A 128-ch Area-Efficient Neurochemical-Sensing Front-End for FSCV Recordings of Dopamine

Abstract

Neurochemical recordings rely on electrochemical reactions of electroactive neurotransmitters such as dopamine, serotonin, and norepinephrine. This electrochemical technique allows for highly sensitive monitoring of neurotransmitters in the brain. Traditionally, single-channel carbon-fiber microelectrode recordings have been considered the gold standard method. However, an alternative approach involves the use of a microelectrode array, which enables high spatiotemporal resolution imaging of electroactive neurotransmitters. To enable neurochemical imaging using a microelectrode array, the development of a high-density current-sensing microchip is necessary. Here, a neurochemical microchip is introduced, featuring a 128-channel current sensing front-end capable of supporting 128 parallel neurochemical measurements. The designed amplifier array employs a highly scalable resistive feedback transimpedance amplifier design. This design allows for a large neurochemical dynamic range of ±5µA with a noise performance as low as 0.22nARMS. With the integration of this microchip, in vivo neurochemical imaging of dopamine can be achieved with high spatiotemporal resolution.

Dopamine Measurement Using Engineered CNT–CQD–Polymer Coatings on Pt Microelectrodes

“…Pioneered by Miller in the 1980s and subsequently popularized by Wightman, FSCV has evolved significantly over the years [ 11 , 12 , 13 ]. Background-subtracted FSCV has been a basis technique for differentiating and characterizing readily oxidizable biological compounds, notably dopamine [ 14 , 15 ]. Tuning the scan rate of the triangular waveform used in FSCV can optimize our differentiation of the electroactive species’ irreversible and quasi-reversible reaction peak potentials, allowing enhanced discrimination between interfering substances and mitigation of issues at the switching potential [ 4 , 10 ].…”