Kinetics and mechanisms of the conversion of silicate (45S5), borate, and borosilicate glasses to hydroxyapatite in dilute phosphate solutions

  • Wenhai Huang
  • Delbert E. Day
  • Kanisa Kittiratanapiboon
  • Mohamed N. RahamanEmail author


Bioactive glasses with controllable conversion rates to hydroxyapatite (HA) may provide a novel class of scaffold materials for bone tissue engineering. The objective of the present work was to comprehensively characterize the conversion of a silicate bioactive glass (45S5), a borate glass, and two intermediate borosilicate glass compositions to HA in a dilute phosphate solution at 37°C. The borate glass and the borosilicate glasses were derived from the 45S5 glass by fully or partially replacing the SiO2 with B2O3. Higher B2O3 content produced a more rapid conversion of the glass to HA and a lower pH value of the phosphate solution. Whereas the borate glass was fully converted to HA in less than 4 days, the silicate (45S5) and borosilicate compositions were only partially converted even after 70 days, and contained residual SiO2 in a Na-depleted core. The concentration of Na+ in the phosphate solution increased with reaction time whereas the PO4 3– concentration decreased, both reaching final limiting values at a rate that increased with the B2O3 content of the glass. However, the Ca2+ concentration in the solution remained low, below the detection limit of atomic absorption, throughout the reaction. Immersion of the glasses in a mixed solution of K2HPO4 and K2CO3 produced a carbonate-substituted HA but the presence of the K2CO3 had little effect on the kinetics of conversion to HA. The kinetics and mechanisms of the conversion process of the four glasses to HA are compared and used to develop a model for the process.


