131 I-labeled PEG and folic acid co-functionalized graphene quantum dots for tumor-targeted imaging

In this study, we successfully synthesized polyethylene glycol (PEG) and folic acid (FA) co-functionalized graphene quantum dots (GQDs) to improve the biocompatibility and tumor-targeting ability of GQDs simultaneously, and labeled GQDs–PEG–FA with 131I for biological behavior evaluation. The in vitro properties, biodistribution and SPECT imaging of 131I-GQDs–PEG–FA were investigated. The uptake of 131I-GQDs–PEG–FA at tumor sites can be clearly examined via SPECT imaging, which can ascribe to enhanced permeability and retention effect and active targeting effect of FA to folate receptors. The results indicate that 131I-GQDs–PEG–FA can be used as a radioactive probe for detection of tumor cells overexpressing folate receptor.