Pluronic/chitosan shell cross-linked nanocapsules encapsulating magnetic nanoparticles.

We have developed novel Pluronic/chitosan nanocapsules encapsulating iron oxide nanoparticles. These nanocapsules were produced by dispersing hydrophobically-modified iron oxide nanoparticles and amine-reactive Pluronic derivatives in an organic solvent, and subsequently emulsification in an aqueous chitosan solution by ultrasonication. The resultant shell cross-linked nanocapsules had a unique core/shell type nanoreservoir architecture: an inner core encapsulating magnetic nanoparticles and a hydrophilic Pluronic/chitosan polymer shell layer, as confirmed by thermogravimetric analysis and transmission electron microscopy. Confocal laser scanning microscopy revealed that the rhodamine-labeled nanocapsules were efficiently internalized by human lung carcinoma cells upon exposure to an external magnetic field. The present study suggested that these novel nanomaterials could be dually utilized for the magnetically-triggered delivery of various anti-cancer agents and for cancer diagnosis with magnetic resonance imaging.