Design of a choline sensor via direct coating of the transducer by photopolymerization of the sensing layer

Abstract

Abstract A choline electrode has been designed based on the direct coating of the transducer tip through in situ polymerization of the sensing layer. Three types of photocrosslinkable polymer, poly(vinyl alcohol)-bearing styrylpyridinium groups (PVA-SbQ), were used. These polymers, characterized by a high stability, possess both a definite degree of polymerization and SbQ content. They were mixed with choline oxidase (ChOD) in a definite ratio PVA-SbQ/ChOD. A minute amount of this solution was directly deposited on a platinum electrode, dried, then photopolymerized. The degree of polymerization of the PVA backbone and the quantity of styrylpyridinium were found to influence the sensitivity of the resulting electrodes. The detection limit was as low as 2.5 × 10−9 M and the linear dynamic range extended up to about 10−4 M choline. Moreover, the response time was as short as ≈ 30 s as a result of the direct coating performed.