A new type of polypeptide(poly(-benzyl-L-glutamate)(PBLG))modified hydroxyapatite(HA)/poly(L-lactide)(PLLA)nanocomposites(PBLG-g-HA/PLLA)were prepared by the solvent-mixing method,and their mechanical and thermal prop...A new type of polypeptide(poly(-benzyl-L-glutamate)(PBLG))modified hydroxyapatite(HA)/poly(L-lactide)(PLLA)nanocomposites(PBLG-g-HA/PLLA)were prepared by the solvent-mixing method,and their mechanical and thermal properties were investigated.The tensile test showed that the mechanical properties of PBLG-g-HA/PLLA nanocomposites were better than that of PLLA,even a 0.3 wt%content of PBLG-g-HA in the nanocomposites could make the tensile strength 12%higher than that of the neat PLLA sample,and the tensile modulus was about 17%higher than that of the PLLA sample.The thermal gravimetric analysis(TGA)showed that the PBLG-g-HA/PLLA composites have better thermal stability than the PLLA sample.The differential scanning calorimetry(DSC)was used to characterize the effect of PBLG-g-HA on the crystallization of PLLA.The isothermal crystallization behavior showed that the half crystallization time(t1/2)of PBLG-g-HA/PLLA was much shorter than that of the PLLA sample.When the PBLG-g-HA content was 10%,t1/2 was only 18.7 min,while t1/2 of the PLLA sample was 61.4 min.The results showed that the PBLG-g-HA worked as a nucleating agent and enhanced the crystallization speed of PLLA.展开更多
Poly（L-glutamic acid）（PLGA） was grafted onto the surface of mesoporous silica nanoparticles（MSN） via the ring opening polymerization of γ-benzyl-L-glutamate N-carboxyanhydride（BLG-NCA） and its subsequent depr...Poly（L-glutamic acid）（PLGA） was grafted onto the surface of mesoporous silica nanoparticles（MSN） via the ring opening polymerization of γ-benzyl-L-glutamate N-carboxyanhydride（BLG-NCA） and its subsequent deprotection of benzyl groups. The PLGA chains were cross-linked with cystamine, and thus forming a type of redox responsive drug delivery system（MSN-cPLGA）. The structures were characterized by Fourier transform infrared spectrometry（FTIR）, transmission electron microscopy（TEM） and energy disperse spectrometry（EDS）, demonstrating that disulfide groups existed on the surfaces of MSN-cPLGA particles. The thermal gravimetric analysis（TGA） results show that the PLGA mass fraction is about 33.4% in the MSN-cPLGA hybrid. The in vitro drug release experiments showed that the MSN-cPLGA hybrid can realize the controlled release of model drugs（5-fluorouracil） in response to redox environment. Even 0.1 mmol/L dithiothreitol（DTT） can accelerate the drug release speed, and a concentration of 10.0 mmol/L DTT is higher enough to trigger the open of cross-linked PLGA network so as to realize rapid release of drugs. All the results demonstrate that the cross-linked PLGA chains on the surface of MSN could act as efficient gatekeepers to control the on-off of the pores, showing potential application in drug delivery system.展开更多
Three novel regular acceptor-donorl-acceptor-donor2（A-D1-A-D2） terpolymers were prepared via em-bedding a second donor（D2） unit into the traditional D-A backbone to manipulate the energy levels and moleculargeomet...Three novel regular acceptor-donorl-acceptor-donor2（A-D1-A-D2） terpolymers were prepared via em-bedding a second donor（D2） unit into the traditional D-A backbone to manipulate the energy levels and moleculargeometry with no complex synthesis or solubility loss. In these A-D1-A-D2 terpolymers, benzodithiophene（BDT, D1）and diketopyrrolopyrrole（DPP, A） were selected as the basic skeleton, and the dithienopyrrole（DTPy）, carbazole（CZ）and fluorine（FL） units with different electron donating ability were chosen as the second donor trait（D2）. The HOMOenergy levels can be effectively modulated by only varying D2 unit because of the push-pull interaction between do-nor and acceptor units. Versus the D-A bipolymer PDPP-BDT, incorporation of the D2 unit into the copolymers candistinctly lower the highest occupied molecular orbital（HOMO） levels to -5.47 eV for