Diamond-Like-Carbon Coated Ultramicroelectrode with Contrallable Exposed Length Based on Microplasma Jet

The effective insulation of ultramicroelectrode (UME) has important effects on its sensitivity and stability in neural signal recording. However, the exposed length of the functional layer at the tip of the existing UMEs cannot be effectively controlled, affecting the signal-to-noise ratio and signal fidelity of cell recording. Thus, this paper reports a diamond-like carbon (DLC) coated UME processed by direct cold atmospheric microplasma jet (CAμPJ). For the first time, DLC was chosen as the insulation layer of UME to achieve excellent mechanical properties, chemical stability and biocompatibility. Benefiting from the site-selective, all-dry and controllable characteristics of CAμPJ, the length of the exposed UME tip can be precisely controlled down to submicron scale. This DLC-UME has a dense and uniform DLC membrane, good electrochemical performance, and excellent implantation stability. This work will contribute to the long-term recording stability of cell signals for accurate diagnosis and monitoring of brain diseases in the future.