Preparation And Research On Tumor Diagnosis And Treatment Properties Of Bi-based Nanocomposite

In recent years,near-infrared(NIR)laser induced light therapy(such as photodynamic and photothermal therapy)has become a promising cancer treatment method due to its deep tissue permeability,which attracting growing attention of researchers.Currently,although a number of integrated multifunctional nanomaterials with diagnostic and therapeutic have been developed,the combination of diagnosis and treatment through a single “element” remains a huge challenge.Recently,many methods have been developed to synthesize metal bismuth nanomaterials,however,the strict experimental process,high temperature,toxic organometallic precursors and long reaction time limits their developments.The reduction method,solvothermal method and microwave method are simple,but the experimental process is not easy to control,which usually leads to poor morphology of bismuth(Bi)nanoparticles.Therefore,it is indispensable to explore an ultra-simple synthesis method without using organic solvents for the synthesis of high-quality pure metal Bi nanoparticles.In this dissertation,poly(vinylpyrrolidone)-protected bismuth nanodots(PVP-Bi nanodots)with good dispersion were synthesized by a concise chemical reduction method.And the particle size of elemental Bi synthesized by this method was only 2-3 nm.We have found that PVP-Bi nanodots can be excited by 1064 nm laser to generate heat,and the photothermal conversion efficiency reached 32.3%.Through cell experiments,we found that the inhibition rate of cancer cells reached 78.7%,which was much more lethal than that excited by 808 nm laser.All results showed that the PVP-Bi nanodots was a very good photothermal reagent.In our research,by using dendritic mesoporous silica as a carrier,PVP-Bi nanodots are coated with a layer of myristyl alcohol to prevent the PVP-Bi nanodots from being oxidized,which greatly improved the its photothermal properties.In vitro and in vivo experiments have shown that Bi-DMSNs@PCM nanocomposites can be applied for photothermal therapy under the irradiation of 1064 nm NIR.