HYDROXYAPATITE PRODUCTION WITH VARIOUS TECHNIQUES FROM SEA URCHIN

Objectives: Natural species of sea origin, such as corals and nacres, always attract special interest in biomaterials science and technology because of excellent biological properties. Their bio-mineralization mechanism has been extensively investigated and documented. Nevertheless, there are only few studies dealing with the use of sea urchins as biomaterials. The aim of this study was to fabricate various types of biological active hydroxyapatite (HA) nano-particles with various methods. Methods: Sea urchin skeletons were collected from beaches of Marmara Sea and then brushed, washed, and dried. The particles were milled until fine powder of 100 mu m was produced. DTA analysis results were used to calculate the equivalent amount of phosphoric acid needed to satisfy the stoichiometry of HA. The collected powder was rinsed into distilled water. For the hydrothermal transformation, the suspension was put separately to ultrasonic bath and hotplate. After 15 minutes, the equivalent phosphoric acid was added drop by drop. The treatment was continued (either in the ultrasonic bath or in the hotplate) for 2 more hours. Then, the precipitates were removed from the suspension. After drying, the powders were sintered for 4 hours in air at 450 degree C and 850 degree C. The sintered bodies were analyzed with FTIR, X-ray diffraction, and SEM. Results: The sintered bodies contained various phases of HA and TCP, as revealed from the XRD and IR analysis. Fine microstructures of nano-sized grains were observed with SEM. Conclusions: This study presented easy production methods of HA with hotplate and ultrasonic. Thus, conventional hydrothermal methods, such as those that employ high-pressure vessels, which could be very dangerous, tedious and expensive, can be omitted.