Post-Synthetic Modification Nanoscale Metal-Organic Frameworks for Targeted Drug Delivery in Cancer Cells

Metal-organic frameworks (MOFs) have shown great potentials as drug delivery carriers, but the conventional methods for MOFs synthesis limited their use in biomedicine. The aim of this study was engineered tumor-targeted zinc nanoscale MOFs encapsulating chemotherapy drug.

We employed post-synthetic modification to construct tumor cell-targeted nanoscale zinc MOFs (nanoMOFs) functionalized with folate as the targeting ligand that binds specifically to folate receptors on tumor cells. The cytoctoxicity of drug-loaded nanoMOFs was measured by MTT assay. The cell target was tested by cell compete assay.

The successful synthesis of folate-targeted nanoMOFs was confirmed by FTIR, ¹H-NMR and ESI-MS analysis. In the drug loading test, the zinc nanoMOFs functionalized with folate quickly adsorbed up to 24 wt % 5-fluorouracil (5-FU) without causing obvious changes in the supramolecular crystalline organization of the material. The in vitro drug release profile of this nanoMOFs in phosphate buffered saline exhibited a biphasic pattern. The drug sustained release is the effect mainly of diffusion of 5-FU molecules, while the degradation of the carrier itself plays a minor role in this process. The drug-loaded nanoMOFs showed a stronger cytotoxicity than free 5-FU against three cancer cell lines in vitro with a distinct selectivity between folate receptors positive and negative cells.

These results encourage further in vivo studies of this nanoMOFs as candidates for tumor-targeted, sustained-release delivery of chemotherapeutic agents.