In Situ Functionalization of Polar Polythiophene-Based Organic Electrochemical Transistor to Interface In Vitro Models

Organic mixed ionic-electronic conductors are promising materials for interfacing and monitoring biological systems, with the aim of overcoming current challenges based on the mismatch between biological materials and convectional inorganic conductors. The conjugated polymer/polyelectrolyte complex poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT/PSS) is, up to date, the most widely used polymer for in vitro or in vivo measurements in the field of organic bioelectronics. However, PEDOT/PSS organic electrochemical transistors (OECTs) are limited by depletion mode operation and lack chemical groups that enable synthetic modifications for biointerfacing. Recently introduced thiophene-based polymers with oligoether side chains can operate in accumulation mode, and their chemical structure can be tuned during synthesis, for example, by the introduction of hydroxylated side chains. Here, we introduce a new thiophene-based conjugated polymer, p(g