A transparent, anti-fatigue, flexible multifunctional hydrogel with self-adhesion and conductivity for biosensors

Hydrogels have received increasing interest as a flexible material. However, the integration of multiple functions into one hydrogel remains a great challenge. For the application of hydrogels in the field of biosensors, both rigidity and toughness of hydrogels are usually necessary. Herein, a kind of multifunctional hydrogel with a combination of ideal properties, including transparency, fatigue resistance, flexibility, conductivity, self-adhesive and low contact impedance is designed. The hydrogel is prepared via a one-pot method by polymerizing the monomers acrylic acid (AA), acrylamide (AM) and [2-(Methacryloyloxy) ethyl] dimethyl-(3-sulfo-propyl) ammonium hydroxide (SBMA) under UV light to form a copolymer. The chemical cross-linking and hydrogen bonding jointly impart the hydrogel with good fatigue resistance and flexibility. Furthermore, the hydrogel can adhere to a wide range of substrate surfaces through intermolecular forces and give precise, stable and clear ECG signals when detecting small physical movements. It is believed that the designed hydrogel will show great prospects in wearable devices and biosensors.