MXene/PEDOT Functional Coatings on Flexible Microelectrode Arrays for Multianalyte In Vivo Neurochemical Sensing and Electrophysiology

MXene-based coatings offer a promising route to multifunctional neural interfaces for in vivo neurochemical sensing. Here, we develop Ti(3)C(2)Tx MXene/poly(3,4-ethylenedioxythiophene) (MXene/PEDOT) composite coatings for glassy carbon (GC) and platinum (Pt) flexible microelectrode arrays (MEAs), enabling multianalyte neurochemical sensing and electrophysiological recording. MXene/PEDOT forms uniform nanostructured films that increase charge storage capacity by one order of magnitude, reduce impedance by similar to 84% at 1 kHz, and enhance charge transfer efficiency for square-wave voltammetry (SWV). Using an optimized SWV waveform, functionalized GC-MEAs detect dopamine (DA) and serotonin (5-HT) individually and simultaneously with low limits of detection (9.6 nM for DA; 4.7 nM for 5-HT), high selectivity, and exceptional resistance to electrochemical fouling (>120 h DA; >40 h 5-HT) and biofouling. In vivo measurements resolve basal extracellular DA in the striatum (99 +/- 29 nM) and 5-HT in the amygdala and prefrontal cortex (20 +/- 7 nM), with their simultaneous striatal detection validated by pharmacological manipulation of neurotransmitter levels. Extending this strategy to Pt-MEAs confers neurochemical sensitivity while preserving single-unit recordings, establishing MXene/PEDOT as a versatile functional coating for multimodal, multianalyte interfaces.