Dual-frequency-channel integrated bioelectronics for in-sensor decoupling high-dimension neurophysiologic signals

Accurate electrophysiological mapping of biological signals with high spatial and temporal resolution has always been an important requirement to elucidate physiological functions. Herein, we develop a photolithographic organic electrochemical transistor (OECT) matrix with two frequency-dependent channels, which can spatiotemporally map electroneurographic and neurotransmitter signals. The active material can be patterned photolithographically, forming a nanoscale interpenetrating network. The porous structure facilitates fast ion transport, establishing a high-frequency channel to monitor electroneurographic signals; meanwhile enzymatic reaction of glutamate on the surface creates a low-frequency channel to detect neurotransmitter signals, due to the relatively slow diffusion and doping processes. A low detection limit down to 900 zM for glutamate is achieved. During the test, the horseshoe network structure of the OECT array gives the device the ability of conformal contact on the surface of the cerebral cortex, avoiding the motion artifact noise, and the signal-to-noise ratio (SNR) can reach ∼40 dB. The dual-frequency channels efficiently decouple electroneurographic and neurotransmitter signals to avoid signal interference. Finally, the photolithographic matrix images dual-mode neurophysiological patterns in the cerebral cortex of mice, and can dynamically colocalize epileptic focus with high resolution for precise neurosurgical intervention.