The paper describes the preparation of the biphasic (hydroxyapatite (HA) and tricalcium phosphate
(TCP)) nanostructured calcium phosphate composite. The product was chemically synthesized from the solution
which contained calcium acetate Са(СН3СОО)2 (0,167 mМ), sodium dihydrogen phosphate NaH2PO4
(0,1 mМ), sodium hydrocarbonate NaHCO3 (0,02 mM). The calcium phosphate composite was formed at
pH=11 with and without the addition of carbonate ions. The samples were analyzed using X-Ray diffraction
after the heat treatment at 900C for 1 h. The derived material contained HA and TCP phases with
their contents change depending on the concentration of the carbonate ions in the solution. The mean crystallite
size of the HA phase in (121) plane is 12 – 14 nm. Further studies will be directed to the using of the
derived composite for the biomedical applications.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3544

Inshyna, Nataliia Mykolaivna

Kulak, A.I.

Kuznetsov, V.N.

Stanislavov, A.S.

Sukhodub, L.B.

Sukhodub, Leonid Fedorovych

Иншина, Наталия Николаевна

Суходуб, Леонид Федорович

Суходуб, Леонід Федорович

Іншина, Наталія Миколаївна

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  
NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 2 No 4, 04NABM15(2pp) (2013) 
 
 
2304-1862/2013/2(4)04NABM15(2) 04NABM15-1  2013 Sumy State University 
Biphasic Calcium Phosphate Composite for Biomedical Applications 
 
L.B. Sukhodub1,*, V.N. Kuznetsov2,†, A.S. Stanislavov2, N.N. Inshyna1, A.I. Kulak3, L.F. Sukhodub1 
 
1 Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy, Ukraine 
2 Institute of Applied Physics, 58, Petropavlovskaya Str., 40000 Sumy, Ukraine 
3 The Institute of General and Inorganic Chemistry, 9/1, Surganova Str., 220072 Minsk, Belarus 
 
(Received 9 June 2013; revised manuscript received 1 July 2013; published online 31 August 2013) 
 
The paper describes the preparation of the biphasic (hydroxyapatite (HA) and tricalcium phosphate 
(TCP)) nanostructured calcium phosphate composite. The product was chemically synthesized from the so-
lution which contained calcium acetate Са(СН3СОО)2 (0,167 mМ), sodium dihydrogen phosphate NaH2PO4 
(0,1 mМ), sodium hydrocarbonate NaHCO3 (0,02 mM). The calcium phosphate composite was formed at 
pH=11 with and without the addition of carbonate ions. The samples were analyzed using X-Ray diffrac-
tion after the heat treatment at 900C for 1 h. The derived material contained HA and TCP phases with 
their contents change depending on the concentration of the carbonate ions in the solution. The mean crys-
tallite size of the HA phase in (121) plane is 12 – 14 nm. Further studies will be directed to the using of the 
derived composite for the biomedical applications. 
 
Keywords: Hydroxyapatite, Tricalcium Phosphate, Biphasic Composite, Heat Treatment, XRD, SEM. 
 
 PACS numbers: 87.85.J –, 87.64.Bx, 87.64.Ee 
 
                                                        
* l.sukhodub@gmail.com 
† vkuznetsov.ua@gmail.com 
1. INTRODUCTION 
 
Synthetic hydroxyapatite (HA) Ca10(PO4)3(OH)2 is 
widely used in medicine for treatment and replacement 
of the damaged bone tissues due to its closeness in 
chemical and physical structure to the inorganic com-
ponent of the native bone. In past decade the replace-
ment of biomaterial with newly created bone was ac-
centuated in the course of the creation of biomaterials 
based on HA, with synthetic materials used as a source 
of necessary elements for bone tissue building. Thus 
the main requirements for biomaterials are their poros-
ity, chemical composition, solubility, presence of the 
elements which diffuse from the material during re-
sorption leading to easier bone regeneration. The bio-
material resorption function is important for its inte-
gration in organism. HA has a low level of solubility 
(solubility product SP  3·10–116 [1]) and dissolves only 
in acid medium which is locally created by osteoclasts 
in an active bone resorption zone. It is surrounded by 
the fibroid capsule of the connective tissue in neutral or 
alkalescent intertissular liquid and remains undis-
solved which could lead to negative consequences. The 
transition to the biphasic composites is one of the 
means to improve the resorption of the materials based 
on HA which contain more soluble components, e. g. 
tricalcium phosphate (TCP) Са3(РО4)2, SP  0,2·10-29 
[1]. 
 
