In this paper, double hydrophilic ionic liquid block copolymers （ILBCs）, poly poly[1-methyl-3-（2-methacryloyloxy propylimidazolium bromine）]-block-（N.isopro. pylacrylamide） （PMMPImB-b-PNIPAAm） was first synthe...In this paper, double hydrophilic ionic liquid block copolymers （ILBCs）, poly poly[1-methyl-3-（2-methacryloyloxy propylimidazolium bromine）]-block-（N.isopro. pylacrylamide） （PMMPImB-b-PNIPAAm） was first synthesized by reversible addition- fragmentation chain transfer （RAFT） and then attached on the surface of gold nanoparticles （Au NPs） via a strong gold-sulfur bonding for preparing hybrid nanoparticles （PMMPImB-b-PNIPAAm-@-Au NPs）. The hybrid NPs had a three layers micelle-like structure, including a gold core, thermo-responsive inner shell and anion responsive outer corona. The self-assembling behavior of thermal- and anion-response from shell and corona were respectively investigated by change of temperature and addition of （CF3SO2）2N-. The results showed the hybrid NPs retained a stable dispersion beyond the lower critical solution temperature （LCST） because of the space or electrostatic protecting by outer PMMPImBo However, with increasing concentration of （CF3SO2）2N-, the micellization of self-assembling PMMPImB-b-PNIPAAm-@-Au NPs was induced to form micellar structure containing the core with hydrophobic PMMPImB- （CF3SO2）2N- surrounded by composite shell of Au NPs-PNIPAAm via the anion- responsive properties of ILBCs. These results indicated that the block copolymers protected plasmonic nanoparticles remain self-assembling properties of block copoly- mers when phase transition from outer corona polymer.展开更多
In this work,zwitterionic polymer(polyzwitterion)coated nanodiamonds(ND)with tumorous pH responsiveness were prepared for efficient application of commercial NDS in tumor cells imaging.Poly(carboxybetaine methacrylate...In this work,zwitterionic polymer(polyzwitterion)coated nanodiamonds(ND)with tumorous pH responsiveness were prepared for efficient application of commercial NDS in tumor cells imaging.Poly(carboxybetaine methacrylate)was firstly grafted on the pristine NDS(PCBMA-@-NDs)by surface-initiated reversible addition-fragmentation chain transfer(RAFT)polymerization.To achieve pH responsiveness and activated interaction with tumor cells,PCBMA-@-NDs were subsequently modified with benzene sulfonamide(PCBSA-@-NDs)via one step carbodiimide chemistry.The surface polymer functionalization was characterized by FTIR,1H NMR and TGA,and PCBMA-@-NDs and PCBSA-@-NDs showed great dispersibility,enhanced fluorescence intensity and excellent antifouling property in contrast to pristine NDs.Moreover,PCBSA-@-NDs was able to switch zwitterionic surface(at pH 7.4)reversibly into positive charge(at pH 6.5)via protonated or deprotonated acylsulfonamide.As expected,PCBSA-@-NDS demonstrated higher cell affinity and better imaging performance than those of zwitterionic NDS at tumor slight acid environment,proven by fluorescence microscopy and flow cytometry.Overall,we provide a feasible and valuable strategy to construct smart NDS,thus encouraging the application of cost-effective fluorescence nanomater-ials in biomedical fields.展开更多
In this paper, double hydrophilic ionic liquid block copolymers （ILBCs）, poly（N-isopropylacrylamide）-block-poly[1-methyl-3-（2-methacryloyloxy propylimidazo- lium bromine）] （PNIPAM-b-PMMPImB）, were polymerized ...In this paper, double hydrophilic ionic liquid block copolymers （ILBCs）, poly（N-isopropylacrylamide）-block-poly[1-methyl-3-（2-methacryloyloxy propylimidazo- lium bromine）] （PNIPAM-b-PMMPImB）, were polymerized by two-step reversible addi- tion-fragmentation chain transfer （RAFT） process. The composition and molecular weight distributions of ILBCs were characterized using 1HNMR and gel permeation chromato- graphy （GPC）. The self-assembly and temperature- and anion-responsive behaviors of ILBCs were investigated by UV-Vis spectroscopy, TEM and dynamic light scattering （DLS）. With increasing the concentration of （CF3SO2）2N-, the micellization of self- assembling PNIPAM-b-PMMPImB was induced to form a core-shell structure containing the core with hydrophilic PMMPIm-（CF3SO2）2N- surrounded by the shell of PNIPAM via the anion-responsive properties of ILBCs. However, upon temperature increasing, PNIPAM-b- PMMPImB formed the micelles composing of PNIPAM core and PMMPImB shell. The ionic liquid segment with strong hydrophilic property enhanced the hydrogen bonding interaction which expanded the temperature range of phase transition and increased the lower critical solution temperature （LCST） of the system. These results indicate that ILBCs prepared in this paper have excellent temperature and anion double responsive properties, and may be applied as a kind of potential environmental responsive polymer nanoparticles.展开更多
