Multiplexer-based system development for multichannel neurochemical sensing

Simultaneous measurement of neurotransmitters in multiple individuals enables more accurate comparison of behavioral and pharmacological responses between subjects. In this study, we developed a system capable of multichannel electrochemical measurements using multiplexers (MUXs). Although MUXs are widely used in analog circuits, their parasitic characteristics can degrade the accuracy of current-based electrochemical systems. Therefore, the effect of parasitic components on electrochemical measurements was examined through dopamine detection experiments and simulations using fast-scan cyclic voltammetry (FSCV). The experimental and simulation results showed that parasitic capacitance increased the background current and noise. In addition, a substantial background current increase of more than 5% was observed when the capacitance exceeded 50 pF. Based on the simulation results, MUX devices such as ADG1206 and TMUX6119, which have parasitic capacitance below 50 pF, were selected, and an optimized system was developed and evaluated. Verification experiments showed that the background current and noise of the optimized system were not significantly different from those of the standalone transimpedance amplifier (TIA) system. High channel uniformity and long-term stability were also achieved, with normalized root mean square error below 0.5%, normalized deviation within ± 3%, and Z-scores within ± 1. In dopamine detection experiments, rapid and consistent current responses verified the system’s reliable detection performance. With a 16-channel MUX configuration, the system supports multichannel simultaneous measurements using user-defined waveforms, including FSCV. It enables up to 11 channels at 10 Hz FSCV and up to 16 channels at 7 Hz FSCV. The proposed hardware can be integrated into existing systems, enabling scalable multichannel capability without the need for extensive redesign. Based on our experimental results, we demonstrated that the developed multichannel system provides reliable and effective detection. This study provides a foundational guideline for MUX-based electrochemical measurement systems. The proposed approach can support efficient experimental design in fields such as behavioral neuroscience and pharmacology by enabling simultaneous multichannel measurements.