Polythiophene is a prominent example of conductive polymers, which combine the advantages of organic polymers and inorganic conductors. They can easily be electropolymerized and deposited as nanostructured thin films and serve as key material in a wide variety of applications, of which chemical sensors and biosensors are trendsetting examples. Although polythiophene outperforms other conductive polymers, such as polypyrrole and polyaniline regarding conductivity and stability, its utilization for the construction of biosensors can barely be seen. We think this owes to the fact that there is a fundamental lack of fast and easy fabrication procedures for polythiophene-based bioreceptor immobilization platforms. Published protocols almost exclusively employ deeply complex synthesis strategies for functionalized monomers, which require a background in synthesis chemistry and well-equipped laboratories.

In this proceedings paper, we want to communicate two alternative approaches that convince with their simplicity: We investigate a literature-known, carboxylated thiophene monomer and present our newly developed method for electrochemical binding of a carboxylated linker to deposited polythiophene films. Aminated bioreceptors can subsequently be immobilized via EDC/NHS click chemistry. Films were electropolymerized and modified by chronopotentiometry, and characterized by electrochemical impedance spectroscopy (EIS), surface-enhanced Raman spectroscopy (SERS), as well as energy-dispersive X-ray spectroscopy (EDS).

Both of the presented methods offer the opportunity to fabricate a polythiophene-based bioreceptor immobilization platform in a straightforward manner – all it takes is a potentiostat/galvanostat, affordable, low hazard chemicals that can be used as received, as well as only a few minutes of time.