MODELING AND COMPUTATION OF HYDROXYAPATITE NANOSTRUCTURES AND PROPERTIES

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MODELING AND COMPUTATION OF HYDROXYAPATITE
NANOSTRUCTURES AND PROPERTIES
V. BYSTROV1), N.BYSTROVA2), E. PARAMONOVA1) ,
A.. SAPRONOVA1), S. FILIPPOV1), 1)Institute of
Mathematical Problems of Byology of RAS
2)Institute of Theoretical and Experimental
Biophysics of RAS, Pushchino, 142290, Moscow
region, Russia E-mailbystrov_at_impb.psn.ru
vsbys_at_yahoo.co.uk http//home.impb.psn.ru
(OPIT Home Page)
Hydroxyapatite (Ca5(PO4)3 OH) (HAp) is a crystal
structural and compositional analogue to
calcified tissues of vertebrates. The biomedical
significance of HAp is its bioactivity HAp
ceramics conduct the formation of new bone on
their surface. HAp properties are ascribed to the
characteristic surface structure of HAp, while
the detailed mechanism is still unknown.
Hydroxyapaptite can occur in a monoclinic phase
(space group P21/b) or in the hexagonal system
(P63/m). In the monoclinic phase, all of the
dipols in all of the tunnels lying in the same
plane parallel to the a,c plane must be either
all up or all down and those in the next plane
b/2 away must be oriented oppositely.
We have used data from CIF (Crystallographic
Information File) lybrary 8 which were edited
with enCIFer 1.1 7 and spg 6. Then in Web Lab
Viewer Lite 1 the structures of both
modification of HAp were created from CIF. Then
obtained data were processed by Hyper Chem OH
positions were optimized. Also in Web Lab Viewer
Lite H-bonds and Van der Waals surfaces were plot.
OH- dipols form so-called OH- ion channels
along c direction. These channels are bounded
within each unit cell be two triangular arrays of
Ca2 ions and by four triangular arrays of O2-
ions, belonging to PO43- groups
References 1. N. Hitmi, D. Chatain, C.
LaCabanne, J. Dugas, J.C.Trombe, C. Rey and G.
Montel, Solid StateCommunications, Vol. 33, pp.
1003-1004, 1980. 2. N. Hitmi, C. LaCabanne and
R.A. Young, J.Phys. Chem. Solids Vol. 47, No6,
pp533-546, 1986. 3. Nakamura, Nakeda and
Yamashita, J. Appl. Phys.,Vol.89, No.10,15 May
2001. Proton transport polarization and
depolarization of hydroxyapatite ceramics 4. G.C.
Maiti, F.Freund. Influence of fluorine
substitution on the proton conductivity of
hydroxyapatite. J.Chem.Soc. Dalton, pp.949-955,
1981 5. http//www.msi.com/viewer 6.
http//www.calidris-em.com/archive.htm 7.
http//www.ccdc.cam.ac.uk/free_services/encifer 8.
ftp//ftp.geo.arizona.edu/pub/xtal/data/CIFfiles/