Selective and Sensitive Detection of Cu⁺ in Living Cells Based on Chelator Modified Carbon Dots

Abstract Cuprous ions (Cu⁺) are essential for various biological activities. However, it is still a great challenge to detect Cu⁺ efficiently in cells in situ. As emerging 0‐D carbon photoluminescence nanomaterials, carbon dots (CDs) exhibit non‐toxicity and ultra stability, which shows great advantages in biosensing and bioimaging. In this work, CDs are prepared by a one‐step microwave‐assisted hydrothermal method. To enhance the selectivity and efficiency of the CDs‐based sensor, the NS₄‐CDs are synthesized by surface modification of CDs using Cu⁺ chelating molecules. The NS₄‐CDs, that carry specific detection molecules, exhibit remarkable selectivity and high sensitivity with an extraordinarily low detection limit (26 nmol L⁻¹). It is noteworthy that the detection response is extremely fast, which only takes 20 s. The PL response mechanism of NS₄‐CDs is also thoroughly investigated. In addition, the NS₄‐CDs possess great biocompatibility and non‐cytotoxicity, which is vital for advanced cellular imaging applications. Finally, the NS₄‐CDs are successfully applied to Cu⁺ detection in cells in situ. This work paves a new path for the design and efficient construction of CDs‐based biosensors for ion detection in cells, which expands the application area of carbon nanomaterials.