AVS 53rd International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeA

Paper BI-WeA1
Polycationic Glycopolymers for the Molecular Assembly of Carbohydrate Functionalized Surfaces: Synthesis and Application

Wednesday, November 15, 2006, 2:00 pm, Room 2014

Session: Bio-Interfacial Modification and Bio-Immobilization II (Honoring Marcus Textor, ETH-Zürich for Substantial Contributions to the Field)
Presenter: K. Barth, ETH Zurich, Switzerland
Authors: K. Barth, ETH Zurich, Switzerland
G. Coullerez, ETH Zurich, Switzerland
R. Castelli, ETH Zurich, Switzerland
L. Nilsson, ETH Zurich, Switzerland
J. Moeller, ETH Zurich, Switzerland
M. Textor, ETH Zurich, Switzerland
Correspondent: Click to Email
Due to their structural diversity, carbohydrates are able to mediate explicit information as markers for biomolecular interactions on mammalian cell surfaces. Usually the bindings of a monosaccharide with proteins are very weak. However, multivalent interactions between carbohydrates and target cell receptors induce strong and specific bindings mediated by clustered carbohydrates. This complexity in glycosciences complicates the study of recognition processes mediated by carbohydrates. Carbohydrate functionalized surfaces and microarrays for high throughput studies now provide versatile tools to identify and classify carbohydrate-binding proteins. A straightforward method will be presented to covalently graft mono-, di- or oligosaccharides at different densities to the polycationic brush-like copolymer poly-(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG), which forms stable molecular assemblies on negatively charged surfaces. As the functionalized PLL-g-PEG is resistant against non-specific protein attachment, density and structure-dependent kinetic parameters for the interactions between carbohydrates and proteins can be obtained using label-free in situ bio-sensing methods. This has been proven for the protein Concanavalin A and a library of mannoside-functionalized surfaces. We were able to study the effects of the carbohydrate density, the nature of the linker and the structure of oligomannosides. In order to create structured surfaces we used a photolithography based method to form well-defined patterns with differences in size and carbohydrate density in a non-interactive background. The applicability of these substrates will be shown in studies of the adhesion behavior of type I fimbriated E. coli regarding the biological activity of the adhered bacteria. Finally, competition experiments with carbohydrates in solution will be done to remove biomolecules selectively from the functionalized surfaces in order to reuse them for several experiments.