Fe@FeGe nanoparticles for MR imaging-guided NIR-driven photodynamic therapy in vivo.

Photodynamic therapy (PDT) has attracted much attention as a useful technique for disease therapy, considering its minimum invasiveness, high spatial-temporal control, and specific lesion destruction. However, the limited generation of singlet oxygen (1O2) in PDT has restricted the practical biomedical applications of photosensitizers. To overcome this issue, we first developed iron nanoparticles as an Fe nanotemplate to synthesize iron germanium nanoalloy coated iron nanoparticles (Fe@Fe3Ge2 NPs), which possess strong near-infrared (NIR) absorption, as a highly stable photosensitizer and to generate 1O2 effectively under irradiation by an 808 nm laser for NIR-PDT via the mitochondrial apoptotic pathway. Taking advantage of the strong magnetic properties of the Fe nanotemplates and the effective generation of 1O2 by Fe3Ge2 nanoshells, Fe@Fe3Ge2 NPs could be applicable for efficient targeted magnetic resonance imaging-guided NIR-PDT in an αvβ3-positive U87MG glioblastoma model. This work marks an important step forward in developing a novel nanoparticulated theranostic agent for accurate clinical cancer theranostics in the future.