Co-reporter:Yan Wang;Jianghu Liang;Minhao Zou
RSC Advances (2011-Present) 2017 vol. 7(Issue 19) pp:11691-11700
Publication Date(Web):2017/02/13
DOI:10.1039/C6RA28456F
A well-defined β-cyclodextrin-core star copolymer with Y-shaped ABC miktoarms, star poly(ethyl methacrylate(-b-poly(2-(diethylamino)ethyl methacrylate)-b-methoxypolyethylene glycols (CD-star-PEMA(-b-PDEA)-b-mPEG), was designed and synthesized via ATRP and click reactions. The copolymer could exhibit unimolecular micelles in aqueous solution. The micelles were characterized by means of DLS, 1H NMR and TEM measurements. In the micelles the PEMA blocks work as a container for storing hydrophobic guest molecules, the mPEG is used as a hydrophilic block, and the PDEA block can respond to change in environmental pH. By using Nile red, celecoxib, and ketoprofen as hydrophobic model drugs, encapsulation and release behaviors of the unimolecular micelles were investigated. It was found that the unimolecular container is a good platform for encapsulating hydrophobic guest molecules. Release of the payload from the unimolecular micelles exhibited pH-sensitivity.
Co-reporter:Luying Niu, Yuyang Liu, Yu Hou, Wenqi Song and Yan Wang
Polymer Chemistry 2016 vol. 7(Issue 20) pp:3406-3415
Publication Date(Web):25 Apr 2016
DOI:10.1039/C6PY00560H
Three kinds of well-defined star triblock copolymers poly(methyl methacrylate)-b-poly(2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol)methyl ether methacrylate) based on a cyclodextrin core, CD-(PMMA63-b-PDEA15-b-PPEGMA9)21 (STBP1), CD-(PMMA63-b-PDEA15-b-PPEGMA14)21 (STBP2) and CD-(PMMA63-b-PDEA20-b-PPEGMA17)21 (STBP3), were designed and synthesized by the core-first ATRP method. The star triblock copolymers have low critical aggregation concentration values in aqueous solutions. Self-assemblies with different morphologies were obtained from the star triblock copolymers. STBP1 could directly self-assemble into micelles in pure water. Unexpectedly, the surrounding pH could induce micelle/vesicle morphology transition of the original STBP1 micelles. The transition was attributed to PDEA moieties responsive to the pH change instead of reassembly. But the pH variation had less influence on the morphologies of the vesicles self-assembled from STBP2. Using doxorubicin (DOX) as a model guest molecule, loading capacities of the star copolymer aggregates and the influence of the presence of the guest molecules on the morphologies of the aggregates were investigated. It was found that the drug loading capacities depended on the compositions of the star copolymers and the feed drug/copolymer ratio. The star polymer with high hydrophilic content showed high drug loading capacity. The DOX release from the loaded self-assemblies was pH tunable.
Co-reporter:Jie Zhu;Liqun Xiao ;Ping Zhou
Macromolecular Chemistry and Physics 2016 Volume 217( Issue 6) pp:773-782
Publication Date(Web):
DOI:10.1002/macp.201500449
Co-reporter:Ping Zhou, Yu-Yang Liu, Lu-Ying Niu and Jie Zhu
Polymer Chemistry 2015 vol. 6(Issue 15) pp:2934-2944
Publication Date(Web):23 Feb 2015
DOI:10.1039/C4PY01804D
We herein report a well-defined six-armed star triblock copolymer poly(2-(diethylamino)ethyl methacrylate)-b-poly(methyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (s-(PDEA62-b-PMMA195-b-PPEGMA47)6) that was synthesized by the core-first ATRP (atom transfer radical polymerization) method. The star triblock copolymer has low critical aggregation concentration (CAC) values in aqueous solutions (0.78–2.5 mg L−1) and shows pH-tunable self-assembly behavior. It could self-assemble into multicompartment micelles at pH 10.5, vesicles at pH 7.4 and micelles at pH 2.0. Regardless of micelles or vesicles, their hydrodynamic diameter (Dh) could respond to the change in environmental pH. Interestingly, the reversible vesicle–micelle transition could be achieved via simply adjusting the surrounding pH. The transition was a result of PDEA moieties being responsive to the pH change instead of reassembly. Using the hydrophobic drug celecoxib as a model guest molecule, loading capacities of the star copolymer aggregates under the above-mentioned three pH conditions and the influence of the presence of the guest molecules on the morphology of the aggregates were investigated. It was found that loading capacities of the star copolymer were 33–35 wt% (relative to the polymer) at pH 7.4, 26–28 wt% at pH 10.5 and 10–15 wt% at pH 2.0, and at pH 7.4, incorporation of 33 wt% celecoxib did not change the morphology of vesicles evidently. However, at pH 10.5, the presence of 26 wt% celecoxib could lead to self-assembly of the star copolymer into vesicles. The celecoxib release from the loaded self-assemblies is pH tunable.