PDDPP-BDT-DTPy, -5.38 eVfor PDDPP-BDT-CZ and -5.23 eV for PDDPP-BDT-FL, which shows the strong dependence on electron-donatingability. Density functional theory（DFT） simulation and X-ray diffraction（XRD） measurements also reveal the effectof the D2 units on the molecular geometry of the terpolymers and their molecular packing. Notably, aPDDPP-BDT-DTPy combined with a thiophene ring and forked tail pendant away from the backbone had less back-bone torsion and more compact packing than the other two counterparts. These results demonstrate that embedding asecond donor（D2） unit into the backbone to construct an A-D1-A-D2 structure can be an effective and direct strategyto manipulate the energy levels and molecular geometry and develop organic semiconducting materials.展开更多
Surface modification of halloysite nanotube（HNT） with in situ grown Fe304 nanoparticles and carbona- ceous layers introduced by a hydrotbermal carbonization process of glucose has been achieved. Structure and mor- p...Surface modification of halloysite nanotube（HNT） with in situ grown Fe304 nanoparticles and carbona- ceous layers introduced by a hydrotbermal carbonization process of glucose has been achieved. Structure and mor- phology investigations demonstrate that iron oxide nanoparticles are uniformly anchored on the halloysite and pre- vent the aggregations of halloysite and carbon, forming a protective layer that stabilizes and improves the property of HNT/Fe3OdC nanocomposite. Magnetism characterization proves the superparamagnetic behavior of HNT/Fe304/C hybrid at room temperature, which makes it easily separated from dye solution under an external magnetic field. Ex- ploration of adsorption ability demonstrates that the maximum adsorption capacity of the as-prepared HNT/Fe304/C nanoeomposite for methylene blue（MB） is about twice and 1.5 times those of HNT/Fe304 and HNT according to Langmuir equation, respectively. The adsorption behavior investigations indicate that HNT/Fe304/C hybrid has a he- terogeneous structure and shows a non-ideal monolayer adsorption that fits the Redlich-Peterson isotherm, and the adsorption process follows a pseudo-second-order kinetic model. Therefore, the as-prepared HNT/Fe304/C hybrid is a fast, separatable and superparamagnetic adsorbent with a good adsorption ability, demonstrating great potential in the application of water treatment.展开更多
基金supported by the National Natural Science Foundation of China (50733003)the International Cooperation Fund of Science and Technology (20071314) from the Ministry of Science and Technology of Chinathe fund from Chinese Academy of Sciences (KGCX-YW-208)
文摘A new type of polypeptide(poly(-benzyl-L-glutamate)(PBLG))modified hydroxyapatite(HA)/poly(L-lactide)(PLLA)nanocomposites(PBLG-g-HA/PLLA)were prepared by the solvent-mixing method,and their mechanical and thermal properties were investigated.The tensile test showed that the mechanical properties of PBLG-g-HA/PLLA nanocomposites were better than that of PLLA,even a 0.3 wt%content of PBLG-g-HA in the nanocomposites could make the tensile strength 12%higher than that of the neat PLLA sample,and the tensile modulus was about 17%higher than that of the PLLA sample.The thermal gravimetric analysis(TGA)showed that the PBLG-g-HA/PLLA composites have better thermal stability than the PLLA sample.The differential scanning calorimetry(DSC)was used to characterize the effect of PBLG-g-HA on the crystallization of PLLA.The isothermal crystallization behavior showed that the half crystallization time(t1/2)of PBLG-g-HA/PLLA was much shorter than that of the PLLA sample.When the PBLG-g-HA content was 10%,t1/2 was only 18.7 min,while t1/2 of the PLLA sample was 61.4 min.The results showed that the PBLG-g-HA worked as a nucleating agent and enhanced the crystallization speed of PLLA.
基金Supported by the National Natural Science Foundation of China（Nos.51203073, 51463013, 51263017） and the Natural Science Foundation of Jiangxi Province, China（Nos.20142BAB203018, 20151BAB206011）.
