• Korean Journal of Materials Research
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• v.24 no.12
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• pp.700-703
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• 2014

Calcium phosphate minerals are biologically important because of their application in the fields of orthopaedics and dentistry. Herein we have tried to synthesize calcium phosphate minerals from biowaste clam shells. A simple microwave method was used to synthesize a mixture of calcium phosphate minerals such as hydroxyapatite, tri-calcium phosphate, and monetite. The microwave induces vibration of the dipole ions in the reagent. The heating and rearrangement of ions and atoms occurs during the process. The phases obtained in the final powder were ascertained by X-ray diffraction; the morphology of each sample was checked using a scanning electron microscope. We were able to obtain a mixture of calcium phosphate minerals using the microwave method; the calcined powder showed a brick like morphology, which is different from the rod shape morphology of the hydroxyapatite obtained using the hydrothermal process.

• Journal of Life Science
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• v.14 no.1
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• pp.174-179
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• 2004

To develop high effiency biofertilizer, a bacterium having ability to solubilize inorganic phosphate was isolated from cultivated soils, using a sucrose minimal agar-hydroxyapatite medium. The strain was identified as Klebsiella sp. DA7l-1, based on the physiological and biochemical properties. The activity of solubilizing inorganic phosphate of Klebsiella sp. DA7l-1 against three types of insoluble phosphate such as tri-calcium phosphate, aluminium phosphate, hydroxyapatite were quantitatively determined. The results indicated that the strain solubilized hydroxyapatite. The MPS (mineral phosphate solubilizing) conditions of Klebsiella sp. DA7l-1, were measured to determine the optimal conditions. The optimal temperature and initial pH to solubilize insoluble phosphate in sucrose minimal medium were $30^{\circ}C$ and pH 6.0, respectively.

• Journal of Life Science
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• v.14 no.3
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• pp.490-495
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• 2004

Phosphate-solubilizing activities of the two strains (Burkholderia sp. DA23 and Klebsiella sp. DA7l-1) against tri-calcium phosphate and hydroxyapatite were quantitatively determined. Two strains were found to solubilize two types of insoluble phosphate different amounts of amino acid solutions in liquid culture. MPS ability of the strains was increased with concentration of amino acid addition. The optimal solubilization condition of insoluble phosphate in sucrose minimal medium were 0.1% amino acid solution, respectively. The efficiency of amino acid addition was no difference between the two types of insoluble phosphate, tri-calcium phosphate and hydroxyapatite.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.275-279
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• 2013

The purpose of this study was to prepare calcium phosphate cement [CPC] for use in artificial bone. Nano-crystalline calcium phosphate [CaP] was precipitated at $37^{\circ}C$ using highly active $Ca(OH)_2$ in DI water and an aqueous solution of $H_3PO_4$. From the XRD measurements, the nano-CaP powder was close to apatitic TCP phase and the powders fired at $800^{\circ}C$ showed a critical ${\beta}$-TCP phase. A mixture of one mole $CaCO_3$ and two moles di-calcium phosphate was calcined at $1100^{\circ}C$ to make a reference ${\beta}$-TCP material. The nano-CaP powders were added to the normal ${\beta}$-TCP matrix and fired at $900^{\circ}C$ to make a ${\beta}$-TCP block. The sintered block showed improved mechanical strength, which was caused by the solid state interaction between nano-CaP and normal ${\beta}$-TCP.

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.439-455
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• 2003

연구목적 : SLA surface dental implant 주위의 3면 골내낭에서 xenogeneic demineralized bone matric putty, porous ${\beta}$-tri-calcium phosphate, 새로이 개발된 non-crystalline calcium phosphate glass를 사용한 치료를 조직학적으로 비교 평가하기 위한 것이다. 연구방법 : 실험동물로는 15개월에서 18개월 사이의 12kg에서 15kg 정도되는 성견을 사용하였다. 20개의 SLA surface implant가 사용되었으며, 성견 하악의 양측에 각각 2개씩 사용되었다. 임플란트 식립전에, 각각의 임플란트 근심면에 straight fissure bur를 이용하여 표준화된 3면 골내앙(근원심 5mm ${\times}$협설 3mm ${\times}$깊이 3mm)을 형성하였다. 형성된 골 결손부에는 demineralized bone matrix putty, porous ${\beta}$-tri-calcium phosphate, non-crystalline calcium phosphate glass를 넣은 것을 각각 실험군으로, 이식재를 넣지 않은 것을 대조군으로 사용하였다. 8주 후에 실험 동물을 희생시키고 조직학적 관찰을 하였다. 결과 : 조직학적 소견상 임플란트 주위에 급성 염증 소견은 보이지 않았으며, non-crystalline calcium phosphate glass은 매우 적은량의 신생골을, ${\beta}$-TCP을 이용한 골내낭에서는 약간의 기저부에서 유래된 신생골이 관찰된다. ${\beta}$-TCP granules 가운데로 상당량의 측면의 골에서 유래된 신생골 형성이 보인다. xenogeneic DBM putty에서는 많은 량의 신생골이 기저부에 형성된 것을 볼수 있으나 대조군과의 차이는 크지 않다. 이식재의 종류와 상관없이 흡수되지 않은 이식재를 임플란트 주위에서 관찰할 수 있었다. 골내낭 안의 이식재들은 모두 connective tissue로 둘러 싸여 있었다. 모든 실험군에서 이식재에서 기인한 신생골 형성과 임플란트 표면에 신생 골유착의 조직학적 증거는 발견되지 않았다.

