The main phase transition temperature of a lipid membrane, which is vital for its biomedical applications such as controllable drug release, can be regulated by encapsulating hydrophobic nanoparticles into the membran...The main phase transition temperature of a lipid membrane, which is vital for its biomedical applications such as controllable drug release, can be regulated by encapsulating hydrophobic nanoparticles into the membrane. However, the exact relationship between surface properties of the encapsulating nanoparticles and the main phase transition temperature of a lipid membrane is far from clear. In the present work we performed coarse-grained molecular dynamics simulations to meet this end. The results show the surface roughness of nanoparticles and the density of surface-modifying molecules on the nanoparticles are responsible for the regulation. Increasing the surface roughness of the nanoparticles increases the main phase transition temperature of the lipid membrane, whereas it can be decreased in a nonlinear way via increasing the density of surface-modifying molecules on the nanoparticles. The results may provide insights for understanding recent experimental studies and promote the applications of nanoparticles in controllable drug release by regulating the main phase transition temperature of lipid vesicles.展开更多
A label-free and low-cost mapping method based on SERS imaging was reported for illustrating the distribution of phospho- lipids with similar structures in binary lipid membranes on Ag nanoparticles （Ag NPs） films. ...A label-free and low-cost mapping method based on SERS imaging was reported for illustrating the distribution of phospho- lipids with similar structures in binary lipid membranes on Ag nanoparticles （Ag NPs） films. The Ag NPs films exhibited strong SERS activity and good reproducibility which were investigated with p-aminothiopbenol （p-ATP） as probe molecules. Atomic force microscope （AFM） measurement proved that compact lipid membranes formed on the Ag NPs films. Basing on the Ag NPs films, the SERS spectra of phospholipids in the mixed lipid membranes were achieved and the inherent vibration of 1,2-dimyristoyl-sn-lycero-3-phosphoglycerol, sodium salt （DMPG）, 1482 cm-1, was used to distinguish between DMPG and dimyristoylphosphatidylcholine （DMPC）. The proportions of phospholipids in the mixed lipid membranes were represented by the intensity ratio of peaks at 1482 cm-1 and 1650 cm1 （R1482/1650） simultaneously： increasing R1482/1650 indicated higher propor- tion of DMPG and lower proportion of DMPC. SERS imaging of the lipid membranes was constructed as a combination of spacial information and the semiquantitative detection of phospholipids according to R1482/1650, which showed that the charged phospholipids, DMPG, aggregated in the hybrid lipid membranes. The presented mapping strategy based on SERS imaging carried out on Ag NPs films supplied a facile, label-free and inexpensive way for potential applications in the research on the structure of the lipid membrane, such as lipid domains and rafts.展开更多
文摘The main phase transition temperature of a lipid membrane, which is vital for its biomedical applications such as controllable drug release, can be regulated by encapsulating hydrophobic nanoparticles into the membrane. However, the exact relationship between surface properties of the encapsulating nanoparticles and the main phase transition temperature of a lipid membrane is far from clear. In the present work we performed coarse-grained molecular dynamics simulations to meet this end. The results show the surface roughness of nanoparticles and the density of surface-modifying molecules on the nanoparticles are responsible for the regulation. Increasing the surface roughness of the nanoparticles increases the main phase transition temperature of the lipid membrane, whereas it can be decreased in a nonlinear way via increasing the density of surface-modifying molecules on the nanoparticles. The results may provide insights for understanding recent experimental studies and promote the applications of nanoparticles in controllable drug release by regulating the main phase transition temperature of lipid vesicles.
基金supported by the National Natural Science Foundation of China (20735003 & 21075120)the National Basic Research Program of China (2009CB930100 & 2010CB933600)
文摘A label-free and low-cost mapping method based on SERS imaging was reported for illustrating the distribution of phospho- lipids with similar structures in binary lipid membranes on Ag nanoparticles （Ag NPs） films. The Ag NPs films exhibited strong SERS activity and good reproducibility which were investigated with p-aminothiopbenol （p-ATP） as probe molecules. Atomic force microscope （AFM） measurement proved that compact lipid membranes formed on the Ag NPs films. Basing on the Ag NPs films, the SERS spectra of phospholipids in the mixed lipid membranes were achieved and the inherent vibration of 1,2-dimyristoyl-sn-lycero-3-phosphoglycerol, sodium salt （DMPG）, 1482 cm-1, was used to distinguish between DMPG and dimyristoylphosphatidylcholine （DMPC）. The proportions of phospholipids in the mixed lipid membranes were represented by the intensity ratio of peaks at 1482 cm-1 and 1650 cm1 （R1482/1650） simultaneously： increasing R1482/1650 indicated higher propor- tion of DMPG and lower proportion of DMPC. SERS imaging of the lipid membranes was constructed as a combination of spacial information and the semiquantitative detection of phospholipids according to R1482/1650, which showed that the charged phospholipids, DMPG, aggregated in the hybrid lipid membranes. The presented mapping strategy based on SERS imaging carried out on Ag NPs films supplied a facile, label-free and inexpensive way for potential applications in the research on the structure of the lipid membrane, such as lipid domains and rafts.
