Switchable sol-gel transition controlled by ultrasound and body temperature

Herein, we reported a new kind of naphthalimide-based derivative (N1), which could undergo direct sol–gel transition accelerated by ultrasound in 2-methoxyethanol. The gels are very sensitive to the body temperature in the range from 35 to 42 °C, which is the scope range of clinical thermometer. The gel-to-sol transition temperatures enhanced with the increased concentrations of the gels. The reversible gel-sol transition, together with emission intensity and morphological changes, controlled by body temperature and ultrasound could be repeated by many circles without fatigue. Therefore, the gel could be developed to an ideal sensor for detecting human body temperature.