Embedding carbon dots and gold nanoclusters in metal-organic frameworks for ratiometric fluorescence detection of Cu 2+

Herein, a dual-emission metal-organic framework based ratiometric fluorescence nanoprobe was reported for detecting copper(II) ions. In particular, carbon dots (CDs) and gold nanoclusters (AuNCs) were embedded into ZIF-8 (one of the classical metal-organic frameworks) to form CDs/AuNCs@ZIF-8 nanocomposites, which exhibited dual-emission peaks at UV excitation. In the presence of Cu2+, the fluorescence attributed to AuNCs can be rapidly quenched, while the fluorescence of CDs serves as reference with undetectable changes. Therefore, the CDs/AuNCs@ZIF-8 nanocomposites were utilized as a ratiometric fluorescence nanoprobe for sensitive and selective detection of Cu2+. A good linear relationship between the ratiometric fluorescence signal of CDs/AuNCs@ZIF-8 and Cu2+ concentration was obtained in the range of 10−3–103 μM, and the detection limit was as low as 0.3324 nM. The current ratiometric fluorescence nanoprobe showed promising prospects in cost-effective and rapid determination of Cu2+ ions with good sensitivity and selectivity. Furthermore, this nanoprobe has been successfully applied for the quantitative detection of Cu2+ in serum samples, indicating its value of practical application.