The Influence Of Microgravity And Osmotic Pressure On The Adsorption Capacity And Adsorption Kinetics Of Nanometer Materials On The Surface Of The Substrate

Along with the development of nanotechnology in biological medicine, we control drug toward the fixed lesions, and release drug, make drug play the best curative effect,improving the drug targeting,which has become the focus in the field of biomedical research. In order to control the directional movement of drug more effectively, and release drug towards the lesions, we need to choose the proper drug carrier improving the drug targeting.Because the gold nanoparticles and liposomes show some excellent characteristics as drug carriers, thus that studying adsorption properties of gold nanoparticles adjusting the endocytosis way of liposomes drug transporting using osmotic pressure way.has been the research hot spot in the field of biomedical forefront.Lipid biomembrane exhibits the broad application prospect in nanobiotechnology. Self-assembly of membrane on surface supplied by biosensor and drug carrier has become a critical question in the interdiscipline of material, physics, and biology. In this thesis, the mechanisms and regulation methods of the key membrane self-assembly behaviors on silica surface, including fusion, hemifusion, and particle adsorption are studied by quartz crystal microbalance, fluorescence microscopy basing on Phospholipids support double membrane system. On the one hand, based on the specific fluorescence quenching effect of gold nanoparticles, using fluorescence microscope, and fluorescence resonance energy transfer (FRET) technology, we studied the effect of gravity on gold nanoparticle adsorption on supported lipid membrane surface by performing the upright and inverted configuration experiments. On the other hand, with the main characterization methods for experiment,such as the quartz crystal micro electronic scales and dissipative coefficient measuring instrument, nanoparticle sizer and so on, we studied the effect of osmotic stress on the nanoscale phospholipid vesicle fusion and adsorption process on silica surface.In the chapter 2.We studied the role of gravity on the nanoparticles absorption process. Adsorption of nanoparticles on biomembrane is one critical problem in bionanotechnology. Using fluorescence microscopy, we studied the effect of gravity on gold nanoparticle adsorption on supported lipid membrane surface by performing the upright and inverted configuration experiments.And established the relationship between the adsorption on the membranes at the top and bottom of medium. and particle deposition, diffusion rate.Further, we went on the study and theoretical analysis of the system for the adsorption difference. It was found that:particle size controls the discrepancy between the adsorption on the membranes at the top and bottom of medium. The adsorption disparity increases linearly with the logarithm of the ratio between the sedimentation and diffusion velocities. Gravity is neglectable in adsorption for nanoparticles less than 14nm, while it is dominant in adsorption for nanoparticles larger than 176nm. The study provides references for drug carrier research and the understanding of the nanoparticle-membrane interaction in real life.In ideal condition, vesicles fuse spontaneously on hydrophilic surface to form supported bilayers. In the chapter 3, we studied the effect of’osmotic stress on the nanoscale phospholipid vesicle adsorption,fusion,rupture,and the change rate toward bilayer membrane.At the beginning with quartz crystal micro balances and dissipative coefficient measuring instrument (QCM-D),we got the quantitative relationship among time parameters in isotonic environment. Then with quartz crystal micro balances and dissipative coefficient measuring instrument (QCM-D),we studied the relationship between the change of time parameters and the vesicle fusion rate in high or low permeability environment. At last,with nanometer particle size instrument,we signed the shape characteristics of the vesicles in different permeability of environment,and analyzed the possible mechanism, which is the effect of vesicle damage symmetry and membrane surface tension on vesicle fusion process.lt is found that, Sugar concentration has little effect on vesicle fusion process.Hypoosmotic stress won’t affect the fusion kinetics within the scope of the test of the osmotic pressure gradient; While hyperosmotic environment, when the osmotic stress gradient is less than 200 mOsm, the effect is not obvious, when the osmotic pressure gradient is higher than the value, the effcet is significant. Energy consideration implies that the majority of chemical potential energy associated with osmotic stress is released in directed transport of water across membrane. Osmotic contributions to vesicle deformation and fusion are therefore small compared to those of adhesion. Our research deepens the understanding of the work done by osmotic stress in fusion. It provides guideline for the proper use of osmotic stress in bionic device construction.At last, we summarize the thesis, and present outlooks for the future work.