Straightforward Approach for Electrochemical Deposition and Modification of Conductive Polythiophene Thin Films for Bioreceptor Immobilization

Abstract

: Biosensors offer exciting opportunities for various clinical applications and constitute a rapid growing research branch due to new generations of bioreceptors, transducers, and biomateri-als with versatile characteristics, such as conductive polymers. Polythiophene is a prominent exam-ple of conducting polymers and convinces with excellent conductivity and stability—and is yet barely used for the construction of biosensors. We want to address the fundamental lack of straightforward fabrication procedures for bioreceptor immobilization platforms based on polythiophene. We investigate the literature-known monomer 3-thiopheneacetic acid and present our newly developed method for electrochemical coupling of the linker p-aminobenzoic acid to deposited polythiophene films. Aminated bioreceptors can subsequently be immobilized via EDC/NHS click chemistry. Films were electropolymerized and modified by chronopotentiometry, characterized by electrochemical impedance spectroscopy, surface-enhanced Raman spectroscopy, as well as energy-dis-persive X-ray spectroscopy. Both of the presented methods allow for the fabrication of functionalized polythiophene thin films of high conductivity and good reproducibility, while convincing with their ease in synthesis.