Poly(acrylic acid)-Modified Fe3O4 Microspheres for Magnetic-Targeted and pH-Triggered Anticancer Drug Delivery

Monodisperse poly(acrylic acid)‐modified Fe3O4 (PAA@Fe3O4) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated. The PAA polymer was encapsulated into the inner cavity of Fe3O4 hollow spheres by a vacuum‐casting route and photo‐initiated polymerization. TEM images show that the samples consist of monodisperse porous spheres with a diameter around 200 nm. The Fe3O4 spheres, after modification with the PAA polymer, still possess enough space to hold guest molecules. We selected doxorubicin (DOX) as a model drug to investigate the drug loading and release behavior of as‐prepared composites. The release of DOX molecules was strongly dependent on the pH value due to the unique property of PAA. The HeLa cell‐uptake process of DOX‐loaded PAA@Fe3O4 was observed by confocal laser scanning microscopy (CLSM). After being incubated with HeLa cells under magnet magnetically guided conditions, the cytotoxtic effects of DOX‐loaded PAA@Fe3O4 increased. These results indicate that pH‐responsive magnetic PAA@Fe3O4 spheres have the potential to be used as anticancer drug carriers. Dual response: Monodisperse poly(acrylic acid)‐modified Fe3O4 (PAA@Fe3O4) hybrid microspheres with dual responses (magnetic field and pH) were successfully fabricated (see figure). The drug release behavior was strongly dependent on pH value due to the unique properties of PAA. Furthermore, doxorubicin (DOX)‐loaded PAA@Fe3O4 composites show an enhanced magnetically guided anticancer effect.