Polyelectrolyte multilayers fabricated from antifungal β-peptides: design of surfaces that exhibit antifungal activity against Candida albicans.

The fungal pathogen Candida albicans can form biofilms on the surfaces of medical devices that are resistant to drug treatment and provide a reservoir for recurrent infections. The use of fungicidal or fungistatic materials to fabricate or coat the surfaces of medical devices has the potential to reduce or eliminate the incidence of biofilm-associated infections. Here we report on (i) the fabrication of multilayered polyelectrolyte thin films (PEMs) that promote the surface-mediated release of an antifungal β-peptide and (ii) the ability of these films to inhibit the growth of C. albicans on film-coated surfaces. We incorporated a fluorescently labeled antifungal β-peptide into the structures of PEMs fabricated from poly-l-glutamic acid (PGA) and poly-l-lysine (PLL) using a layer-by-layer fabrication procedure. These films remained stable when incubated in culture media at 37 °C and released β-peptide gradually into solution for up to 400 h. Surfaces coated with β-peptide-containing films inhibited the growth of C. albicans , resulting in a 20% reduction of cell viability after 2 h and a 74% decrease in metabolic activity after 7 h when compared to cells incubated on PGA/PLL-coated surfaces without β-peptide. In addition, β-peptide-containing films inhibited hyphal elongation by 55%. These results, when combined, demonstrate that it is possible to fabricate β-peptide-containing thin films that inhibit the growth and proliferation of C. albicans and provide the basis of an approach that could be used to inhibit the formation of C. albicans biofilms on film-coated surfaces. The layer-by-layer approach reported here could ultimately be used to coat the surfaces of catheters, surgical instruments, and other devices to inhibit drug-resistant C. albicans biofilm formation in clinical settings.