Contact-active microbicidal gold surfaces using immobilization of quaternary ammonium thiol derivatives.

Contact-active auto-bactericidal surfaces were obtained by grafting of specially designed thiol derivatives containing antimicrobial quaternary ammonium moieties on gold substrates. The formation and quality of the self-assembled monolayers (SAMs) were characterized by X-ray photoelectron spectroscopy, cyclic voltammetry and contact angle measurements. The bactericidal activity of the modified gold surface was evaluated against Staphylococcus aureus using an original procedure. This activity was demonstrated to be dependent on the length of the alkyl chain borne by the charged nitrogen atom of the quaternary ammonium moiety, and on the contact time.