Nickel Nanoclusters Fluorescent Probes for Cu2+ Sensing

Abstract

Efficient and accurate copper ions (Cu2+) sensing holds broad prospects in environmental detection and biomedical monitoring. However, developing Cu2+ sensing approaches with high sensitivity, low limit of detection (LOD), wide detection range, rapid response, great stability, excellent specificity, low biological toxicity, and simple and safe preparation simultaneously remains challenging. Herein, we synthesize photoluminescent nickel nanoclusters (Ni NCs) using a simple and green bottom-up approach at room temperature under normal atmospheric pressure and further purify them using amino-grafted mesoporous silica nanoparticles (NH2-MSNs). The purified Ni NCs, as efficient fluorescent probes, are further applied in Cu2+ sensing and exhibit excellent sensing sensitivity and a low LOD (0.036 μM) within a wide linear detection range (0–20 μM), which is comparable to or better than other fluorescent probes reported recently. Moreover, it demonstrates good sensing stability and specificity, and maintains high reliability, satisfactory accuracy, and precision in complex real-water samples. Furthermore, a smartphone-based visual sensing platform is also established and shows good sensing performance (detection range: 0–10 μM, LOD: 0.069 μM), allowing simple and rapid Cu2+ detection. This research provides an effective and feasible strategy for the green synthesis of Ni NCs and demonstrates their potential for rapid and accurate Cu2+ optical sensing, which is promising for environmental monitoring and shows preliminary biocompatibility in cell tests.