Synthesis Of UCNPs Nano-Materials And Their Application In The Field Of Multi-Functional Cancer Therapy

Recently,nanoparticles have gained much attention from researchers for using in drug delivery systems,which provide simultaneous cancer diagnostics and therapy within a single systems.Among all the nanoparticles,lanthanide doped upconversion nanoparticles?UCNPs?,Which can convert longer wavelength radiation to UV or visible light via a two-photon or multiphoton mechanism,are being considered for a number of biomedical applications.UCNPs has been identified as perfect carrier of the photosensitizer due to its conceivable advantages including excellent chemical stability,low toxicity,low fadedness of light,outstanding penetrability to biological tissue and so on.Besides the up-conversion properties,Gd-doped and Yb-doped UCNPs show great potential as the CT contrast agent.In this dissertation,multistage core-shell lanthanide doped luminescent nanomaterials were synthesized by thermal decomposition method,and the nanomaterials were modified by Au NCs.The nanomaterials luminescence properties,biocompatibility,multimodality imaging,effect of photodynamic and photothermal therapy were investigated in detail.Au NCs/UCNPs composite materials has been designed.The three-core-shell NaGdF₄:Yb/Er@NaGdF₄:Yb@NaNdF₄:Yb nanomaterials were synthesed in a solvent thermal method,the as-prepared nanoparticles show good uniform morphology and can be dispersed in water,the product show bright up-conversion fluorescence under 980 nm laser excitation,compared with using the UV.Then the surface of nanomaterials were modified by Au NCs,combined up-conversion/CT multi-modal imaging for cancer diagnosis and treatment.In the experiment of EGFP plasmid transfection,the composite nanomaterials show good transfection efficiency,also through the cell toxicity,biocompatibility and hemolytic experiment,shows the good applications in biological field.Finally,the multi-modal imaging property was assessed in vivo.The nanomaterials shows great potential as a contrast agent in CT,it also exhibits a good skin penetration ability in mice.