Study Of The Mechanism Of The Influence Of Engineering Nanoparticles On Trypsin Structure And Conformation

Understanding the factors that affect proteins adsorb to the most representative engineered nanoparticles in the environment is important for revealing the interaction mechanism between nanoparticles and proteins.Here,this thesis focuses on the interaction mechanism between protein and nanoparticles of different properties,such as sizes,concentrations,surface hydrophobicity and species.The main contents are as follows:(1)Silver nanoparticles(Ag NPs)of different sizes and excellent uniformity were prepared by seed synthesis methods.The effects of different sizes and concentrations of Ag NPs on the formation of protein corona after interacted with trypsin were investigated.Various methods,such as circular dichroism(CD),ultraviolet-visible spectrophotometry(UV-Vis),and fluorescence spectroscopy(FL),were used to detect the effects of Ag NPs on trypsin molecules.The results showed that after trypsin interacted with Ag NPs,the secondary structure and conformation of trypsin changed,the position of the maximum absorption peak as well as the absorption intensity of Ag NPs changed.The reason for these changes is that the interaction between trypsin and Ag NPs may affect the particle size distribution of NPs.As the size of NPs decreases,the fluorescence quenching efficiency decreases.Therefore,it can be confirmed that different sizes and concentrations of Ag NPs can cause the properties and conformation of trypsin changes.(2)Ag NPs with different hydrophilic and hydrophobic properties were preparated.Hydrophobicity property was used as the influencing factor to investigate the effect of different surface hydrophobic Ag NPs on trypsin interactions.The surface hydrophobicity of Ag NPs is characterized by contact angle measurement and adsorption of hydrophobic probe molecules,and it is basically confirmed that the hydrophilic to hydrophobic order is as follows: Ag-CIT,Ag-PVP,Ag-GA,Ag-SA and Ag-OA.CD,UV-Vis and FL methods were used to detect the effect of different surface hydrophobic Ag NPs on trypsin molecules.According to the CD spectrum,after trypsin interacted with Ag NPs,the secondary structure and conformation of trypsin changed.The experimental results confirmed that the weaker the surface hydrophobicity of Ag NPs,the less amount of trypsin adsorbed on the surface.(3)The effects of different sizes and concentrations of ZnO NPs on trypsin interaction were explored.Adding ZnO NPs of different sizes to the trypsin solution will cause the fluorescence intensity of trypsin to undergo significant fluorescence quenching and change in UV-visible absorption peaks,as well as the secondary structure and conformation.It was confirmed that when the concentration of ZnO NPs increased,the number of NPs in the same volume increased,which caused the environment of the protein to be crowded and the protein macromolecules fully contacted the NPs.And the increase of the number of NPs will greatly increase the total specific surface area of NPs in the system.These two factors will greatly increase the amount of protein adsorbed on the surface of NPs,causing trypsin denaturation.