Synthesis And Theranostics Of Polypyrrole Coated Bismuth Nanoparticles For Anticancer Treatments

In recent years,the number of deaths caused by cancer increased year by year,cancer has become a major killer to human health,so the diagnosis of early tumors and effective treatment in clinical has become an urgent matter.Traditional methods of cancer treatment are surgical,chemotherapy and radiotherapy,but these traditional methods of treatment have intrinsic drawbacks,such as the tumor can not be completely eradicated,the treatment cycle is long,increase the patient’s pain and so on.With advances in science and technology,near-infrared light-induced photothermal therapy(PTT)has aroused people’s attention as a “green therapy” for the treatment of cancer.It can localized eliminating the tumor cells without affecting the surrounding healthy tissues.To improve the photothermal effect and achieve real-time monitoring of the tumor during anticancer therapy,medical imaging is required to provide the location and size of the tumor in vivo.Therefore,combining imaging and PTT has become an alternative direction for cancer treatment,and looking for multi-functional nanomaterials that both have imaging and PTT functions is of great interest to the society.Herein,we report the synthesis and bio-application of a multifunctional theranostic nano agent based on polyethylene glycol(PEG)-modified polypyrrole(PPy)-coated bismuth(Bi)nanohybrids(referred to as Bi@PPy-PEG NHs)for X-ray computed tomography/photoacoustic(CT/PA)dual-mode imaging and photothermal therapy.The obtained Bi@PPy-PEG NH reveal a distinct core-shell structure with Bi nanoparticles(NPs)as the inner core,and polypyrrole self-assembled via a facile one-step chemical oxidation polymerization on the outer surface as the shell.PEG is used to further modify the NHs to enhance the physiological stability.The obtained Bi@PPy-PEG NHs show excellent physiological stability/compatibility and no/low cytotoxicity.Importantly,the NHs exhibit strong NIR absorbanceand outstanding photothermal effect/stability,withan admirable photothermal conversion efficiency up to ~ 46.3%.By utilizing the strong PTT effect,highly effectively in vitro phototherm alablation of cancer cells has been finally achieved after treated with the NHs plus NIR laser irradiation.Furthermore,a dual-modal imaging,i.e.,X-ray computed tomography(CT)and photoacoustic(PA)imaging,has been realized both in vitro and in vivo,showinggreat potential to provide accuratediagnosisinformation for antitumor treatment.In conclusion,inorganic materials(Bi)with high X-ray attenuation coefficient were combined with organic materials(PPy)with strong photothermal capacity,and then modified by materials with good physiological stability.The obtained nanohybrids have advantages of both of them,ang overcoming their drawbacks.The obtained Bi@PPy-PEG NHshad both CT/PA imaging and photothermal therapy,showing good physiological compatibility and low cytotoxicity,laying the foundation for further clinical research.