Fe@Fe 3 Ge 2 Nanoparticles In Tumor MR Imaging And Phototherm/photodynamic Therapy

Magnetic nanomaterials have been widely applied in magnetic resonance imaging(MRI)and photothermal therapy(PTT)in vivo due to their excellent magnetic properties and optical properties.However,the resistance to heat can decrease the effect of photothermal therapy.Nanomaterials with both photothermal and photodynamic effects(PDT)can overcome this shortcoming by the action of reactive oxygen species under laser irradiation.However,the current study is difficult to achieve PTT and PDT with the same wavelength.Therefore,we designed and synthesized novel core/shell Fe@Fe3Ge2 nanoparticles.The nanoparticles not only have good magnetic properties,but also have photothermal and photodynamic effect under the 808 nm laser irradiation.This thesis consists of two parts:In the first part,Fe@Fe3Ge2 nanoparticles were synthesized by pyrolysis.The nanoparticles had high saturation magnetization(~ 53.3 emu / g).Irradiated by the near infrared light,they had high photothermal conversion efficiency(~ 20.9%)and the ability of singlet oxygen generation.In order to improve the water solubility and biocompatibility of nanoparticles,distearyl phosphatidylethanolamine-polyethylene glycol(DSPE-PEG)was coated on the surface of Fe@Fe3Ge2 nanoparticles to obtain a new diagnostic agent(MNPs-PEG)with a small diameter(~ 50 nm),MR imaging,photothermal and photodynamic therapy.Cell experiments showed that MNPs-PEG had obvious killing effect on cells by photothermal and photodynamic effects under the 808 nm laser irradiation.Further studies showed that the contribution of photodynamic effect to cell death was higher than that of photothermal effect.MNPs-PEG was injected into the 4T1 tumor mice by tail vein.MR imaging experiments showed that the nanoparticles showed the strongest targeting effect on the tumor after 2 hours.MNPsPEG was used to achieve effective photothermal / photodynamic therapy for tumor under the 808 nm laser irradiation(1.27 W/cm2)under the MR imaging guidance.In the second part,in order to achieve the active targeting of nanoparticles,we modified RGD to the surface of Fe@Fe3Ge2 nanoparticles,and successfully prepared MNPs-RGD with targeted property.In the cell experiment,MR imaging and MTT experiments showed that the nanoparticles had good active targeting and photothermal / photodynamic therapy for U87-MG cells.