co-reporter:Jiao-Tong Sun, Lu-Yang Zhao, Chun-Yan Hong and Cai-Yuan Pan

Chemical Communications 2011 vol. 47(Issue 38) pp:10704-10706

Publication Date(Web):05 Sep 2011

DOI:10.1039/C1CC13437J

Selectivity for the Diels–Alder cycloaddition reaction of the electron-rich diene with single-walled carbon nanotubes was first investigated. This chemistry is a complete departure from the curvature-dependent reactivity based on the carbon pyramidalization angle.

Surface modification of carbon nanotubes with dendrimers or hyperbranched polymers

Co-reporter:Jiao-Tong Sun, Chun-Yan Hong and Cai-Yuan Pan

Polymer Chemistry 2011 vol. 2(Issue 5) pp:998-1007

Publication Date(Web):04 Jan 2011

DOI:10.1039/C0PY00356E

Carbon nanotubes (CNTs) are of increasing interest to scientists because of their unique electronic, chemical and mechanical properties. However, the poor solubility in solvents limits the manipulation of CNTs and hampers their applications in many promising fields. Surface modification of CNTs with polymers is an efficient method to solve this problem. In comparison with linear polymers, dendrimers and hyperbranched polymers are highly branched macromolecules with three-dimensional architecture, and they have good solubility, low melt viscosity, and extremely high density of functional groups at the surface. By surface modification with dendrimers or hyperbranched polymers, the solubility of CNTs could be improved greatly. Moreover, the resultant composites can be endowed with novel properties by further functionalization, which enlarges the applications of CNTs. This review makes emphasis on discussing the methods for functionalization of CNTs with dendrimers or hyperbranched polymers, meanwhile, the unique properties and potential applications of the resultant composites are also summarized in an attempt to facilitate the progress in this interesting area.

Synthesis and micellization of thermoresponsive galactose-based diblock copolymers

Co-reporter:Ying Wang;Xin Li;Chunyan Hong;Caiyuan Pan

Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 15) pp:3280-3290

Publication Date(Web):

DOI:10.1002/pola.24763

Abstract

Thermoresponsive double hydrophilic diblock copolymers poly(2-(2′-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol) methacrylate)-b-poly(6-O-methacryloyl-D-galactopyranose) (P(MEO₂MA-co-OEGMA)-b-PMAGP) with various compositions and molecular weights were obtained by deprotection of amphiphilic diblock copolymers P(MEO₂MA-co-OEGMA)-b-poly(6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-D-galactopyranose) (P(MEO₂MA-co-OEGMA)-b-PMAlpGP), which were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization using P(MEO₂MA-co-OEGMA) as macro-RAFT agent. Dynamic light scattering and UV–vis studies showed that the micelles self-assembled from P(MEO₂MA-co-OEGMA)-b-PMAlpGP were thermoresponsive. A hydrophobic dye Nile Red could be encapsulated by block copolymers P(MEO₂MA-co-OEGMA)-b-PMAGP upon micellization and released upon dissociation of the formed micelles under different temperatures. The galactose functional groups in the PMAGP block have specific interaction with HepG2 cells, and P(MEO₂MA-co-OEGMA)-b-PMAGP has potential applications in hepatoma-targeting drug delivery and biodetection. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Morphology transitions in RAFT polymerization

Co-reporter:Weimin Cai, Wenming Wan, Chunyan Hong, Chuanqun Huang and Caiyuan Pan

Soft Matter 2010 vol. 6(Issue 21) pp:5554-5561

Publication Date(Web):14 Sep 2010

DOI:10.1039/C0SM00284D

Polymerization-induced self-assembly and re-organization (PISR) was used to prepare polymeric nanostructured materials with a variety of morphologies. Reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene in a selective solvent, methanol, was carried out using cyanoisopropyl dithiobenzoate-terminated poly(2-dimethylaminoethyl methacrylate) (PDMAEMA-DBT) as the macro chain transfer agent and stabilizer for investigation of the factors influencing the formation of morphologies. Various morphologies, including spherical micelles, nanostrings, vesicles and large compound vesicles, with different shapes were obtained by changing the feed ratios and reaction conditions. The sequential morphologic transitions from spherical micelles to nanostrings, to vesicles and to large compound vesicles via increasing the chain length ratio of the hydrophobic block to the hydrophilic one in the same system were observed for the first time. This approach can be performed at a high concentration, thus it can be scaled up for the reproducible preparation of nanostructured materials in a relatively high volume.

