Facile surface functionalization of upconversion nanoparticles with phosphoryl pillar[5]arenes for controlled cargo release and cell imaging.

Upon surface functionalization and stabilization of β-NaYF4:Yb/Er upconversion nanoparticles (UCNPs) with phosphoryl pillar[5]arenes (PP5) via a facile ligand exchange method, we constructed a new hybrid material (PP5-UCNPs) with good water dispersibility especially in a physiological environment and superior capability of controlled cargo release and cell imaging.