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Hydrothermal conversion of Malaysian coral to hydroxyapatite, a bone substitute synthesis, characterization and in-vitro solubility studies / Mimi Rahayu Samsudin

Hydrothermal conversion of Malaysian coral to hydroxyapatite, a bone substitute synthesis, characterization and in-vitro solubility studies_Mimi Rahayu Samsudin_K4_2005_MYMY

Abstract Tujuan kajian ini adalah untuk mensintesis hidroksiapatit, Ca1o(P04)s(OH)2 daripada batu karang Malaysia spesis Porites lutea, untuk digunakan sebagai tulang gantian dalam perubatan dan pergigian. Batu karang telah dicirikan menggunakan pembelauan sinar-x (XRD}, jelmaan fourier infra-merah (FT-IR), pendarfluor sinar-x (XRF}, analisis permeteran gravity haba (TGA) dan mikroskop imbasan elektron (SEM). Kajian pencirian melibatkan penentuan fasa batu karang, kandungan unsur, morfologi dan kestabilan terma batu karang yang digunakan dalam kajian ini. Pencirian telah dilakukan untuk memastikan batu karang yang digunakan dalam kajian ini adalah bahan mentah yang sesuai. Keputusan pencirian menunjukkan bahawa batu karang terhasil daripada 97.76% kalsium karbonat dalam fasa aragonit, manakala baki 2.24% dimiliki oleh unsur-unsur minor dan surih. Analisis terma batu karang menunjukkan bahawa kira-kira 44% pengurangan berat berlaku pada 791°C yang sama dengan kalsium karbonat komersil. Batu karang spesis ini memiliki struktur berliang yang tersaling hubung diseluruh rangka. Ia mempunyai saiz liang yang seragam iaitu kirakira 117 f..Ull. Batu karang telah be~aya ditukarkan kepada hidroksiapatit, melalui tindak balas hidroterma. Tindak balas hidroterma telah dijalankan di dalam reaktor kelompok bertekanan tinggi pada suhu di antara 150°C - 250°C dan tekanan 34 atmosfera, yang cJijanakan oleh wap air. Banyak parameter yang telah dikaji untuk mencari keadaan :>ptimum pembentukan hidroksiapatit, seperti suhu tindak balas (150°C- 250°C}, masa ;entuh (1 - 42 jam), jumlah DAP (pengurangan dan lebihan daripada nisbah molar ;toikiometri) dan nilai pH (pH 9 - 11) Jarutan awal. Pembentukan fasa tunggal lidroksiapatit dengan kestabilan terma yang unggul dan kandungan karbonat yang ninima telah diperolehi pada suhu 250°C, 6 jam masa sentuh, 30% lebihan DAP dan pH 9 larutan awal. Pada keadaan ini, pembentukan fasa-fasa lain seperti kalsium hidroksida dan kalsium karbonat tidak dapat dikesan. Kajian kestabilan in-vitro hidroksiapatit telah dilakukan dalam penimbal air masin berfosfat (PBS) dan air ternyah-ion pada 37°C untuk menentukan keterlarutannya dalam keadaan fisiologi. Hidroksiapatit yang dihasilkan pada keadaan optimum adalah yang paling stabil apabila direndam dalam kedua-dua larutan selepas 55 jam. _______________________________________________________________________ The purpose of this study is to synthesize hydroxyapatite, Ca1o(P04)s(OH)z from Malaysian coral of species Porites Jutea, to be used as bone substitute in medicine and dentistry. Coral was characterized using x-ray diffraction (XRD}, fourier transform infrared (FT-IR), x-ray fluorescence (XRF), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The characterization study involves the determination of coral phases, element content, morphology and thermal stability of coral used in this study. The characterization was carried out in order to ensure that the coral used in this study was suitable raw material. Characterization results revealed that coral was made up of 97.76% calcium carbonate 1n aragonite phase, while the remaining 2.24% belongs to minor and traces element. Thermal analysis of coral showed that about 44% weight loss occurred at 791 oc which was identical to that of commercial calcium carbonate. Coral of this species possessed porous structure with interconnectivity throughout the skeletal. It has a consistent pore size of around 117,...m. Coral was successfully converted into hydroxyapatite, through hydrothermal reaction. Hydrothermal reaction was carried out in a high-pressure batch reactor at temperature range between 150°C - 250°C and pressure of 34 atmospheres, generated by water vapor. Many parameters have been studied in order to find the optimum conditions of hydroxyapatite formation, such as reaction temperature (150°C- 250°C), contact time (1 - 42 hours}, amount of DAP (less and excess than stoichiometric molar ratio) and pH value (pH 9 -11) of initial solution. The formation of single phase hydroxyapatite with excellent thermal stability and minimal carbonate content was obtained at 250°C, 6 hours of contact time, 30% excess of DAP and at pH 9 of the initial solution. At this operating condition, the formation of other phases such as calcium hydroxide and calcium carbonate were not detected. The in-vitro stability studies of hydroxyapatite were performed in phosphate buffer saline (PBS) and de-ionized water at 37°C to determine its solubility in physiological environment. Hydroxyapatite synthesized at optimum conditions was the most stable when immersed in both solutions after 55 hours.

Contributor(s): Mimi Rahayu Samsudin - Author Primary Item Type: Thesis Identifiers: Accession Number : 875008977 Language: English Subject Keywords: Hydrothermal ; hydroxyapatite ;in-vitro solubility studies Sponsor - Description: Pusat Pengajian Kejuruteraan Kimia - First presented to the public: 8/1/2005 Original Publication Date: 12/18/2020 Previously Published By: Universiti Sains Malaysia Place Of Publication: School of Chemical Engineering Citation: Extents: Number of Pages - 150 License Grantor / Date Granted:   / ( View License ) Date Deposited 2020-12-18 11:10:26.098 Submitter: Mohamed Yunus Yusof

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