Biocompatible graphene oxide as a folate receptor-targeting drug delivery system for the controlled release of anti-cancer drugs

A novel graphene oxide (GO)-based nanocarrier has been designed for the targeting and pH-responsive controlled release of anti-cancer drugs via the classic amidation of the carboxyl groups of carboxylated graphene oxide (CG) with the amine end-groups of functional poly(ethylene glycol) (PEG) terminated with an amino group and a folic acid group (FA–PEG–NH2). The carboxylated graphene oxide conjugated folate-terminated poly(ethylene glycol) (CG–PEG–FA) nanocarrier containing 44.4 wt% of functional PEG brushes exhibits stable dispersibility in PBS media, outstanding cytocompatibility, high drug-loading capacity (0.3993 mg mg−1 for DOX) via π–π stacking interactions, perfect folate receptor-targeting and pH-activated controlled release properties, demonstrating that the nanocarrier could be a promising drug delivery system (DDS) for cancer therapy.