Bioinspired High-Sensitivity Temperature Sensor for Rapid and Autonomous Early Warning of Abnormal High Temperatures

As wearable technologies continue to advance, the need for flexible temperature sensors that can not only detect subtle thermal changes but also respond independently to dangerous heat levels has grown more urgent. Drawing inspiration from nature─specifically, the extraordinary sensitivity of slit sensilla in scorpions and the petal-opening behavior of gentian flowers in response to heat─we have developed a flexible, bioinspired temperature sensor capable of both high-resolution detection and self-triggered thermal alerts. The sensor adopts a bilayer heterogeneous architecture, consisting of a poly(ethylene oxide) (PEO)-graphene-based temperature-sensitive ink layer and a crack-based polylactic acid (PLA) layer. The ink layer exhibits excellent temperature sensitivity in the low-temperature range (30-40 °C), achieving a high sensitivity of up to 5.1% °C^-1, while the cracked PLA layer operates effectively in the high-temperature range (40-70 °C) through a synergy of thermal bending and tunneling effects, delivering a sensitivity of up to 0.146% °C^-1. Integrated into a system, the sensor rapidly responds to sudden temperature spikes, triggering a safety alert in just 11.27 s. By harmonizing bioinspired design with functional engineering, this sensor not only supports conventional wearable temperature monitoring but also provides reliable protection in abnormal high-temperature conditions, demonstrating broad application potential in smart wearables, intelligent workplaces, and fire warning systems.