Highly fluorescent carbon dots as selective and visual probes for sensing copper ions in living cells via an electron...

As an integral part of many important enzymes, Cu²⁺ is involved in a number of vital biological processes, which is linked to the oxidative damage and environmental contamination when Cu²⁺ is excessive. In this work, Cu²⁺ can be captured by the amino groups of carbon dots (CDs) to form complexes, resulting in a strong fluorescence quenching of CDs via a nonradiative electron transfer process, which offered a rapid, visual, and selective methodology for Cu²⁺ detection. The probe exhibited a wide response concentration range (0.01-2μM) to Cu²⁺ with a detection limit of 6.7nM. Significantly, the CDs presented excellent biocompatibility and high photostability, which were applicable for the visualization of Cu²⁺ dynamic invasion into living cells and Tilapia mossambica. Furthermore, the toxicity of Cu²⁺ ions to living cells could be inhibited with CDs by the formation of complexes.