Immobilization of antibacterial metallic cations (Ga3+, Zn2+ and Co2+) in a polypyrrole coating formed on Nitinol

Gallium, zinc and cobalt species were immobilized in hollow rectangular-sectioned microtubes of polypyrrole (PPy) electrosynthesized on Nitinol (NiTi) alloy by means of two different methods. One of them involved the immobilization after the PPy electropolymerization and the other one during the electrosynthesis process. The antibacterial activity of the coating against Escherichia coli (E. coli) was evaluated and the best results were obtained with gallium species. Characterization results demonstrated that gallium is incorporated into the PPy matrix as Ga3+ ions. The PPy film with gallium species incorporated during the electropolymerization exhibited a good corrosion protection performance.