Co-reporter:Yu-Yang Liu;Song Lan ;Li-Qun Xiao
Macromolecular Chemistry and Physics 2015 Volume 216( Issue 7) pp:749-760
Publication Date(Web):
DOI:10.1002/macp.201400538
Co-reporter:Yong Cai ;Yu-Yang Liu
Macromolecular Chemistry and Physics 2013 Volume 214( Issue 8) pp:882-891
Publication Date(Web):
DOI:10.1002/macp.201200598
Co-reporter:Wei-Qing Liu, Yu-Yang Liu, Xiao-Qing Liao, Wei Tian
Materials Science and Engineering: C 2012 Volume 32(Issue 4) pp:953-960
Publication Date(Web):1 May 2012
DOI:10.1016/j.msec.2012.02.001
Drug release behavior of a hydrogel is related to its transport mechanism, which is dominated by structure of the hydrogel. Therefore, we prepared pH-sensitive poly(4-vinylpyridine) (P4VP) hydrogels with hyperbranched poly(4-vinylbenzyl chloride) (PVBC; Mn = 2391 g/mol, PDI = 1.87, the minimum percent linearity = 12.4%) moieties (P4VP-PVBC) by atom transfer radical polymerizations (ATRP) in two steps. A PVBC moiety provides the hydrogel with a microenvironment, which may encapsulate guest molecules like drug. The presence of the microenvironment could affect drug transport in the hydrogel matrices. To understand this, we used Ftorafur as drug molecule, and investigated release behavior of the P4VP-based hydrogels. Diffusion and transport mechanism of Ftorafur in the P4VP-based hydrogels was analyzed by early-time and late-time approximation diffusion coefficients. It was found that the transport behavior of Ftorafur was related to the presence of the PVBC moiety and external pH. The presence of the PVBC moiety could sustain release of Ftorafur.Highlights► pH-sensitive P4VP hydrogels with hyperbranched PVBC moieties was prepared by ATRP. ► The PVBC moieties may encapsulate guest molecules like drug. ► Diffusion and transport mechanism of Ftorafur in the P4VP hydrogels was analyzed. ► The presence of PVBC moieties could sustain release of Ftorafur from the hydrogel.
Co-reporter:Yu-Yang Liu, Yao-Bing Zhong, Jiang-Kun Nan, and Wei Tian
Macromolecules 2010 Volume 43(Issue 24) pp:10221-10230
Publication Date(Web):November 23, 2010
DOI:10.1021/ma1019973
We designed and synthesized novel star poly(N-isopropylacrylamide) (star-PNIPAm) and star-PNIPAm with cyclodextrin (CD) end groups (star-PNIPAm-CD) by atom transfer radical polymerization (ATRP). In the synthesis, β-CD-core with 21 initiation sites, heptakis[2,3,6-tri-O-(2-chloropropionyl)]-β-cyclodextrin (21Cl-β-CD), was first synthesized by the reaction of β-CD with 2-chloropropionyl chloride (CPC). Then, 21-arm star-PNIPAm (PDI = 1.03) was synthesized by ATRP of N-isopropylacrylamide (NIPAm) initiated via 21Cl-β-CD. Finally, a star-PNIPAm-CD (PDI = 1.02) was synthesized by ATRP of a monovinyl β-CD (GMA-EDA-β-CD) initiated via star-PNIPAm. The obtained star-PNIPAm and star-PNIPAm-CD were characterized by means of SEC/MALLS, NMR, IR, and DSC. By using 8-anilino-1-naphthalenesulfonic acid ammonium salt hydrate (ANS), 1-adamantanamine hydrochloride (ADA-NH3Cl), and ibuprofen sodium salt (ibuprofen-Na) as guest molecules, thermal sensitivity and inclusion behaviors of the star polymers were investigated by fluorescence spectrophotometer and DLS. It is found that the star polymers can combine both thermal sensitivity of PNIPAm and inclusion behavior of β-CD. Interestingly, the star polymers can self-assembly to form nanosized aggregates in aqueous solution above their LCSTs. The self-assembly behavior shows molecular recognition capability. And formation and dissociation of the nanosized aggregation can change reversibly by changing temperature above and below the LCST.
