A de novo theranostic nanomedicine composed of PEGylated graphene oxide and gold nanoparticles for cancer therapy

A de novo drug delivery nanosystem based on gold nanoparticles (GNPs), decorated poly(ethylene glycol) (PEG), and folate (FA)-conjugated graphene oxide (GO) was designed and developed successfully. Initially, the graphite (G) powder was oxidized to the GO, and then functionalized with chloroacetic acid to afford a carboxylated graphene oxide (GO–COOH). The obtained GO–COOH was functionalized with an amine end-caped PEG, FA, as well as 3-amino-1-propanethiol to produce a GO–PEG–FA–SH. In another experimental section, GNPs were synthesized through a citrate-mediated reduction approach, and subsequently decorated onto/into GO–PEG–FA–SH through the formation of Au–S bond to afford a GO–PEG–FA/GNP nanosystem. The resultant nanosystem was loaded with doxorubicin hydrochloride (DOX) as a model anticancer drug, and its drug-loading capacity as well as pH-dependent drug release behavior were investigated. The anticancer activity of the developed theranostic nanomedicine was extensively evaluated using MTT assay against human breast cancer cells (MCF7). The developed GO–PEG–FA/GNPs–DOX theranostic nanomedicine exhibited an excellent cancer chemotherapy feature. In addition, this nanomedicine can be used in chemo-photothermal therapy of solid tumors because of the presence of GO and GNPs in its structure.