• Journal of Life Science
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• v.23 no.2
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• pp.242-248
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• 2013

The objective of this study was to develop a mineral phosphate-solubilizing bacterium as a biofertilizer. A mineral phosphate-solubilizing bacterium HR-1019 was isolated from cultivated soils. It was identified as Bacillus subtilis by 16S rDNA analysis. The phosphate-solubilizing activities of the HR-1019 strain against three types of insoluble phosphate, hydroxyapatite, tri-calcium phosphate, and aluminum phosphate were quantitatively determined. When 5% of glucose concentration was used as a carbon source, the strain showed marked mineral phosphate-solubilizing activity. Mineral phosphate solubilization was directly related to pH drop in the culture solution of the strain. The pathogenic activity and antifungal effects of the HR-1019 strain were measured inclear zones formed in PDA media.

• The Korean Journal of Ceramics
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• v.7 no.1
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• pp.41-44
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• 2001

A composite of $Ca_3$(PO$_4$)$_2$ and MgAl$_2$O$_4$ spinel is biologically active and has enduring strength. Its strength depends on the spinel phase. The flaws in the spinel depend on the grain size of the calcium phosphate phase and are not altered by dissolution. The calcium phosphate, ${\alpha}$ tri-calcium phosphate, controls the tissue response. Bone bonds to the implant. A design for a bone graft as a replacement for a section of the diaphysis of a canine femur provides for tensile, compressive, torsional and bending load; and for the physiological processes of bonding and remodeling. A bone plate, used to stabilize the implant at time of surgery was removed after about one year. Over seven years of service have been achieved without internal or external fixation.

• Korean Journal of Poultry Science
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• v.15 no.3
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• pp.219-227
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• 1988

This experiment was carried out to evaluate biological availability of Ca and P in 4 different sources of tricalcium phosphate in young chicks. One hundred and twenty five-day-old male Single Comb White Leghorn chicks (10 treatments$\times$3replication$\times$4chicks) were used in trial 1 and 2, respectively, for 12 days of feeding period. Trial I was to evaluate the availability of phosphorus in the supplements, Standard purified diets were prepared to supply 0.07, 0.14 and 0.21％P using a mixture (1 : 1) of NaH$_2$PO$_4$ and KH$_2$PO$_4$ as the reference Phosphorus sources. Bone breaking strength of the tibia determeined by an Instron instrument appeared inadequate to be used as a criterion due to very high variations of the measurement within a treatment. Thus, tibia bone ash content was utilized as a criterion to evaluate th biological avilability of phosphorus in the supplements. The levels of the biological availability of the four different sources of dicalcium phoshate were 77.1, 91.0, 96.4 and 95.5％, respectively, and those of the three tricalcium phosphate sources were 94.1, 95.0 and 99.5％ , respectively. Trial 2 was to determeine the levels of Ca biologically available in the supplements. Standard purified diets were made to supply 0.2, 0.3 and 0.4％ Ca using CaCo$_3$ as the reference calcium source. When bone ash content was utilized as a criterion for the availability, the levels of calcium biologically available to the chicks were 78.3, 234.1, 87.6 and 244.5％, respectively, for the 4 different sources of dicalcium phosphate and 99.5, 84.0 and 101.5％ , respectively, for the 3 different sources of tricalcium phosphate. The observation that two calcium sources appeared to be utilized with an unusual efficiency can hardly be explained at this moment. When they were revaluated on the basis of body weight gain, the availabilities of the four sources of dicalcium phosphate were 89.2, 58.2, 104.1 and 103.1％ and of the three tricalcium phosphate were 112.6, 106.0 and 96.3％ , respectively.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.670-675
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• 2016

Calcium phosphate crystallites were prepared by wet chemical method for use in artificial bone. In order to obtain ${\beta}$-tricalcium phosphate (TCP), nano-crystalline calcium phosphate (CaP) was precipitated at $37^{\circ}C$ and at $pH5.0{\pm}0.1$ under stirring using highly active $Ca(OH)_2$ in DI water and an aqueous solution of $H_3PO_4$. The precipitated nano-crystalline CaP solution was kept at $90^{\circ}C$ for the growth of CaP crystallites. Through the growing process of CaP crystallites, we were able to obtain various sizes of rectangular CaP crystallites according to the crystal growing times. Dry nano-crystalline CaP powders at $37^{\circ}C$ were mixed with dry macro-crystalline CaP crystallites and the shaped mixture sample was fired at $1150^{\circ}C$ to make a ${\beta}-TCP$ block. Several tens of nm powders were uniformly coated on the surface, which was comprised of powders of several tens of ${\mu}m$, using a vibrator. The mixing ratio between the nanometer powders and the micrometer powders greatly affected the mechanical strength of the mixture block; the most appropriate ratio of these two materials was 50 wt% to 50 wt%. The sintered block showed improved mechanical strength, which was caused by the solid state interaction between the nano-crystalline ${\beta}-TCP$ and the macro-crystalline ${\beta}-TCP$.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.865-870
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• 1998

The surfaces of titanium specimens were modified by immersion in calcium phosphate buffered solutions (pH 5.8, 7.0, 8.0) for 10 days and simulated body fluid(SBF) for 30 days by turns. The modified surfaces were characterized using scanning electron microscopy(SEM), X-ray diffractometery(XRD) and Fourier transform infrared spectrophotometer(FT-IR), and compared with specimen immersed in only SBF. The results indicated that the immersion in calcium phosphate buffered solutions accelerated the formation of the surface films. The formed layer showed granular shaped microstructure, and recognized as calcium phosphate such as a hydroxyapatite(HA) or a $\beta$-tri-calcium phosphate($\beta$-TCP). The thickness of the layer increased of the buffered solutions in order of pH 8.0, 7.0 and 5.8 and the density increased in order of pH 7.0, 8.0 and 5.8.