Local pH and oxygen concentration at the interface of Zn alloys in Tris-HCl or HEPES buffered Hanks’ balanced salt solution

Abstract

Although Tris-HCl and HEPES are typically used pH buffers for in vitro studies, they are recently proven to be unable to stabilize local pH at Mg interface in simulated body fluids. In this study, local pH close to physiological (7.1–7.5) was found at metal/fluid interface of pure Zn, Zn-0.8 wt%Ca and Zn-0.8 wt%Mg alloys in Tris-HCl or HEPES buffered Hanks’ balanced salt solution (HBSS) at 37 °C under hydrodynamic conditions. High rate oxygen consumption was detected above Zn alloys in various HBSS electrolytes. These findings support the previous recommendation of using synthetic pH buffers for in vitro studies of biodegradable Zn-based alloys.