A novel electrochemical biosensing platform based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) composites

A commercially available aqueous poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (PEDOT:PSS) as the immobilization matrix of biologically active species for the development of sensing and biosensing devices has not been widely reported due to its swelling and disintegration in aqueous solution. In this paper, a lowly swelling and disintegrating PEDOT:PSS composite films as the electrochemical biosensing platform was successfully developed by the incorporation of the biocompatible binding agent and common ionic liquid. Nafion was selected as a binding agent, mainly because Nafion could provide the biocompatible environment for biologically active species, improve the adhesion and binding force between films and electrode interface, and prevent peeling off of both enzyme molecules and films. 1-Butyl-3-methylimidazolium tetrafluoroborate, one of common ionic liquids, was used for the secondary dopant and enhancer to improve the water-resistance and electrochemical properties of PEDOT:PSS films. Ascorbate oxidase was used as a mode for the development and application of the electrochemical biosensor. The prepared PEDOT:PSS composite modified electrode exhibited the pronounced water-stability. Moreover, the fabricated biosensor displayed an excellent bioelectrocatalytic activity to the oxidation of vitamin C, fast current response, high sensitivity, wide linear range, low detection limit, high bioaffinity and specificity, and satisfactory results in practical application, indicating that the fabricated biosensor has good electrochemical biosensing performance. Meanwhile, the excellent water-stability, repeatability, reproducibility, storage stability, and electrochemical biosensing performance also make PEDOT:PSS composite modified matrix an interesting candidate for the sensing and biosensing application in the near future.