Porous and Bioactive Alumina Ceramics for Bone Grafts and Tissue Engineering Scaffolds

An environmentally friendly direct foaming method was investigated to produce porous alumina ceramics. Egg white protein was used as a binder and foaming agent. The microstructures show that pores are interconnected with pore size of a few hundreds μm and pore window size of ca. 50 μm. The compressive strength of alumina foam is up to 100 MPa depending on porosity. Bioactivation of alumina was carried out using an alkaline solution treatment. Hydroxylation of alumina was achieved using 5M NaOH at 80°C for 4 days. In vitro assessments of the alumina in a human osteoblast cell-like cell (MG63) culture showed that the bioactivated alumina foams exhibited better cellularity and alkaline phosphatase (ALP) activity compared to untreated alumina foams. The results indicate that it is possible to improve the osseointgration of alumina ceramics by structural and surface modifications and to extend the applications of biocompatible alumina ceramics in biomedical implants and tissue engineering scaffolds.