High strength, biodegradable and cytocompatible alpha tricalcium phosphate-iron composites for temporal reduction of bone fractures.

E.B. Montufar, M. Casas-Luna, M. Horynová, S. Tkachenko, Z. Fohlerová, S. Diaz-de-la-Torre, K. Dvorak, L. Celko, J. Kaiser. High strength, biodegradable and cytocompatible alpha tricalcium phosphate-iron composites for temporal reduction of bone fractures. Acta Biomaterialia 2018, 70: 293–303.

https://doi.org/10.1016/j.actbio.2018.02.002

Abstract

In this work alpha tricalcium phosphate (α-TCP)/iron (Fe) composites were developed as a new family of biodegradable, load-bearing and cytocompatible materials. The composites with composition from pure ceramic to pure metallic samples were consolidated by pulsed electric current assisted sintering to minimise processing time and temperature while improving their mechanical performance. The mechanical strength of the composites was increased and controlled with the Fe content, passing from brittle to ductile failure. In particular, the addition of 25 vol% of Fe produced a ceramic matrix composite with elastic modulus much closer to cortical bone than that of titanium or biodegradable magnesium alloys and specific compressive strength above that of stainless steel, chromium-cobalt alloys and pure titanium, currently used in clinic for internal fracture fixation. All the composites studied exhibited higher degradation rate than their individual components, presenting values around 200 μm/year, but also their compressive strength did not show a significant reduction in the period required for bone fracture consolidation. Composites showed preferential degradation of α-TCP areas rather than β-TCP areas, suggesting that α-TCP can produce composites with higher degradation rate. The composites were cytocompatible both in indirect and direct contact with bone cells. Osteoblast-like cells attached and spread on the surface of the composites, presenting proliferation rate similar to cells on tissue culture-grade polystyrene and they showed alkaline phosphatase activity. Therefore, this new family of composites is a potential alternative to produce implants for temporal reduction of bone fractures.