Fig. 4: PEDOT:PSS-based bioelectronics for invasive, semi-invasive, and non-invasive brain modulation approaches.

PEDOT:PSS-based bioelectronics for invasive (a–c), semi-invasive (d–f), and non-invasive (g–i) brain modulation. a–c PEDOT:PSS thin-film microelectrode arrays (MEAs) for brain stimulation and single-unit recording¹⁶⁶. Copyright 2022, The American Association for the Advancement of Science (Fig. S4). a The implantation process of a surface MEA (for surface stimulation) and a depth neuro-probe (for single-unit recording). Using a carrier glass pipette, the shank extension of the MEA was partially inserted into the brain, with ten electrodes reaching up to 500 μm below the pial surface. A micrograph of the MEA is shown (middle). b Illustration of the implanted MEA positioned both inside and on the brain surface, with PEDOT:PSS electrodes highlighted in blue. c Spike waveforms computed by averaging 50 traces recorded with the depth probe at 160 μm below the pial surface from a single neuron. d–f Block-Brush PEDOT:PSS film for ECoG recording¹⁷⁴. Copyright 2024, John Wiley and Sons (Fig. S5). d Schematic illustration of a 16-channel array implanted on the surface of the rat brain for barrel cortex recording under air-puff whisker stimulation. e Microscope image of the electrode array on the surface of the brain. The Block-Brush structure produced by SI-ATRP exhibited excellent conformity with the brain surface, whereas the electrode film fabricated by spin coating (SpinGA) presented an air gap. f Stimulation responses recorded from six individual low-impedance channels in the Block-Brush array. The dashed line indicates the timing of air-puff stimulation. g–i PEDOT:PSS hydrogel-based electrode for EEG¹⁸⁹. Copyright 2023, Springer Nature (Fig. S6). g A photograph of a subject undergoing EEG monitoring. h Illustration of the EEG electrode. i EEG waveforms recorded using hydrogel, wet, and dry electrodes. The signals from the hydrogel electrode closely resembled those from the wet electrode but differed from those recorded with the dry electrode