Modification of Porous Alumina Ceramics with Bioinert and Bioactive Glass Coatings

Abstract

Porous biomaterials including porous bioceramics play important roles for hard tissue replacement and regeneration. In this paper, porous alumina (with and without zirconia addition) ceramics were produced via coating polyurethane (PU) foams with Al2O3 (ZrO2) slurries, followed by drying at room temperature and sintering at 1300 oC. The advantage of the PU foam method was the achieved high pore interconnectivity, but the mechanical properties of the porous ceramics were rather poor due to the high macroporosity and the high microporosity. To remove the microporosity and strengthen the porous alumina ceramics, a lanthanum-modified aluminosilicate (LAS) glass was used to infiltrate the alumina struts. Nevertheless, the resulting LAS-modified macroporous alumina ceramics would have no ability to bond to bone tissue. To impart a bioactivity (i.e. the ability of bone bonding) to the bioinert porous ceramics, a bioactive glass layer was applied by dipping with the bioactive glass slurry and sintering at 1200 oC. The twice coated porous alumina ceramics would exhibit high compressive strengths, allow bone tissue ingrowth, and form strong bone-material integration. A biodegradable filler of calcium phosphate cement was also incorporated for additional drug delivery function. A possible application of the porous bioceramics would be for the maxillofacial reconstruction.