Study Of Polyamidoamine Modified Graphene Oxide As Drug And Gene Or Drug And Durg Co-delivery Carrier

This thesis consists of two parts:(1)A polyamidoamine dendrimer functionalized graphene oxide for DOX and MMP-9 shRNA plasmid co-delivery;(2)A polyamidoamine dendrimer functionalized graphene oxide co-deliver DOX and CsA for reversing multidrug resistance of tumor cells.Ⅰ.A polyamidoamine dendrimer functionalized graphene oxide for DOX and MMP-9 shRNA plasmid co-delivery(Second Charpter)Graphene oxide(GO),because of its unique two-dimensional monolayer structure,can be used to deliver highly loading Doxorubicins(DOXs)by π-π stacking interactions.Polyamidoamine dendrimer(PAMAM)exhibits a dendritic structure and positively charged zeta potential for complexing DNA or RNA.In recent years,more and more GO and PAMAM have been used for drug or gene delivery,and achieved exciting results.In order to solve multidrug resistance in tumor treatment,this work will combine the advantages of GO and third generation polyamidoamine(PAMAM 3.0G)to prepare PAMAM 3.0G functionalized GO(GO-PAMAM 3.0G)as drug carrier to co-deliver DOX and MMP-9 shRNA for anti-tumor.The results showed that GO-PAMAM 3.0G has a high loading capacity of 28.63% to DOX and pH-controlled DOX release.Besides,it had efficient gene transfected ability.The transfection efficiency is significantly better than that of PEI-25 k in the presence of serum,and it can significantly inhibit the expression of MMP-9 protein in MCF-7 cells from the result of Western Blot.The antitumor efficiency of DOX and MMP-9 shRNA plasmid co-delivery was more significant than that of the single drug.Moreover,GO-PAMAM 3.0G exhibited lower cytotoxicity compared to PEI-25 k in CCK-8 assays,and also showed a good biocompatibility in vivo.Therefore,GO-PAMAM 3.0G will have broad prospects for co-delivery of drug and gene,and it can provide a new way to treat multidrug resistance.Ⅱ.A polyamidoamine dendrimer functionalized graphene oxide co-deliver DOX and CsA for reversing multidrug resistance of tumor cells(Third Chapter)It is a common phenomenon in cancer therapy that multidrug resistance of tumor cells would lead to ineffective treatment.The results of multidrug resistance of tumor cells can be attributed in two aspects: on the one hand,chemotherapy drugs may interfere with the process of tumor cell apoptosis;on the other hand,the membrane proteins on the surface of the tumor cells,can exclude or expel the chemotherapy drugs from the cell,which reduce the amount of drug accumulation in the cells and lead to ineffective tumor chemotherapy.In the study of multidrug resistance,the major proteins related to multidrug resistance generally involved in drug transport P-glycoprotein(Pgp),multidrug resistance associated protein,antigen processing related transporter,and so on.Studies have shown that Cyclosporin A(CsA)can significantly inhibit the formation of intracellular P-gp,which reduce the exclusion of chemotherapy drugs and alleviate or reverse multidrug resistance.Based on these studies,the codelivery system of DOX and CsA was designed and investigated for the inhibitory effect on multidrug resistance tumor cells.The results showed that DOX and CsA could significantly inhibit the growth of multidrug-resistant cells under the condition of appropriate drug ratio.Therefore,the appropriate drug carrier is needed to accurately regulate the proportion of DOX and CsA and control drug release.On the basis of the second chapter,the final drug carrier GO-PAMAM 4.0G was prepared for by using the fourth generation polyamidoamine(PAMAM 4.0G)to functionalize GO.The more wide dendritic PAMAM 4.0G is used to load CsA and GO is used to load DOX by the π-π stacking interactions,achieving the co-delivery of DOX and CsA.The experimental results showed that no significant inhibitory effect on doxorubicin resistant MCF-7 cells(MCF-7/DOX cells)was found by delivering DOX or CsA.However,when GO-PAMAM 4.0G was used to co-deliver DOX(194 μg/mg)and CsA(45.1 μg/mg),it was exhibited to significantly inhibit the growth of MCF-7/DOX cells,reversing the drug resistance of tumor cells and enhancing the anti-tumor effect.The results of this study maybe provide a new solution for the current drug resistance problems.