文摘Poly（L-glutamic acid）（PLGA） was grafted onto the surface of mesoporous silica nanoparticles（MSN） via the ring opening polymerization of γ-benzyl-L-glutamate N-carboxyanhydride（BLG-NCA） and its subsequent deprotection of benzyl groups. The PLGA chains were cross-linked with cystamine, and thus forming a type of redox responsive drug delivery system（MSN-cPLGA）. The structures were characterized by Fourier transform infrared spectrometry（FTIR）, transmission electron microscopy（TEM） and energy disperse spectrometry（EDS）, demonstrating that disulfide groups existed on the surfaces of MSN-cPLGA particles. The thermal gravimetric analysis（TGA） results show that the PLGA mass fraction is about 33.4% in the MSN-cPLGA hybrid. The in vitro drug release experiments showed that the MSN-cPLGA hybrid can realize the controlled release of model drugs（5-fluorouracil） in response to redox environment. Even 0.1 mmol/L dithiothreitol（DTT） can accelerate the drug release speed, and a concentration of 10.0 mmol/L DTT is higher enough to trigger the open of cross-linked PLGA network so as to realize rapid release of drugs. All the results demonstrate that the cross-linked PLGA chains on the surface of MSN could act as efficient gatekeepers to control the on-off of the pores, showing potential application in drug delivery system.
文摘Three novel regular acceptor-donorl-acceptor-donor2（A-D1-A-D2） terpolymers were prepared via em-bedding a second donor（D2） unit into the traditional D-A backbone to manipulate the energy levels and moleculargeometry with no complex synthesis or solubility loss. In these A-D1-A-D2 terpolymers, benzodithiophene（BDT, D1）and diketopyrrolopyrrole（DPP, A） were selected as the basic skeleton, and the dithienopyrrole（DTPy）, carbazole（CZ）and fluorine（FL） units with different electron donating ability were chosen as the second donor trait（D2）. The HOMOenergy levels can be effectively modulated by only varying D2 unit because of the push-pull interaction between do-nor and acceptor units. Versus the D-A bipolymer PDPP-BDT, incorporation of the D2 unit into the copolymers candistinctly lower the highest occupied molecular orbital（HOMO） levels to -5.47 eV for PDDPP-BDT-DTPy, -5.38 eVfor PDDPP-BDT-CZ and -5.23 eV for PDDPP-BDT-FL, which shows the strong dependence on electron-donatingability. Density functional theory（DFT） simulation and X-ray diffraction（XRD） measurements also reveal the effectof the D2 units on the molecular geometry of the terpolymers and their molecular packing. Notably, aPDDPP-BDT-DTPy combined with a thiophene ring and forked tail pendant away from the backbone had less back-bone torsion and more compact packing than the other two counterparts. These results demonstrate that embedding asecond donor（D2） unit into the backbone to construct an A-D1-A-D2 structure can be an effective and direct strategyto manipulate the energy levels and molecular geometry and develop organic semiconducting materials.
基金Supported by the National Natural Science Foundation of China（No. 51125011）.
文摘Surface modification of halloysite nanotube（HNT） with in situ grown Fe304 nanoparticles and carbona- ceous layers introduced by a hydrotbermal carbonization process of glucose has been achieved. Structure and mor- phology investigations demonstrate that iron oxide nanoparticles are uniformly anchored on the halloysite and pre- vent the aggregations of halloysite and carbon, forming a protective layer that stabilizes and improves the property of HNT/Fe3OdC nanocomposite. Magnetism characterization proves the superparamagnetic behavior of HNT/Fe304/C hybrid at room temperature, which makes it easily separated from dye solution under an external magnetic field. Ex- ploration of adsorption ability demonstrates that the maximum adsorption capacity of the as-prepared HNT/Fe304/C nanoeomposite for methylene blue（MB） is about twice and 1.5 times those of HNT/Fe304 and HNT according to Langmuir equation, respectively. The adsorption behavior investigations indicate that HNT/Fe304/C hybrid has a he- terogeneous structure and shows a non-ideal monolayer adsorption that fits the Redlich-Peterson isotherm, and the adsorption process follows a pseudo-second-order kinetic model. Therefore, the as-prepared HNT/Fe304/C hybrid is a fast, separatable and superparamagnetic adsorbent with a good adsorption ability, demonstrating great potential in the application of water treatment.
