In vivo degradation behaviour and bone response of a new Mg-rare earth alloy immobilized in a rat femoral model

Abstract

A new type of Mg-rare earth (Ce, La) and the AZ31 alloy sheets were prepared by vertical twin-roll casting (TRC) technology under identical casting conditions, and their microstructural features, degradation behaviours and bone responses were investigated. The microstructural characterization showed that the Mg-RE (rare earth) exhibited a higher amorphous forming ability than the AZ31. Moreover, the results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization indicated that the Mg-RE sheets displayed a higher corrosion resistance compared with the AZ31 sheets. Additionally, the Ti, Mg-RE and AZ31 sheet implants were immobilized and implanted in a rat femur model to observe degradation behavior during 16 weeks. in vivo tests showed that no significant change in the femur surrounding the Ti group, which excluded the external factor that the new bone formation resulting from bone remodeling. Furthermore, the Mg-RE group induced more newly formed bones, which met the necessary conditions for the prevention of pathological fractures. Therefore, the novel Mg-RE alloy appear to hold a healing candidate as the biodegradable implant material.