Preparation and characterization of hyperbranched polymer grafted mesoporous silica nanoparticles via self-condensing atom transfer radical vinyl polymerization

Co-reporter:Xin Li, Chun-Yan Hong, Cai-Yuan Pan

Polymer 2010 Volume 51(Issue 1) pp:92-99

Publication Date(Web):6 January 2010

DOI:10.1016/j.polymer.2009.11.020

Hyperbranched poly(2-((bromobutyryl)oxy)ethyl acrylate) (HPBBEA) was grafted onto the exterior surface of mesoporous silica nanoparticles (MSNs) by surface-initiated self-condensing atom transfer radical vinyl polymerization (SCATRVP). The MSNs with ATRP initiator anchored on the exterior surface (MSN-Br) were prepared by the reaction of 5,6-dihydroxyhexyl-functionalized MSNs (MSN-OH) with α-bromoisobutyryl bromide. Afterwards, MSN-Br was utilized as initiator in the SCATRVP of inimer BBEA, resulting in core–shell nanoparticles with MSN core and HPBBEA shell (MSN-g-HPBBEA). The molecular weight of HPBBEA increased with the increasing ratio of BBEA to MSN-Br. In view of the high density of bromoester groups on the surface of HPBBEA shell, MSN-HPBBEA was used to initiate the successive polymerization of (2-dimethylamino-ethylmethacrylate) (DMAEMA), forming core–shell nanoparticles MSN-g-HPBBEA-g-PDMAEMA. The resultant products were characterized by FT-IR, NMR, HRTEM and thermogravimetric analysis (TGA), etc. The pH-responsive property of MSN-g-HPBBEA-g-PDMAEMA was characterized by measuring the hydrodynamics radius at different pH values, and this core–shell nanostructure may have potential applications in biomedicine and biotechnology.

Preparation of Photoluminescent Nanorings with Controllable Bioreducibility and Stimuli-Responsiveness

Co-reporter:Ye-Zi You Dr.;Zhi-Qiang Yu;Meng-Meng Cui Dr.

Angewandte Chemie International Edition 2010 Volume 49( Issue 6) pp:1099-1102

Publication Date(Web):

DOI:10.1002/anie.200906707

Fabrication of smart nanocontainers with a mesoporous core and a pH-responsive shell for controlled uptake and release

Co-reporter:Chun-Yan Hong, Xin Li and Cai-Yuan Pan

Journal of Materials Chemistry A 2009 vol. 19(Issue 29) pp:5155-5160

Publication Date(Web):09 Jun 2009

DOI:10.1039/B820534E

A facile and versatile method to prepare mesoporous core-shell nanostructures with a reversibly switchable nanoshell is reported. Reversible addition-fragmentation chain transfer (RAFT) functionalities were anchored to the exterior surface of mesoporous silica nanoparticles (MSNs), forming RAFT agent coated MSNs. RAFT polymerization was then conducted to graft a poly(acrylic acid) (PAA) shell onto the exterior surface of MSNs, producing novel smart nanocontainers with a MSN as the container and a pH-responsive PAA nanoshell as a smart nanovalve. The PAA nanovalve can control the access of guest molecules to and from the MSN nanocontainer. This core-shell nanostructure should have potential applications in drug and gene delivery.

Functionalized carbon nanotubes responsive to environmental stimuli

Co-reporter:Chun-Yan Hong and Cai-Yuan Pan

Journal of Materials Chemistry A 2008 vol. 18(Issue 16) pp:1831-1836

Publication Date(Web):08 Feb 2008

DOI:10.1039/B713559A

Carbon nanotubes (CNTs) have many potential applications in biological and biomedical sciences as nanoscale probes and sensors, which need CNTs to be able to respond to biologically relevant stimuli, such as pH, temperature, glucose, glutathione, various ions, enzymes and proteins, etc. This highlight examines several representative CNTs responsive to pH, temperature, glucose, ions and DNA, covering both noncovalently and covalently functionalized CNTs for advanced biosensors and bioprobes.

