Mussel-Inspired Nanocomposite Hydrogel-Based Electrodes with Reusable and Injectable Properties for Human Electrophysiological Signals Detection

Recently, ion-conducting hydrogels have received much attention in the preparation of noninvasive electronics. However, there have been few studies on the simultaneous integration of multiproperties of hydrogels to meet the actual needs of flexible electrodes. Herein, we prepared mussel-inspired proanthocyanins (PC)-coated cellulose nanofibrils (CNF) nanocomposites, which were dispersed in the guar gum (GG) and glycerol solution to prepare a PC-CNF-GG-glycerol hydrogel. This hydrogel exhibits great adhesion (7.9 KPa) and UV-blocking ability (82%). Moreover, the borax solution used as a cross-linker also imparts ion-conducting property to the hydrogel, and the strain sensor fabricated by the hydrogel exhibits low-weight detection ability (200 mg) and fast response speed (33 ms). The adhesive, conductive, and injectable PC-CNF-GG-glycerol hydrogel can also be used for preparing wearable, portable, and editable electrodes. The new electrode can accurately detect human electrophysiological signals. Interestingly, the hydrogel electrode also has advantages of reusability. In summary, this ion-conducting hydrogel has the potential to become a new generation of portable and biofriendly bioelectrodes, sensors, and dressings.