Zn-alloy provides a novel platform for mechanically stable bioresorbable vascular stents

PLoS One. 2019 Jan 2;14(1):e0209111. doi: 10.1371/journal.pone.0209111. eCollection 2019.

Abstract

Metallic Zn alloys have recently gained interest as potential candidates for developing platforms of bioresorbable vascular stents (BVS). Previous studies revealed that Mg alloys used for BVS can degrade too early, whereas PLLA materials may fail to provide effective scaffolding properties. Here we report on results of a new bioresorbable, metallic stent made from a Zn-Ag alloy studied in a porcine animal model of thrombosis and restenosis. While the tensile strength (MPa) of Zn-3Ag was higher than that of PLLA and resembled Mg's (WE43), fracture elongation (%) of Zn-3Ag was much greater (18-fold) than the PLLA's or Mg alloy's (WE43). Zn-3Ag exposed to HAoSMC culture medium for 30 days revealed degradation elements consisting of Zn, O, N, C, P, and Na at a 6 nm surface depth. Platelet adhesion rates and blood biocompatibility did not differ between Zn-3Ag, PLLA, Mg (WE43), and non-resorbable Nitinol (NiTi) stent materials. Balloon-expandable Zn-3Ag alloy BVS implanted into iliofemoral arteries of 15 juvenile domestic pigs were easily visible fluoroscopically at implantation, and their bioresorption was readily detectable via X-ray over time. Histologically, arteries with Zn-3Ag BVS were completely endothelialized, covered with neointima, and were patent at 1, 3, and 6 months follow-up with no signs of stent thrombosis. Zn-3Ag alloy appears to be a promising material platform for the fabrication of a new generation of bioresorbable vascular stents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorbable Implants
  • Alloys / chemistry*
  • Animals
  • Drug-Eluting Stents*
  • Polyesters / chemistry
  • Swine
  • Thrombosis / surgery
  • Zinc / chemistry*

Substances

  • Alloys
  • Polyesters
  • nitinol
  • poly(lactide)
  • Zinc

Grants and funding

All authors received financial support from the BMBF research foundation, Germany (13GW0035B). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Optimed GmbH and Limedion GmbH provided support in the form of research materials and salaries for authors (Optimed GmbH: E. N. and H. F., Limedion GmbH: S. S. and A. K.], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.”