Nico Michaelis

Biofunctional surfaces based on dendronized cellulose.

Biofunctionalized surfaces based on dendronized cellulose were prepared either by embedding 6-deoxy-6-(1,2,3-triazolo)-4-polyamidoamine (PAMAM) cellulose (degree of substitution, DS 0.25), obtained by homogeneous conversion of 6-deoxy-6-azido cellulose with propargyl-PAMAM dendron via the copper-catalyzed Huisgen reaction, in a cellulose acetate (DS 2.50) matrix or by the heterogeneous functionalization of deoxy-azido cellulose film with the dendron. The amount of amino groups provided by the solid supports was determined and the covalent attachment of enzyme was proven with glucose oxidase as model enzyme after activation with glutardialdehyde. The quality of glucose oxidase immobilization was defined by determining of the specific enzyme activity, coupling efficiency, storage stability, and reproducibility. Although the heterogeneous functionalization of the deoxy-azido film yields a product that binds more enzyme compared to the blend of dendronized cellulose derivative with cellulose acetate, the coupling efficiency is comparatively small. Nevertheless, the different approaches for the preparation of biofunctionalized surfaces based on dendronized cellulose provide an excellent reproducibility and good storage stability.

Protein-like oligomerization of carbohydrates.

Sugar can, too: Many proteins form noncovalent and thermodynamically reversible oligomers, which can dictate a proteins functionality. For the first time, the presence of multiple oligomeric forms is shown in a whole class of polymeric carbohydrates, the 6-deoxy-6-aminocelluloses, using analytical ultracentrifugation as a probe.