Figure 4.

Demonstration of the first bioinspired artificial injury response system with advanced functions, including a sense of pain, sign of injury, and healing, under different scenarios. a) Schematic illustration of the physiological protection modality of human bodies under noxious stimuli, including a sense of pain, sign of injury, and healing. b) Schematic illustration of the bioinspired artificial injury response to emulate a sense of pain, sign of injury and healing based on the integration of a triboelectric generator (artificial mechanoreceptor), a memristor (artificial nociceptor), and a light emitting diode (LED) (artificial bruise) and a power source of 2.4 V. c) Circuit diagram of the corresponding artificial injury response system. d–g) Demonstration of the injury response under a gentle touch. (d) The voltage output generated by a gentle touch on the triboelectric generator, (e) the corresponding memristor circuit current (≈10⁻⁸A), and (f–g) the photographs of the corresponding state of the LED (off), which suggests a gentle touch would cause no pain nor harm. h–j) Demonstration of the injury response under a mild hit. (h) The voltage output generated by a mild hit on the triboelectric generator. (i) The corresponding memristor circuit current and (j) the photographs of each state of the LED over time, which suggests a mild hit would cause a mild pain and light bruise, but it would heal fast (2 s). k–m) Demonstration of the injury response under a hard hit. (k) The voltage output generated by a hard hit on the triboelectric generator. (l) The corresponding memristor circuit current and (m) the photographs of each state of the LED over time, which suggests a hard hit would cause a more intensive pain (high current) and more serious bruise (higher brightness), and it would take a longer time to recover.