The Synthesis And Theranostics Of Bismuth Nano-carriers For Anticancer Treatments

Cancer has become a major threat to the human health.At present,there are no effective methods and measures to diagnose the early tumors in clinical practice.As a result,symptoms of the disease appear in the mid-late stage or late stage.The conventional methods of treating tumors(such as surgical removal,chemotherapy and radiotherapy)all show different degrees of defects.The common characteristics of this therapies are:the tumor cannot be eliminated completely,the treatment period is long,increase the patients'pain and maybe causing irreversible damage to the body.With the continuous development of medical technology,researchers had proposed a nanometer platform to diagnosis and tumor treatments.Meanwhile,they had also found a new treatment--photothermal therapy(PTT),which uses near-infrared laser(NIR)irradiate photothermal reagent to convert light energy into heat energy,in order to eliminate tumors.This method has little damage to the function of human body and greatly reduces the toxicity to the whole body system.Therefore,photothermal therapy is expected to be the technology of treating tumors in the future.In this paper,bismuth nanoparticles were synthesized by one-step thermal reduction method,then the mesoporous bismuth nanoparticles(p Bi NPs)were obtained by etching.For improved its stability,we modified the nanoparticles with polyvinylpyrrolidone(PVP),obtained nano-microspheres with X-ray tomography(CT)imaging.It is proved that p Bi NPs has good thermal stability,biocompatibility and low cytotoxicity with experiments of thermal stability and cytotoxicity.In addition,the photothermal conversion experiment of p Bi NPs showed it has strong absorption of near-infrared light and high photothermal transformation,and the photothermal conversion efficiency is 48.5%.Animal and cell experiments in vivo and in vitro showed that p Bi NPs had good photothermal ablation and radiotherapy effects,as well as strong CT imaging signals and chemotherapy effects.It was demonstrated that this material could be used in combinating with photothermal therapy,radiotherapy and chemotherapy under the guidance of biological imaging.This paper is about the synthesis method of a kind of multifunctional nanomaterials Bi₂S₃@Au-PEG,a single material containing a variety of functions.It can realize the heat treatment(PTT)and chemical treatment under the guide of X-ray computed tomography imaging(CT),polyethylene glycol(PEG)modification enhances its biological property.The gold shell of this material is mesoporous structure,which can realize the delivery of chemotherapy drugs(DOX),greatly improving the treatment of chemotherapy drugs to tumors.In vitro photothermal experiments also confirmed the photothermal effect of this materials.In summary,the new materials have a promising prospect for the treatment of tumors.The two multifunctional nanocarriers synthesized in this paper,include the combination of diagnosis and treatment,further explored the application of multimode therapy under the guidance of tumor imaging,and established a foundation for the future application of nanocarriers in medicine.