Study On The Preparation Of Tocopherol-albumin Nanoparticles And Their Applications In Chemotherapy-photothermal Combined Therapy Of Tumor

Objective:The chemotherapy-photothermal combined therapy has proven to be a promising strategy for cancer treatment.Various nanomaterials have shown great potential in the combination therapy,including gold,graphene oxide,iron oxide,etc.However,their undefinable toxicity in vivo greatly slowed down their development for clinical application.Here,we expect to develop a multifunctional nanoparticle with good biocompatibility,containing human serum albumin(HSA),D-?-tocopherol succinate(TOS),indocyanine green(ICG),and doxorubicin(DOX).This nanoparticle can combine chemotherapy with photothermal therapy(PTT)to treat cancer.Notably,all of the four components have been approved by the Food and Drug Administration or applied in clinic for many years.Methods:1.The novel biocompatible nanoparticle(HIT-NPs)was self-assembled through the intrinsic interaction between D-?-tocopherol succinate(TOS),human serum albumin(HSA)and indocyanine green(ICG).Doxorubicin(DOX)was then loaded due to the ion pairing between DOX and TOS.DOX-loaded HIT-NPs were carefully characterized by transmission electron microscopy(TEM),malvern zetasizer nano,UV-vis spectrophotometer.The photothermal conversion ability and drug release ability of the nanoparticles were also evaluated.2.CCK8 assay was used to evaluate the cytotoxicity of nanoparticles.The cytotoxicities againsted murine breast cancer cells(4T1 cells)and human normal liver cells(HL-7702 cells)were studied to evaluate the antitumor effect and biocompatibility of nanoparticles,respectively.Under near-infrared laser irradiation,the chemotherapy-photothermal combined therapeutic effects against 4T1 cells were also studied.3.The 4T1 subcutaneous tumor model was builded up.In vivo distribution of nanoparticles was obtained at 2,8 and 24 h after injection using an in vivo imaging system in 4T1 tumor-bearing mice,and the photothermal efficacy after intravenous injection was also evaluated in the tumor site.4.The results of previous studies showed that ICG was the main component of the photothermal treatment effect in HIT-NPs.In order to increase the amount of ICG and improve the effect of photothermal treatment,we have optimized the synthetic prescription.The synthetic HSA-ICG-TOS nanoparticles?(abbreviated as HIT-NPs~?)were carefully characterized by UV-vis spectrophotometer and malvern zetasizer nano,etc.Then,the CCK8 experiment was used to evaluate the killing effect of HIT-NPs~?on multidrug resistant breast cancer cells(MCF-7/ADR cells).Results:1.Transmission electron microscopy(TEM)and malvern zetasizer nano showed that DOX-loaded HIT-NPs were spherical with a diameter of 190.2±3.0 nm.The UV-vis-NIR spectra result suggested the successful binding of ICG,DOX into nanoparticles.The maximum temperature of DOX-loaded HIT-NPs under laser irradiation was found to be 50.6?.The DOX-loaded HIT-NPs showed accelerated drug release under acidic condition and NIR laser irradiation.2.At the cellular level,HIT-NPs showed no cytotoxicity against human normal liver cells(HL-7702 cells)but obvious killing effects on murine breast cancer cells(4T1 cells).Compared with free DOX,DOX-loaded HIT-NPs had obvious toxic effects on 4T1 cells.DOX-loaded HIT-NPs had a low toxicity on HL-7702 cells than that of free DOX,suggesting that nanoparticles could reduce the toxic side effects of DOX chemotherapy on normal liver cells.The chemotherapy-photothermal combined therapeutic effects against 4T1 cells were also successfully obtained under NIR laser irradiation.3.The mouse 4T1 breast cancer model was successfully established.DOX-loaded HIT-NPs could effectively accumulate in 4T1 subcutaneous tumor,and the tumor temperatures rapidly increased to 49.0?under laser exposure.4.The ICG content in the synthesized HIT-NPs~?increased significantly.HIT-NPs~?had ICG concentration-dependent heating ability and good dispersibility.Cell experiment results indicatied that HIT-NPs~?showed negligible toxic effects on normal liver cells(HL-7702),but had obvious toxic side effects on MCF-7 cells and MCF-7/ADR cells.Under the near-infrared laser irradiation,the killing effect of HIT-NPs~?on MCF-7 cells and MCF-7/ADR cells was stronger than that of HIT-NPs~?alone.Conclusion:First,we successfully prepared nanoparticles(HIT-NPs)using the internal forces of HSA,TOS and ICG.DOX could be effectively loaded in these nanoparticles.HIT-NPs exhibited good photothermal effect under NIR laser irradiation.DOX-loaded HIT-NPs could significantly inhibit the growth of 4T1 cells in vitro,indicating that it had good chemotherapeutic effect.Under near-infrared laser irradiation,the inhibition effect on 4T1 cells was significantly enhanced,reflecting a significant combined effect of chemotherapy and PTT.Notably,HIT-NPs showed negligible cytotoxicity on normal liver cells(HL-7702)and even resisted the toxic side effect induced by DOX,demonstrating an excellent biocompatibility.Then,we established a 4T1 breast cancer mouse transplantation model.After intravenous injection,nanoparticles could preferentially accumulate in xenografted tumors,showing good photothermal effect under laser irradiation,which laid the foundation for the next step in vivo photothermal therapy research.Finally,we optimized the synthesis method and increased the content of photothermal component ICG in nanoparticles.HIT-NPs~?combined with photothermal therapy had a obvious killing effect on the level of MCF-7/ADR cells.Therefore,this kind of nano-drug with good biocompatibility will have a broad prospect in chemotherapy-photothermal combined therapy of tumor.