Facile preparation of surface functional carbon dots and their application in doxorubicin hydrochloride delivery

•Glycine as precursor and PEG 2000 as modifier were used to prepare PEG-CDs.•The PEG-CDs had 12nm of dimension and 28.58% of fluorescence quantum yield.•A greater loading capacity and encapsulation efficiency for DOX in PEG-CDs were achieved.•The mechanism of drug loading and behavior of DOX release were discussed. A novel form of carbon dots (PEG-CDs) was prepared by using one-step hydrothermal synthesis with glycine as the precursor and polyethylene glycol (PEG)-2000 as the surface modifier. The prepared PEG-CDs were characterized with HRTEM, XRD, PL, FTIR and UV. The results showed that they were quasi spherical particles with a diameter of approximately 12nm and had a fine fluorescence property, good water solubility, favorable stability and high quantum yield with 28.58%. Doxorubicin hydrochloride (DOX) as a potential anti-cancer drug was loaded on the PEG-CDs. The drug loading capacity was 24.25mg/g and the encapsulation efficiency was 77.23% at pH 9.0 with 36h of dialysis; DOX release in PBS system with a pH of 5.5 could reach up to 76.67% in 23h.