Lanthanide-doped calcium phosphate nanoparticles with high internal crystallinity and with a shell of DNA as fluorescent probes in cell experiments

Calcium phosphate nanoparticles were prepared by precipitation and stabilized as colloids by coating with DNA. They were doped with europium or terbium during this precipitation (about 2.5 wt%) and showed good fluorescence in the visible part of the spectrum. The fluorescence efficiency depended strongly on the internal crystallinity, i.e. amorphous nanoparticles of the same composition showed much weaker fluorescence. These particles are biocompatible and are easily taken up by cells (T-HUVEC), i.e. they can be used as fluorescing markers. Different colours can be realized by doping with different lanthanides.