Recent advances of luminescent sensors for iron and copper: Platforms, mechanisms, and bio-applications

Iron and copper are two essential metal elements in living systems, and their homeostasis is extremely important to maintain normal biological activities. Deficiency or overload of these two metal ions are associated with pathological events. Especially, overload of these two species can induce unique cell death in characteristic pathways, i.e., ferroptosis and cuproptosis, respectively. Therefore, it is quite valuable to develop reliable detecting tools to study the biology of iron and copper. To date, a mountain of luminescent sensors has been presented for the detection of iron and copper ions, including molecular and nano sensors. These sensors have greatly contributed to the development of related metal biology. In this review, we summarize luminescent sensors for iron and copper ions that have been used for bioimaging purposes since 2017, including fluorescence, phosphorescence, and bioluminescence. The detecting mechanisms of these sensors will be emphasized, as well as their optical and biological performance. Finally, the merits and demerits of different types of sensors are discussed, as well as achievements and further directions in this field.