Antibacterial polyelectrolyte micelles for coating stainless steel

In this study, we report on the original synthesis and characterization of novel antimicrobial coatings for stainless steel by alternating the deposition of aqueous solutions of positively charged polyelectrolytes micelles doped with silver based nanoparticles with a polyanion. The micelles are formed by electrostatic interaction between two oppositely charged polymers, a polycation bearing 3,4-dihydroxyphenylalanine units (DOPA, a major component of natural adhesives) and a polyanion (poly(styrene sulfonate), PSS) without using any block copolymer. DOPA units are exploited for their well-known ability to anchor to stainless steel and to form and stabilize biocidal silver nanoparticles (Ag0). The chlorine counter-anion of the polycation forms and stabilizes biocidal silver chloride nanoparticles (AgCl). We demonstrate that two layers of micelles (alternated by PSS) doped by silver particles are enough to impart to the surface a strong antibacterial activity against Gram-negative E. coli. Moreover, micelles that are reservoirs of biocidal Ag+ can be easily reactivated after depletion. This novel water-based approach is convenient, simple and attractive for industrial applications