Synthesis of low toxicity metal-organic framework carrier for drug release

In this study, the [Zn(4,4′-bipy)(formic acid)₂(NO₃)₂] (4,4′-bipy = 4,4′-bipyridine) metal-organic framework (MOF) (1) was synthesized using Zn(NO₃)₂·6H₂O and 4,4′-bipyridine according to the solution solvothermal approach. In addition, thermogravimetric analysis (TGA), power X-ray diffraction (XRD), UV spectrophotometry, and Fourier transform infrared spectroscopy (FTIR) were carried out to determine the crystal phase and characterizations of 1. Thereafter, 1 was adopted to carry 5-fluorouracil (5-FU), which displayed a 5-FU loading of 37.9 wt%. Besides, the 5-FU-loaded 1 displayed pH-sensitive behavior with the release of 5-FU in acidic environment. Typically, the 5-FU release process was progressive and under efficient control, and 93% 5-FU was released in acidic environment at 72 h later, but only 58% 5-FU was released in the phosphate buffered saline (PBS, pH = 7.4). Furthermore, the toxicity of 1 was evaluated through cytotoxicity assays in HeLa and L02 cell lines, which showed significantly low toxicity of 1. Taken together, these results indicate that, the prepared 1 may potentially serve as a suitable carrier for drug delivery applications.