An upswing in haze weather during autumn and winter has been observed over North and Northeast China in re- cent years, imposing adverse impacts upon local socioeconomic development and human health. However, such an ...An upswing in haze weather during autumn and winter has been observed over North and Northeast China in re- cent years, imposing adverse impacts upon local socioeconomic development and human health. However, such an increase in the occurrence of haze events and its association with natural climate variability and climate change are not well understood. To investigate the climatology of the meteorological factors associated with haze events and their natural variability, this study uses a meteorological pollution index called PLAM （Parameter Linking Air-qual- ity to Meteorological conditions） and ERA-Interim reanalysis data. The results suggest that high PLAM values tend to occur over southern parts of northem China, implying the weather conditions over this area are favorable for the occurrence of haze weather. For the period 1979-2014, the regional mean PLAM shows an overall increase across Beijing, Tianjin, and Hebei Province, and parts of Shanxi Province. Also, a periodicity of 28-34 months is found in the temporal variation of PLAM, which implies a potential association of PLAM with the stratospheric Quasi-Bian- nual Oscillation （QBO）. By using the QBO index during the autumn and winter seasons in the preceding year, an in- crease in PLAM is found for the westerly phases of the QBO, relative to the easterly phases. An upper-tropospheric warming is also found in the westerly phases, which can induce a stable stratification that favors the increase in PLAM across the midlatitudes. The modulations of large-scale environmental factors, including moist static stability, vertical velocity, and temperattu＇e advection, also act to enhance PLAM in the westerly phases. However, the baro- clinic term of moist potential vorticity at 700 hPa tends to decrease over the south, and an increase in low-level as- cent is found over the north. These factors can reduce PLAM and possibly limit the statistical significance of the in- creased PLAM in the westerly phases of the QBO.展开更多
文摘In this paper, double hydrophilic ionic liquid block copolymers （ILBCs）, poly poly[1-methyl-3-（2-methacryloyloxy propylimidazolium bromine）]-block-（N.isopro. pylacrylamide） （PMMPImB-b-PNIPAAm） was first synthesized by reversible addition- fragmentation chain transfer （RAFT） and then attached on the surface of gold nanoparticles （Au NPs） via a strong gold-sulfur bonding for preparing hybrid nanoparticles （PMMPImB-b-PNIPAAm-@-Au NPs）. The hybrid NPs had a three layers micelle-like structure, including a gold core, thermo-responsive inner shell and anion responsive outer corona. The self-assembling behavior of thermal- and anion-response from shell and corona were respectively investigated by change of temperature and addition of （CF3SO2）2N-. The results showed the hybrid NPs retained a stable dispersion beyond the lower critical solution temperature （LCST） because of the space or electrostatic protecting by outer PMMPImBo However, with increasing concentration of （CF3SO2）2N-, the micellization of self-assembling PMMPImB-b-PNIPAAm-@-Au NPs was induced to form micellar structure containing the core with hydrophobic PMMPImB- （CF3SO2）2N- surrounded by composite shell of Au NPs-PNIPAAm via the anion- responsive properties of ILBCs. These results indicated that the block copolymers protected plasmonic nanoparticles remain self-assembling properties of block copoly- mers when phase transition from outer corona polymer.
基金the financial support from the National Natural Science Foundation of China(Project U1704150)the Scientifc and Technological Projects of Henan province(182102410017).
