| Due to its physical properties on the nanoscale,precious metal nanoparticles have a wide application prospect in the fields such as drug detection analysis,bioimaging,drug therapy,data storage and sensing detection with unique optical properties such as surface plasmon resonance scattering,Raman scattering and coupling effect.Local surface plasmon resonance technology means that precious metal nanoparticles will trigger the collective oscillation of electrons on the surface of precious metal nanoparticles stimulated by incident rays while being irradiated by larger wave lengths,and this coherent oscillation will generate strong light scattering and produce a strong absorption peak in the spectrum.The intensity and position of scattering peak depend on the shape,size and structure of nanoparticles and the refractive index of surrounding mediums.In virtue of the role combining with Dark Field microscopy,a further research on the scattered spectroscopy of local surface plasmon resonance can be made,which promotes the application of surface plasmon resonance technology in biosensing and biological detection.Taking precious metal nanoparticles as the substrate,this paper fixes the proteins with free sulfydryl on the surface of probe by using Au-S or Ag-S bond assembly technology.The refractive index change due to the protein structure change can significantly affect the plasmon exciton scattering spectral peak position,so that a highly sensitive nano plasmon protein conformation sensor can be constructed.This sensor can be used for real-time,highly sensitive and stable monitoring of protein unfolding and folding processes.Besides,taking advantage of the reversible denaturation of proteins,the circle detection of the changes in protein structure is researched.First of all,seed-growth method is applied to prepare gold nanospheres.Then,the nanospheres are coated with sliver,which synthesizes Au@Ag core-shell nanocubes as the optical nanoprobe.Then,free sulfydryl brought by bovine serum albumin is used to construct Au@Ag NCs-protein assembly biosensor through Au-S or Ag-S bond.A series of characterizations are made by TEM,Uv-vis and DFM.According to the characterization result,the nanostructure constructed accords with the experimental result.In addition,optical nanoprobe constructed is used to synthesize the assembly biosensor,and the denaturant is applied to make the real-time,stable and sensitive circle detection of the unfolding and folding processes of protein structure according to the principle that the denaturation of proteins is reversible.Meanwhile,based on the stable Au@Ag NCs-protein assembly biosensor constructed above,different denaturation conditions are employed to denaturate proteins while discussing the detection of temperature changes and protein structure changes by its assembly biosensor and researching the influence of temperature on bovine serum albumin.Secondly,seed-mediated growth method is adopted to prepare a gold nanorod with the aspect ratio of 1-5,and the influence of different amounts of silver nitrate on the growth of gold nanorods is examined.Next,the gold nanorod with a small aspect ratio is selected as the optical nanoprobe,and Au-S bond is used to construct the Au NRs-protein assembly biosensor;characterizations are made by TEM,UV-vis and DFM.Based on the principle that the denaturation of proteins is reversible,Au NRs-protein assembly biosensor constructed is used to make a real-time,stable and sensitive detection of the unfolding and folding processes of protein denaturation.Besides,the detection of the changes in pH and protein structure by the assembly biosensor is discussed,and the influence of pH on bovine serum albumin is researched.At the end,the detection of the changes in protein structure with different nanoparticles as the optical probes is discussed by using Localized Surface Plasmon Resonance(LSPR),indicating the possibility of applying Local Surface Plasmon Resonance to the research on the dynamic changes in protein structure. |
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