Optische und magnetische Eigenschaften Selten-Erd-dotierter Apatite

In this work REE3+-doped luminescent, magnetic and luminomagnetic apatite nanoparticles were synthesized and investigated with respect to their optical and magnetic properties and the resulting suitability as biomedical nanoparticle contrast agent. Investigations of the crystal chemical properties have shown that the crystal lattices of HAp and FAp are capable of incorporating the dopants Eu3+, Dy3+, Nd3+ and Gd3+, despite a different valence and the associated vacancy formation and lattice distortions. Investigations of the optical properties of REE:Ap have shown that doping with Eu3+ and Nd3+ respectively causes luminescence in HAp and FAp. Furthermore, it has been demonstrated that it is possible to transfer the optical properties of these crystallites into a composite material by adding luminescent REE:Ap to bone cement. It was shown that the optical properties of the REE:Ap crystallites are significantly improved in REE:CPC. The substitution of REE3+, which have a high magnetic moment, such as Dy3+ and Gd3+, leads in HAp and FAp to increasing magnetizations with increasing strength of an externally applied magnetic field. In addition, it could be shown that Dy:HAp and Gd:FAp lead to a significant reduction of the transverse relaxation times of water protons, which is shown as dark contrast in MR images. Consequently, REE:Ap are suitable for use as negative T2 contrast media. The combination of optical and magnetic properties in a solid solution could be achieved by co-doping Eu3+ and Dy3+ in HAp or Nd3+ and Gd3+ in FAp. The REE:Ap investigated in the present work show photoluminescence, magnetism or embody the combination of both properties in the form of luminomagnetic nanoparticles. Their excellent biological properties make the synthesized REE:Ap suitable nanoparticle contrast media for biomedical imaging.