Formation of Escherichia coli biofilms on the titanium alloy Ti6Al4V: analysis of the interface and assessment of corrosion

Abstract

Bacterial biofilm that formed when the Ti6Al4 V alloy was exposed to Escherichia coli, was monitored over 48 h by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) to estimate the rate of corrosion and the influence of the bacteria on this process. High-resolution scanning electron microscopy was used to examine bacterial growth, colonisation and the process of biofilm formation. Our results highlighted several critical points regarding the impact of E. coli and its use as a model for monitoring biofilm formation and the biocorrosion of this alloy. Impedance spectra revealed the formation of a compact passive film after 48-hour exposure to an aging culture of E. coli in chloride media. The formation of the biofilm influenced the resistance to corrosion. Biofilm impedance parameters that emerged over time corresponded directly to the properties of a typical exponential bacterial growth curve determined by ultraviolet-visible light spectroscopy.