Polymer Chemistry
·
2015
·Vol. 6
·期 12
·2274-2282
·
IF 5.52
Weiwei Zhang,Weiwei Jiang,Delong Zhang,Guangyue Bai,Pengxiao Lou,Zhiguo Hu
Two new amphiphilic linear-dendritic block copolymers (LDBCs) composed of poly(ethylene oxide) (PEO) and a dendron derived from 2,2′-bis(hydroxymethyl)propionic acid (bis-MPA), PEO(5k)-b-G3-(C18H35O2)8 and PEO(5k)-b-G3-(C2H3O2)8 were synthesized by click chemistry. The structures of the LDBCs were determined by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). Furthermore, their aggregation behaviors at 298.15 K for these two synthesized polymers were studied by fluorescence spectroscopy and isothermal titration calorimetry (ITC). The fluorescence measurements indicate that both of the synthesized polymers have evident aggregation behavior in aqueous solution due to the significant hydrophobic interactions between the branched groups. Thus we characterized the thermodynamics of their aggregation by ITC and obtained their critical micelle concentrations (CMC), as well as the positive enthalpy of micellization for (PEO(5k)-b-G3-(C18H35O2)8), which suggests that its molecular self-assembly process is entropy-driven. Furthermore, the micellar morphologies of the copolymers in aqueous solution were verified by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The spherical polymeric micelles of PEO(5k)-b-G3-(C18H35O2)8 and PEO(5k)-b-G3-(C2H3O2)8 were observed and their diameters are 70 nm and 160 nm, respectively. The length of the alkyl chain of the periphery carboxylic acid affects their CMCs and the size of micelles. Finally, the biocompatibility of both LDBCs was evaluated, and they were found to have relatively low cytotoxicity, which provides potential opportunities for a variety of biomedical applications.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2015
·Vol. 38
·期 4
·683-689
·
IF 2.737
Li Liu,Xin Zhou,Chun Wang,Qiuhua Wu,Zhi Wang
A novel microextraction method, ordered mesoporous carbon reinforced hollow fiber liquid-phase microextraction coupled with high-performance liquid chromatography and fluorescence detection, was developed for the determination of some organic pollutants in water samples. Four polycyclic aromatic hydrocarbons (fluorene, anthracene, fluoranthene, and pyrene) were selected to validate this new method. Main parameters that could influence the extraction efficiency such as extraction time, fiber length, stirring rate, the type of the extraction solvent, pH value, the concentration of ordered mesoporous carbon, and salt effect were optimized. Under the optimal extraction conditions, good linearity was observed in the range of 2–1000 ng/L, with the correlation coefficients of 0.9954–0.9986. The recoveries for the spiked samples were in the range of 88.96–100.17%. The limits of detection of the method were 0.4–4 ng/L. The relative standard deviations varied from 4.2–5.9%. The results demonstrated that the newly developed method was an efficient pretreatment and enrichment procedure for the determination of polycyclic aromatic hydrocarbons in environmental water samples.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE
·
2013
·Vol. 24
·期 9
·2093-2100
·
IF 2.141
Guo Rui,Chen Lili,Cai Shushan,Liu Zonghua,Zhu Yi,Xue Wei,Zhang Yuanming
Polysaccharides based polyelectrolyte complex nanoparticles (PCNs) intended for use in the delivery of macromolecules were prepared by the self-assembly of deoxycholic acid hydrophobically modified chitosan (CS-DCA) core and then coated with sodium alginate (ALG) shell. The CS-DCA capable of forming nano-sized self-aggregates in medium was prepared by the grafting of DCA to CS. In order to increase the stability of nanoparticles and prevent burst release of drug in bloodstream, polyanionic ALG was coated on the surface of positively charged CS-DCA nanoparticles to form PCNs. Dynamic light scattering results revealed that the mean diameter of the PCNs was about 330 nm, larger than that of uncoated nanoparticles (~150 nm). The zeta potential was big enough to keep the stability of PCNs (−28 mV); no size change was found even upon 1 month storage. Bovine serum albumin could be easily incorporated into the PCNs with encapsulation efficiency (>44 %) and keep a sustained manner without burst release when exposed to PBS (pH 7.4) at 37 °C. These results suggested that PCNs may be a promising drug carrier for a prolonged and sustained delivery in the bloodstream.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2013
·
IF 4.612
Xingmei Guan,Chuande Zhao,Xiaoyan Liu,Haixia Zhang
