Wearable and Flexible Hydrogels for Strain Sensing and Wound Electrical Stimulation

Conductive hydrogels have attracted a great deal of interest in health testing and electrical stimulation therapy. To improve the inherent brittleness and stickiness of hydrogels, a multifunctional electronic skin mediated by dopamine-modified carbon nanotubes and gelatin was fabricated. In this work, a flexible, conductive, and biocompatible adhesive hydrogel was prepared directly without further processing by simply mixing dopamine-modified carbon nanotubes, gelatin, and acrylamide. Carbon nanotubes play a dominant role in the electromechanical and mechanical properties of the hydrogel. The polydopamine gives the hydrogel good and reproducible adhesion properties. At the same time, the hydrogels obtained have good sensing properties and can detect mechanically conducted signals of human motion. In addition, the hydrogels are able to act as conductive media to deliver electrical stimuli generated by poly(vinylidene fluoride-trifluoroethylene) piezoelectric membranes to accelerate wound healing. In conclusion, this work provides a feasible method to prepare hydrogel sensors with good biocompatibility, good mechanical properties, and good adhesion, which can be widely used in human motion detection, smart skin, and electrical stimulation therapy.