Antibacterial properties of sophorolipid-modified gold surfaces against Gram positive and Gram negative pathogens.

Sophorolipids are bioderived glycolipids displaying interesting antimicrobial properties.We show that they can be used to develop biocidal monolayers against Listeria ivanovii, aGram-positive bacterium. The present work points out the dependence between thesurface density and the antibacterial activity of grafted sophorolipids. It also emphasizesthe broad spectrum of activity of these coatings, demonstrating their potential againstboth Gram-positive strains (Enteroccocus faecalis, Staphylococcus epidermidis,Streptococcus pyogenes) and Gram-negative strains (Escherichia coli, Pseudomonasaeruginosa and Salmonella typhymurium). After exposure to sophorolipids grafted ontogold, all these bacterial strains show a significant reduction in viability resulting frommembrane damage as evidenced by fluorescent labelling and SEM-FEG analysis.