Study On The Effects Of Ion Concentration On The Structure And Behavior Of MO Molecules At The Interface Of DOTAP Phospholipid Membrane

Among the influencing factors of the kinetic behavior of molecular adsorption and transport on the surface of the phospholipid membrane,the chemical environment is an important factor.In different types of chemical environments,the influence of ion concentration on the adsorption and transport of molecules on the surface of the phospholipid membrane cannot be ignored.An in-depth understanding of the effect of ion concentration on the structure and behavior of probe molecules on phospholipid membranes can further provide an important theoretical basis for research in physical chemistry,biomedicine and other fields.The Second Harmonic Generation(SHG)of nonlinear spectroscopy technique with surface and interface selectivity and sensitivity,which is used to study the internal mechanism of the influence of different chemical environments on the molecular behavior and structure of the phospholipid membrane surface probes.In this thesis,the SHG transmission measurement system is used to monitor the kinetic process of the adsorption and transport of the azobenzene compound Methyl Orange(MO)molecules on the surface of the vesicle membrane in real time,and the ion concentration is deeply analyzed by changing the chemical environment.The mechanism that affects the adsorption and transport behavior of MO at the vesicle interface.The results of the study show that by adding three salt solutions containing the same cation but with different anions,that is,changing the ion species and ion concentration in the solution will promote the adsorption and transport rate of MO on the surface of the vesicle membrane.More importantly,the dynamic behavior of MO molecules will also show significant differences depending on the type of salt solution added.In this thesis,the SHG reflection measurement system is used to first explore the saturated adsorption density of MO molecules on the Langmuir membrane interface of the phospholipid molecule at the air/water interface.Secondly,studying the interaction between the phospholipid molecule Langmuir membrane and the MO molecule in different chemical environments.In addition,combining with the analysis of the polarization dependence data,the spatial orientation and configuration changes of the molecules on the interface are obtained.The calculation results show that the spatial orientation of MO molecules on the interface will change greatly with the change of ion concentration in the solution,that is,as the ion concentration increases,the orientation angle of MO molecules will gradually increase.In summary,on the one hand,this paper obtains information on the dynamic process of interface molecules through time-dependent data analysis of SHG signals,which helps to further understand the influence of ion concentration on the interaction of drug molecules with vesicles.On the other hand,combining the polarization-dependent data analysis of the SHG signal,the spatial orientation and configuration change information of the interface molecules can be obtained,so as to provide important clues and basis for in-depth understanding of the empirical rules of the drug interface structure and action process.