Ln 3+ -doped hydroxyapatite nanocrystals: controllable synthesis and cell imaging

In this paper we report two different doping strategies to prepare a series of novel HAp:Ln(3+) (Ln = Eu or Tb) nanocrystals with tunable aspect ratios via facile hydrothermal synthetic routes. Adopting a one-pot synthetic strategy, with increasing rare-earth doping dosage, the as-prepared nanocrystals have relatively weak fluorescence intensity, and change from nanorods with lengths of about 150 nm into nanowires with lengths of about 2 μm. Using the synthetic pure HAp nanorods as matrices, they are endowed with bright green or red luminescent properties by doping Tb(3+) or Eu(3+) ions via a second hydrothermal process, and simultaneously retain their original morphologies (diameter 8 nm, length 150 nm). The hydrophobic HAp:Ln(3+) nanorods with strong optical properties are converted into hydrophilic particles with a surfactant (Pluronic F127) and successfully applied to live cell imaging.