Highly efficient phosphors in cancer sensing and PDT

Highly efficient upconverting phosphors (NaYF4) doped with erbium ions are bio-conjugated and used for cancer imaging and photodynamic therapy. Once they are conjugated, the particles are injected into mice to demonstrate that cancer imaging with a near-infrared excitation source is possible. Finally, the particles are also conjugated with a photosensitive molecule with strong absorption near the upconversion emission peak (~ 550nm). The upconversion energy causes the photosensitive molecule to create highly reactive oxidative species, which puncture and kill the cell to which it is attached. These particles are then used in a mouse model, and the size of the tumors is modeled as a function of the dosage and duration of the photodynamic therapy.