Strong and tough magnesium wire reinforced phosphate cement composites for load-bearing bone replacement

Calcium phosphate cements are brittle biomaterials of low bending strength. One promising approach to improve their mechanical properties is reinforcement with fibers. State of the art degradable reinforced composites contain fibers made of polymers, resorbable glass or whiskers of calcium minerals. We introduce a new class of composite that is reinforced with degradable magnesium alloy wires. Bending strength and ductility of the composites increased with aspect ratio and volume content of the reinforcements up to a maximal bending strength of 139±41 MPa. Hybrid reinforcement with metal and polymer fibers (PLA) further improved the qualitative fracture behavior and gave indication of enhanced strength and ductility. Immersion tests of composites in SBF for seven weeks showed high corrosion stability of ZEK100 wires and slow degradation of the magnesium calcium phosphate cement by struvite dissolution. Finally, in vitro tests with the osteoblast-like cell line MG63 demonstrate cytocompatibility of the composite materials.

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► Mg wire reinforced phosphate cements as novel composite materials for bone replacement.
► Composites have a bending strength up to 140 MPa and show quasi-ductile bending behavior.
► Hybrid reinforcement by PLA fibers and Mg wires improves qualitative bending behavior.
► Corrosion of the Mg wires is substantially retarded by the surrounding cement matrix.