Bacteria accumulate copper ions and inhibit oxide formation on copper surface during antibacterial efficiency test

Copper surface after antibacterial test against E. coli was examined in the aspect of corrosion. Results from scanning electron microscope (SEM), grazing incidence X-ray diffractometer (GIXRD) and Raman spectroscopy together confirmed less oxidation on copper surface with the presence of E. coli. The inhibition of the cuprous oxide (Cu₂O) layer instead ensured the continuous exposure of copper surface, letting localised corrosion attacks observable and causing a stronger release of copper ions. These phenomena are attributed to the fact that E. coli act as ions reservoirs since high amount of copper accumulation were found by energy dispersive X-ray spectroscopy (EDS).