Zn-Li alloy after extrusion and drawing: Structural, mechanical characterization, and biodegradation in abdominal aorta of rat

Mater Sci Eng C Mater Biol Appl. 2017 Jul 1:76:301-312. doi: 10.1016/j.msec.2017.02.167. Epub 2017 Mar 11.

Abstract

Zinc shows great promise as a bio-degradable 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 LiZn4 phase. Mechanical testing proved that incorporating 0.1wt% of Li into Zn increased its ultimate tensile strength from 116±13MPa (pure Zn) to 274±61MPa while the ductility was held at 17±7%. Implantation of 10mm Zn-Li wire segments into abdominal aorta of rats revealed an excellent biocompatibility of this material in the arterial environment. The biodegradation rate for Zn-Li was found to be about 0.008mm/yr and 0.045mm/yr at 2 and 12months, respectively.

MeSH terms

  • Alloys / chemistry*
  • Animals
  • Aorta, Abdominal*
  • Lithium
  • Magnesium
  • Materials Testing
  • Rats
  • Rats, Sprague-Dawley
  • Zinc

Substances

  • Alloys
  • Lithium
  • Magnesium
  • Zinc