A dual drug delivery system based on pH-sensitive metal-organic frameworks: Synthesis, characterization, in vitro release and anticancer effect

The zeolitic imidazolate framework-8 (ZIF-8) is a metal-organic framework(MOF) that decomposes rapidly in tumor cells and other low-pH situations, but maintains structural stability under neutral physiological conditions. Here, a nanoscale dual medication delivery system, OR@ZIF-8, was successfully designed, which was prepared with good morphology and uniform particle size, and could successfully load both Oridonin (Ori) and Resveratrol (Res) drugs, especially with a high drug loading capacity of Ori. The in vitro release of OR@ZIF-8 demonstrated pH sensitivity, showing slow release under neutral conditions and rapid release in weakly acidic environments. Anti-tumor tests showed that the nano particles of ZIF-8 showed low cytotoxicity, while OR@ZIF-8 showed high cytotoxicity to KYSE140 cells compared with free Ori and Ori@ZIF-8 at the same dosage of Ori. These findings suggest that the pH-responsive nanoscale OR@ZIF-8 system holds promise as an effective technique for targeted drug delivery to cancer cells.