2. MATERIALS AND METHODS 
 
2.1 Materials 
 
The biphasic product which contains HA and TCP 
was derived during our studies. The output synthesis 
materials were calcium acetate Са(СН3СОО)2 
(0,167 mМ), sodium dihydrogen phosphate NaH2PO4 
(0,1 mМ), sodium hydrocarbonate NaHCO3  (0,02 mM). 
Equal conditions for simultaneous interaction of РО43– 
and СО32
 ions with Са2 and ОН ions were provided 
by adding mixed solution of NaH2PO4 and NaHCO3. 
The calcium phosphate composite was formed under 
pH  11 and 10 M of NaOH aqueous solution at 80C. 
The formed calcium phosphate suspension after aging 
for 24 h was carefully washed with deionized water and 
heated in a muffle furnace at 900C for 1 h. The sam-
ples with and without the addition of NaHCO3 were 
synthesized. 
 
2.2 Methods  
 
The crystallinity and structure of the synthesized 
samples were examined using an X-ray diffractometer 
DRON-3 (Bourevestnik, Inc., Saint-Petersburg, Russian 
Federation) connected to a computer-aided system for 
the experiment control and data processing. The current 
and the voltage of the X-ray tube were 20 mA and 40 kV 
respectively. All experimental data was processed by 
means of the program package DIFWIN-1 (Etalon PTC, 
Ltd., Moscow, Russian Federation). Identification of 
crystal phases was done using a JCPDS card catalog 
(Joint Committee on Powder Diffraction Standards).  
The crystallite sizes L were calculated using the 
Scherrer equation [2]: 
 
 

 
 ,
cos
K
L  (2.1) 
 
where K is the form coefficient (K=1),  is the wave-
length,  is the peak broadening,  is the diffraction 
angle. 
The quantitative phase analysis was done using the 
reference intensity ratio (RIR) method [3]: 
 
 ,
1
1










 
n
i
rel
ii
i
i
rel
ii
i
IK
I
I
IK
C  (2.2) 
 
where Ci is the concentration of the i-phase, Ki is the 
 L.B. SUKHODUB, V.N. KUZNETSOV, A.S. STANISLAVOV ET AL. PROC. NAP 2, 04NABM15 (2013) 
 
 
04NABM15-2 
corundum number of the i-phase, Ii is the peak integral 
intensity of the i-phase, reliI  is the peak relative inten-
sity of the i-phase. 
The Ca/P ratio was calculated using method de-
scribed in [4]: 
 
,
/2/)100(6
/3/)100(10
HAPTCPHAPTCP
HAPTCPHAPTCP
MCMC
MCMC
P
Ca


  (2.3) 
 
where CTCP is the TCP phase concentration (), MHAP is 
the molar mass. 
The scanning electronic microscopy (SEM) was used 
for studying the morphology of the samples. The beam 
voltage was 20 kV. 
 
3. RESULTS AND DISCUSSION  
 
The derived results show that the chosen solution 
composition for the HA synthesis with the organic com-
ponent decreases the crystallinity of the resulting prod-
uct compared to the composition with inorganic salt so-
lutions (Fig. 1). The mean crystallite sizes of the HA 
phases in (121) plane in the heat treated at 600C sam-
ples are 12 (without the carbonate ions addition) and 14 
nm (with the carbonate ions addition) which approaches 
to the biological apatite, and at 900C – 43 and 53,2 nm 
respectively. The phase concentrations and Ca/P ratios 
of the studied samples are shown in Table 1. 
 
