目的对自制的脂质囊泡超声造影剂进行质量评价,研究不同剂量与正常猪肝彩色多普勒显影效果间的相互关系。方法显微镜观察脂质囊泡的形态、激光粒度测定仪测定粒径及粒度分布,用血细胞分析仪统计不同放置时间条件下和配制浓度粒径在28μ...目的对自制的脂质囊泡超声造影剂进行质量评价,研究不同剂量与正常猪肝彩色多普勒显影效果间的相互关系。方法显微镜观察脂质囊泡的形态、激光粒度测定仪测定粒径及粒度分布,用血细胞分析仪统计不同放置时间条件下和配制浓度粒径在28μm范围内的囊泡浓度以及光照和温度对囊泡浓度和平均粒径的影响。进行造影剂剂量与正常猪肝实质彩色多普勒显影效果间的相互关系实验,观察3个不同剂量造影剂对彩色多普勒显影视频强度及增强时间的影响。结果自制的脂质囊泡形态圆整,平均粒径3.33.5μm,囊泡浓度超过4×10^8个/m l。正常猪肝实质区彩色多普勒显影增强强度和增强时间基本呈剂量依赖性,0.02 m l/kg剂量水平对正常猪肝实质区显像增强强度和增强时间最好。结论自制的脂质囊泡可以在动物实验中作为有效的超声造影剂。展开更多
An implicit solvent coarse-grained （CG） lipid model using three beads to reflect the basically molecular structure of two-tailed lipid is developed. In this model, the nonbonded interaction employs a variant MIE pot...An implicit solvent coarse-grained （CG） lipid model using three beads to reflect the basically molecular structure of two-tailed lipid is developed. In this model, the nonbonded interaction employs a variant MIE potential and the bonded interaction utilizes a Harmonic potential form. The CG force field parameters are achieved by matching the structural and mechan-ical properties of dipalmitoylphosphatidylcholine （DPPC） bilayers. The model successfully reproduces the formation of lipid bilayer from a random initial state and the spontaneous vesiculation of lipid bilayer from a disk-like structure. After that, the model is used to sys-tematically study the vesiculation processes of spherical and cylindrical lipid droplets. The results show that the present CG model can effectively simulate the formation and evolution of mesoscale complex vesicles.展开更多
A solvent-non-solvent method invented in our laboratory for preparing non-covalently con- nected micelles （NCCM） was used to intercalate melamine （MA） molecules into stearic acid （SA） bilayers to form tile compo...A solvent-non-solvent method invented in our laboratory for preparing non-covalently con- nected micelles （NCCM） was used to intercalate melamine （MA） molecules into stearic acid （SA） bilayers to form tile composite nanoparticles with an intercalated nanostructure in which a melamine bilayer is sandwiched between two stearic acid bilayers, NCCM method helps to sufficiently mix the two components in nanospace and meanwhile inhibits the strong tendency of self-crystallization of MA, leading to the intercalation. Although the nanopar- ticles have a regular inner structure, the primary MA/SA nanoparticles have an irregular morphology. Regular nanoparticles were obtained through annealing the suspension of the primary nanoparticles. Through annealing at different temperatures, the MA/SA compos- ite nanowires and vesicles with an intercalated structure were prepared respectively. It is proposed that the morphological change results from the change in the intercalated structure.展开更多
Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorptio...Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorption to zwitterionic PC and anionic mixed PC/PG SUVs. Protein adsorption is investigated in SUVs along with changes of fluorescence emission spectra. Partition coefficients and cooperativity parameters are calculated. At pl binding obtains maximum while at lower or higher pHs binding decreases. In Gouy-Chapman formalism activity coefficient goes with square charge, which deviations indicate asymmetric location of anionic phospholipid in the inner leaflet, in mixed SUVs for lysozyme- and myoglobin-PC/PG systems, in agreement with experiments and molecular dynamics simulations. Vesicles bind myoglobin anti-cooperatively while lysozyme-BSA cooperativitivey. A model is proposed for both, which composes two protein sub-layers with different structures and properties. Hill coefficient reflects subunit cooperativity of bi and tridomain proteins.展开更多
