Poly(styrene- b-acrylic Acid) Nanoparticles with High Magnetic Loading for Magnetic Hyperthermia Cancer Therapy

Magnetic polymeric nanoparticles (MPNPs), a cluster of magnetic nanoparticles (MNPs) or superparamagnetic iron oxide nanoparticles embedded into a poly(styrene27-b-acrylic acid120) P(S27-b-AA120) particle, were prepared via a one-step chemically mild method. By controlling the type of solvent used for MNPs, the balance between the magnetic loading at a weight fraction of 70 wt % and the P(S27-b-AA120) contents in a range of 0.1-0.5 wt % promoted the formation of well-defined MPNPs, while achieving high oleic acid (OA)-MNP loading. The MPNPs were generated via an induced co-self-assembly mechanism of hydrophobic interactions between OA coated on MNPs and the PS segments of the block copolymer. Without the use of a surfactant or cross-linking agent, high stability of MPNPs in an aqueous medium was achieved from the contribution of long hydrophilic polyelectrolyte brush blocks containing carboxylic groups. Because of the high superparamagnetic nanoparticle loading, monodispersity, and high stability, the as-prepared MPNPs are highly responsive to an external magnetic field and can efficiently generate heat under the application of an alternating magnetic field. The as-prepared MPNPs have a high potential for use as magnetic hyperthermia materials for cancer therapy applications.