Encapsulation of drug microparticles with self-assembled Fe3O4/alginate hybrid multilayers for targeted controlled release

The magnetic-targeted drug-delivery system was developed with the Fe3O4 nanoparticles as the self-assembling material to form the hybrid multilayer shells. Layer-by-Layer stepwise self-assembly of the natural polyelectrolytes sodium alginate and the Fe3O4 nanoparticles was used to create the magnetic hybrid multilayers around drug microparticles (similar to 400 nm in diameter) for the purpose of targeted controlled release. The obtained drug microparticles encapsulated with hybrid multilayers were characterized with dynamic light scattering, transmission electron microscope, and vibrating sample magnetometer. UVvis spectroscopy was employed to monitor the drug releasing behaviors in pH 1.8 and 7.4 buffer solutions. It was found that the release of drug molecules from the pH-sensitive magnetic-targeted drug-delivery system was mainly dependent on the following factors: the permeability of the hybrid multilayer shells and the solubility of the drug molecules in the bulk solutions. The results revealed that it could achieve the quick and continuous controlled release via the magnetically-guide to the target tissue of organism. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.