Multifunctional fluorescent PEGylated fluorinated graphene for targeted drug delivery: An experiment and DFT study

A facile strategy to synthesize multifunctional nanosized fluorinated graphene oxide (FGO), a novel nanocarrier to controllably and specifically deliver single or mixed anticancer drugs, was demonstrated. FGO was prepared by a mild process to tune its size into nanoscale and modify its surface with oxygen groups, and then functionalize with folic acid (FA) pre-linked amino-polyethylene glycol (PEG), rendering good solubility and specifical targetability toward cancer cells with FA receptors. Moreover, anticancer drugs of doxorubicin and camptothecin were effectively loaded onto FGO-PEG-FA separately or together in a well-controlled manner, and density functional theory calculations revealed that non-covalent interactions were the driving forces for drug loading and fluorine atoms provided more active sites for intermolecular interactions. Good control over surface and structure further endowed FGO unique and roust photoluminescence (PL) as well as high near infrared (NIR) absorbance. The former for the first time made FGO an excellent sensor to visually monitor drug loading by inner filter effects, while the latter guaranteed FGO an effective photothermal therapy (PTT) agent. Based on these, a three-in-one therapy model combined with mixed drug treating and PTT was constructed, and further cancer inhibition experiments revealed that remarkably higher treatment effect was achieved compared to single or two-in-one therapy. The presented work to design, synthesize and modify FGO as a novel nanocarrier and study on the interactions with drugs provided novel insights into developing new drug delivery systems, and the unique PL combined with high NIR absorbance made this work potentially valuable in many fields.