Methotrexate-loaded Fe-metal organic frameworks: Synthesis, characterizations, and drug release investigations

Efficient diagnoses and effective treatment of diseases like cancer can be achieved by designing and developing targeted and controlled drug delivery systems. Metal-organic frameworks (MOFs) are promising drug delivery systems due to large surface area, tunable pore sizes, and controlled drug release. Herein, we report the loading and release of methotrexate (MTX) in MIL -101 -Fe MOF as a drug delivery system. The functional groups, crystal structure, and morphology of the as-synthesized MOF was determined by Fourier transform infrared spectroscopy (FTIR), powdered X-ray diffraction and scanning electron microscopy (SEM), respectively. Interestingly, the MOF exhibited 84 % encapsulation efficiency for MTX and 62 % release in the initial 50 h at pH 5.5, which is ideal for tumor tissue. The MTX@MIL-101-Fe effectively killed the HeLa cells from human cervical cancer. Particularly noteworthy was that neither MIL -101 -Fe nor MTX@MIL-101-Fe showed toxicity to healthy Vero cells. It proves that the Methotrexate was released from MTX@MIL-101-Fe in cancer cells at pH 5.5 and caused apoptosis. Theoretical studies used density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to explore three possible Methotrexate-MIL-101-Fe encapsulation complexes. The complex with the drug attached at the carboxylate-bridge site showed the highest binding. Moreover, a decrease in the calculated band gap was also observed during the encapsulation process. This study suggests that MIL -101 -Fe can be a promising candidate for target-specific and efficient delivery of Methotrexate to cancer cells with reduced side effects.