A polymer monolith column was prepared using click chemistry for on-line solid phase microextraction of polycyclic aromatic hydrocarbons (PAHs), using 2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene(TES) and 1,4-bis(6-azidoalkoxy)benzene (BAB) as monomers, and Cu(PPh 3 ) 3 Br as the catalyst. The polymer with spirocyclic cross-links was porous and presented an appropriate interspace of PAHs. Enrichment of PAHs, in the range of 100 to more than 1000 times, was due to the π – π stacking interaction and the effect of small size. The factors affecting the on-line microextraction efficiency were optimized, and the analytical conditions were evaluated to ensure reliability.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHYSICAL CHEMISTRY B
·
2013
·
IF 3.607
Jingjing Li,Kaiqi Fan,Libo Niu,Yuanchao Li,Jian Song
The effect of salt on the gelatinization of 2,4-(3,4-dichlorobenzylidene)-d-sorbitol (DCBS), a novel low-molecular-weight gelator, was studied. DCBS showed pronounced hydrogelation and the electron micrographs indicated that the hydrogels consists of globular aggregates. Addition of NaCl to the aqueous medium accelerated the gelation process and also caused the gel’s morphology to change from globular to long fibers. In addition, the thermal properties of the hydrogels were improved with the addition of NaCl. UV–vis and fluorescence emission spectra showed that extensive aggregation of the phenyl rings was responsible for the gelation. The presence of NaCl induced a red shift in the emission peaks of DCBS and a decrease of the pyrene polarity index I1/I3 in the gels, which indicated that there was more π–π stacking in the hydrogels with NaCl than in the gels without NaCl. Variable-temperature 1H NMR spectra further demonstrated that the π–π interactions were enhanced by NaCl. FTIR studies showed that hydrogen bonding was also a contributing factor in the gelation process. Wide-angle X-ray diffraction (WXRD) showed that the hydrogels had a layered structure which did not change with the addition of NaCl. Density functional theory (DFT) calculations indicated the possible molecular packing of the gelator in the nanofibers.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2015
·
IF 3.545
Qing Wang,Yao Long,Lin Yao,Li Xu,Zhi-Guo Shi,Lanying Xu
A mixed-mode chromatographic stationary phase , C18-DTT (dithiothreitol) silica (SiO 2 ) was prepared through “thiol-ene” click chemistry. The obtained material was characterized by fourier transform infrared spectroscope, nitrogen adsorption analysis and contact angle analysis. Chromatographic performance of the C18-DTT was systemically evaluated by studying the effect of acetonitrile content, pH, buffer concentration of the mobile phase and column temperature. It was demonstrated that the novel stationary phase possessed reversed phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode property. The stop-flow test revealed that C18-DTT exhibited excellent compatibility with 100% aqueous mobile phase. Additionally, the stability and column-to-column reproducibility of the C18-DTT material were satisfactory, with relative standard deviations of retention factor of the tested analytes (verapamil, fenbufen , guanine , tetrandrine and nicotinic acid) in the range of 1.82–3.72% and 0.85–1.93%, respectively. Finally, the application of C18-DTT column was demonstrated in the separation of non-steroidal anti-inflammatory drugs, aromatic carboxylic acids , alkaloids, nucleo-analytes and polycyclic aromatic hydrocarbons . It had great resolving power in the analysis of various compounds in HILIC and RPLC chromatographic conditions and was a promising RPLC/HILIC mixed-mode stationary phase.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2015
·
IF 3
Xuemin Xiao,Dandan Liu,Yujun Yan,Zhilin Wu,Zhansheng Wu,Giancarlo Cravotto
Coal-based activated carbons (CAC) were prepared from coal in Xinjiang China by microwave-assisted activation. The effects of preparation conditions on adsorption capabilities of CAC for methylene blue (MB) and iodine were investigated. The microwave activation was carried out with coal activator ratio of 1:3 for 12 min at 700 W of power, the adsorption capacities of the prepared CAC achieved the maximal values of 312 and 1048.19 mg/g for MB and iodine. The increasing of CAR, activation time, and microwave power reduced the surface functional groups and improved the pH PZC of CAC. The BET surface area and total pore volume of CAC prepared were identified as 1770.49 m 2 /g and 0.99 cm 3 /g, respectively. Hence, the work demonstrates that the use of microwave heating for preparing CAC is more rapid, cheaper and efficient. The adsorption behaviors of typical polycyclic aromatic hydrocarbons (PAHs) in ethanol aqueous solution on CAC were also explored. Equilibrium data were favorably described by the Langmuir and Freundlich isotherms, and adsorption kinetics was fitted to the pseudo-second-order model well. The equilibrium adsorption amounts were 117.17 mg/g for pyrene, 111.39 mg/g for phenanthrene, and 78.18 mg/g for naphthalene. Thus, CAC prepared by microwave activation could have a very effective application in removal of these PAHs.
