Luminescent nucleotide/Tb3+ coordination polymer for Fe(ii) detection in human serum

Abstract

Metal–organic coordination polymers (CPs) have emerged as attractive functional nanomaterials because of their flexible composition and diverse architecture. Herein, we designed and synthesized a luminescent sensing nucleotide/Tb³⁺ CP, utilizing the self-assembly of adenosine triphosphate (ATP) as a biomolecule, Tb³⁺ as a luminescent ion, and 1,10-phenanthroline (Phen) as a cofactor ligand. The switched-on luminescence of ATP-Tb with Phen as a sensitizer was due to the removal of coordinating water molecules and the concomitant Phen-to-Tb³⁺ energy transfer. Employing Phen as a recognition unit with a high affinity to Fe²⁺, the configured ATP-Tb-Phen CP exhibited high sensitivity and selectivity to Fe²⁺. The decrease of luminescence intensity was linearly correlated with the Fe²⁺ concentration in the range of 20 nM to 1.5 μM, with a detection limit of 20 nM. More importantly, a long luminescence lifetime of the ATP-Tb-Phen CP allowed time-resolved fluorimetric detection of Fe²⁺ ions in human serum, and can highly enhance its sensitivity by eliminating the background signal. Thus, our results indicate that metal–organic CPs are well suited for designing smart sensing materials, and feature unique advantages for the sensing of certain analytes.