Removal forces and adhesion properties of Saccharomyces cerevisiae on glass substrates probed by optical tweezer
Résumé
We used an optical tweezer to investigate the adhesion of yeast Saccharomyces cerevisiae onto a glass substrate at the initial contact. Micromanipulation of free-living objects with single-beam gradient optical trap enabled to highlight mechanisms involved in this initial contact. As a function of the ionic strength and with a displacement parallel to the glass surface, the yeast adheres following different successive ways: i) Slipping and rolling at 1.5 mM NaCl, ii) slipping, rolling, and sticking at 15 mM NaCl, and iii)only sticking at 150 mM. These observations were numerous and reproducible. A kinetic evolution of these adhesion phenomena during yeast movement was clearly established. The nature, range, and relative intensity of forces involved in these different adhesion mechanisms have been worked out as a quantitative analysis from Derjaguin–Landau–Verwey–Overbeek (DLVO) and extended DLVO theories. Calculations show that the adhesion mechanisms observed and their affinity with ionic strength were mainly governed by the Lifshitz–van derWaals interaction forces and the electrical double-layer repulsion to which are added specific contact forces linked to “sticky” glycoprotein secretion, considered to be the main forces capable of overcoming the short-range Lewis acid-base repulsions.
Origine | Fichiers produits par l'(les) auteur(s) |
---|