Smart Core−Shell Nanostructure with a Mesoporous Core and a Stimuli-Responsive Nanoshell Synthesized via Surface Reversible Addition−Fragmentation Chain Transfer Polymerization

Co-reporter:Chun-Yan Hong ; Xin Li ;Cai-Yuan Pan

The Journal of Physical Chemistry C 2008 Volume 112(Issue 39) pp:15320-15324

Publication Date(Web):September 9, 2008

DOI:10.1021/jp805028z

A facile and versatile method to prepare mesoporous core−shell nanostructure with a stimuli-responsive nanoshell was reported. Reversible addition−fragmentation chain transfer (RAFT) functionalities were anchored to the mesoporous silica nanoparticle (MSN), and RAFT polymerization of N-isopropylacrylamide (NIPAAm) was subsequently conducted to graft thermo-sensitive PNIPAAm to the exterior surface of the MSN. The nanoshell undergoes reversible switches between solvated, incompact nanoshell and compact nanoshell upon changing the temperature of the solution, which makes this novel core−shell nanostructure highly attractive for controlled release of drugs, DNAs, and proteins.

Functionalized multi-walled carbon nanotubes with poly(N-(2-hydroxypropyl)methacrylamide) by RAFT polymerization

Co-reporter:Chun-Yan Hong;Ye-Zi You;Cai-Yuan Pan

Journal of Polymer Science Part A: Polymer Chemistry 2006 Volume 44(Issue 8) pp:2419-2427

Publication Date(Web):2 MAR 2006

DOI:10.1002/pola.21341

In this study, we grafted water-soluble biocompatible polymer, poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA), onto the surface of multi-walled carbon nanotubes (MWNTs). The reversible addition-fragmentation chain transfer (RAFT) agents, dithioesters, were successfully immobilized onto the surface of MWNTs first, PHPMA chains were then subsequently grafted onto MWNTs via RAFT polymerization by using dithioesters immobilized on MWNTs as RAFT agent. FTIR, XPS, ¹H NMR, Raman and TGA were used to characterize the resulting products and to determine the content of water-soluble PHPMA chains in the product. The MWNTs grafted with PHPMA chains have good solubility in distilled water, PBS buffer, and methanol. TEM images of the samples provide direct evidence for the formation of a nanostructure that MWNTs coated with polymer layer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2419–2427, 2006

Dendrimer-star polymer and block copolymer prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization with dendritic chain transfer agent

Co-reporter:Chun-Yan Hong;Ye-Zi You;Jun Liu;Cai-Yuan Pan

Journal of Polymer Science Part A: Polymer Chemistry 2005 Volume 43(Issue 24) pp:6379-6393

Publication Date(Web):28 OCT 2005

DOI:10.1002/pola.21098

A new reversible addition-fragmentation chain transfer (RAFT) agent, dendritic polyester with 16 dithiobenzoate terminal groups, was prepared and used in the RAFT polymerization of styrene (St) to produce star polystyrene (PSt) with a dendrimer core. It was found that this polymerization was of living characters, the molecular weight of the dendrimer-star polymers could be controlled and the polydispersities were narrow. The dendrimer-star block copolymers of St and methyl acrylate (MA) were also prepared by the successive RAFT polymerization using the dendrimer-star PSt as macro chain transfer agent. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6379–6393, 2005

Synthesis of a Dendritic Core–Shell Nanostructure with a Temperature-Sensitive Shell

Co-reporter:Y.-Z. You;C.-Y. Hong;C.-Y. Pan;P.-H. Wang

Advanced Materials 2004 Volume 16(Issue 21) pp:

Publication Date(Web):30 NOV 2004

DOI:10.1002/adma.200400362

Temperature-sensitive core–shell nanostructures are synthesized by functionalizing a hydroxyl-terminated dendrimer with a reversible addition-fragmentation chain transfer (RAFT) polymerization chain-transfer agent. RAFT polymerization of N-isopropylacrylamide produces a shell around the dendrimer (see Figure). In aqueous solution, changing the temperature by 10 °C can reversibly open and close the poly(N-isopropylacrylamide) shell. Entrapment and temperature-induced liberation of pyrene from the nanostructures is demonstrated.

