Phenylboronic acid (PBA) moieties are grafted onto the backbone of poly(acrylic acid) (PAA) forming the PAA-PBA polyelectrolyte The PAA-PBA and polysaccharide dextran (Dex) are then assembled layer by-layer (LbL) into {PAA-PBA/Dex}(n) films on electrode surface through the boronic acid-chol specific recognition between them The cyclic voltammetric response of feirocenedicarboxylic acid (Fc(COOH)(2)) at the film electrodes is sensitive to the environmental pH At pH 5 5 the CV peak currents are quite large and the films are at the on state at pH 80 however the CV response is significantly suppressed with the films at the off state This pH-sensitive on-off property of the films toward the probe can be used to switch the bioelectrocatalysis of glucose mediated by Fc(COOH)(2) in the present of glucose oxidase (GOD) in solution by changing the surrounding pH Furthermore PAA-PBA and the glycoenzyme GOD are also assembled into {PAA-PBA/GOD}(n) LbL films by the boronic acid-diol specific interaction between them so that the immobilization of the enzyme on electrodes can be realized The {PAA-PBA/GOD}(n) films also show pH-sensitive on-off behavior in bioelectrocatalysis of glucose with Fc(COOH)(2) as the mediator This model system may open a new way to establish a foundation for fabricating pH-responsive biosensors based on enzymatic electrocatalysis (C) 2010 Elsevier Ltd All rights reserved