title: Determination of the van der Waals, electron donor and electron acceptor surface tension components of static Gram-positive microbial biofilms.
abstract: A large number of studies have shown the influence of the physico-chemical properties of a surface on microbial adhesion phenomenon. In this study, we considered that the presence of a bacterial biofilm may be regarded as a "conditioning film" that may modify the physico-chemical characteristics of the support, and thus the adhesion capability of planktonic micro-organisms coming into contact with this substratum. In this context, we adapted a protocol for biofilm formation that allows, under our experimental conditions, contact angle measurements, the reference method to determine the energetic surface properties of a substratum. This made it possible to determine the van der Waals, electron acceptor and electron donor properties of static biofilms grown at 25 degrees C on stainless-steel slides with six Gram-positive bacteria isolated in dairy plants. A variance analysis indicated significant effects (P<0.05) of the bacterial strains and of the physiological state of the micro-organisms (planktonic or sessile) on the contact angles. To link the energetic properties of the six biofilms with direct adhesion experiments, we measured the affinity of fluorescent carboxylate-modified polystyrene beads for the different biofilm surfaces. The results correlated best with the electron-acceptor components of the biofilm surface energies, stressing the importance of Lewis acid-base interactions in adhesion mechanisms.
authors.affiliation: Institut National de la Recherche Agronomique, Unité de Recherche en Bioadhésion et Hygiène des Matériaux, 25 Avenue de la République, 91300, Massy, France
authors.forename: R
authors.initials: R
authors.lastname: Briandet
authors.forename: J -M.
authors.initials: J
authors.lastname: Herry
authors.forename: M -N.
authors.initials: M
authors.lastname: Bellon-Fontaine