Preparation Of Non-Covalently Modified Nanocomposites Based On Magnetic Graphene Oxide And Its Application In Drug Delivery

At present,cancer constructs a serious threat to human health all over the world as the biggest enemy of human diseases.In recent years,nanomaterials targeting therapy has made some breakthroughs regarding cancer treatment.Graphene,found in2004,with its advantages of good dispersibility,favorable biocompatibility and large specific surface area,has been largely applied in biomedicine,including gene and drug delivery and intracellular tracking.However,unmodified graphene oxide is easy to agglomerate under physiological conditions.Therefore,layer-by-layer self-assembly technology can be used to adjust the surface charges according to different purposes and modify the outermost types by exchanging material order,so as to adapt to different conditions.In addition,layer-by-layer self-assembly can provide more binding sites for functionalized nanomaterials and realize the multi-functionalization of the film surface.Graphene oxide was functionalized with graphene oxide as base material in this study.Meanwhile a variety of graphene oxide nanocomposites were prepared and characterized by FTIR,AFM and TEM.At the same time,the nanomaterials were evaluated in vitro and in vivo.The specific research results are as follows:(1)GO was modified with chitosan and sodium carboxymethyl cellulose using GO as base material.The composites were characterized by FTIR,AFM and TEM.The results show that GO-CS/CMC has been successfully prepared.The material has good stability under physiological conditions,and reduces the non-specific protein adsorption of the material.Studies concerning drug loading and drug release show that the composite has a high loading effect on doxorubicin(DOX).Meanwhile,drug release is strongly dependent on pH,with accelerating release rate d under acidic conditions and increasing cumulative release,which is helpful to cancer treatment.(2)MGO was synthesized by hydrothermal preparation and modified with chitosan and sodium alginate.The composites were characterized by FTIR,AFM andTEM.The results show that MGO-CS/SA has been successfully prepared.Chitosan /sodium alginate modified magnetic graphene oxide nanocomposites were used as the research object,on which we loaded with large capacity DOX.Drug-loaded nanocomposites(MGO-CS/SA-DOX)can significantly improve the performance of dispersibility and pH-sensitive drug release,which is beneficial to the release of DOX in tumor cells.Cell studies have shown that MGO-CS/SA has magnetic targeting characteristics and favorable photothermal effect,and MGO-CS/SA-DOX has concentration-dependent cytotoxicity.(3)MGO was synthesized by the same preparation method and modified by chitosan and dextran.The composites were characterized by FTIR,AFM and TEM.The results show that MGO-CS/DEX has been successfully prepared.As a drug carrier,MGO-CS/DEX shows performance of certain sustained-release and pH-dependence in the process of drug release.The drug release rate under acidic pH condition was higher than that under neutral pH condition,which was of great significance for the targeted treatment of solid tumor under acidic pH condition.Magnetic nanocomposites could be internalized by A549 cells,so as to take the cytoplasm as its target.Pure magnetic nanocomposites show no sign of cytotoxicity,however,DOX loaded magnetic nanocomposites have strong dose-dependent cytotoxicity.