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 44
·35282-35290
·
IF 3.84
Si Chen,Guodong Tang,Bozhen Wu,Meng Ma,Xu Wang
The key effect of the self-assembly mechanism of dendritic gelators is researched by a comprehensive investigation of the gelation behavior of L-lysine dendritic gelators with different structures of three generations in 20 different solvents. The solvents investigation, 1H NMR, tube inversion method, DSC, rheology, FTIR and rheological measurements show that the reported dendritic gelators self-assemble through the main driving force of hydrogen bonds and the second driving force of π–π stackings. So the key effect of the self-assembling mechanism is that these factors can influence the driving force of the self-assembly process. This is the reason that L-lysine dendritic gelators tend to gelate in solvents with low α and β parameter values, which have less influence on the formation of hydrogen bonds between the gelators. Higher generations provide a much greater hydrogen bond density in the gelators, which makes them have a higher gelation ability. The benzyl terminal groups provide the second driving force of π–π stacking, making the Bzl-Gly-Lys gelators have much stronger gelation ability. This research reports a comprehensive insight into the precise ways in which the solubility parameters of the solvents, the gelator generation and the terminal group effects can influence the self-assembly and gelation of dendritic gelators. Gaining this type of fundamental understanding is essential if the key effect of this important class of self-assembling soft materials is to be truly understood.
✓ 已验证
产品关联
DOI
高影响因子
BIOMACROMOLECULES
·
2015
·
IF 5.75
Zhao Wang,Ting Luo,Ruilong Sheng,Hui Li,Jingjing Sun,Amin Cao
In this work, a series of diblock terpolymer poly(6-O-methacryloyl-d-galactopyranose)-b-poly(methacrylic acid-co-6-cholesteryloxy hexyl methacrylate) amphiphiles bearing attached galactose and cholesterol grafts denoted as the PMAgala-b-P(MAA-co-MAChol)s were designed and prepared, and these terpolymer amphiphiles were further exploited as a platform for intracellular doxorubicin (DOX) delivery. First, employing a sequential RAFT strategy with preliminarily synthesized poly(6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-d-galactopyranose) (PMAIpGP) macro-RAFT initiator and a successive trifluoroacetic acid (TFA)-mediated deprotection, a series of amphiphilic diblock terpolymer PMAgala-b-P(MAA-co-MAChol)s were prepared, and were further characterized by NMR, Fourier transform infrared spectrometer (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and a dynamic contact angle testing instrument (DCAT). In aqueous media, spontaneous micellization of the synthesized diblock terpolymer amphiphiles were continuously examined by critical micellization concentration assay, dynamic light scattering (DLS), and transmission electron microscopy (TEM), and the efficacies of DOX loading by these copolymer micelles were investigated along with the complexed nanoparticle stability. Furthermore, in vitro DOX release of the drug-loaded terpolymer micelles were studied at 37 °C in buffer under various pH conditions, and cell toxicities of as-synthesized diblock amphiphiles were examined by MTT assay. Finally, with H1299 cells, intracellular DOX delivery and localization by the block amphiphile vectors were investigated by invert fluorescence microscopy. As a result, it was revealed that the random copolymerization of MAA and MAChol comonomers in the second block limited the formation of cholesterol liquid-crystal phase and enhanced DOX loading efficiency and complex nanoparticle stability, that ionic interactions between the DOX and MAA comonomer could be exploited to trigger efficient DOX release under acidic condition, and that the diblock terpolymer micellular vector could alter the DOX trafficking in cells. Hence, these suggest the pH-sensitive PMAgala-b-P(MAA-co-MAChol)s might be further exploited as a smart nanoplatform toward efficient antitumor drug delivery.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2015
·
IF 2.358
Caixia Xu,Hongxiang Chen,Andong Xie,Hailun Chen,Yu Zhou,Yanjun Li,Minghua Yang
The rheological behavior of waterborne polyurethane dispersion (PUD) thickened by the hyperbranched waterborne polyurethane (HWPU) was studied by rheological measurements. The results showed that the flow activation energy depended on the structure and concentration of HWPU. Based on the relationship between the structure, concentration and flow activation energy, we could infer that during HWPU associating thickening process PUD experienced Duckweed state (appropriate HWPU-latex particles linker), 3D network structure (HWPU-latex particles three-dimensional network) or Bead-like texture (HWPU monomolecular micelles or multi-molecular micelles). The role of interaction between particles in the structure of thickening system was explored by dynamic light scattering, refraction analysis and fluorescence spectroscopy. The combination of hydrophobic groups of HWPU with latex particles resulted in associating thickening, while the intramolecular or intermolecular association of HWPU might lead to a decrease in thickening efficiency or no thickening.
