N-Methylene phosphonic chitosan （NMPCS）, an amphiphilic macromolecule with powerful chelating ability of Ca^2＋ ions, was synthesized and characterized. The physicochernical properties of NMPCS and the interactions ...N-Methylene phosphonic chitosan （NMPCS）, an amphiphilic macromolecule with powerful chelating ability of Ca^2＋ ions, was synthesized and characterized. The physicochernical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR, ^13C NMR, X-ray, agarose gel electrophoresis retardation assay, atomic force microscopy （AFM） and circular dichroism （CD）. The results suggest that at charge ratio 2：1 or above, DNA could be completely entrapped and spherical complexes with mean size of 80-210 nm were formed. Taking HeLa as host cell, luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.展开更多
A modified chitosan （ N-methylene phosphonic Chitosan, NMPC） was synthesized to improve solubility and ability to bind calcium ion. The properties of the raw material chitosan and its derivative NMPC were characte...A modified chitosan （ N-methylene phosphonic Chitosan, NMPC） was synthesized to improve solubility and ability to bind calcium ion. The properties of the raw material chitosan and its derivative NMPC were characterised using FTIR , ^1H- NMR . The aim of this study was to enhance the compressive CPC by reinforcing with NMPC. A formulation consisting of CPC powder , buffer solution and gelling agent was used for preparation of the CPC. CPC powder coasisted of tetracalcium phosphate（ TTCP ） and dicalcium phosphate anhydrous （ DCPA ）. NMPC which acted as the gelling ageut was dissohed into KH2PO4-Na2 HPO4 buffer solution. Each specimen in the mold was sandciched between two fritted glass sides and kept for 24 hours. Compressive strengths were determined, the setting product was identified using X-ray diffraction and scanning electron microscopy was used to investigate the hydroxyapatite particles size and porosity. The experimental results showed that the dominating influence on the compressive strengths of CPC-AMPC was the HA panicle size, its uniformity and appropriate porosity.展开更多
基金supports from National Natural Science Foundation of China(No.50233020,30300086)the financial support from Natural Science Foundation of Tianjin(No.05YFJMJC10200).
文摘N-Methylene phosphonic chitosan （NMPCS）, an amphiphilic macromolecule with powerful chelating ability of Ca^2＋ ions, was synthesized and characterized. The physicochernical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR, ^13C NMR, X-ray, agarose gel electrophoresis retardation assay, atomic force microscopy （AFM） and circular dichroism （CD）. The results suggest that at charge ratio 2：1 or above, DNA could be completely entrapped and spherical complexes with mean size of 80-210 nm were formed. Taking HeLa as host cell, luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.
文摘A modified chitosan （ N-methylene phosphonic Chitosan, NMPC） was synthesized to improve solubility and ability to bind calcium ion. The properties of the raw material chitosan and its derivative NMPC were characterised using FTIR , ^1H- NMR . The aim of this study was to enhance the compressive CPC by reinforcing with NMPC. A formulation consisting of CPC powder , buffer solution and gelling agent was used for preparation of the CPC. CPC powder coasisted of tetracalcium phosphate（ TTCP ） and dicalcium phosphate anhydrous （ DCPA ）. NMPC which acted as the gelling ageut was dissohed into KH2PO4-Na2 HPO4 buffer solution. Each specimen in the mold was sandciched between two fritted glass sides and kept for 24 hours. Compressive strengths were determined, the setting product was identified using X-ray diffraction and scanning electron microscopy was used to investigate the hydroxyapatite particles size and porosity. The experimental results showed that the dominating influence on the compressive strengths of CPC-AMPC was the HA panicle size, its uniformity and appropriate porosity.
