Nanocellulose composites based on embedded europium-containing coordination polymers for the detection of antibiotics

Developing sensitive and reliable methods for detecting antibiotics in water solutions is essential for protecting public health and the environment. Here, we report a novel fluorescent film with superior mechanical properties and detection response to ciprofloxacin (CIP), achieved through the in-situ growth of europium-based metal-organic frameworks on TEMPO-oxidized cellulose nanofibrils (TOCNF). Firstly, Eu(III) and 2,6-pyridinedicarboxylic acid (DPA) served as precursors, and a simple self-assembly strategy was employed to grow the composite film material (Eu-DPA@TOCNF) in situ on TOCNF, which exhibited characteristic emission peaks. Benefiting from the growth balance and control of Eu-DPA by TOCNF, the sensor based on Eu-DPA@TOCNF showed higher stability and practicability, allowing sensitive and selective detection of CIP, with a good linear relationship in the range of 0-200 μM, showing an inverse relationship between the fluorescence intensity at 619 nm and CIP concentration. The quenching mechanism of CIP on Eu-DPA@TOCNF could be attributed to the combined effects of both static and dynamic quenching processes. Consequently, the Eu-DPA@TOCNF fluorescent film provides a novel strategy for developing pollutant detection sensors based on fluorescent specificity.