FUNCTIONAL FIBER-BASED AND 3D-PRINTED PEDOT

The field of organic bioelectronics is rapidly evolving as we move away from traditional rigid electronics toward more flexible devices that could be seamlessly integrated with biological tissues. These technologies rely on materials that can interact with the human body and environment while enabling real-time monitoring of different stimuli. Organic mixed ionic-electronic conductors (OMIECs), a subclass of organic semiconductors, are especially promising due to their ability to couple ionic and electronic transport. This research advances OMIEC-based devices through two complementary processing strategies: electronic fibers and 3D printing, both using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), a widely studied OMIEC valued for its stability and processability. Among the many platforms enabled by OMIECs, organic electrochemical transistors (OECTs) stand out for their low-voltage operation, high sensitivity to environmental changes, and compatibility with biological systems. First, PEDOT:PSS fibers were fabricated and used as the active channel material in OECTs. The fiber spinning process induced chain alignment, which, combined with contact engineering, yielded record-high charge carrier mobility. Their axon-like geometry further enabled dopamine sensing for bio-hybrid applications. In addition, to advance neuromorphic functionality, we also investigated ionic-electronic coupling within fiber-OECTs, providing new insights into the design of next-generation devices for neuromorphic computing. Beyond neuromorphic devices, the conductivity and flexibility of PEDOT:PSS fibers were utilized in fully textile-based pressure sensors. By sewing interdigitated electrodes from PEDOT:PSS yarns and, for the first time, producing PEDOT:PSS nonwovens, we created durable pressure sensors that were integrated into a robotic arm, enabling real-time pressure monitoring and safe object handling. In parallel, PEDOT:PSS-based inks were developed for additive manufacturing, allowing direct 3D printing of electrodes onto flexible substrates. This platform enabled the fabrication of electrodes for OECTs and organic microelectrode arrays (OMEAs), with future applications in neural activity monitoring. Altogether, these fiber-based and 3D printed strategies offer a cost-effective and customizable way to scalable device fabrication and lay the foundation for a new generation of organic bioelectronics. The insights gained into ion–electron interactions, material design, and scalable processing open pathways toward wearable health monitors, neuromorphic circuits, smart textiles, and brain–machine interfaces. By bridging the gap between living systems and electronic technologies, this work advances both the fundamental understanding and real-world applications of bioelectronics.