Physicochemical Analysis Of Lipid Monolayer Structure By Hydrophilic/hydrophobic Fe₃O₄ Nanoparticles

Nanoparticles have a variety of properties and can be used as carriers to achieve a variety of biological functions.Mitochondria are considered as amplifiers of cellular stress and apoptosaer signals in biology.When a cell is injured,the mitochondria's own stress response affects membrane rigidity.Nanoparticles can affect many properties of membranes,and Langmuir-Blodgett film technology can characterize a series of changes in the physical and chemical properties of membranes.In this study,Fe3O4 nanoparticles with dispersion and stability of small size were prepared,modified and characterized by different methods.Using LB film technology,Fe3O4 nanoparticles were combined with single-component film,two-component mixed film,three-component mixed film and mitochondrial inner membrane model membrane for theoretical calculation and analysis.To explore the interaction mode and mechanism between Fe3O4 nanoparticles and mitochondrial intimal model.Specific experimental contents and results are as follows:(1)Study on the interaction between Fe3O4 nanoparticles and 1-palmitoyl-2-oleoylsn-glycero-3-Phosphor-ethanolamine(POPE)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)/Cardiolipin(BHC1)lipid m onolayers.There were electrostatic interactions between hydrophilic Fe3O4 nanoparticles and POPE and POPC monolayers,and they bind to the polar head in the subphase;Electrostatic repulsion existed between Fe3O4 and BHCl monolayer.The hydrophobic Fe3O4 nanoparticles binded to the polar head of POPC and POPC monolayers by electrostatic interaction and hydrophobic interaction.The hydrophobic interaction and van der Waals force between Fe3O4 and BHCl monolayer molecules were stronger than the electrostatic repulsion.(2)Study on the Interaction between Fe3O4 Nanoparticle and Mixed POPE/POPC monolayer.The interaction between Fe3O4 Nanoparticle and Mixed POPE/POPC Monolayer was electrostatic.With the passage of time,Fe3O4 nanoparticle molecules continued to be adsorbed to the monolayer,and the greater the concentration of Fe3O4 nanoparticle,the more significant the adsorption.Compared with hydrophilic Fe3O4 nanoparticles,the adsorption of hydrophobic Fe3O4 nanoparticles on the mixed POPE/POPC monolayer was stronger,which was due to the enhanced electrostatic adsorption of hydrophobic Fe3O4 nanoparticles.(3)Study on the interaction between Fe3O4 nanoparticles and mixed POPE/POPC/Cholesterol(Chol)monolayers.Fe3O4 nanoparticles binded to lipid monolayers by electrostatic interaction and van der Waals forces.In the presence of Chol,the collapse pressure was higher than that of mixed POPE/POPC monolayers,indicating that Chol increased the stability of the mixed membrane.The hydrophobic Fe3O4 nanoparticles were more electrically charged than the hydrophilic Fe3O4 nanoparticles,which can generated electrostatic interaction and van der Waals forces between the mixed POPE/POPC/Chol monolayers.Hydrophobic Fe3O4 nanoparticles carried more charge than hydrophilic Fe3O4 nanoparticles,and the adsorption of hydrophobic Fe3O4 nanoparticles on the mixed POPE/POPC/Chol monolayers was stronger with the help of electrostatic adsorption.The excess average molecular area and excess Gibbs free energy were negative,indicating that the interaction between the molecules was an attractive interaction and there was attraction.(4)Study on the interaction between Fe3O4 nanoparticles and the mitochondrial inner membrane model membrane.Fe3O4 nanoparticles can produce electrostatic interaction and van der Waals forces between IMM monolayer molecules.Hydrophobic Fe3O4 nanoparticles carried more charge than hydrophilic Fe3O4 nanoparticles,and the adsorption of hydrophobic Fe3O4 nanoparticles was stronger with the help of electrostatic adsorption.The values of excess mean molecular area and excess Gibbs free energy were positive,indicating that the interactions between the four molecules of IMM were repulsive interactions.The interaction between the more electronegative hydrophobic Fe3O4 nanoparticles and the negatively charged lipid molecules BHCl and Chol can further enhance their mutual repulsion.Through the above studies,LB film technology was used to combine Fe3O4 nanoparticles with the mitochondrial intimal model membrane,so as to conduct a more comprehensive study on the whole process of interaction between Fe3O4 and the mitochondrial intimal model membrane from mono,binary and ternary.Based on the experimental data,the interaction mode and possible mechanism of Fe3O4 nanoparticles with the mitochondrial membrane model were speculated through theoretical calculation and analysis,which provided certain theoretical support for the related studies of cell membrane system,mitochondrial stress and mitochondrial diseases.