(A-6) Development of Polyacrylic Acid-Coated Zeolitic Imidazolate Framework Nanoparticles for Drug Delivery

Metal-Organic Frameworks (MOF) are compounds that are formed by an organic-inorganic crystalline porous material.Among MOF, zeolite Imidazolate framework (ZIF)-8 is interesting because of its zeolite-like structure comprising zinc ions (Zn2+) and 2-methylimadzole (2-MIm) with large pores. In addition, ZIF-8 can be prepared as monodisperse nanoparticles with controlled size by changing the molar ratio of Zn2+ and MIm. These qualities allow ZIF-8 nanoparticles to be desirable in drug and pharmaceuticalingredients. However, studies have shown relatively low chemical stability of ZIF-8 crystalline structure in aqueous solutions, which limits the medical applications of ZIF-8 nanoparticles. In this project, ZIF-8 nanoparticles were coated with polyacrylic acid (PAA) to improve chemical stability by inhibiting the degradation of the crystalline structure of ZIF-8. To coat the surface of ZIF-8, ZIF-8 was mixed with PAA at the molar ratios of zinc ion and PAA. The PAA-coated ZIF-8 nanoparticles showed enhanced stability in water as well as phosphate buffered saline (PBS).