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2015
·
IF 4.152
Man Li,Min Gao,Yunlan Fu,Chao Chen,Xuan Meng,Aiping Fan,Deling Kong,Zheng Wang,Yanjun Zhao
On-demand curcumin delivery via stimuli-responsive micellar nanocarriers holds promise for addressing its solubility and stability problem. Polymer-curcumin prodrug conjugate micelle is one of such nanosystems. The diversity of linker and conjugation chemistry enabled the generation and optimization of different curcumin micelles with tunable stimuli-responsiveness and delivery efficiency. The aim of the current work was to generate and assess acetal-linked polymeric micelles to enrich the pH-responsive curcumin delivery platforms. Curcumin was slightly modified prior to conjugating to amphiphilic methoxy poly(ethylene glycol)-poly(lactic acid) (mPEG-PLA) copolymer via an acetal bond, whereas an ester bond-linked conjugate was used as the control. The acetal-containing micelles showed a hydrodynamic diameter of 91.1 ± 2.9 (nm) and the accompanying core size of 63.5 ± 7.1 (nm) with a zeta potential of −10.9 ± 0.7 (mV). Both control and pH-labile micelles displayed similar critical micelle concentration at 1.6 μM. The acetal-containing nanocarriers exhibited a pH-dependent drug release behavior, which was faster at lower pH values. The cytotoxicity study in HepG2 cells revealed a significantly lower IC 50 at 51.7 ± 9.0 (μM) for acetal-linked micelles in contrast to the control at 103.0 ± 17.8 (μM), but the polymer residue showed no cytotoxicity upon drug release. The acetal-linked micellar nanocarrier could be a useful addition to the spectrum of currently available stimuli-responsive curcumin nano-formulations.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2015
·
IF 4.074
Wuxia Zhang,Dongqi Dong,Peng Li,Dongdong Wang,Haibo Mu,Hong Niu,Jinyou Duan
Polysialic acid (PSA), a non-immunogenic and biodegradable natural polymer, is prone to hydrolysis under endo-lysosomal pH conditions. Here, we synthesized an intracellular pH-sensitive polysialic acid-ursolic acid conjugate by a condensation reaction. To further test the drug loading capability, we prepared paclitaxel-loaded polysialic acid-based amphiphilic copolymer micelle (PTX-loaded-PSAU) by a nanoprecipitation method. Results showed PTX-loaded-PSAU exhibited well-defined spherical shape and homogeneous distribution. The drug-loading was 4.5% with an entrapment efficiency of 67.5%. PTX released from PTX-loaded-PSAU was 15% and 42% in 72 h under simulated physiological condition (pH 7.4) and mild acidic conditions (pH 5.0), respectively. In addition, In vitro cytotoxicity assay showed that PTX-loaded-PSAU retained anti-tumor (SGC-7901) activity with a cell viability of 53.8% following 72 h incubation, indicating PTX-loaded-PSAU could efficiently release PTX into the tumor cells. These results indicated that the pH-responsive biodegradable PTX-loaded-PSAU possess superior extracellular stability and intracellular drug release ability.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）