Sugar response of boronic acid-substituted azobenzene dye-modified polymer

We synthesized a boronic acid-appended azobenzene dye (BA) and attached it to poly(ethyleneimine) (polyBA) for studying its sugar response. The addition Of D-glucose induced a significant change in the UV-visible absorption spectra of the polyBA solution. The binding constants for D-glucose (K(glu)) and D-fructose (K(fru)) were calculated to be 54 M(-1) and 110 M(-1), respectively. The selectivity for D-glucose was higher in polyBA as compared with that of monomeric BA (K(glu) = 1.2 M(-1), K(fru) = 17 M(-1)). We also fabricated multilayered films composed of polyBA and polyanions (poly(vinyl sulfate) (PVS), carboxymethylcellulose (CMC)} using a layer-by-layer deposition technique. In (PVS/polyBA)(10) films, the affinity for D-glucose was relatively low (K(glu) = 1.7 M(-1), K(fru) = 28 M(-1)). In contrast, (CMC/polyBA)(5) films showed a high affinity for D-glucose (K(glu)=18 M(-1), K(fru) = 42 M(-1)). The loosely packed structure of the (CMC/polyBA)5 film and the suitable chemical structures of CMC probably led to a high affinity for D-glucose. (C) 2008 Elsevier B.V, All rights reserved