Advances in Fluorescence/Colorimetric Dual-Signal Sensors Enabled by Diverse Signal Activation Mechanisms

To meet the growing demand for sensing technologies, it is imperative to develop novel sensors with higher sensitivity, portability, and low cost. Conventional single-signal sensors suffer from limitations such as low sensitivity, narrow detection range, and susceptibility to false positives. Integrating two sensing signals into a single system to design dual-signal sensors effectively addresses these issues. Among optical sensors, fluorescence and colorimetric signals are the most well-developed and have been widely applied in food safety, environmental monitoring, and biomedical fields. Fluorescence/colorimetric dual-signal sensors not only combine the advantages of both modalities but also synergistically enhance detection accuracy, broaden the detection range, and improve flexibility, significantly boosting detection efficiency. In recent years, such sensors have undergone rapid development. This review focuses on the signal activation strategies and design principles of fluorescence/colorimetric dual-signal sensors, particularly the specific recognition mechanisms for diverse targets, aiming to provide insights for the design of next-generation sensors.