Processing of bioresorbable closed-cell Mg foam for bone implant applications

ABSTRACT

Magnesium is the most promising element as a bioresorbable material in bone repairing applications. Closed-cell Mg-2Zn-2Ca foam was fabricated through melt processing route by using economical biocompatible pure dolomite+MgCO₃ as dual-blowing agent with favorable advantages of uniform pore structure, improved mechanical properties and good biocompatibility. In addition, residuals of blowing agent act as biocompatible particles during degradation. Mg-2Zn-2Ca foam was characterized for its physical, mechanical, in vitro degradation properties and microstructure characterization. Mg-2Zn-2Ca foams having relative density 0.41–0.45, average uniform pore size in the range of 0.25–0.75 mm revealed plastic compression strength up-to 50.1 MPa, plateau strength up to 43.2 MPa with 56.3% densification strain and 30 MJ/m³ of energy absorption per unit volume were obtained. Moreover, Mg foam exhibited adequate compressive behavior during in vitro degradation up to 4 weeks in simulated body fluid. Despite higher amount of hydrogen release in initial stage, Mg foam observed stable degradation mechanism after 2 weeks due to formation and deposition of degradation products on cellular surfaces. Based on the processing method and results obtained, Mg-2Zn-2Ca closed-cell foam satisfied the requirement of physical, mechanical and in vitro degradation properties compared to natural bone properties and recommended as cost effective, biocompatible and bone substitution mechanical implant material.

KEYWORDS:

• Foam
• Mg-Zn-Ca
• CaMg(CO₃)₂
• in vitro
• lightweight

Acknowledgements

This work was supported by Department of Science and Technology; Science and Engineering Research Board, Government of India (Grant No. ECR/2016/001518). The authors acknowledged the Institute for Plasma Research, Gandhinagar, India, for support, and are thankful to Dr. Dheeraj K. Singh for FTIR analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Science and Engineering Research Board [ECR/2016/001518]