Co-reporter:Yu-Yang Liu;Xia Su;Min-Feng Tang;Jie Kong
Macromolecular Chemistry and Physics 2007 Volume 208(Issue 4) pp:415-422
Publication Date(Web):22 FEB 2007
DOI:10.1002/macp.200600400
Using ethyl acrylate and methyl methacrylate as hydrophobic monomers, a series of hydrophobic nanoparticle dispersions were prepared by one-step polymerization (i.e., soap-free batch emulsion polymerization). To obtain stable aqueous nanoparticle dispersions, a small amount of ionic comonomer, sodium 4-ω-acryloyloxy-β-hydroalkyl sulfonate (Cops-1) was used. The nanoparticles were characterized by TEM, Zetasizer and DSC. It was found that number average diameter () values range from 144 to 202 nm at 25 °C, and the diameter distribution () from 1.11 to 1.14. These results indicate that the nanoparticles show a narrow distribution of sizes. Zeta potentials of the obtained nanoparticles are in range of −38.8 to −29.7 mV at 25 °C. This suggests that they can be well dispersed in water. Using salicylic acid (SA) as model drug molecules, a novel swelling method was developed for loading SA into the nanoparticles in an aqueous dispersion state, and both related loading processes and controlled release behavior were investigated. It was found that the nanoparticles can sustain SA release, and compared to different types of nanoparticles, PMMA nanoparticles can retard SA release more effectively.
Co-reporter:Yu-Yang Liu;Jian Lü;Ying-Hui Shao
Macromolecular Bioscience 2006 Volume 6(Issue 6) pp:452-458
Publication Date(Web):7 JUN 2006
DOI:10.1002/mabi.200600007
Summary: In order to investigate the influence of hydrophobic moieties formed by poly(N-isopropylacrylamide) (PNIPAm) in a hydrogel matrix on the release behavior of the hydrogel, a series of poly(N-isopropylacrylamide) (PNIPAm)-modified poly(2-hydroxyethyl acrylate-co-2-hydroxyethyl 2-hydroxyethyl methacrylate) (P(HEA-co-HEMA)) via interpenetrating polymer networks (IPNs) were prepared by a sequential UV solution polymerization. Interestingly, it was found that P(HEA-co-HEMA)/PNIPAm IPN indicated a single glass transition temperature (Tg) and the Tgs of the IPNs increased with an increase in the PNIPAm component. This phenomenon may be attributed to hydrogen bonding between the two polymer networks, but the hydrogen bonding exerts less influence on the swelling behavior of the IPNs, due to the fact that IPNs can respond to changes in temperature like PNIPAm. Using 2-[(diphenylmethyl)sulphiny]acetamide (modafinil, MOD) and p-hydroxybenzoic acid (HBA) as model drug compounds, the release behavior of the IPNs was studied at body temperature, and it was found that the presence of PNIPAm could retard drug release regardless of the solubility of the drugs.
Co-reporter:Yu-Yang Liu, Ying-Hui Shao, Jian Lü
Biomaterials 2006 Volume 27(Issue 21) pp:4016-4024
Publication Date(Web):July 2006
DOI:10.1016/j.biomaterials.2006.02.042
Two pH-induced thermosensitive amphiphilic gels for controlled drug release were constructed with thermosensitive poly(N-isopropylacrylamide) (PNIPAm) and hydrophobic poly(ethyl acrylate) (PEA) by interpenetrating polymer network (IPN) technology. To obtain pH-induced thermosensitive functionality at physiological temperature, 5 mol% of acrylic acid (AAc) and N, N-dimethyl aminoethyl methacrylate (DMA) were incorporated into PNIPAm chain by their copolymerization. It is found that the IPN hydrogels show pH-induced thermosensitivity at physiological temperature. When the amphiphilic gels with IPN structure were immersed in water, the hydrophobic moieties formed by PEA have the potential to act as reservoirs for hydrophobic drugs, from which drug may be released slowly. Using drug daidzein (DAI) as a model molecule, controlled release behaviors of the IPNs were investigated. It is found that the presence of permanently hydrophobic PEA network can indeed slow the release rate of DAI and to some extent overcome disadvantageous burst effect of PNIPAm-based networks in hydration state. The release kinetics of DAI from the IPNs seems to follow pseudo-zero-order release character, regardless of the hydrogels in swollen or shrunken state.
