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diamond, there are identified graphite and carbon, while the amorphous material is also significant (26%). The diamond peaks
show a significant base (2theta) which means that the structure of this phase is probably crypocrystallic and also are symmetrical
which means that the diamond phase is well crystallized.
The BG/ND sample presents two strong peaks at about 10-13 o 2theta and 25-37 o 2theta, while there are two less intense
peaks at about 17-24 o 2theta and 28-55 o 2theta. Significantly, the first peak (10-13 o 2theta) is less intense to the pure BG sample,
which indicates a possible transition from the amorphous state to a primary amorphous-cryptocrystallic state. Additionally, the
amorphous part of the pure ND sample affects the total amount and the morphology of amorphous in the BG/ND sample, while
the peak between 28-55 o 2theta can be attributed to the cryptocrystallic structure of diamond that appears between 43-44 ο 2theta.
Amorphous
SCS: Sodium Calcium Silicate, Ca SiO
86-0399 ICDD card
D: Diamond, C, 06-0675 ICDD card
G: Graphite, C, 75-2078 ICDD card
C: Carbon, C, 26-1069 ICDD card
C
G
ND pure
D
SCS
SCS
5 15 25 35 45 55 65 75
SCS
Amorphous
SCS
SCS BG/ND
SCS SCS
SCS SCS SCS
SCS
SCS
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 BG pure 80
Amorphous
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
D
Fig. 1. XRD patterns of the BG/ND system
and of pure BG and ND
In Fig. 2 are presented the FTIR spectra of the BG/ND system and pure
BG before and after the immersion in c-SBF, for 6, 12 and 24 hours. In the
spectra of both samples before the immersion, is observed a broad trend
between 840 and 1370cm -1 that can be attributed to the amorphous phase of the
samples. The two shoulders at 850 and 965 cm -1 can be assigned to the
crystalline phase of dicalcium silicate (Ca 2 SiO 4 ) [9] . Finally, the strong band at
460cm -1 occurs due to the bending mode of Si-O-Si.
After 6 hours of soaking,
a new band appears at 585cm -1
in both BG/ND system and
pure BG, which corresponds to
the antisymmetric vibrational
mode of P-O in amorphous
calcium phosphate phase.
After 12 hours in c-SBF, the
IR spectrum of both samples is
analogous to that observed
after 6 hours. However, after
24 hours a double peak at 568
and 602cm -1 is developed to
both samples, that are
attributed to the bending of P-O mode and proves the development of a
crystalline phase of HCAp layer [10] . Comparing the bioactive response of both
samples with that of the commercial sol-gel derived bioactive glass [7] (Bioglass®
58S) proves a retardation of our samples, that is probably caused by the growth
of the crystalline phase of dicalcium silicate (Ca 2 SiO 4 ).
Conclusions
The XRD pattern of the BG/ND system indicates that the nanodiamonds
result in the re-arrangement of the BG amorphous phase, producing an
amorphous phase with a primary amorphous-cryptocrystallic structure. The fact
that this new phase is also highly bioactive, even though there is a small
retardation of bioactive response in comparison with pure Bioglass® 58S, makes
the sol-gel-derived BG/ND system a promising bioactive composite.
2 4
References
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[3]. Hench L.L. and Andersson O. in An introduction to Bioceramics, editors:
Hench L.L. and Wilson J., World Scientific, 41, 1993
[4]. Ekimov E.A., Gromnitskaya E.L., Gierlotka S., Lojkowski W., Palosz B.,
Swiderska-Sroda A., Kozubowski J.A. and Naletov A.M., J. of Materials
science letters, 21, 1699 , 2002
[5]. Kulakova I. I., Physics of the Solid State, 46, 636, 2004
[6]. Xu K. and Xue Q., Physics of the solid state, 46, 649, 2004
[7]. Zhong J., Greenspan D., J Biomed Mater Res, 53, 694, 2000
[8]. Ohtsuki C., Kushitani H., Kokubo T., Kotani S., Yamamuro T., J Biomed Mater Res, 25, 1363, 1991
400 600 800 1000 1200 1400 1600
[9]. Henning O., Cements: the Hydrated Silicates and Aluminates in The Infrared Spectra of Minerals, editor: Farmer V.C.
London, Mineralogical Society, 1974
[10]. Kontonasaki E., Zorba T., Papadopoulou L., Pavlidou E., Chatzistavrou X.., Paraskevopoulos K., Koidis P., Cryst. res.
technol., 37, 1165, 2002
Absorbance
24h
12h
6h
0h
wavelength (cm -1 )
BG/ND
pure BG
Fig.2. FTIR spectra of pure BG and the
BG/ND system before and after 6, 12 and
24h of immersion in c-SBF
183