New ZnFe2O4@SiO2@graphene quantum dots as an effective nanocarrier for targeted DOX delivery and CT-DNA binder

The current study pronounces the synthesis and characterization of ZnFe2O4, ZnFe2O4@SiO2, graphene quantum dots (GQDs) and ZnFe2O4@SiO2@GQDs nanoparticles by different techniques such as VSM, XRD, IR, UV–Vis and SEM. For application in targeted drug delivery, then GQDs were immobilized on the surface ZnFe2O4@SiO2 via covalent linkage to surface amino groups. The competence of ZnFe2O4@SiO2@GQDs nanoparticles was assessed by loading and releasing of doxorubicin (DOX) as a standard anticancer drug at pH = 5 (pH of cancerous cell) and pH = 7.4 (pH of healthy cell). The attained results authenticate the pH sensitive release behavior of ZnFe2O4@SiO2@GQDs nanoparticles by releasing more DOX at cancerous pH (70%) than healthy pH (28%). To appraise the biological manner, ZnFe2O4@SiO2@GQDs nanoparticles were screened for their CT-DNA binding tendency by means of spectroscopic methods. The gained results of absorption spectroscopy and competitive fluorescence studies disclosed that nanoparticles bind to DNA through the intercalation mode and the loading of DOX on the nanocarrier has increased CT-DNA binding affinity up to 300 times. The cytotoxicity activity of ZnFe2O4@SiO2@GQDs and ZnFe2O4@SiO2@GQDs/DOX by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed on cancerous HeLa cell and healthy HEK-293 cell revealed that both nanoparticles exhibit concentration-dependent behavior on both cell lines, so that with increasing nanoparticle concentration, the cell viability percentage decreases, although nanocarriers containing DOX expression a more severe effect. Treatment of HeLa cells with 10 µg/mL of the ZnFe2O4@SiO2@GQDs/DOX nanoparticles showed that the nanoparticles induce cell death by apoptosis and cause detention of cell cycle in G2 phase. The results of the study expression the potential of the nanocarrier for targeted and controlled drug delivery, which should be given more attention and modified as a nanocarrier.