DEVELOPMENT OF METAL DOPEDHYDROXYAPATITE FOR BONE IMPLANT APPLICATION SHARIFAH ADZILA BINTI SYED ABU BAKAR

Transcription

1 DEVELOPMENT OF METAL DOPEDHYDROXYAPATITE FOR BONE IMPLANT APPLICATION SHARIFAH ADZILA BINTI SYED ABU BAKAR THESIS SUBMITTED IN FULFILLMENT OF THE REQUIREMENTS FOR THE DGEREE OF DOCTOR OF PHILOSOPHY FACULTY OF ENGINEERING UNIVERSITY OF MALAYA KUALA LUMPUR

2 ABSTRACT Hydroxyapatite (HA) powder with nanosize particles was successfully synthesized by mechanochemical method in a dry state at 170 rpm, 270 rpm and 370 rprn rotation speeds in 15 hours respectively. The research revealed that among the three rotation speeds employed, 370 rpm synthesized powder showed better characteristics as determined by X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR) and Field Emission Scanning Electron Microscopy (FESEM) analyses. Similarly, the sintering properties of these powders showed maximum densification, Vickers hardness and fracture toughness with values of 96.8%, 5.29 GPa and 1.49 M~a.m"~, respectively were obtained when sintered at 1250 C. The rotation speed of 370 rpm was subsequently employed to prepare the Na-doped HA and Mg-doped HA. The study found that the decrease of the XRD peak intensities and the decrease of FTIR adsorption bands corresponded to HA phase were related to the increase of Na' and M ~ ions ~ ' concentration. The substitution of the ions also changed the lattice parameters, the unit cell volumes and the crystal size of HA. Sintering and ion doping also influenced the stability of the HA phase where the decomposition occurred between 1000 C-1300 C sintering temperature and with increasing Na' and M ~ ions ~ concentration + in the HA lattice. This has led to the increase of HA phase decomposition due to Na+ and Mg2' replacing the ~a'+ sites. Increasing sintering temperature has led to the decrease of relative densities, Vickers hardness and fracture toughness of undoped HA, Na-doped HA and Mg-doped HA. The 1% Na-doped HA was found to have maximum densification and Vickers hardness of 99.2% and 5.47 GPa, respectively when sintered at 1250 C. The 1% Na-doped HA also exhibited a high fracrure toughness of 1.84 ~~a-rn'" when sintered at 1300 C. Na' doping was more effective in enhancing the mechanical perforn~ance of HA compared to ~g'+ doping. Na-doped HA and Mg- doped HA increased the biocompatibility of HA as the maximum growth of calcium phosphate was significantly shown in the 7% Na-doped HA after 7 days of exposure. However. osteoblast cell culture showed that increasing Na' and M ~" concentration to 7% - 9% molar concentration induced the formation of dead cells near to the samples. The study found that Na' and M~" in higher molar concentration particularly 9% doping was detrimental as it affected the mechanical properties as well as the biocompatibility of the hydroxyapatite ceramic.

3 ABSTRAK Serbuk hidroksiapatit dengan zarah saiz nano telah Berjaya dihasilkan melalui kaedah mekanokimia pada kelajuan putaran 170 rpm, 270 rpm dan 370 rpm rpm dalam 15 jam. Kajian telah menunjukkan antara ketiga-tiga kelajuan putaran yang digunakan, serbuk yang disintesis pada 370 rpm telah menunjukkan pencirian yang lebih baik melalui analisis X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR) dan Field Emission Scanning Electron Microscope (FESEM). Sifat-sifat pensinteran serbuk yang disintesis pada 370 rpm ini juga menunjukkan pernadatan, Vickers kekerasan dan keliatan patah yang maksimum dengan 96.8%, 5.29 GPa dan 1.49 ~ ~a.rn"~, di perolehi masing-masing apabila disinter pada suhu 1250 C. Bagi logam dop, 370 rpm digunakan untuk sintesis Na-dop HA dan Mg-dop HA dalarn 1% - 9mo1% kandungan masing- masing. Na-dop HA dan Mg-dop HA telah berjaya disintesis melaiui kaedah yang sama di mana penurunan keamatan puncak dan penurunan kumpulan penjerapan telah menunjukkan kesepadanan dengan fasa HA dengan peningkatan kandungan Na' dan ~ g " ion melalui analisis XRD dan FTIR. Penggantian ion juga telah mengubah parameter kekisi, isipadu unit sel dan saiz kristal HA. Pensinterandan ion-ion dop juga mempengaruhi kestabilan HA di mana penguraian berlaku antara suhu pensinteran 1000 C C dan peningkatan kandungan ion-ion Na' dan Mg' telah membawa kepada peningkatan penguraian masing-masing kerana kekurangan kalsium berlaku disebabkan oleh penggantian ion-ion Na' dan ~ g " ke dalam kedudukan ca2*. Peningkatan suhu pensinteran telah membawa kepada penurunan ketumpatan relatif. Vickers kekerasan dan keliatan patah HAI Na-dop HA dan Mg-dop HA. 1% NaHA telah meningkatkan ciri-cin HA di mana nilai ~naksimu~n pemadatan dan kekerasan Vickers, 99.2% dan 5.47 GPa teiah diperolehi masing-masing pada 1250 C. 1% NaHA

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34 REFERENCES Adzila, S., Murad, M. C. and Sopyan, 1. (2012). Doping metal into calcium phosphate phase for better performance of bone implant materials. Rec Pat Muter Sci., 5, Albrektsson, T. and Johansson, C. (2001). Osteoinduction, osteoconduction and osseointegration. Eur. Spine J., 10, Amarh-Bouali, S., Rey, C., Lebugle, A. and Bernache, D. (1994). Surface modifications of hydroxyapatite ceramics in aqueous media. Baomaterials, 15, Aminian, A., Hashjin, M. S., Sainadikuchaksaraei, A., Bakhshi, F., Gorjipour, F., Farzadi, A. and Schmucker, M. (201 1). Synthesis of silicon-substituted hydroxyapatite by a hydrothermal method with two different phosphorous sources. Ceramics International, 37, Anee, T. K., Palanichamy, M., Ashok, M., Sundaram, N. M. and Kalkura. S. N. (2004). Influence of iron and temperature on the crystallization of calcium phosphates at the physiological ph. Materials Letters. 58, Aoki, H. (1991). Science and Medical Applications of Hydroxyapatite: Japanese Association of Apatite Science, Tokyo, Japan.