PEGylated FePt@Fe2O3 core-shell magnetic nanoparticles: potential theranostic applications and in vivo toxicity studies.

Herein, we develop FePt@Fe2O3 core-shell magnetic nanoparticles as a T2 magnetic resonance (MR) imaging contrast agent as well as a drug carrier for potential cancer theranostic applications. The FePt@Fe2O3 core-shell nanoparticles are synthesized and then functionalized with polyethylene glycol (PEG). Folic acid (FA) is conjugated on the surface of FePt@Fe2O3-PEG nanoparticles for effective targeting of folate receptor (FR)-positive tumor cells. A chemotherapy drug, doxorubicin (DOX), is then loaded onto those nanoparticles via hydrophobic physical adsorption, for targeted intracellular drug delivery and selective cancer cell killing. We then use those FePt@Fe2O3-PEG nanoparticles for in vivo MR imaging, observing obvious tumor MR contrasts, which resulted from both passive tumor accumulation and active tumor targeting of nanoparticles. Moreover, both in vitro and in vivo studies uncover no obvious toxicity for FePt@Fe2O3-PEG nanoparticles. Therefore, our PEGylated FePt@Fe2O3 core-shell nanoparticles could serve as a promising multifunctional theranostic nano-platform in imaging guided cancer therapy. FROM THE CLINICAL EDITOR: In this study of PEGylated FePt@Fe2O3 core-shell magnetic nanoparticles, both therapeutic and diagnostic applications are demonstrated. Folic acid surface-conjugation resulted in uptake by folate receptor positive cancer cells, the iron oxide particles enabled MRI imaging using T2* weighted sequences, and the absorbed doxorubicin provided treatment effects in this model. Similar multi-modality approaches will hopefully find their way to clinical applications in the near future.