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

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.