Design and fabrication of a naphthalimide@TX-100 nanomicellar fluorescent platform for highly sensitive and selective detection of bilirubin in aqueous environments

Abstract Sensitive and accurate detection of biologically significant bilirubin is of great importance in the field of clinical diagnostics and disease monitoring. The present study introduces the TX-100 based nanomicellar fluorescent sensing platform 3@TX-100 comprising of 1,8-naphthalimide possessing schiff base and pyrene moiety for the selective and ultrasensitive detection of bilirubin in aqueous solutions. The proposed sensor 3@TX-100 exhibited an excellent “turn-off” fluorescence response toward bilirubin with an ultralow detection limit (LOD) of 0.68 nM. A concentration-dependent decrease in the emission intensity of 3@TX-100 was noted upon the addition of bilirubin, with saturation achieved at ~ 75 µM of bilirubin. Notably, the system displayed approximately 29-fold fluorescence quenching (≈ 96.6% decrease), highlighting the high sensitivity of the sensing platform. Furthermore, the 3@TX-100 ensemble displayed outstanding selectivity for bilirubin over 18 coexisting interferents. The mechanistic analysis confirmed that the sensing phenomenon is a result of synergistic hydrophobic, hydrogen bonding, and charge transfer interactions made possible by the TX-100 micellar environment. The binding constant between 3@TX-100 and bilirubin was estimated to be 3.55 × 104 M− 1. Overall, this work establishes 3@TX-100 as a water-compatible and highly sensitive nanomicellar sensing platform for the selective detection of biologically important bilirubin.