In vitro and in vivo corrosion and histocompatibility of pure Mg and a Mg-6Zn alloy as urinary implants in rat model

Pure Mg and a Mg-6wt.% Zn alloy were investigated as potential candidates for biodegradable implants for the urinary system. The in vitro corrosion behavior was studied by potentiodynamic polarization and immersion tests in simulated body fluid (SBF) at 37°C. The in vivo degradation and histocompatibility were examined through implantation into the bladders of Wistar rats. The alloying element Zn elevated the passivation potential and increased the cathodic current density. Both in vitro and in vivo degradation tests showed a faster corrosion rate for the Mg-6Zn alloy. Tissues stained with hematoxylin and eosin (HE) suggested that both pure Mg and Mg-6Zn alloy exhibited good histocompatibility in the bladder indwelling implantation and no differences between pure Mg and Mg-6Zn groups were found in bladder, liver and kidney tissues during the 2weeks implantation. Overall, this work presented instructive information on the degradation properties and histocompatibility of pure Mg and the Mg-6Zn alloy in the urinary system. [Display omitted] •Zn enhanced the passivation layer, but it increased the cathodic current density.•Mg-6Zn alloy showed a faster degradation rate than Mg in SBF and bladder of rat.•Mg and Mg-6Zn alloy showed good histocompatibility for the bladder model of rat.