The Research Of Cancer Diagnosis And Treatment Based On Graphene Encapsulated Noble Metal Nanoparticle

In recent years, using nanomaterials to develop multimodal systems hasgenerated cutting-edge biomedical functions. Graphene, a single layer graphite withclose-packed conjugated hexagonal lattices, has attacted tremendous attentionand research interest owing to its Good biocompatibility, easily modified, the unique properties of two-photon fluorescence, Raman performance, large surface area,strong adsorption capacity and so on. Noble metal nanoparticles is a class ofnanomaterials with good performance and widely used in the biological field, butthere are some drawbacks limiting its use. Based on the above excellent performanceand disadvantages, this paper prepared a new aristocratic metallic graphenenano-materials by chemical vapor deposition, to expoler the developmen t of itsproperties for biological detection, diagnosis and treatment of cancer. The maincontents of this thesis are as follows:(1) We develop a simple chemical-vapor-deposition method to fabricate grapheme-isolated-Au-nanocrystal (GIAN) nanostructures. A thin layer of graphene is preciselydeposited on the surfaces of gold nanocrystals to enable unique capabilities. First, assurface-enhanced-Raman-scattering substrates, GIANs quench backgroundfluorescence and reduce photocarbonization or photobleaching of analytes. Second,GIANs can be used for multimodal cell imaging by both Raman scattering andnear-infrared (NIR) two-photon luminescence.(2) GIANs provide a platform for loading anticancer drugs such as doxorubicin(DOX) for therapy. Finally, their NIR absorption properties give GIANs photothermaltherapeutic capability in combination with chemotherapy. Controlled release of DOXmolecules from GIANs is achieved through NIR heating, significantly reducing thepossibility of side effects in chemotherapy. The GIANs have high surface areas andstable thin shells, as well as unique optical and photothermal properties, making thempromising nanostructures for biomedical applications.(3) Noble metals especially gold, have been widely used in plasmon reson anceapplications. Silver has stronger plasmonic properties and lower cost than Au. Butsilver attracts fewer attention due to its easy corrosion by the surroundings, formingAg2O or Ag2S on the surface, which degrades the optical signals and limits itsapplications. Encapsulating the silver surface with graphene could producesuperstable Ag nanoparticles. However, the weak catalytic activity of silver makes it hard to grow high quality graphene onto its surface. Fortunately, inexpensive coppercould help to grow graphene onto the surface of silver based on two points:1) Coppercould catalyze the growth of graphene;2) silver and copper can form good alloys.Herein, AgCu/Graphene (ACG) nanoparticles were synthesized through a facile way.By growing several layers of graphene onto the surface of AgCu nanoparticles,surroundings were completely separated and couldn’t contaminate the surface of Ag.ACG displayed a strong SERS effect based on the AgCu core, and the stable andstrong Raman signals from the graphitic shell also made it an ideal Raman tag for fastlive cells imaging. Further combining with alkyne-polyethylene glycol, which ownedstrong Raman vibrations in Raman-silent region of the cell, the ACG displayedcommendable capability of co-localized imaging. This work provided a simpleapproach to fabricate corrosion resistant and water soluble graphene-protected AgCunanoparticles, which had strong SERS effect appropriate for sensing and imaging.