Graphene-hydrogel electrodes stretch to 8,000% and keep their grip through sweat, hair and motion for continuous biosignal monitoring

Researchers from Drexel University and Penn State University have developed a printable hydrogel electrode, reinforced with laser-induced graphene (LIG) and reduced graphene oxide (rGO), that combines an ultralow Young’s modulus of 1.08 kPa with roughly 8,000% stretchability (able to stretch to about 80 times its original size) and strong wet adhesion – properties aimed at solving one of wearable biosensing’s persistent problems: keeping an electrode in stable contact with skin through sweat, body hair and everyday movement.

The deposited gel on the skin. Image from: Scienc Advances

Continuous, simultaneous monitoring of signals from the heart, brain, muscles and eyes is valuable for both physical and mental health tracking, since these physiological signals are interrelated – anxiety, for instance, shows up as coordinated changes across the heart, sweat glands, muscles and lungs. But conventional metal- or gel-based bioelectrodes tend to lose performance on hairy skin, under sweating conditions, or simply from the mechanical mismatch between a stiff electrode and soft, stretchy skin during long-term wear.

The deposited gel on the skin. Image from: Scienc AdvancesContinuous, simultaneous monitoring of signals from the heart, brain, muscles and eyes is valuable for both physical and mental health tracking, since these physiological signals are interrelated – anxiety, for instance, shows up as coordinated changes across the heart, sweat glands, muscles and lungs. But conventional metal- or gel-based bioelectrodes tend to lose performance on hairy skin, under sweating conditions, or simply from the mechanical mismatch between a stiff electrode and soft, stretchy skin during long-term wear.

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