Preparation and characterization of iron/β-tricalcium phosphate bio-cermets for load-bearing bone substitutes

Ceramic-metal composite materials, namely cermets, are provided with characteristics of both ceramic and metal. Herein, for the first time bio-cermets based on β-tricalcium phosphate (β-TCP) bioceramic with biodegradable iron being reinforcement phase, were fabricated using the powder metallurgic method. The phase composition, microstructure, mechanical properties and in vitro cell behaviors of bio-cermets were investigated. The results revealed that atomic diffusion occurred between the iron and β-TCP matrix during the sintering process. The bio-cermets attained remarkable increase in fracture toughness (1.16-1.55 MPa m1/2) compared to the β-TCP bioceramic (0.54 MPa m1/2). The bio-cermets with 10 vol% iron showed the highest compressive strength (640 MPa), significantly higher than that of plain β-TCP bioceramic (285 MPa). The in vitro cell behaviors test indicated that the bio-cermets did not showed any sign of toxicity; the iron ions released from bio-cermets up-regulated bone-related gene expression of bone mesenchymal stem cells. The bio-cermets developed in this study represent potential bone substitutes for application in the load-bearing bone defects.