Magnetic Fe3O4@ZIF-8 nanoparticles as a drug release vehicle: pH-sensitive release of norfloxacin and its antibacterial activity

Metal-organic frameworks (MOFs) have a high specific surface area and inherent biodegradability due to their unique structure and composition. As well, owing to the properties of nanomaterials and especially their magnetic features, Fe3O4 nanoparticles and MOFs composite materials have great potential in the design and application of drug release. The present work: firstly, investigated norfloxacin loading in magnetic metal organic framework (Fe3O4@ZIF-8); and secondly, studied the release of norfloxacin and its antibacterial activity. Results showed the release efficiencies reached 97 % at 310 K after 84 h (pH 7.4). Drug release behavior was tested at various pH levels and it was found that Fe3O4@ZIF-8 has pH-sensitive properties. Furthermore, the release model calculation illustrated that the release process fitted well to the Bhaskar model. The magnetic properties of Fe3O4@ZIF-8 confirmed that the composite has potential application for a targeted drug delivery system. The mechanism of pH-responsive norfloxacin release was combined with diffusion, ion exchange and electrostatic repulsion. Furthermore, the antibacterial activities of Fe3O4@ZIF-8 and NOR-Fe3O4@ZIF-8 were tested against Escherichia coli. Results showed that Fe3O4@ZIF-8 had good biocompatibility while NOR-Fe3O4@ZIF-8 can deter or inhibit the actions of microorganisms.