Ahmad Fadli

Porous alumina-hydroxyapatite composites through protein foaming-consolidation method.

This report presents physical characterization and cell culture test of porous alumina-hydroxyapatite (HA) composites fabricated through protein foaming-consolidation technique. Alumina and HA powders were mixed with yolk and starch at an adjusted ratio to make slurry. The resulting slip was poured into cylindrical shaped molds and followed by foaming and consolidation via 180 °C drying for 1 h. The obtained green bodies were burned at 600 °C for 1 h, followed by sintering at temperatures of 1200-1550 °C for 2 h. Porous alumina-HA bodies with 26-77 vol.% shrinkage, 46%-52% porosity and 0.1-6.4 MPa compressive strength were obtained. The compressive strength of bodies increased with the increasing sintering temperatures. The addition of commercial HA in the body was found to increase the compressive strength, whereas the case is reverse for sol-gel derived HA. Biocompatibility study of porous alumina-HA was performed in a stirred tank bioreactor using culture of Vero cells. A good compatibility of the cells to the porous microcarriers was observed as the cells attached and grew at the surface of microcarriers at 8-120 cultured hours. The cell growth on porous alumina microcarrier was 0.015 h(-1) and increased to 0.019 h(-1) for 0.3 w/w HA-to-alumina mass ratio and decreased again to 0.017 h(-1) for 1.0 w/w ratio.

Preparation of porous alumina for biomedical applications through protein foaming- consolidation method

Abstract The present work reports a novel method for preparation of porous alumina using egg yolk both as consolidator and foaming agent. Suspensions with an alumina to yolk ratio of 1 in weight were prepared by stirring for 3 h and the resulting slip was poured into cylindrical shaped moulds followed by foaming and consolidation by drying at temperatures of 110 and 180°C. The dried green bodies were then burned to remove the pore creating agent at 600°C for 1 h, followed by sintering at 1550°C for 2 h. The density of the porous bodies was 2·27 g cm–3 when foamed at 110°C and it decreased to 1·80 g cm–3 at 180°C foaming temperature. The compressive strength was found to drop from 5·72 MPa at 43·6% porosity to 4·57 MPa at 50·4% porosity. Macropores of the porous bodies were found to fall in the range of 100–500 μm, showing promising applicability for scaffold devices.

Porous Alumina from Protein Foaming-Consolidation Method Containing Hydrothermal Derived Hydroxyapatite Powder

Porous alumina containing hydrothermal derived hydroxyapatite (HA) composite were successfully fabricated via protein foaming-consolidation method. Alumina and HA powders were mixed with yolk, starch and darvan 821 A at an adjusted mass ratio to make slurry. The slurries were cast into cylindrical shaped molds and then dried for foaming and consolidation process. Subsequently, the dried bodies were burned at 600°C for 1 h, followed by sintering at temperatures of 1300 - 1400°C for 2 h. The porous alumina-HA composites with pore size in the range of 95-300 µm and density of 2.7 – 2.9 g cm-3 were obtained. Porosity of bodies decreased from 31.7 to 27.6% when sintering temperatures increased from 1300 to 1400°C. The increasing HA-to-alumina mass ratio from 0.2 to 0.8 w/w increased compressive strength of sintered bodies from 2.3 to 10.0 MPa. XRD pattern results show intensity of tricalcium phosphate (TCP) phase increased with sintering temperatures and also found that the sintering process did not alter phases in the porous bodies.

Protein Foaming-Consolidation Method for Fabrication of High Performance Porous Bioceramics

Protein foaming-consolidation method is a facile technique for production of porous materials using egg yolk as pore creating agent. Usage of the yolk in the process offers a number of advantages over other proteins such as egg white and bovine serum albumin (BSA). Various materials were successfully fabricated using this technique. The present paper gives a brief review of the preparation and characterization of the materials through protein foaming-consolidation technique for biomedical application.

Porous Alumina through Protein Foaming-Consolidation Method: Effect of Stirring Time and Drying Temperature on the Physical Properties

The porous alumina ceramics were fabricated through protein foaming-consolidation method using egg yolk as pore creating agent. The influence of stirring time and drying temperature on the physical properties of the porous bodies was investigated. The porosity of the 3 h stirring time’s sample was 42% and it increased to 71% at 24 h stirring time. As the drying temperature increased, the pores became interconnected with less dense and thinner pore and were found in the range of 100-650 µm. The density of 180°C drying temperature’s sample was 1.5 g/cm3 and it increased to1.9 g.cm-3 when dried at 100°C. An alumina-to-yolk ratio of 1.4 in weight was found to be optimum composition to give porous bodies with higher compressive strength. The compressive strength of the porous bodies increased from 3.7 MPa at 61.1% porosity to 7.7 MPa at 42.5% porosity, showing that the compressive strength is strongly dependent on porosity.

Isotherm Study on the Adsorption of Cadmium (II) onto Hydroxyapatite from Sea Shells Synthesized by Low Temperature Hydrothermal Method

The release of Cadmium (Cd2+) ion onto the water as a result of industrial activities and its waste stream causes a negative impact on the environment and human health. The potential of synthesized HAp to remove Cd2+ from aqueous solutions was investigated in a batch reactor under different experimental condition. Hydroxyapatite (HAp) were prepared from sea shells by low temperature hydrothermal method. This study also investigates the effects of process parameter such as initial concentration and adsorbent dosage to determine the appropriate model between Langmuir and Freundlich. The experimental results show that adsorption capacity (qe) increased with increasing initial concentration of Cd2+ (Co). Initial concentration increased from ~20 to ~40 mg/L, qe increased from 19,24 to 37,32; 12,81 to 25,49 and 9,62 to 19,31 mg/g when adsorbent dosage was 1; 1,5 and 2 g/L respectively. The percentage of removal increased with increasing adsorbent dosage. Adsorbent dosage increases from 1 to 2 g/L, the adsorption percentage increased from 96,51 to 96,93; 96,79 to 97,06 and from 94,81 to 97,07% at the initial concentration of Cd2+ ~20, 30 and 40 mg/L, respectively. The adsorption data described well by the Freundlich isotherm model, indicating heterogeneous adsorbent surface during adsorption of Cd2+ onto Hap.