Self-consistent Field Theory Study Of The Interaction Between Nanoparticles And Biomembranes

The interactions between nanoparticles and biomembranes have important influences on nanoparticles applications in cell imaging, biosensor design, drug delivery, disease diagnoses and therapy, and so on. In recently years,lots of studies may yield some theoretical insights into the relevant area applications of nanoparticles, such as biological, physics, chemistry and so on.Biological membranes are one kind of bilayers, the cell and their inner organelles are enveloped by them, and be separated from their surrounding environments. So, biological membranes play an important role in the organism. With nanoparticles embedded within the membranes surface or intramembranes, the shape of membranes were leaded to chang, at the same time, the other intramembranous moleculars should be influced, further rearranged. On the contrary, this deformation could affect effective interaction and distribution between nanoparticles and membranes. At home and abroad, experimental and theoretical studies for the interactions between nanoparticles and menbranes are relatvely active, but in the small size and hightly exisce of the system, it's difficult for some system to do experimental studies, plus, the interaction between nanoparticles and membranes are very complex. Therefore, it's not still understand for the microscopic properties of system and most experimental physical mechanism. In this paper, the morphological deformation of the biomembranes and the change of the free energy of the system during the translocation of a rodlike nanoparticle across the biomembranes under the conditions of different interactions is investigated with the self-consistent field theory. The results show that, during the translocation of nanoparticles across the biomembranes, the morphology of the biomembranes is deformed differently with varying the interactions between the nanoparticles and the biomembranes; furthermore, through analyzing the change of the free energy of the system, it is found that the interactions between nanoparticles and biomembranes can obviously influence the translocation of the nanoparticles across the biomembranes. These results may yield some theoretical insights into the relevant biological applications of nanoparticles.In this thesis, we theoretically investigate that the interactions between nanoparticles and biomembranes impact on the translocation of a rodlike nanoparticle across the biomembranes.Our results account well for some most recent experimental work, predict some new results that are not observed in the experiments, and further provide one possible method to control theorganization in the membrane. This thesis mainly includes following aspects.ChapterⅠ, simply understand the biomembrane system and its molecular composition. Mainly introduct some research progress and applications of the interaction between biomembranes and nanoparticles, and related effect factors in the process of micro-dynamics of the transmenbrane transport of nanoparticles.ChppterⅡ, introduct study progress and method of the biomembrane model, contains microscopic all atom scale model, phenomenological model and mesoscopic coarse-grained field theory model. Based on the canonical ensemble, self-consistent field theroy model was highlighted. Using the Gaussian model to gradually calculate evolutionary process of the SCFT, further study SCFT in the simple system of block copolymer. The above works play an important role in the interaction of between nanoparticles and biomembranes. As a coarse-grained model of the mean field theory, it's easy to deal with a larger size of the biomembrane system, and give free energy, entropy, interaction energy, the microscopic structure of system and so on, although ignoring some molecular details, can properly consider the amphophilic property and effective shapes of the lipid molecules, as well as the flexibility of chains, and so on.ChapterⅢ, introduct the application of SCFT in the system of the interaction between biomembranes and nanoparticles, analyze the interaction between uncharged nanoparticles and biomembranes, such as, Fe3O4,coated by PEG, which have an effect on free energy changes in the system and deformation of the biomembranes in the process of transmembrane transport of nanoparticles. Thought the change of the interaction between biomembranes and nanoparticles, reveal that interaction influces the microscopic mechanisms of the transmembrane transport of nanoparticles.ChapterⅣ, conclusions and outlook are given.