Europium coordination polymer particles based electrospun nanofibrous film for point-of-care testing of copper (II) ions

Excess free copper in serum has been identified to induce neurodegenerative diseases such as Alzheimer's disease, thus it is very important to determine copper (II) ions (Cu 2+ ) content for human health test. Herein we developed a point-of-care testing (POCT) platform through a luminescence “on-off” recognition mechanism of serum copper. Microsized europium coordination polymer particles (Eu-CPs), which was prepared with citric acid (CA) and europium nitrate hexahydrate through a hydrothermal route, were then successfully loaded with the mixture of 2,6-pyridinedicarboxylic acid (DPA) and poly(vinyl alcohol) (PVA) to form electrospun nanofibrous films (ENFFs). The as-prepared Eu-CPs/DPA/PVA ENFFs exhibited red emission at 618 nm when exciting at 280 nm, with the quantum yields of 22.2% owing to the antenna effect from DPA to Eu 3+ . Furthermore, the strong luminescence could be selectively quenched by Cu 2+ through coordination with DPA to interrupt the antenna effect. With that, Cu 2+ was successfully detected in the range of 2–45 μM with a detection of limit of 1.3 μM, well matching with the requirement of clinic test of excess free copper induced neurodegenerative diseases. As a proof of concept at last, this POCT platform was used to detect free copper in spiked serum samples with a recovery of 101.1%–105.2%, demonstrating that this platform provides significant potential for use in clinical test.