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

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 omega cm2. The corresponding cathodic charge storage capacity (CSCc) and charge injection capacity (CIC) are up to approximate 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 x 108 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, approximate to 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. A facile two-step electrochemical micromachining route is proposed to prepare versatile MXene/PDA bioelectrodes in situ on a metallic substrate. The composites present a low impedance, high cathodic charge storage capacity (CSCc) and charge injection capacity (CIC), robust chronic stability, and excellent biocompatibility. Superior photothermal and photoelectrochemical responses are also observed. This holds promise for developing new-generation bioelectronic interfaces and offers appeal for implantable/wearable and other biological applications. image