Preparation And Application Of Polypyrrole Nano-composite In Tumor Theraty

With the development of nanoparticals and clinical imaging technology,it has become the hot spot in the study to constructe new theranostic platform.Compared with the traditional tumor therapy,phototherapy including photothermal therapy（PTT）and photodynamic therapy（PDT）has great application potential due to its excellent specificity,effective curative-effect and simple operation.However,single treatment modality can’t perish tumor completely.Therefore,with excellent optical absorbing polypyrrole（PPy）as nano-carrier,we design ultifunctional theranostic platform for imaging guided PTT/PDT/chemotherapy combined tumor therapy.We further explore its application performance and provide a new basis for the field of tumor treatment.In the second chapter,PPy-PVP nanoparticals were synthesized by“one pot”in-situ oxidation and polymerization method for combined tumor photothermal-chemotherapy.Firstly,the steric hindrance effect of polyvinylpyrrolidone（PVP）ensures the colloid stability and biocompatibility of the material,which lays a foundation for the research on the living body level.Secondly,PPy with good optical properties endow the materials remarkable photothermal performance,which can be admirably used in the photothermal treatment of cancers.Finally,we were systematically studied the influence of molecular weight and concentration of PVP on the photothermal feature,drug loading performance,and antitumor efficiency of the resultant PPy-PVP NPs.The results proved that the size of PPy-PVP increase and the effect of combined tumor therapy strengthen with the decrease of molecular weight and concentration of PVP.Hence,by choosing PVP with a molecular weight of 360 kDa（concentration of 5 mg/mL）as the optimal technological parameter during the synthesis.Findings in this study are anticipated to provide an in-depth understanding of the important character of surface engineering in the rational design and biomedical applications of PPy NPs.In the third chapter,an intelligent theranostic nanoplatform-based PPy nanomaterials for T₁-MRI-guided enhanced combined PTT and PDT of tumors.We successfully introduced MnO₂ via using potassium permanganate（KMnO₄）as the oxidant,which not only could enhance the tumor T₁-MRI ability,but also could continuously catalyze H₂O₂ into endogenous oxygen to relieve the hypoxia inside the tumor for enhancing the tumor PDT effect.Bovine serum albumin（BSA）as stabilizer ensure colloid stability and biocompatibility.Then,after loading with photosensitizer chlorin e6（Ce6）,the PPy@MnO2-BSA（Ce6）nanoparticle could produce the cellular toxic singlet oxygen（¹O₂）to trigger the tumor PDT.PPy,with a high optical characteristic,endowes nanoenzyme PTT.In vitro and in vivo experiments have affirmed the great potential of PPy@MnO2-BSA（Ce6）nanoparticle in MRI-guided combined PDT and PTT for tumor.This research lays a solid foundation for the polymert heoretical design and clinical application of theranostic nanoprobe in the future.