文摘目的对自制的脂质囊泡超声造影剂进行质量评价,研究不同剂量与正常猪肝彩色多普勒显影效果间的相互关系。方法显微镜观察脂质囊泡的形态、激光粒度测定仪测定粒径及粒度分布,用血细胞分析仪统计不同放置时间条件下和配制浓度粒径在28μm范围内的囊泡浓度以及光照和温度对囊泡浓度和平均粒径的影响。进行造影剂剂量与正常猪肝实质彩色多普勒显影效果间的相互关系实验,观察3个不同剂量造影剂对彩色多普勒显影视频强度及增强时间的影响。结果自制的脂质囊泡形态圆整,平均粒径3.33.5μm,囊泡浓度超过4×10^8个/m l。正常猪肝实质区彩色多普勒显影增强强度和增强时间基本呈剂量依赖性,0.02 m l/kg剂量水平对正常猪肝实质区显像增强强度和增强时间最好。结论自制的脂质囊泡可以在动物实验中作为有效的超声造影剂。
基金We thank Professor Dr. Markus Deserno （Department of Physics, Carnegie Mellon University）, Jemal Guven （Institute of Nuclear Science, Universidad Nacional Autonoma de Mexico）, and Zhan-chun Tu （Department of Physics, Beijing Normal University） for their valuable advice. This work is supported by the National Natural Science Foundation of China （No.20974078, No.21274107, and No.91127046）. The computation and simulation are partly carried out in High Performance Computing Center of Tianjin University.
文摘An implicit solvent coarse-grained （CG） lipid model using three beads to reflect the basically molecular structure of two-tailed lipid is developed. In this model, the nonbonded interaction employs a variant MIE potential and the bonded interaction utilizes a Harmonic potential form. The CG force field parameters are achieved by matching the structural and mechan-ical properties of dipalmitoylphosphatidylcholine （DPPC） bilayers. The model successfully reproduces the formation of lipid bilayer from a random initial state and the spontaneous vesiculation of lipid bilayer from a disk-like structure. After that, the model is used to sys-tematically study the vesiculation processes of spherical and cylindrical lipid droplets. The results show that the present CG model can effectively simulate the formation and evolution of mesoscale complex vesicles.
文摘A solvent-non-solvent method invented in our laboratory for preparing non-covalently con- nected micelles （NCCM） was used to intercalate melamine （MA） molecules into stearic acid （SA） bilayers to form tile composite nanoparticles with an intercalated nanostructure in which a melamine bilayer is sandwiched between two stearic acid bilayers, NCCM method helps to sufficiently mix the two components in nanospace and meanwhile inhibits the strong tendency of self-crystallization of MA, leading to the intercalation. Although the nanopar- ticles have a regular inner structure, the primary MA/SA nanoparticles have an irregular morphology. Regular nanoparticles were obtained through annealing the suspension of the primary nanoparticles. Through annealing at different temperatures, the MA/SA compos- ite nanowires and vesicles with an intercalated structure were prepared respectively. It is proposed that the morphological change results from the change in the intercalated structure.
文摘Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorption to zwitterionic PC and anionic mixed PC/PG SUVs. Protein adsorption is investigated in SUVs along with changes of fluorescence emission spectra. Partition coefficients and cooperativity parameters are calculated. At pl binding obtains maximum while at lower or higher pHs binding decreases. In Gouy-Chapman formalism activity coefficient goes with square charge, which deviations indicate asymmetric location of anionic phospholipid in the inner leaflet, in mixed SUVs for lysozyme- and myoglobin-PC/PG systems, in agreement with experiments and molecular dynamics simulations. Vesicles bind myoglobin anti-cooperatively while lysozyme-BSA cooperativitivey. A model is proposed for both, which composes two protein sub-layers with different structures and properties. Hill coefficient reflects subunit cooperativity of bi and tridomain proteins.
