Egg Yolk as Pore Creating Agent to Produce Porous Tri-calcium Phosphate for Bone Implant Application A.R. Fariza a , A. Zuraida b and I.Sopyan c Department of Manufacturing and Materials Engineering, Faculty of Engineering, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur, Malaysia a fariza_iiu@yahoo.com, b zuraidaa@iiu.edu.my, c sopyan@iiu.edu.my Keywords: Porous tri-calcium phosphate, egg yolk, porosity, compressive strength Abstract. Porous tri-calcium phosphate which is to be applied as artificial bone was prepared via protein consolidation method and egg yolk is used to give binding effect as well as to create porosity. In this experiment, fractions of egg yolk is controlled from 50 wt%, 60 wt%, 70wt% and 80 wt% and the mixture of egg yolk and tri-calcium phosphate powder were dried at 60 °C before undergone uniaxial compaction method. Subsequently, pressure of 68.5 MPa is given to the mold to produce cylindrical shape samples with diameter to height ratio of 1:2. Samples were then sintered at 1100°C to achieve porous tri-calcium phosphate. This method produced porous tri-calcium phosphate with desired porosity of 20-54.5% and acceptable compressive strength between 0.7-0.07 MPa. Besides, microporosity of 0.4-1µm and macroporosity in the range of 100-800µm were successfully obtained from this method. Introduction There are a lot of concerns have been put in order for the researchers to consider the best way to respond to the demand on the biomaterials products since there are a lot of shortcomings derived from allograft and autograft as bone substitutes. They tried to discover as simple as possible method plus reducing in cost as an advantage. Besides, the usage of environmental-friendly materials should also be considered as it becomes the main concern these days. Then again, the produced artificial bones must meet several criteria before it can be applied to human body. These are the major challenges in order to develop porous artificial bone with desired porosity and acceptable mechanical strength. For synthetic bone applications, bioceramics from calcium phosphate family is often used due to its properties that mimic the natural human bone. However, hydroxyapatite (HA) and tri-calcium phosphate (TCP) are the most favorable because of their good biocompatibility and osteointegrative properties [1]. When comparison is made between these two bioceramics, TCP has more preferences for the reason that it dissolves and desorbs much more quickly than HA. Moreover, HA shows almost no absorption and remains in the body for a long time as foreign substances [2]. In order for the artificial bone to be accommodated by the host tissues, it must exhibit porosity as to encourage cell growth within the three dimensional structure. Yet, the pores must be interconnected to each other in order to mimic the architecture of the mineral phase of living bone [3]. Previously, there are many inspired ways of producing porous artificial bones such as by polymeric sponge method and conversion of marine coral skeleton. Alternatively, as the porosity of the artificial bone needs to be controlled, researchers nowadays are using pore creating agents either organic or inorganic materials to achieve the desired porosity. Examples of the prominent pore creating agents are polymethylmethacrylate micro beads (PMMA), sodium chloride (NaCl), carbon beads, starch, ice and naphthalene. In general, these pore creating agents will decomposed from the prepared samples during sintering thus creating the porosities [4-6]. The employment of egg yolk as emulsifier in food industry promotes the idea that it can be an excellent binder plus creating porosity when heated. Normally in food production, proteins in yolk coagulate and form a solid or semisolid structure when exposed to heat at the temperature between 60- 70°C. This feature turns egg yolk to be a desired binder that holds elements together. Besides, its readily available film-forming properties preserve the moisture between particles [7]. From these unique Advanced Materials Research Vols. 264-265 (2011) pp 760-764 Online available since 2011/Jun/30 at www.scientific.net © (2011) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.264-265.760 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 210.48.222.9-05/09/11,10:02:38)