Fast Electrodeposition of MXene/PDA Composites for High‐Performance Bioelectronic Interfaces: An In Vitro Evaluation

Abstract Bioelectrode is critical to many biomedical researches. However, traditional materials (typically noble metals) and manufacturing techniques limit the large‐scale production of bioelectrodes. Herein, a fast electrochemical approach is proposed to deposit versatile MXene/polydopamine (PDA) composites on a metalized substrate. PDA coating can improve the adhesion between MXene and the substrate, while MXene provides rough surfaces with unique micro/nanostructure and outstanding electrical/optical/thermal performance. The impedance of the as‐prepared bioelectrode at 1 kHz is down to 8.48 Ω cm 2 . The corresponding cathodic charge storage capacity (CSC c ) and charge injection capacity (CIC) are up to ≈250 and 6.59 mC cm −2 respectively, much superior to that of bare Pt and other conventional material‐based electrodes. The MXene/PDA composites also demonstrate robust stability under continuous electrostimulation for 1 × 10 8 pulse cycles and 1000 CV cycles. Moreover, MXene/PDA composites show a high and rapid photothermal response. Photoelectrochemical activity is also observed with high photocurrent, ≈40 folds larger than that of bare Pt. The utility of this new electrode in ascorbic acid sensing is demonstrated. Excellent biocompatibility is verified via neuron adhesion test and viability assay.