Multifunctional NaYF:Yb,Er@PE@FeO nanocomposites for magnetic-field-assisted upconversion imaging guided photothermal therapy of cancer cells.

Even though various theranostic agents have been exploited for effective cancer therapy over the years, appropriate design and fabrication of theranostic agents with simple composition, convenient preparation, high theranostic efficiency and minimal side effects on non-cancer cells are still urgently needed. Herein, multifunctional NaYF:Yb,Er@polyelectrolyte (PE)@FeO nanocomposites, with upconversion luminescence, superparamagnetism and photothermal performance, are prepared by a layer-by-layer self-assembly technique. Compared with FeO nanoparticles (NPs), the nanocomposites exhibited nearly 2-fold strong absorption at 808 nm, and thus resulted in an enhanced near-infrared photothermal effect.