Liposome-coated metal-organic frameworks as the efficient drug delivery system for therapeutic applications

Abstract

Zeolitic imidazole framework-8 (ZIF-8) particles, composed of zinc ions (Zn²⁺) and 2-methylimidazolate, were used as carriers for incorporating iron oxide (Fe₃O₄) nanoparticles, resulting in Fe₃O₄@ZIF-8 particles. Due to the toxicity of Zn²⁺ to cell membranes, liposomes were employed to reduce this toxicity. Fluorescent dyes were loaded into ZIF-8 or Fe₃O₄@ZIF-8 nanoparticles as the mock drugs to facilitate tracking during cellular studies. The encapsulation efficiency of fluorescein (Flu) and nile red (NiR) in the MOFs was calculated to be around 40%–60%. A burst release of Flu was observed under acidic conditions within 30 min, while natural PBS was significantly release in 6 h. The release kinetic of the whole platform was fixed as the Higuchi equation which referred to diffusion release. Liposome coating significantly decreased the toxicity of the MOFs, as evidenced by an increase in IC₅₀ values from approximately 30 to 120 µg/mL. The LDH release from L929 cells was confirmed when particles were used at exceeding 100 µg/mL. The cellular uptake of the liposome-coated dye-loaded MOFs was confirmed after 3 hour-incubation. These findings suggested that liposome-coated MOFs could be served as an alternative carrier in biomedical engineering field.