Molecular imprinting in double-network-hydrogel-based organic electrochemical transistor channel for glucose sensing

In this study, we investigated the effect of molecular imprinting on a poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) (PEDOT:PSS)-based channel–organic electrochemical transistor (OECT) for glucose sensing. An interpenetrating polymer network with phenylboronic acid (PBA) was incorporated into the PEDOT:PSS channel as a double network (DN) hydrogel. The DN hydrogel with or without glucose templates, which was homogeneously polymerized in a cap tube, showed good responsivity to glucose in cyclic voltammetry and OECT measurements because anionic PBA–glucose esters were effectively formed in the entangled polymer chains. In particular, the plotted data based on the electrical signals to glucose were fitted to the bi-Langmuir isotherm equation; consequently, the binding constant ( K a ) was calculated to be 1.4 × 10 5 M −1 for the molecularly imprinted-DN-hydrogel-channel–OECT. This clearly demonstrated that the introduction of the glucose template contributed to one order of magnitude improvement in K a compared with that measured by the nonimprinted-DN-hydrogel-channel–OECT. Moreover, the selectivity and considered limit of detection have been improved to some extent owing to the molecular imprinting, depending on K a .