Nanobiotechnology for health-care

Laser spectroscopy of bi-phasic calcium phosphate powders doped by the Nd3+ ions

E.A. Vagapova1,2, E.O. Orlovskaya2, A.V. Popov2, L. Puust1, A.S. Vanetsev1,2,
Z. Stankeviciute3, J. Januskevicius3, Matas Janulevičius3,
A. Kareiva3, Yu.V. Orlovskii1,2

1Institute of Physics, University of Tartu, W.Ostwaldi st.1, Tartu 50411, Estonia
E-mail:ekaterina.vagapova@ut.ee
2A.M. Prokhorov General Physics Institute RAS, Vavilov st. 38, 119991, Moscow, Russia
3Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania

The great interest in the study of apatite minerals and, in particular, hydroxyapatite (Ca10(PO4)6(OH)2), is associated primarily with their compatibility with human biological tissues. Currently, synthetic hydroxyapatite (CHAp) is used in many areas of biomedicine, such as traumatology, dentistry, etc. [1, 2].
In this work we have studied so-called bi-phasic calcium phosphate (BCP), annealed two times at 1000°C for 24 hours, which is considered to be optimal material for artificial bone regeneration. By adjusting the ratio between more stable (CHAp) and more soluble calcium triphosphate (-TCP) phase, it allows for precision tuning of resorption rate [3].
Using selective and time-resolved laser spectroscopy at liquid helium temperature (10K) for both phases, we selected fluorescence spectra for two different crystal phases. The fluorescence decay kinetics was measured, and spontaneous decay times were determined for each crystal phase. From the obtained fluorescence spectra of BCP, the concentration of both phases were calculated. We showed that spectroscopic method allows to determine low concentrations of impurity crystal phases in the samples with high accuracy comparable with XRD method of phase analysis.

1.	H. Oonishi, Biomaterials, 1993, 12, 171-178
2.	J.M. Triglia, C.Scheiner, J. Gouvernet, M. Cannoni, Arch. Otolar. Head & Neck Surg., 1993,119, 87-91
3.	G. Daculsi, R.,Woodhead Publishing Series in Biomaterials, 2008, P. 395-423