Circularly polarized light triggered enantioselective thiol–ene polymerization reaction

Co-reporter:Guang Yang, Yang Y. Xu, Zi D. Zhang, Long H. Wang, Xue H. He, Qi J. Zhang, Chun Y. Hong and Gang Zou

Chemical Communications 2017 - vol. 53(Issue 10) pp:NaN1738-1738

Publication Date(Web):2017/01/13

DOI:10.1039/C6CC09256J

Herein, circularly polarized light is utilized to trigger an enantioselective polymerization reaction, resulting in the synthesis of an optically active polymer from racemic monomers in the absence of any chiral dopant or catalyst.

The photo-controlled polymerization-induced self-assembly and reorganization process for fabrication of polymeric nanomaterials

Co-reporter:Jiemei Zhou, Chunyan Hong and Caiyuan Pan

Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 6) pp:NaN1206-1206

Publication Date(Web):2017/01/24

DOI:10.1039/C6QM00380J

A visible light mediated reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) is conducted in ethanol using poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) as a macro-chain transfer agent (macro-CTA), affording polymeric nanomaterials with various morphologies. Unlike the polymerization-induced self-assembly and reorganization (PISR) process initiated by thermal stimuli, the photo-controlled PISR can be performed under more mild conditions, such as visible light and room temperature. Photoredox catalysis is employed to regulate the polymerization via a photoinduced electron transfer (PET) process. It is observed that the polymerization can be affected by catalyst concentration and light intensity, and “ON/OFF” control over polymerization is also demonstrated.

Functionalized carbon nanotubes responsive to environmental stimuli

Co-reporter:Chun-Yan Hong and Cai-Yuan Pan

Journal of Materials Chemistry A 2008 - vol. 18(Issue 16) pp:NaN1836-1836

Publication Date(Web):2008/02/08

DOI:10.1039/B713559A

Carbon nanotubes (CNTs) have many potential applications in biological and biomedical sciences as nanoscale probes and sensors, which need CNTs to be able to respond to biologically relevant stimuli, such as pH, temperature, glucose, glutathione, various ions, enzymes and proteins, etc. This highlight examines several representative CNTs responsive to pH, temperature, glucose, ions and DNA, covering both noncovalently and covalently functionalized CNTs for advanced biosensors and bioprobes.

Fabrication of smart nanocontainers with a mesoporous core and a pH-responsive shell for controlled uptake and release

Co-reporter:Chun-Yan Hong, Xin Li and Cai-Yuan Pan

Journal of Materials Chemistry A 2009 - vol. 19(Issue 29) pp:NaN5160-5160

Publication Date(Web):2009/06/09

DOI:10.1039/B820534E

A facile and versatile method to prepare mesoporous core-shell nanostructures with a reversibly switchable nanoshell is reported. Reversible addition-fragmentation chain transfer (RAFT) functionalities were anchored to the exterior surface of mesoporous silica nanoparticles (MSNs), forming RAFT agent coated MSNs. RAFT polymerization was then conducted to graft a poly(acrylic acid) (PAA) shell onto the exterior surface of MSNs, producing novel smart nanocontainers with a MSN as the container and a pH-responsive PAA nanoshell as a smart nanovalve. The PAA nanovalve can control the access of guest molecules to and from the MSN nanocontainer. This core-shell nanostructure should have potential applications in drug and gene delivery.

