Eu3+/Tb3+-modified Cd(ii) coordination polymers for effective detection of uric acid and lung cancer biomarker N-acetylneuraminic acid

Abstract

Nowadays, lung cancer is a severe health burden worldwide and the major challenge faced in this disease is that more than half of the patients are diagnosed in later stages. The measurement of N-acetylneuraminic acid (NANA) levels, an important biomarker, could serve as a useful indicator for the early diagnosis of this disease. In this work, 1D coordination polymer Cd-CP2 was obtained and explored as a luminescence probe for detecting the urinary biomarker uric acid (UA) via a quenching effect. The presence of free carboxylic groups in the coordination polymer leads to the formation of Eu³⁺/Tb³⁺-functionalized samples, named Eu³⁺@Cd-CP2 and Tb³⁺@Cd-CP2, via post-synthesis modification (PSM). Both of these samples were able to sense NANA via a ratiometric effect with the enhancement of ligand-centered peaks and quenching of rare earth peaks. The luminescence probe has several appealing merits, including a high selectivity, excellent sensitivity, low detection limit (0.89 μM for Eu³⁺@Cd-CP2 and 0.19 μM for Tb³⁺@Cd-CP2), and fast response time (less than 2 min). Furthermore, these fluorescent materials were explored as logic gates and test papers for potential application.