10 15 20 25 30 35 40 45 50 55 60
With CO
3
2–
 ions, 900 
o
C
Without CO
3
2–
 ions, 900 
o
C
With CO
3
2–
 ions, 600 
o
C


Without CO
3
2–
 ions, 600 
o
C
In
te
n
si
ty
 (
co
u
n
ts
)
2 (
o
)
| JCPDS 84-1998

 
 
Fig. 1 – X-Ray diffraction spectra of biphasic calcium 
phosphate composites of the different synthesis heat treated 
at 600 and 900C; major TCP peaks are marked with ♦ 
 
Table 1 – Phase concentrations and Ca/P ratios of biphasic 
calcium phosphate composites of the different synthesis 
 
Sample 
HA TCP 
Са/Р, 
at.  JCPDS 
Concentra
tion,  
JCPDS 
Concentra
tion,  
With 
CO32– 
ions 
84-1998 65 51-422 35 1,64 
Without 
CO32– 
ions 
84-1998 90 9-348 10 1,66 
 
The formation of the significant portion of TCP after 
the heat treatment indicates that the crystallization of 
nonstehiometric apatite has occurred under the influ-
ence of the organic component, and also the presence of 
the defects in the crystal lattice due to the partial substi-
tution of Са2 ions with close in size Na ions (0,99Å and 
0,98Å respectively) which are present in the solution. 
Additional local defects in the crystal lattice could’ve 
been induced by the incorporation of carbonate-ions 
which affect the biological behavior of the resulting 
product increasing its resorption degree. 
The micrographs of particles and their conglomerates 
are shown in Fig. 2. The particles have the arbitrary 
shape and their sizes vary from 2 to 15 m. 
 
 
 
Fig. 2 – Micrographs of particles and their conglomerates of 
biphasic calcium phosphate composites of the different syn-
thesis heat treated at 900C with (A, B) and without (C, D) the 
addition of carbonate ions 
 
4. CONCLUSIONS 
 
The changes of physical and chemical synthesis 
characteristics (solution composition, temperature, pH 
value) regulate the phase composition of the resulting 
biphasic calcium phosphate composite.  
The sample synthesized with the addition of car-
bonate ions after the heat treatment at 900C shows the 
increase of the crystallite sizes of the both phases in the 
major planes and the concentration of the TCP phase 
with the decrease of the Ca/P ratio. 
The dependence of the resorption rate from the phase 
composition would be defined in future studies.  
 
AKNOWLEDGEMENTS 
 
This work was carried out in the framework of joint 
grant of the State Fund for Fundamental Researches of 
Ukraine (NF54.4/012) and Belarusian Republican 
Foundation for Fundamental Research. 
 
 
REFERENCES 
 
1. J.C. Elliott, Structure and Chemistry of the Apatites and 
Other Calcium Orthophosphates (London: Elsevier: 1994). 
2. H.P. Klug, L.E. Alexander, X-Ray Diffraction Procedures: 
For Polycrystalline and Amorphous Materials (New York: 
Wiley: 1974). 
3. F.H. Chung, J. Appl. Crystallogr. 8, 17 (1975). 
4. S. Raynaud, E. Champion, D. Bernache-Assollant, J.-
P. Laval, J. Am. Ceram. Soc. 84 No2, 359 (2001). 


