By amidation reaction

folic acid (FA) was grafted to hydrophilic polymer poly(glycidyl methacrylate)-g-poly(ethylene glycol)) (PGMA-g-PEG).Nuclear magnetic resonance (NMR) and infrared spectroscopy (FTIR) tests showed that polymer PGMA-g-(PEG)(FA)was successfully synthesized and the grafting level of FA was 1.7%.In order to prepare water-soluble quantum dots

the polymer PGMA-g-(PEG)(FA) was used to modify quantum dots (QDs) by ligand exchange.And using glutaraldehyde

the anti-cancer drug doxorubicin (DOX) was attached to the surface of the water-soluble quantum dots by the imine groups to form the final folic acid targeted theranostics system QDs@PGMA-g-(PEG)(FA)(DOX).UV-Visible spectra (UV-Vis) showed that the folic acid targeted theranostics system had the characteristic absorption peaks of QDs

DOX

and FA.The result illustrated that the folic acid targeted theranostics system was successfully prepared.The drug release study showed that the system was pH sensitive

had large drug release amount at pH 5.0

and was stable at pH=7.4.Hela cells experimental studies showed that compared with the theranostics system

the folic acid targeted theranostics system had greater cytotoxicity and higher concentrations of QDs in the cytoplasm and higher concentrations of DOX in the nucleus.All above

compared with the theranostics system

folic acid targeted theranostics system can be better applied to cell imaging and tumor treatment in the future.