A porous Sr(II)-organic framework for 5-fluorouracil delivery and anti-cancer activity against human melanoma cells

A new Sr(II)-based metal organic framework (MOF) formulated as [Sr(HTATB)(H₂O)₂](DMF)₄ (<b>1</b>) has been prepared by reaction of Sr(NO₃)₂ with the rigid tricarboxylic acid linker 4,4′,4″-s-triazine-2, 4, 6-triyltribenzoic acid (H₃TATB) in a mixed solvent of N,N-dimethylformamide (DMF) and water. Complex <b>1</b> has been characterized by powder X-ray diffraction (PXRD), elemental analysis (EA) and single crystal X-ray diffraction (SCXRD). In light of its large inner spaces as well as widely distributed open metal sites, the guest-free <b>1</b> (<b>1a</b>) has been used as a crystalline vessel for delivering small-molecule chemotherapeutics such as 5-fluorouracil (5-Fu), which exhibits an outstanding loading capacity around 36.48 wt%. Furthermore, the cumulative release value of 5-Fu at 48 h was about 96.5% in phosphate buffer saline (PBS). In addition, the 3-(4,5-dimethyl-2-thiazolyl)−2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was employed to evaluate the <i>in vitro</i> cytotoxicity of the carrier 5-Fu loaded <b>1a</b> against the human melanoma cell lines.