In Vitro Study: Synthesis and Evaluation of FeO/CQD Magnetic/Fluorescent Nanocomposites for Targeted Drug Delivery, MRI, and Cancer Cell Labeling Applications.

In the present study, first, FeO nanoparticles were functionalized using glutaric acid and then composited with CQDs. Doxorubicin (DOX) drug was loaded to evaluate the performance of the nanocomposite for targeted drug delivery applications. The XRD pattern confirmed the presence of characteristic peaks of CQDs and FeO. In the FTIR spectrum, the presence of carboxyl functional groups on FeO/CQDs was observed; DOX (positive charge) is loaded onto FeO/CQDs (negative charge) by electrostatic absorption. FESEM and AFM images showed that the particle sizes of FeO and CQDs were 23-75 and 1-3 nm, respectively. The hysteresis curves showed superparamagnetic properties for FeO and FeO/CQDs (57.3 and 8.4 emu/g). The FeO hysteresis curve showed superparamagnetic properties (Ms and Mr: 57.3 emu/g and 1.46 emu/g. The loading efficiency and capacity for FeO/CQDs were 93.90% and 37.2 mg DOX/g MNP, respectively. DOX release from FeO/CQDs in PBS showed pH-dependent release behavior where after 70 h at pH 5 and 7.4, about 50 and 21% of DOX were released. Fluorescence images of FeO/CQD-treated cells showed that FeO/CQDs are capable of labeling MCF-7 and HFF cells. Also, T-weighted MRI scans of FeO/CQDs in water exhibited high relaxivity (86.56 mM S). MTT assay showed that DOX-loaded FeO/CQDs are highly biocompatible in contact with HFF cells (viability = 95%), but they kill MCF-7 cancer cells (viability = 45%). Therefore, the synthesized nanocomposite can be used in MRI, targeted drug delivery, and cell labeling.