Folate Hypoxia Double-targeting New Polymer Micelle Preparation And Diagnosis And Treatment Integration Research

The occurrence and development of tumors are complex and diverse.Chemotherapy drugs are generally lack of targeting,leading to side effects and poor efficacy.In most malignant tumors,there are hypoxic and anaerobic regions.The distribution of hypoxic regions and degrees in tumor is uneven,which is difficult to predict.In this paper,according to the physiological characteristics of tumor,amphiphilic polymers are used as carrier materials to modify tumor targeting groups and hypoxic selective groups on their surfaces,and a new traceable drug delivery system with dual targeting of tumor cells and hypoxic regions is designed and constructed In order to achieve the goal of integrated diagnosis and treatment of tumor and imaging,paclitaxel with cytotoxic effect and quantum dots with imaging effect were loaded together to develop a new nano drug delivery system with double targets of folic acid and hypoxia.At the same time,combined with quantum dots imaging technology,carrier dynamic tracing and regional imaging of hypoxia were realized.Part?:OverviewIn this part,firstly,the research progress of tumor hypoxia is briefly summarized;secondly,the application and characteristics of nano drug carrier and quantum dots of paclitaxel and fluorescence imaging material are briefly introduced;finally,the research progress of tumor targeting mediated by folate receptor in anti lung cancer is introduced.These four parts are consistent with the research content of this topic,which can provide theoretical basis for the follow-up work.Part?:Synthesis and characterization of amphiphilic block polymersIn this chapter,the amphiphilic block polymer PS-P(HEMA-DMAM)was prepared by the polymerization of monomers HEMA,DMAM and St controlled by DDAT.At the same time,the amphiphilic block polymer was modified by carbodiimide method with folate(FA)and 2-(2-nitroimidazole)ethylamine(NI),which had tumor targeting effect and tumor hypoxia targeting effect.The modified polymersNI-PS-P(HEMA-DMAM),FA-PS-P(HEMA-DMAM)and NI-FA-PS-P(HEMA-DMAM)were obtained.The successful synthesis of the polymer was determined by ~1H-NMR and FTIR.Part?:Preparation and in vitro properties of targeted traceable drug loaded micellesIn this part,firstly,paclitaxel and quantum dots were self-assembled into amphiphilic block polymer micelles to prepare drug loaded micelles,and the formulation was optimized by single factor investigation and response surface design.The results show that the particle size distribution is uniform,the particle size is45.566.3nm,and the polydispersity coefficient is 0.21.The potential was-20.86±5.12 MV.The encapsulation efficiency of PTX and QDs were 74.59%and 66.28%respectively,and the drug loading of PTX and QDs were 10.52%and 1.03%respectively.The results of in vitro release showed that the release rate of PTX in drug loaded micelles was significantly slower than that of API.Part?:Antitumor effect,targeting effect and safety of drug loaded micelles in vitroMTT assay showed that the blank carrier material had good safety,drug loaded micelles could enhance the inhibition of PTX tumor cells,double targeted drug loaded micelles had the strongest antitumor effect,and the antitumor effect was significantly stronger under the condition of hypoxia than that under the condition of normal oxygen.The results showed that double modified micelles could significantly enhance the antitumor effect of PTX on hypoxic tumor cells.The results of cell uptake experiments showed that Ni and FA could improve the efficiency of drug loaded micelles uptake,which was related to the active targeting effect of NIi and FA on tumor cells.The double modified micelles could significantly enhance the apoptosis of PTX cells.At the same time,hemolysis experiment and vascular stimulation experiment show that amphiphilic block polymer nano micelles can reduce the stimulation of drugs and improve the safety.Part?:Studies on pharmacokinetics,tissue distribution and pharmacodynamics in vivoFirstly,a HPLC method for the determination of PTX in vivo was established.The results show that the method has good specificity and is suitable for the determination of blood concentration in SD rats.The results of pharmacokinetics showed that the elimination half-life of PTX increased from 0.632 h to 2.957 h,and the average retention time(MRT)of paclitaxel in vivo also changed from 1.314 h to4.324 h,indicating that the modified micelles had a significant sustained-release effect.The targeting of NI-FA-PS-P(HEMA-DMAM)/QDs was evaluated by in vivo imaging,After injection of NI-FA-PS-P(HEMA-DMAM)/QDs into caudal vein,it was concentrated in tumor tissue by active and passive targeting,which showed that the prepared NI-FA-PS-P(HEMA-DMAM)/QDs had good targeting,could effectively increase the concentration of PTX in tumor tissue and prolong the retention time,improve the anti-tumor effect and reduce the side effects.TUNEL staining section of tumor showed that the green fluorescence of small and medium-sized mice in PBS group and PTX API Group was significantly lower than that of NI-FA-PS-P(HEMA-DMAM)/PTX group;quantitative analysis of green fluorescence showed that the green fluorescence intensity of NI-FA-PS-P(HEMA-DMAM)/PTX was 2.7 times of that of PTX group and 6.6 times of that of PBS group.Therefore,double modified drug loaded micelles could significantly increase the anti-tumor effect of PTX.The results showed that NI-FA-PS-P(HEMA-DMAM)/PTX could effectively enhance the antitumor effect through the active targeting of folate receptor and the tumor hypoxia targeting of NI.NI-FA-PS-P(HEMA-DMAM)/PTX has no obvious toxicity to all organs and has good safety.