Journal of Materials Research and Technology (Jan 2025)
Synergetic effects of H2O2 concentration and pH value on corrosion behavior of biomolecular coatings on 3D-printed porous low elastic modulus titanium alloy scaffolds under equilibrium conditions
Abstract
We investigated the synergistic effects of H2O2 concentration and pH on corrosion behavior of biomolecular, type I collagen, coatings on 3D-printed porous low elastic modulus Ti–24Nb–4Zr–8Sn (Ti2448) alloy scaffolds under equilibrium conditions in simulated inflammatory environment (i.e., acidic environment containing H2O2). Corrosion behavior in pH 7.4 or 5.2 simulated body fluid (SBF) containing 0, 30, or 150 mM H2O2 was assessed using potentiodynamic polarization curve near corrosion potential, electrochemical impedance spectroscopy at open-circuit potential (OCP), and ion release at OCP. For biomolecular-coated scaffolds, decreasing pH concurrent with the presence of H2O2 led to increase corrosion potential. In SBF with 30 mM H2O2, decreasing pH had no effect on corrosion rate or polarization resistance of biomolecular-coated scaffolds. However, in SBF with 150 mM H2O2, decreasing pH led to decrease corrosion rate and increase polarization resistance. The impedance of biomolecular-coated scaffolds decreased with increasing H2O2 concentration and decreasing pH. Regardless of H2O2 concentration and pH, the electrochemical equivalent circuit corresponding to the surface-untreated scaffolds under equilibrium conditions was a resistor-capacitor (RC) circuit, whereas the biomolecular-coated scaffolds presented two RC circuits corresponding to a dense inner protective film and a non-dense outer film. In acidic SBF containing 150 mM H2O2, the metal ions release from the biomolecular-coated scaffolds under equilibrium conditions was roughly half that from the untreated scaffolds. These findings confirmed under equilibrium conditions in simulated inflammatory environment, the type I collagen coatings on Ti2448 alloy scaffolds improved corrosion resistance by minimizing susceptibility to H2O2 concentration and acidic environment.
