fig9

Figure 9. Non-invasive hydrogel interfaces with in-suit gelling method. (A and B) The hydrogel-based electrodes exhibit exceptional performance in impedance and resistance to noise and other interference^[34]; (C and D) The phase transition property of the hydrogen can be used for EEG monitoring on hairy scalps^[35]; (E-G) PAAS-MXene significantly reduces the impedance between electrode and skin and improves the quality of bioelectrical signals^[97]. EEG: Electroencephalogram; PAAS: sodium polyacrylate.