Bioactive Glass Phosphate Solution Glass Particle Borate Glass 45S5 Glass 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    L. L. HENCH, R. J. SPLINTER, W. C. ALLEN and T. K. GREENLEE, Jr., J. Biomed. Mater. Res. 2 (1971) 117.CrossRefGoogle Scholar
  2. 2.
    L. L. HENCH and J. WILSON, Science 226 (1984) 630.Google Scholar
  3. 3.
    L. L. HENCH, in Handbook of Bioactive Ceramics, edited by T. YAMAMURO, L. L. HENCH and J. WILSON (CRC Press, Boca Raton, FL, 1990) Vol. 1, p. 7.Google Scholar
  4. 4.
    L. L. HENCH, J. Am. Ceram. Soc. 74 (1991) 1487.CrossRefGoogle Scholar
  5. 5.
    L. L. HENCH, J. Am. Ceram. Soc. 81 (1998) 1705.CrossRefGoogle Scholar
  6. 6.
    T. NAKAMURA, T. YAMAMURO, S. HIGASHI, T. KOKUBO and S. ITO, J. Biomed. Mater. Res. 19 (1985) 685.CrossRefGoogle Scholar
  7. 7.
    U. GROSS and V. STRUNZ, J. Biomed. Mater. Res. 19 (1985) 251.CrossRefGoogle Scholar
  8. 8.
    W. HOELAND, W. VOGEL, K. NAUMANN, and J. GUMMEL, J. Bomed. Mater. Res. 19 (1985) 303.CrossRefGoogle Scholar
  9. 9.
    T. KOKUBO, S. SAKKA and T. YAMAMURO, J. Mater. Sci. 21 (1986) 536.CrossRefGoogle Scholar
  10. 10.
    S. YOSHII, Y. KAUTANI, T. YAMAMURO, T. NAKAMURA, T. KITSUGI, M. OKA, T. KOKUBO and M. TAKAGI, J. Biomed. Mater. Res. 22 (1988) 327.CrossRefGoogle Scholar
  11. 11.
    T. KITSUGI, T. YAMAMURO and T. KOKUBO, J. Bone Joint Surg. 71 (1989) 264.Google Scholar
  12. 12.
    K. H. KARLSSON, H. FROBERG and K. RINGBOM, J. Non-Cryst. Solids 112 (1989) 69.CrossRefGoogle Scholar
  13. 13.
    T. KOKUBO, H. KUSHITANI, S. SAKKA, T. KITSUGI and T. YAMAMURO, J. Biomed. Mater. Res. 24 (1990) 721.CrossRefGoogle Scholar
  14. 14.
    S. D. CONZONE, R. F. BROWN, D. E. DAY and G. J. EHRHARDT, J. Biomed. Mater. Res. 60 (2002) 260.CrossRefGoogle Scholar
  15. 15.
    D. E. DAY, J. E. WHITE, R. F. BROWN and K. D. MCMENAMIN, Glass Technol. 44 (2003) 75.Google Scholar
  16. 16.
    Q. WANG, W. HUANG, D. WANG, B. W. DARVELL, D. E. DAY and M. N. RAHAMAN, J. Mater. Sci.: Mater. Med. (2005), in press.Google Scholar
  17. 17.
    M. N. C. RICHARD, M. S. Thesis, University of Missouri-Rolla, 2000.Google Scholar
  18. 18.
    N. W. MARION, W. LIANG, G. REILLY, D. E. DAY, M. N. RAHAMAN and J. J. MAO, Mech. Adv. Mater. Struct. 12 (2005) 239.Google Scholar
  19. 19.
    L. L. HENCH and H. A. PASCHALL, J. Biomed. Mater. Res. Symp. 4 (1973) 25.CrossRefGoogle Scholar
  20. 20.
    T. KOKUBO, S. ITO, Z. T. HUANG, T. HAYASHI, S. SAKKA, T. KITSUGIO and T. YAMAMURO, J. Biomed. Mater. Res. 24 (1990) 331.CrossRefGoogle Scholar
  21. 21.
    P. DUCHEYNE, J. Biomed. Mater. Res. 21 (1987) 219.Google Scholar
  22. 22.
    J. A. WOJCIK, M. S. Thesis, University of Missouri-Rolla, 1999.Google Scholar
  23. 23.
    G. BORDAS and C. C. TRAPALIS, J. Sol-Gel Sci. Technol. 9 (1997) 305.Google Scholar
  24. 24.
    S. MATSUYA and Y. MATSUYA, J. Mater. Sci.: Mater Med. 9 (1998) 325.CrossRefGoogle Scholar
  25. 25.
    H. MORGAN, R. M. WILSON, J. C. ELLIOTT, S. E. P. DOWKER and P. ANDERSON, Biomaterials 21 (2000) 617.CrossRefGoogle Scholar
  26. 26.
    X. LU and Y. LENG, Biomaterials 26 (2005) 1097.CrossRefGoogle Scholar
  27. 27.
    A. S. POSNER, N. C. BLUMENTHAL and F. BETTS, in Phosphate Minerals, edited by J. O. Nriagu and P. B. Moore (Springer-Verlag, Berlin, 1984) p. 331.Google Scholar
  28. 28.
    R. Z. LEGEROS and J. P. LEGEROS, in Phosphate Minerals, edited by J. O. Nriagu and P. B. Moore (Springer-Verlag, Berlin, 1984) p. 351.Google Scholar
  29. 29.
    J. BARRALET, S. BEST and W. BONFIELD, J. Biomed. Mater. Res. 41 (1998) 79.CrossRefGoogle Scholar
  30. 30.
    R. K. ILER, in The Chemistry of Silica (Wiley, New York, 1979).Google Scholar

Copyright information

© Springer Science + Business Media, LLC 2006

Authors and Affiliations

  • Wenhai Huang
    • 1
    • 2
  • Delbert E. Day
    • 1
    • 3
  • Kanisa Kittiratanapiboon
    • 4
  • Mohamed N. Rahaman
    • 1
    • 3
    Email author
  1. 1.Materials Research CenterUniversity of Missouri-RollaRolla
  2. 2.School of Materials Science and EngineeringTongji UniversityShanghaiChina
  3. 3.Department of Materials Science and EngineeringUniversity of Missouri-RollaRolla
  4. 4.Center for Environmental Science and TechnologyUniversity of Missouri-RollaRolla

Personalised recommendations