Development of Terbium based luminescent platform as a “Turn-off” sensor for the detection of bilirubin

The sensitive and selective fluorescent probes for biomolecule detection have significant application in clinical diagnosis and bioanalysis. Hyperbilirubinemia is a disease condition in which the excessive or less production of bilirubin in blood resulting in jaundice. In this work, we have synthesised Terbium based bright green, fluorescent lanthanide complex (Tb-DPA) with emission at λem = 544 nm for the detection of Bilirubin. A one-step synthesis approach was adopted with 2,6-pyridine dicarboxylic acid (DPA) as ligand and Sodium dodecyl sulphate (SDS) as surfactant. The green fluorescence of Tb-DPA was quenched with the addition of bilirubin due to the inner filter effect mechanism. The fluorescence intensity of Tb-DPA decreases as bilirubin concentration increases and a linear "turn-off" response is obtained. Even in presence of other coexisting biomolecules and ions, the Tb-DPA probe exhibited good selectivity and sensitivity for the detection of bilirubin. The limit of detection (LOD) of 2.6 mg/dL was obtained. Furthermore, the proposed fluorescent probe was applied in Human serum and urine samples with satisfactory recoveries in the range of 92–122 %. Based on the result obtained, it has probability to be used as a rapid detection method for bilirubin in biological samples at bedside.