Te-containing carbon dots for fluorescence imaging of superoxide anion in mice during acute strenuous exercise or emotional changes

Acute strenuous exercise and emotional changes are closely related to important aspects of human health. The superoxide anion (O₂˙^-), as one of the primary reactive oxygen species (ROS), is intimately associated with major diseases. However, there is no relevant in vivo research for directly indicating the link between O₂˙^- level and acute physical exercise or emotional changes. Hence, we constructed three fluorescent probes for the detection of O₂˙^-, including a Te-containing molecular probe and Se- and Te-containing CDs, and evaluated their properties such as selectivity, sensitivity, instantaneity and dynamic response to O₂˙^-. Through performance comparisons, we found that the Te-containing CDs exhibited reversibility, instantaneity and the highest sensitivity (LOD ∼ 8.0 pM), under guarantees of specific recognition of O₂˙^-, which ensure they are suitable for tracing native level changes in O₂˙^- within living systems. The probe was applied for monitoring the levels of O₂˙^- in mice under the state of intense exercise, irritability and mild depression, which led to the levels of O₂˙^- significantly increasing compared to the normal condition. Furthermore, we used the Te-containing CDs for real-time and dynamic imaging of O₂˙^- fluxes in the brain of mild depression mice and witnessed a positive correlation between O₂˙^- levels and depression. This work provides a new strategy for studying the relationship between acute exercise or emotional changes and diseases at the level of ROS.