Zn-3Li Alloy after Extrusion and Drawing: Structural, Mechanical Characterization, and Biodegradation in Abdominal Aorta of Rat

• Published in: Materials science & engineering. C, Materials for biological applications Vol. 76; pp. 301 - 312
• Main Authors: Zhao, Shan, Seitz, Jan-M., Eifler, Rainer, Maier, Hans J., Guillory, Roger, Earley, Elisha, Drelich, Adam, Goldman, Jeremy, Drelich, Jaroslaw W.
• Format: Journal Article
• Language: English
• Published: 11.03.2017
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2017.02.167

Zinc shows great promise as a bioabsorbable metal. Our early in vivo investigations implanting pure zinc wires into the abdominal aorta of Sprague-Dawley rats revealed that metallic zinc does not promote restenotic responses and may suppress the activities of inflammatory and smooth muscle cells. However, the low tensile strength of zinc remains a major concern. A cast billet of the Zn-Li alloy was produced in a vacuum induction caster under argon atmosphere, followed by a wire drawing process. Two phases of the binary alloy identified by x-ray diffraction include the zinc phase and intermetallic LiZn 4 phase. Mechanical testing proved that incorporating 3 at.% of Li into Zn increased its ultimate tensile strength from 116 ± 13 MPa (pure Zn) to 274 ± 61 MPa while the ductility was held at 17 ± 7%. Implantation of 10 mm Zn-3Li wire segments into abdominal aorta of rats revealed an excellent biocompatibility of this material in the arterial environment. The biodegradation rate for Zn-3Li was found to be about 0.008 mm/yr and 0.045 mm/yr at 2 and 12 months, respectively.