A biosensor material with robust mechanical properties, fatigue-resistance, biocompatibility, biodegradability, and anti-freezing capabilities

The shortage of fossil energy and environmental changes have driven the development of high-performance biosensors. However, these biosensors are usually made from conductive hydrogels with water solvent as the dispersion medium, while obtaining biosensors for reliable fatigue-resistance, robust mechanical properties, anti-freezing performance and high conductivity is still a great challenge. Here, we organically combine strawberry-type BaTiO3 (BT) particles, soy protein isolate (SPI) chains, polyethylene glycol-200 (PEG-200), and glycerin (GL) to fabricate a series of SPI-based film materials. The resultant material, named SPI-BT@Ag0.5, simultaneously exhibits outstanding yield strength (37.6 MPa), toughness (19.0 MJ m(-3)), and fatigue-resistance as well as being an easily processable, low-cost, and highly conductive wearable strain biosensor. Furthermore, this wearable biosensor successfully monitors human physiological signals and movement states, such as wrist pulse, throat activity, spinal posture, and gait. More importantly, it displays excellent biocompatibility and biodegradability, avoids the occurrence of an immune response, and can accurately monitor various types of human joint motions and successfully remains operable at low temperature (-30 degrees C). Evidently, this strain sensor provides a promising strategy for the rapid development of next-generation multifunctional flexible wearable biosensors.