Optimal fluorescence and photosensitivity properties of dual-functional NaYb(1−x)F(4):Tm(x)(3+) nanoparticles for applications in imaging guided photodynamic therapy

The fluorescence and photosensitivity properties of NaYb(1−x)F(4):Tm(x)(3+) nanoparticles were optimized to develop noninvasive near-infrared fluorescence imaging-guided photodynamic therapy. The emission at 800 nm from Tm(3+) presented an exponential increase with an increase in the Tm(3+) doping concentration from 0 to 2%. The photosensitivity properties of NaYb(1−x)F(4):Tm(x)(3+) nanoparticles were also studied via the chemoprobe method, which used a reactive oxygen quencher, 1,3-diphenylisobenzofuran (DPBF). With the increase in the doping concentration of Tm(3+), the generation rate of reactive oxygen species in NaYb(1−x)F(4):Tm(x)(3+) nanoparticles decreased linearly at a rate of 0.3. The doping concentration of Tm(3+) had two opposite effects on the 800 nm emission and generation rates of reactive oxygen species. The competitive relationship was discussed and an optimal value for the Tm(3+) doping concentration of approximately 1% was determined. At this concentration, the energy of the Yb(3+) excited state can be fully utilized, and the fluorescence and photosensitivity properties are an effective combination.