Preparation Of Bismuth Gadolinium Vanadate@Polydopamine Nanocomposite Core-shell Materials For Tumor Theranostic

Cancer is the biggest killer threatening human health,radiotherapy plays a very significant role in the treatment of cancer.Using nanomaterials containing high Z element as radiotherapy sensitizer can not only reducing the radiation dose,but also achieving better therapeutic effect,so as to reduce the damage to normal tissues during radiotherapy.As a non-toxic and cheap high Z element,Bi has excellent X-ray absorption characteristics and is a good radiotherapy sensitizer.Accurate diagnosis is the first step to treatment.Computed tomography（CT）imaging is relatively inexpensive,simple and suitable for emergency care,but in some areas there are too many bone artifacts that can interfere with the display of surrounding soft tissue.Magnetic resonance（MR）imaging has sensitivity for soft tissue imaging,which can make up for the shortcoming that CT imaging can not be directly planar imaging.Photoacoustic（PA）imaging can be monitored in real time,and is a non-ionization and non-damage imaging technology.Various imaging methods can complement each other to improve the diagnostic effect.In this paper,based on Bi_0.3Gd_0.7VO₄nanoparticles and polydopamine（PDA）as structural elements,nanocomposite core-shell materials for tumor diagnosis and treatment were constructed.Bi is a high Z element with high X-ray absorption coefficient,which can be used as radiotherapy sensitizer and CT imaging contrast agent.Gd³⁺has unpaired electrons and can be used as contrast agent for MRI.On the one hand,PDA can absorb near-infrared light and convert it into heat energy,which can be used in photothermal therapy.On the other hand it is used as PA imaging contrast agent.The following two aspects of research have been carried out,the specific research contents are as follows:The first part,in order to Bi_0.3Gd_0.7VO₄nanoparticles as a primitive structure,using hydrophobic-hydrophobic interactions as a driving force through self-assembly technology to build super particle structure,then coated on the surface shell,PDA and modify the catalase（CAT）and folic acid（FA）,to the preparation of both radiotherapy、photothermal therapy、CT、MRI and PA of Bi_0.3Gd_0.7VO₄SPs@PDA@CAT&FA core-shell materials.Since CAT can convert high concentration of H₂O₂in tumor cells to O₂,Bi_0.3Gd_0.7VO₄SPs@PDA@CAT&FA nanocomposite core-shell materials can effectively increase the O₂ content in tumor cells,and thus improve the sensitivity of tumor cells to radiotherapy.The second part,in order to Bi_0.3Gd_0.7VO₄nanoparticles and polyene paclitaxel（DTX）as a primitive structure,using hydrophobic-hydrophobic interactions as a driving force through self-assembly technology to build super particle structure,then coated on the surface shell,PDA last modified FA,to the preparation of radiotherapy、chemotherapy、photothermal therapy、CT、MRI and photoacoustic imaging features of Bi_0.3Gd_0.7VO₄-DTX SPs@PDA@FA core-shell materials.Thanks to the photothermal conversion ability and degradability of PDA,Bi_0.3Gd_0.7VO₄-DTX SPs@PDA@FA nanocomposite core-shell materials can controllable release of DTX.