Construction of a platform based on biocompatible near-infrared Ag 2 S quantum dots for detection of copper ions in real samples and cellular environments

The persistent challenge of real-time copper analysis in complex biological matrices underscores the urgent need for advanced sensing paradigms. To overcome the conventional trade-offs among response speed, detection accuracy, and biocompatibility, we have developed a near-infrared Ag 2 S quantum dots (QDs) platform through one-pot microwave synthesis. The as-prepared Ag₂S QDs exhibit remarkable water solubility, excellent dispersibility, and optical properties. Benefiting from these features, the sensing system enables rapid Cu 2 ⁺ detection with a response time of only 30 s, greatly improving analytical efficiency. Moreover, the near-infrared emission and large Stokes shift (290 nm) characteristics effectively reduce background scattering and autofluorescence interference, facilitating highly sensitive quantitative detection of Cu 2+ with a limit of detection (LOD) of 21 nM. More importantly, this strategy demonstrates excellent selectivity and biocompatibility, successfully applied for the detection and visualization of Cu 2+ in real samples and living cells. Overall, this strategy offers a powerful and practical approach for Cu 2 ⁺ monitoring, showing great potential in environmental surveillance and Cu 2+ -related disease research.