Introducing novel bioabsorbable Zn–Ag–Mg alloys intended for cardiovascular applications

Abstract

Zn is considered an excellent candidate material for endovascular applications due to its outstanding combination of biodegradability and biofunctionality. The present work introduces two novel Zn–Ag–Mg alloys with highly desirable mechanical, corrosion, and biological performance. Microstructural characterization revealed a significant grain refinement as a consequence of alloying (Ag) in conjunction with an adequate thermomechanical processing route for both alloy systems. Tensile test results indicated that the best mechanical properties in terms of yield strength (YS), ultimate tensile strength (UTS), and elongation to failure (% E) were achieved for the unidirectional rolled (UR) Zn–6Ag–0.5Mg alloy with values of ∼ 300 MPa, ∼ 370 MPa, and ∼ 40%, respectively. However, a superior UTS was exhibited for the Zn–10Ag–0.9Mg alloy with a value of ∼ 430 MPa. The observed corrosion rate (CR) trend measured by potentiodynamic polarization test was Zn–6Ag–0.5Mg = 2.232 (mm/year) > Zn–10Ag–0.9Mg = 1.405 (mm/year) > pure Zn = 0.935 (mm/year). When static immersion tests were performed, it was observed an unexpected static corrosion rate (SCR) with the following trend: pure Zn = 0.14 (mm/year) > Zn–6Ag–0.5Mg = 0.07 (mm/year) > Zn–10Ag–0.9Mg = 0.05 (mm/year). Moreover, the indirect cell test showed grade 0 of cytotoxicity at 10% and 1% of metal extracts for both ternary alloys. Finally, the proposed alloys possess excellent hemocompatibility characteristics indicating an ideal balance between mechanical integrity and biocompatibility required for the intended application.