Breakthrough Brain Microsystem Tracks Electrical Activity and Dopamine in Real Time

Researchers from the Aerospace Information Research Institute at the Chinese Academy of Sciences have created a dual-mode wireless microsystem. It can simultaneously monitor electrical activity and dopamine levels in the brain. The device addresses a long-standing challenge in neuroscience by capturing real-time neural dynamics. The microsystem integrates 32 independent electrophysiological channels with high sampling rates. It also includes dopamine-sensitive electrochemical pathways within the same compact design. Electrodes use platinum nanoparticles and PEDOT:PSS for enhanced conductivity and stability, enabling precise recordings of spikes and local field potentials.

An electrochemical site tailored for dopamine sensing combines reduced graphene oxide and Nafion. This creates a PtNPs/PEDOT:PSS/rGO/Nafion composite, boosting sensitivity and selectivity. The device’s hybrid acquisition system pairs a specialised electrophysiological chip with the AD5941 electrochemical front end. Control comes from an FPGA and ESP32 microcontroller, ensuring efficient data handling.

In vitro tests confirmed the system’s sensitivity, selectivity, and ability to transmit data wirelessly up to 25 metres. In vivo trials in rats’ prelimbic cortex demonstrated its capacity to monitor electrical firing patterns and dopamine changes under pharmacological effects. Data streams for electrophysiology and electrochemistry are transmitted separately via distinct TCP ports, preserving temporal alignment. The microsystem has proven effective in both lab and animal tests. It offers a new way to study complex neural and chemical interactions in the brain. Future plans include embedding custom integrated circuits, adding closed-loop control, expanding to multiple brain regions, and validating results with other neurochemical methods.