Fig. 1: Electrochemically stable carbon coating.
From: Stabilized carbon coating on microelectrodes for scalable and interoperable neurotransmitter sensing
a Schematic of the surface type CCM array and penetration probe integrating CCM with electrophysiological recording sites (indicated by green). The presence of the oxide groups, sp2 carbon, and defects in the carbon coating contributes to achieving high-performance DA sensing. The compatibility of CCMs with the FSCV technique enables sub-second neurochemical dynamics measurement. The yellow trace represents phasic DA transients measured by FSCV using a CCM in awake animals. b Charge transfer resistance (Rct) and double-layer capacitance (Cdl) extracted from a simplified Randles equivalent circuit model as a function of the soak time (n = 4 CCMs, mean ± SD) in PBS (pH 7.4) at 37 °C. CFE: carbon fiber electrode. c Transmission Electron Microscopy images of cross-sectional CCM: as deposited (left) and 250 °C annealed (right). Inset: magnified view of horizontally stacked carbon flakes in the coating. d Grazing incidence X-ray diffraction pattern of the carbon coating, revealing the characteristic peaks corresponding to the parallel stacking of the carbon flakes. e Atomic ratio of oxygen obtained from Energy-dispersive X-ray spectroscopy (n = 4 CCMs, mean ± SD). f Schematic of the interface of the electrolyte and carbon coating to show the effect of annealing on the infiltration of water and ions into the carbon coating. Inset: equivalent circuit model for CCMs in PBS. Rs: solution resistance. The annealed carbon coating can resist the infiltration of water and ions because of the decrease of interlayer spacing and the removal of the oxide groups.