文摘In this work,zwitterionic polymer(polyzwitterion)coated nanodiamonds(ND)with tumorous pH responsiveness were prepared for efficient application of commercial NDS in tumor cells imaging.Poly(carboxybetaine methacrylate)was firstly grafted on the pristine NDS(PCBMA-@-NDs)by surface-initiated reversible addition-fragmentation chain transfer(RAFT)polymerization.To achieve pH responsiveness and activated interaction with tumor cells,PCBMA-@-NDs were subsequently modified with benzene sulfonamide(PCBSA-@-NDs)via one step carbodiimide chemistry.The surface polymer functionalization was characterized by FTIR,1H NMR and TGA,and PCBMA-@-NDs and PCBSA-@-NDs showed great dispersibility,enhanced fluorescence intensity and excellent antifouling property in contrast to pristine NDs.Moreover,PCBSA-@-NDs was able to switch zwitterionic surface(at pH 7.4)reversibly into positive charge(at pH 6.5)via protonated or deprotonated acylsulfonamide.As expected,PCBSA-@-NDS demonstrated higher cell affinity and better imaging performance than those of zwitterionic NDS at tumor slight acid environment,proven by fluorescence microscopy and flow cytometry.Overall,we provide a feasible and valuable strategy to construct smart NDS,thus encouraging the application of cost-effective fluorescence nanomater-ials in biomedical fields.
文摘In this paper, double hydrophilic ionic liquid block copolymers （ILBCs）, poly（N-isopropylacrylamide）-block-poly[1-methyl-3-（2-methacryloyloxy propylimidazo- lium bromine）] （PNIPAM-b-PMMPImB）, were polymerized by two-step reversible addi- tion-fragmentation chain transfer （RAFT） process. The composition and molecular weight distributions of ILBCs were characterized using 1HNMR and gel permeation chromato- graphy （GPC）. The self-assembly and temperature- and anion-responsive behaviors of ILBCs were investigated by UV-Vis spectroscopy, TEM and dynamic light scattering （DLS）. With increasing the concentration of （CF3SO2）2N-, the micellization of self- assembling PNIPAM-b-PMMPImB was induced to form a core-shell structure containing the core with hydrophilic PMMPIm-（CF3SO2）2N- surrounded by the shell of PNIPAM via the anion-responsive properties of ILBCs. However, upon temperature increasing, PNIPAM-b- PMMPImB formed the micelles composing of PNIPAM core and PMMPImB shell. The ionic liquid segment with strong hydrophilic property enhanced the hydrogen bonding interaction which expanded the temperature range of phase transition and increased the lower critical solution temperature （LCST） of the system. These results indicate that ILBCs prepared in this paper have excellent temperature and anion double responsive properties, and may be applied as a kind of potential environmental responsive polymer nanoparticles.
文摘An upswing in haze weather during autumn and winter has been observed over North and Northeast China in re- cent years, imposing adverse impacts upon local socioeconomic development and human health. However, such an increase in the occurrence of haze events and its association with natural climate variability and climate change are not well understood. To investigate the climatology of the meteorological factors associated with haze events and their natural variability, this study uses a meteorological pollution index called PLAM （Parameter Linking Air-qual- ity to Meteorological conditions） and ERA-Interim reanalysis data. The results suggest that high PLAM values tend to occur over southern parts of northem China, implying the weather conditions over this area are favorable for the occurrence of haze weather. For the period 1979-2014, the regional mean PLAM shows an overall increase across Beijing, Tianjin, and Hebei Province, and parts of Shanxi Province. Also, a periodicity of 28-34 months is found in the temporal variation of PLAM, which implies a potential association of PLAM with the stratospheric Quasi-Bian- nual Oscillation （QBO）. By using the QBO index during the autumn and winter seasons in the preceding year, an in- crease in PLAM is found for the westerly phases of the QBO, relative to the easterly phases. An upper-tropospheric warming is also found in the westerly phases, which can induce a stable stratification that favors the increase in PLAM across the midlatitudes. The modulations of large-scale environmental factors, including moist static stability, vertical velocity, and temperattu＇e advection, also act to enhance PLAM in the westerly phases. However, the baro- clinic term of moist potential vorticity at 700 hPa tends to decrease over the south, and an increase in low-level as- cent is found over the north. These factors can reduce PLAM and possibly limit the statistical significance of the in- creased PLAM in the westerly phases of the QBO.