English

Biphasic Calcium Phosphate Composite for Biomedical Applications

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 2 No 4, 04NABM15(2pp) (2013)   2304-1862/2013/2(4)04NABM15(2) 04NABM15-1  2013 Sumy State University Biphasic Calcium Phosphate Composite for Biomedical Applications  L.B. Sukhodub1,*, V.N. Kuznetsov2,†, A.S. Stanislavov2, N.N. Inshyna1, A.I. Kulak3, L.F. Sukhodub1  1 Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy, Ukraine 2 Institute of Applied Physics, 58, Petropavlovskaya Str., 40000 Sumy, Ukraine 3 The Institute of General and Inorganic Chemistry, 9/1, Surganova Str., 220072 Minsk, Belarus  (Received 9 June 2013; revised manuscript received 1 July 2013; published online 31 August 2013)  The paper describes the preparation of the biphasic (hydroxyapatite (HA) and tricalcium phosphate (TCP)) nanostructured calcium phosphate composite. The product was chemically synthesized from the so-lution which contained calcium acetate Са(СН3СОО)2 (0,167 mМ), sodium dihydrogen phosphate NaH2PO4 (0,1 mМ), sodium hydrocarbonate NaHCO3 (0,02 mM). The calcium phosphate composite was formed at pH=11 with and without the addition of carbonate ions. The samples were analyzed using X-Ray diffrac-tion after the heat treatment at 900C for 1 h. The derived material contained HA and TCP phases with their contents change depending on the concentration of the carbonate ions in the solution. The mean crys-tallite size of the HA phase in (121) plane is 12 – 14 nm. Further studies will be directed to the using of the derived composite for the biomedical applications.  Keywords: Hydroxyapatite, Tricalcium Phosphate, Biphasic Composite, Heat Treatment, XRD, SEM.   PACS numbers: 87.85.J –, 87.64.Bx, 87.64.Ee                                                          * l.sukhodub@gmail.com † vkuznetsov.ua@gmail.com 1. INTRODUCTION  Synthetic hydroxyapatite (HA) Ca10(PO4)3(OH)2 is widely used in medicine for treatment and replacement of the damaged bone tissues due to its closeness in chemical and physical structure to the inorganic com-ponent of the native bone. In past decade the replace-ment of biomaterial with newly created bone was ac-centuated in the course of the creation of biomaterials based on HA, with synthetic materials used as a source of necessary elements for bone tissue building. Thus the main requirements for biomaterials are their poros-ity, chemical composition, solubility, presence of the elements which diffuse from the material during re-sorption leading to easier bone regeneration. The bio-material resorption function is important for its inte-gration in organism. HA has a low level of solubility (solubility product SP  3·10–116 [1]) and dissolves only in acid medium which is locally created by osteoclasts in an active bone resorption zone. It is surrounded by the fibroid capsule of the connective tissue in neutral or alkalescent intertissular liquid and remains undis-solved which could lead to negative consequences. The transition to the biphasic composites is one of the means to improve the resorption of the materials based on HA which contain more soluble components, e. g. tricalcium phosphate (TCP) Са3(РО4)2, SP  0,2·10-29 [1].  2. MATERIALS AND METHODS  2.1 Materials  The biphasic product which contains HA and TCP was derived during our studies. The output synthesis materials were calcium acetate Са(СН3СОО)2 (0,167 mМ), sodium dihydrogen phosphate NaH2PO4 (0,1 mМ), sodium hydrocarbonate NaHCO3  (0,02 mM). Equal conditions for simultaneous interaction of РО43– and СО32 ions with Са2 and ОН ions were provided by adding mixed solution of NaH2PO4 and NaHCO3. The calcium phosphate composite was formed under pH  11 and 10 M of NaOH aqueous solution at 80C. The formed calcium phosphate suspension after aging for 24 h was carefully washed with deionized water and heated in a muffle furnace at 900C for 1 h. The sam-ples with and without the addition of NaHCO3 were synthesized.  2.2 Methods   The crystallinity and structure of the synthesized samples were examined using an X-ray diffractometer DRON-3 (Bourevestnik, Inc., Saint-Petersburg, Russian Federation) connected to a computer-aided system for the experiment control and data processing. The current and the voltage of the X-ray tube were 20 mA and 40 kV respectively. All experimental data was processed by means of the program package DIFWIN-1 (Etalon PTC, Ltd., Moscow, Russian Federation). Identification of crystal phases was done using a JCPDS card catalog (Joint Committee on Powder Diffraction Standards).  