Preparation,Assembly And Application Of Janus Graphene Oxide Nanosheets

In recent years,graphene has been found as a new type of carbon material with excellent properties.Owing to its good biocompatibility,graphene has a promise application in medicine.Janus particals have a wide range application because of their unique asymmetric structures.Therefore,Janus graphene oxide used as drug delivery matrials has a potential application in the cancer treatment.In this paper,a facile method for the synthesis of Janus graphene oxide(GO)nanosheets with different structures based on electrostatic assembly of GO was described.In this approach,cationic polystyrene(PS)microspheres are chosen as templates.And the drug loading and release of Janus GO nanosheets and its self-assembly structure were investigated.The main contents are as follows:(1)Preparation of Janus GO nanosheetsGO nanosheets with negative charges can be assembled on the surface of the cationic PS microspheres via the electrostatic interaction.The poly(2-(dimethylamino)ethyl methacrylate)(PDMAEMA)chains with terminal pyrene groups are anchored to the surface of GO nanosheets via the π-π stacking interaction.Upon dissolving the PS microspheres in tetrahydrofuran(THF)and the removal of the free PS chains,GO nanosheets with hydrophobic PS chains on one side and hydrophilic PDMAEMA chains on the other side are obtained.After treatment with THF,PS chains were attached at the GO surface by the electrostatic interaction.Janus GO nanosheets can be easily functionalized with a template polymer or defunctionalized by altering the ionic potential of the system.The Janus GO nanosheets with single-side modification or double-side can be obtained.A facile and versatile method for the synthesis of Janus graphene oxide(GO)nanosheets with different structures is reported.(2)Study on the drug release of Janus GO nanosheets and its self-assembly structureJanus GO nanosheets with hydrophilic polypoly(ethylene glycol)methyl ether methacrylate(PPEGMA)chains on one side are prepared based on electrostatic assembly of GO nanosheets and PS microspheres.Doxorubicin hydrochloride(DOX)are anchored to the other side of Janus GO-PPEGMA nanosheets via the π-π stacking interaction.Under ultrasonic conditions,the self-assembly structure of Janus DOX-GO-PPEGMA nanosheets are formed.The drug release of Janus GO nanosheets and its self-assembly structure in different pH value are investigated.