Synthesis and characterization of colloidal grapheneol quantum dots decorated with folic acid for highly selective drug delivery application potential

The development of novel nanocarriers for drug delivery has established a foundation for enhancing the formulations of targeted cancer therapies. Graphene quantum dots (GQDs) and their derivatives have shown promising characteristics for precisely transporting anticancer drugs to tumor cells. Herein, grapheneol quantum dots (GQDs) derived from poly (L-lactic acid) and decorated with folic acid were prepared, for the first time, via a sonochemical approach. The synthesized GQDs were functionalized with folic acid to improve their affinity for folate-positive breast cancer cells, thereby extending their circulation time. Ultimately, these GQDs were loaded with the anticancer agent methotrexate (MTX) to mitigate its adverse effects. Transmission electron microscopy (TEM) and atomic force microscopy confirmed the formation of grapheneol quantum dots with a lateral size of around 2.1 ± 0.2 nm. The UV–vis spectrophotometer measurements showed that the GQDs exhibit a strong quantum confinement effect with an optical band gap energy around 3.2 eV. The photoluminescence measurements showed that the GQDs exhibited high luminescence with intense blue emission and a quantum yield exceeding 72 %. The Raman, X-ray photoelectron spectroscopy, and FTIR measurements revealed that the folic acid decorated the surface of the GQDs. The hydrodynamic light scattering (DLS) and zeta potential measurements indicated that the lateral size of GQDs increases from 2.1 nm to 10 nm, confirming the attachment of the folic acid to the surface of the GQDs. However, the zeta potential of the GQDs changed from −7.6 meV to −14.3 meV, implying the enhancement of the dispersion stability of the GQDs due to the presence of folic acid on their surfaces. The FA-decorated GQDs were used as nanocarriers for the pharmaceutical cancer drug (methotrexate). The results revealed that the FA/GQDs nanocarriers with co-receptors (FA and MTX) enhanced the therapeutic effectiveness with precise targeting to breast cancer cells. • GQDs derived from poly (L-lactic acid) were prepared via a sonochemical approach. • GQDs have strong confinement, a wide band gap, and a highly blue emission. • FA converts the GQDs from a 2D monolayer structure to a 3D multilayer structure. • GQD nanocarriers with co-receptors (FA and MTX) enhanced the therapeutic effectiveness. • MTX/FA/GQDs have precise targeting to breast cancer cells.