Glycoprotein-based bioimaging of HeLa cancer cells by folate receptor and folate decorated graphene quantum dots

Abstract Folate receptor (FR, 38 kDa) is a glycosylphosphatidylinositol glycoprotein which overexpressed on the surface of various cancer cells and has been utilized for wide applications. Folic acid (FA) functionalized nitrogen doped graphene quantum dots wrapped terbium (III) tungstate nanoparticles (Tb2(WO4)3NPs@N-GQDs-FA or Tb-W@GQDs-FA) as a smart nanocomposite was synthesized and used for specific imaging of folate receptor (FR) positive HeLa cancer cells. The mechanism of action is based on the attachment of FA decorated nanomaterials to the FR on the surface of cancer cells. This bioimaging probe emits fluorescence emission at 450 nm upon excitation on 345 nm. Flow cytometry and fluorescence microscopy techniques were applied to evaluate the efficiency of uptake of Tb-W@GQDs-FA to the cancer cells. Also, the selective attachment of Tb-W@GQDs-FA particles towards FR-positive HeLa cancer cells was verified by incubation of Tb-W@GQDs-FA with FR-negative normal cells. The cellular toxicity of the produced Tb-W@GQDs-FA nanocomposite was evaluated and results approved its biocompatible nature at the concentration of about 400 µg/mL. In conclusion, Tb-W@GQDs-FA could be effectively applied for noninvasive bio-imaging of HeLa cancer cells.