The student, Sarah Hamid, obtained a PH degree for her dissertation entitled " Preparation and Characterization of Biodegradable Ceramic from Hydroxyapatite " in the field of Applied Sciences / MaterialsTechniques.

The discussion committee consisted of Dr. Balkis Muhammad as Chairman, Dr. Ahmed M. Hassan Al-Ghabban, Dr.Nihaya Nima Hussein, Dr. Muzaffar F. Jamil, Dr. Ghassan Abdul Hamid Naji as members , Dr. Muzaffar A. Muhammad Supervisor and Dr. Ali Abdul Rahman Taha as co- Supervisor.

This study stated “Hydroxyapatite ceramics have been widely used in medical application due to its excellent biocompatibility and biodegradability. In the physiological environment, its able to gradually degrade, absorbed and promote bone growth. Ultimately, they are capable of replacing the damaged bone with new tissue but its low mechanical properties limited its application.

To obtain sufficient compression property as well as high biocompatibility is the goal of this study. The current work focuses on the preparation and characterization of porous Hydroxyapatite (HAp) by polymeric sponge method with different solid loadings ranging between (35 to 55 wt. %) and then sintered to 1250 °C.

Tri calcium phosphate and calcium hydroxides were used as raw materials to prepare the HAp powder. It was found that the optimum ratio when the solid loading is (55wt. %) with porosity (77.1 %), viscosity (284 MPa.s), foam density (0.77 g/cm3) and compression strength (6.34 MPa).

Furthermore, Titania, Zirconia and Alumina were added to hydroxyapatite to enhance the compression property of the samples in range between (5 to 25 wt. %) from the total solid loading. When Titania, Zirconia and Alumina were added, with ratios of (25, 20 and 25 wt. %), respectively, it was found that the porosity of the samples was (60.9, 73.9 and 65.7%), viscosity (414, 410 and 403 MPa.s), foam density (1.7, 1.2 and 1.5 g/cm3) and compression strength (9.6, 10.1 and 8.25 MPa), respectively.

Optical, XRD, SEM and EDX analysis to study the crystallinity of the materials, especially HAp after the solid state reaction to confirm the HAppeaks, process of densification and cell walls thickness. It was found out when the solid loading increases the cell walls increase as well which improve the mechanical properties.

In vitro test for the selected samples was conducted by immersing them for 30 days in a simulated body fluid at 37 °C. Ca/P ratios were decreased due to the formation of bone like apatite on the surfaces of specimens.

The antibacterial activities of the selected samples were examined against Escherichia coli, Pseudomonas aeruginosa (as Gram – ve bacteria) and Staphylococcus aureus (as Gram + ve bacteria), and their bacterial adhesion at 4, 25 and 37 °C which the highest bacterial adhesion is found in Staphylococcus aureus (0.131) when the temperature is 37 °C and the values of bacterial adhesion decrease when the concentration of the samples increase.

The anti-biofilm activity of HAp was determined. The HAp and HAp composites revealed anti-biofilm activity when incubated with Pseudomonas aeruginosa for 24 hr at 37°C.

Furthermore, HAp and HAp composites showed that the low hemolysis activity at all concentrations is less than (4.89%) when incubated with fresh blood at 37 °C for 1 hr.

The cell viability of samples against L20B (the source of Fibroblast Mouse L cells) and Lymphocytes (human) cell lines was estimated by MTT assay. The HAp and HAp composites exhibited high cell viability effect against (Lymphocytes cell line) which is (987%) and (183%) (L20B cell line), respectively.

Keywords: Hydroxyapatite, bioceramic, bioactive ceramic, vacuum, microwave, polymeric sponge method, bacterial adhesion, cell viability, simulation body fluids, Titania, Zirconia and Alumina, porous ceramic”.