Size and surface controllable metal–organic frameworks (MOFs) for fluorescence imaging and cancer therapy

Abstract

Benefiting from their porous structures, metal–organic frameworks (MOFs) have attracted intensive attention for use in drug release. However, the controllable synthesis of MOFs with proper particle sizes is still very challenging, which largely limits its applications. Here, UIO-66-NH₂ with controlled particle sizes in the range of 20–200 nm has been achieved successfully. The amine on UIO-66-NH₂ is demonstrated for the feasible post-modifying of UIO-66-NH₂ to obtain multifunctional MOFs, overcoming the limitations of functional simplicity and broadening the range of applications. After covalent grafting the targeting reagent folic acid (FA) and the fluorescence imaging agent 5-carboxyfluorescein (5-FAM), UIO-66-NH₂-FA-5-FAM/5-FU can target the cancer cells HePG-2 and display excellent fluorescence imaging in vitro. Moreover, the in vivo biodistribution and antitumor assays indicate that UIO-66-NH₂-FA-5-FAM/5-FU can accumulate in the tumor and display stronger antitumor efficiency due to the long-time drug release. Taken together, this study integrates the imaging section and the treated section in a single platform successfully and the present approach can be a good use of therapeutic MOFs to achieve the desired objective, a better treatment.