Fabrication and characterization of silica nanotubes with controlled dimensions

Co-reporter:Wen-Jian Zhang, Chun-Yan Hong and Cai-Yuan Pan

Journal of Materials Chemistry A 2014 - vol. 2(Issue 21) pp:NaN7828-7828

Publication Date(Web):2014/04/15

DOI:10.1039/C4TA00465E

Silica nanotubes with controlled diameters and lengths were fabricated by a template-directed method. Nanowires composed of poly(2-dimethylaminoethyl methacrylate)-block-polystyrene (PDMAEMA–PS), which were fabricated by RAFT dispersion polymerization of styrene in methanol using PDMAEMA as a macro-RAFT agent, were used as sacrificial templates. The diameter of the polymeric nanowires can be adjusted by changing the degree of polymerization (DP) of the hydrophilic PDMAEMA block. As the chain length of the hydrophilic PDMAEMA block increases, the DP of the PS block for formation of the nanowires increases, leading to the diameter increase of the corresponding nanowires. Moreover, the polymeric nanowires with controlled lengths and diameters of the core and the shell can be fabricated on a large scale through polymerization-induced self-assembly and reorganization, conveniently. The weak polyelectrolyte, PDMAEMA shell, is an ideal nanoreactor for deposition of silica to form hybrid nanowires. Silica nanotubes were prepared by calcination of the hybrid nanowires.

Bioreducible nanogels/microgels easily prepared via temperature induced self-assembly and self-crosslinking

Co-reporter:Zhi-Qiang Yu, Jiao-Tong Sun, Cai-Yuan Pan and Chun-Yan Hong

Chemical Communications 2012 - vol. 48(Issue 45) pp:NaN5625-5625

Publication Date(Web):2012/03/29

DOI:10.1039/C2CC30908D

A facile temperature induced self-assembly and self-crosslinking method has been developed for preparing bioreducible nanogels/microgels without need of any stabilizer, catalyst or additional crosslinking agent. The size of formed nanogels/microgels can be easily tuned via the polymer concentration.

Selective Diels–Alder cycloaddition on semiconducting single-walled carbon nanotubes for potential separation application

Co-reporter:Jiao-Tong Sun, Lu-Yang Zhao, Chun-Yan Hong and Cai-Yuan Pan

Chemical Communications 2011 - vol. 47(Issue 38) pp:NaN10706-10706

Publication Date(Web):2011/09/05

DOI:10.1039/C1CC13437J

Selectivity for the Diels–Alder cycloaddition reaction of the electron-rich diene with single-walled carbon nanotubes was first investigated. This chemistry is a complete departure from the curvature-dependent reactivity based on the carbon pyramidalization angle.

Unimolecular micelles of camptothecin-bonded hyperbranched star copolymers via β-thiopropionate linkage: synthesis and drug delivery

Co-reporter:Liang Qiu, Qing Liu, Chun-Yan Hong and Cai-Yuan Pan

Journal of Materials Chemistry A 2016 - vol. 4(Issue 1) pp:NaN151-151

Publication Date(Web):2015/12/02

DOI:10.1039/C5TB01905B

In order to develop pH- and redox-responsive unimolecular micelles composed of camptothecin (CPT)-conjugated hyperbranched star copolymers via acid-labile β-thiopropionate linkage, a new monomer, methacryloyloxy-3-thiohexanoyl–CPT, is synthesized through conjugation of CPT with methacrylate via β-thiopropionate linkage, and then used in synthesis of the CPT-conjugated hyperbranched star copolymers by two steps of atom transfer radical polymerization (ATRP): self-condensation vinyl polymerization of the CPT-based monomer, 2-hydroxypropyl methacrylate and inimer, and subsequent ATRP of oligo(ethylene glycol) methacrylate using the obtained hyperbranched polymers as the macroinitiator. The obtained polymers dissolve in water to form unimolecular micelles, and their release of CPT in water at various pHs and their anticancer efficacy are studied. The CPT-loaded unimolecular micelles with diameters of 3.56–6.08 nm are quite stable under neutral environment, and are easily triggered by mild acidic pH, such as 6.0 and 5.0. They can be easily internalized by the tumor cells, releasing the CPT. The CPT-conjugated unimolecular micelles via acid-labile β-thiopropionate linkage have potential for application as tumor-targeted drug release systems.

TOPICS

Abstract

Abstract