Wearable Fiber-Based Organic Electrochemical Transistors as a Platform for Highly Sensitive Dopamine Monitoring.

Fiber-based organic electrochemical transistors (FECTs) provide a new platform for the realization of ultrafast and ultrasensitive biosensor, especially for the wearable dopamine (DA) monitoring device. Here, we presented a fully filament integrated fabric, it exhibited remarkable mechanical compatibility with human body, and the minimum sensing unit was an organic electrochemical transistor (OECT) based on PVA-co-PE nanofibers (NFs) and polypyrrole (PPy) nanofiber network. The introduction of NFs notably increased the specific surface area and hydrophilicity of the PA6 filament, resulting in the formation of a large area of intertwined PPy nanofiber network. The electrical performance of PPy nanofiber network modified fibers improved considerably. For the common FECTs, the typical on/off ratio was up to 2 orders of magnitude, the temporal recovery time between on and off state was lower to 0.34 s, meanwhile the device exhibited continuous cycling stability. In addition, the performances of FECTs based dopamine sensors depending on different gate electrodes have also been investigated. The PPy/NFs/PA6 filament-based dopamine sensor was more superior to the gold and platinum (Pt) wires, and the sensor presented long-term sensitivity with a detection region from 1 nM to 1 uM, rapid response time to a set of DA concentrations, remarkable selectivity in the presence of sodium chloride, uric acid, ascorbic acid and glucose as well as superior reproducibility. Moreover, it could also be woven into the fabric product. The novel and wearable FECTs device shows the potential to become the state-of-art DA monitoring platform.