A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles（MSNs） functionalized on the pore outlets with poly（4-vinylphenybronic acid-co-2-（dimethylamino...A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles（MSNs） functionalized on the pore outlets with poly（4-vinylphenybronic acid-co-2-（dimethylamino）ethyl acrylate） [P（VPBA-DMAEA）]. Four kinds of P（VPBA-DMAEA）-gated MSNs were synthesized and applied for the p H-sensitive controlled release. The results showed that P（VPBADMAEA） can work as a p H-sensitive nanovalve. The release behavior of the hybrid nanoparticles could be adjusted by changing the mole ratio of VPBA and DMAEA. With the increasing of the mole ratio of VPBA,the leakage of the entrapped molecules in the pores of MSNs could be decreased at neutral and alkaline conditions. By altering the p H of buffer from 4.0 to 8.0, the valve could be switched ‘‘on＇＇ and ‘‘off＇＇reversibly. In addition, cells viability results indicated that these P（VPBA-DMAEA）-gated MSNs had good biocompatibility. We believe that these MSNs based p H-sensitive controlled release system will provide a promising nanodevice for sited release of drug delivery.展开更多
The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The p...The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The polymer chains were anchored onto the surface of nano-CaCO3 through use of a cou- pling agent, triethoxyvinyl silane （TEVS）. Ammonium persulfate （APS）, sodium dodecyl sulfate （SDS） and n-pentanol were used as the initiator, surfactant and cosurfactant, respectively. The polymeriza- tion mechanism of the core-shell latex particles is discussed. The encapsulation of nano-CaCO3 by PMMA was confirmed using a transmission electron microscope （TEM）. The grafting percentage of the core-shell particles was investigated by thermogravimetric analysis （TGA）. The nano-CaCO3/PMMA core-shell par- ticles were characterized by Fourier transform infrared （FTIR） spectroscopy and differential scanning calorimetry （DSC）. The FTIR results revealed the existence of a strong interaction at the interface of the nano-CaCO3 particle and the PMMA, which implies that the polymer chains were successfully grafted onto the surface of the nano-CaCO3 particles through the link of the coupling agent, In addition, the TGA and DSC results indicated an enhancement of the thermal stability of the core-shell materials compared with that of the pure nano-PMMA, The nano-CaCO3/PMMA particles were blended into a polypropylene （PP） matrix by melt processing. It can also be observed using scanning electron microscopy （SEM） that the PMMA chains grafted onto the CaCO3 nanoparticles interfere with the aggregation of CaCO3 in the polymer matrix （PP matrix） and thus improve the compatibility of the CaCO3 nanoparticles with the PP matrix.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 21190040, 21175035, 21375034)National Basic Research Program of China (No. 2011CB911002)International Science & Technology Cooperation Program of China (No. 2010DFB30300)
文摘A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles（MSNs） functionalized on the pore outlets with poly（4-vinylphenybronic acid-co-2-（dimethylamino）ethyl acrylate） [P（VPBA-DMAEA）]. Four kinds of P（VPBA-DMAEA）-gated MSNs were synthesized and applied for the p H-sensitive controlled release. The results showed that P（VPBADMAEA） can work as a p H-sensitive nanovalve. The release behavior of the hybrid nanoparticles could be adjusted by changing the mole ratio of VPBA and DMAEA. With the increasing of the mole ratio of VPBA,the leakage of the entrapped molecules in the pores of MSNs could be decreased at neutral and alkaline conditions. By altering the p H of buffer from 4.0 to 8.0, the valve could be switched ‘‘on＇＇ and ‘‘off＇＇reversibly. In addition, cells viability results indicated that these P（VPBA-DMAEA）-gated MSNs had good biocompatibility. We believe that these MSNs based p H-sensitive controlled release system will provide a promising nanodevice for sited release of drug delivery.
基金the University Grants Commission(UGC),New Delhi for providing the financial support[project fileNo:40-10/2011(SR),dated-July 14,2011]to conduct this research
文摘The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The polymer chains were anchored onto the surface of nano-CaCO3 through use of a cou- pling agent, triethoxyvinyl silane （TEVS）. Ammonium persulfate （APS）, sodium dodecyl sulfate （SDS） and n-pentanol were used as the initiator, surfactant and cosurfactant, respectively. The polymeriza- tion mechanism of the core-shell latex particles is discussed. The encapsulation of nano-CaCO3 by PMMA was confirmed using a transmission electron microscope （TEM）. The grafting percentage of the core-shell particles was investigated by thermogravimetric analysis （TGA）. The nano-CaCO3/PMMA core-shell par- ticles were characterized by Fourier transform infrared （FTIR） spectroscopy and differential scanning calorimetry （DSC）. The FTIR results revealed the existence of a strong interaction at the interface of the nano-CaCO3 particle and the PMMA, which implies that the polymer chains were successfully grafted onto the surface of the nano-CaCO3 particles through the link of the coupling agent, In addition, the TGA and DSC results indicated an enhancement of the thermal stability of the core-shell materials compared with that of the pure nano-PMMA, The nano-CaCO3/PMMA particles were blended into a polypropylene （PP） matrix by melt processing. It can also be observed using scanning electron microscopy （SEM） that the PMMA chains grafted onto the CaCO3 nanoparticles interfere with the aggregation of CaCO3 in the polymer matrix （PP matrix） and thus improve the compatibility of the CaCO3 nanoparticles with the PP matrix.