The crystallite sizes L were calculated using the Scherrer equation [2]:     ,cosKL  (2.1)  where K is the form coefficient (K=1),  is the wave-length,  is the peak broadening,  is the diffraction angle. The quantitative phase analysis was done using the reference intensity ratio (RIR) method [3]:   ,11 nireliiiireliiiIKIIIKC  (2.2)  where Ci is the concentration of the i-phase, Ki is the  L.B. SUKHODUB, V.N. KUZNETSOV, A.S. STANISLAVOV ET AL. PROC. NAP 2, 04NABM15 (2013)   04NABM15-2 corundum number of the i-phase, Ii is the peak integral intensity of the i-phase, reliI  is the peak relative inten-sity of the i-phase. The Ca/P ratio was calculated using method de-scribed in [4]:  ,/2/)100(6/3/)100(10HAPTCPHAPTCPHAPTCPHAPTCPMCMCMCMCPCa  (2.3)  where CTCP is the TCP phase concentration (), MHAP is the molar mass. The scanning electronic microscopy (SEM) was used for studying the morphology of the samples. The beam voltage was 20 kV.  3. RESULTS AND DISCUSSION   The derived results show that the chosen solution composition for the HA synthesis with the organic com-ponent decreases the crystallinity of the resulting prod-uct compared to the composition with inorganic salt so-lutions (Fig. 1). The mean crystallite sizes of the HA phases in (121) plane in the heat treated at 600C sam-ples are 12 (without the carbonate ions addition) and 14 nm (with the carbonate ions addition) which approaches to the biological apatite, and at 900C – 43 and 53,2 nm respectively. The phase concentrations and Ca/P ratios of the studied samples are shown in Table 1.  10 15 20 25 30 35 40 45 50 55 60With CO32– ions, 900 oCWithout CO32– ions, 900 oCWith CO32– ions, 600 oCWithout CO32– ions, 600 oCIntensity (counts)2 (o)| JCPDS 84-1998  Fig. 1 – X-Ray diffraction spectra of biphasic calcium phosphate composites of the different synthesis heat treated at 600 and 900C; major TCP peaks are marked with ♦  Table 1 – Phase concentrations and Ca/P ratios of biphasic calcium phosphate composites of the different synthesis  Sample HA TCP Са/Р, at.  JCPDS Concentration,  JCPDS Concentration,  With CO32– ions 84-1998 65 51-422 35 1,64 Without CO32– ions 84-1998 90 9-348 10 1,66  The formation of the significant portion of TCP after the heat treatment indicates that the crystallization of nonstehiometric apatite has occurred under the influ-ence of the organic component, and also the presence of the defects in the crystal lattice due to the partial substi-tution of Са2 ions with close in size Na ions (0,99Å and 0,98Å respectively) which are present in the solution. Additional local defects in the crystal lattice could’ve been induced by the incorporation of carbonate-ions which affect the biological behavior of the resulting product increasing its resorption degree. The micrographs of particles and their conglomerates are shown in Fig. 2. The particles have the arbitrary shape and their sizes vary from 2 to 15 m.    Fig. 2 – Micrographs of particles and their conglomerates of biphasic calcium phosphate composites of the different syn-thesis heat treated at 900C with (A, B) and without (C, D) the addition of carbonate ions  4. CONCLUSIONS  The changes of physical and chemical synthesis characteristics (solution composition, temperature, pH value) regulate the phase composition of the resulting biphasic calcium phosphate composite.  The sample synthesized with the addition of car-bonate ions after the heat treatment at 900C shows the increase of the crystallite sizes of the both phases in the major planes and the concentration of the TCP phase with the decrease of the Ca/P ratio. The dependence of the resorption rate from the phase composition would be defined in future studies.   AKNOWLEDGEMENTS  This work was carried out in the framework of joint grant of the State Fund for Fundamental Researches of Ukraine (NF54.4/012) and Belarusian Republican Foundation for Fundamental Research.   REFERENCES  1. J.C. Elliott, Structure and Chemistry of the Apatites and Other Calcium Orthophosphates (London: Elsevier: 1994). 2. H.P. Klug, L.E. Alexander, X-Ray Diffraction Procedures: For Polycrystalline and Amorphous Materials (New York: Wiley: 1974). 3. F.H. Chung, J. Appl. Crystallogr. 8, 17 (1975). 4. S. Raynaud, E. Champion, D. Bernache-Assollant, J.-P. Laval, J. Am. Ceram. Soc. 84 No2, 359 (2001). 

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Biphasic Calcium Phosphate Composite for Biomedical Applications

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