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

Abstract

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.