Silica nanoparticles with dual visible-NIR luminescence affected by silica confinement of Tb complexes for cellular imaging application

The work introduces silica confinement of Tb(III) and Yb(III) complexes with p-sulfonatothiacalix[4]arene (TCAS) arisen from their doping into silica nanoparticles (51-60 nm) as the reason for efficient dual green-NIR luminescence. pH-regulated water solubility of the lanthanide complexes is highlighted as prerequisite for the balance between efficient doping of the complexes into silica nanoparticles and their size/shape university. The impact of Tb(III) [right arrow] Yb(III) energy transfer on the NIR and visible luminescence of the nanoparticles was revealed from photophysical studies of the nanoparticles doped with different couples of lanthanide complexes (Tb-Gd, Tb-Yb, Yb-Gd) at various molar ratios. The optimal balance between green and NIR luminescence is achieved for the silica nanoparticles doped with Tb-Yb complexes at 2:1 (Tb:Yb) ratio due to both Tb(III) [right arrow] Yb(III) energy transfer and specific distribution of Tb(III) and Yb(III) complexes within silica nanoparticles. The dual luminescent nanoparticles exhibit efficient cellular uptake behavior after amino-decoration of their surface, which is confirmed by confocal microscopy images of the cells incubated by the heterometallic nanoparticles.