Probing the role of polysaccharides as adhesion mediators by AFM and parallel flow cell

• Research unit: COST
• Project number: C07.0075

Key words (English)

Polysaccharides; Direct Force Measurements; Adhesion; Single Molecule Force Spectroscopy; Biofilms

Research programs (English)

COST-Action D33 - Electrochemical and Bio-Processes (Corrosion) at Solid-Aqueous Interfaces of Industrial Materials

Short description (English)

The adhesion of polysaccharides and colloidal particles can be considered as model system for the adhesion of extracellular polymer substances to solid surfaces. In this project the interaction forces between polysaccharide-coated substrates and colloidal particles are determined by direct force measurements with the atomic force microscope (AFM). The adhesion behavior is compared to the detachment of the same particles due to shear stress in a parallel flow cell. A quantification scale for the adhesion, which can be applied to both techniques, will be proposed. An application of this approach is a novel method for the characterization of biofilms by the simultaneous detachment of chemically different particles in a parallel flow setup.

Further information (English)

Full name of research-institution/enterprise: Université de Genève Department of Inorganic, Analytical and Applied Chemistry Sciences II - CHIAM

Partners and International Organizations (English)

AT, BE, CH, CZ, DE, DK, ES, FI, FR, HU, IT, LT, NL, RO, UK

Abstract (English)

This project studied the interaction of extracellular polysaccharides with inorganic and organic surfaces. In order to probe the interaction of the polysaccharide with different surfaces the polysaccharide layer was covalently immobilized on a flat surface and colloidal particles with different surface chemistry have been attached to the end of cantilevers. The interaction forces were measured by atomic force microscopy. The resulting force profiles have been acquired in aqueous solutions under defined conditions in terms of pH and ionic strength. The force profiles upon separation of the colloidal probe and the polysaccharide film show contributions of bridging adhesion as well as solvent exclusion in the contact area. The later contribution depends primarily on the electrostatic interactions and the interfacial energy of the surfaces. In order to investigate the former contribution we performed additionally some experiments where the chitosan was covalently immobilized on a nm-sized AFM-tip. In this manner it was possible to probe the interaction of a single polymer strand with a flat surface. In order to provide highly defined surface chemistries we utilized for these experiments thiol-layers terminating in different functional groups and silicon wafers.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C07.0075