Multifunctional Superparticles for Magnetically Targeted NIR‐II Imaging and Photodynamic Therapy.

Theranostics, the combination of diagnostics and therapies, has been considered as a promising strategy for clinical cancer treatment. Nonetheless, building a smart theranostic system with multifunction for different on‐demand applications still remains elusive. Herein, an easy and user‐friendly microemulsion based method is developed to modularly assemble upconversion nanoparticles (UCNPs) and Fe3O4 nanoparticles together, forming multifunctional UCNPs/Fe3O4 superparticles with highly integrated functionalities including the 808 nm excitation for real‐time NIR‐II imaging, magnetic targeting, and the upconversion luminescence upon 980 nm excitation for on‐demand photodynamic therapy (PDT). With a magnet placed nearby the tumor, in vivo NIR‐II imaging uncovers that superparticles tend to migrate toward the tumor and exhibit intense tumor accumulation, ≈6 folds higher than that without magnetic targeting 2 h after intravenous injection. NIR laser irradiation is then used to trigger PDT, obtaining an outstanding tumor elimination under magnetic tumor targeting, which shows a high potential to be applied in targeted cancer theranostics. [ABSTRACT FROM AUTHOR]