Selective doxorubicin sensing in urine with water-stable fluorescence of Tb(III)-induced polystyrene-b-poly(acrylic acid) nanoaggregates

Patient urine may provide relatively convenient access to biomarkers, but it is challenging to directly and visibly sense drugs via fluorescence quenching or enhancement. This study reports the synthesis of water-soluble and fluorescence-stable terbium-induced nanoaggregates (TIPAs) of polystyrene-poly(acrylic acid) (PS- b -PAA), containing a novel [Tb( acac )Cl 2 ( phen )Cyclen] complex, to sense doxorubicin ( dox ) in urine. The TIPAs demonstrated remarkable water stability, maintaining high fluorescence intensity in aqueous environments, with a fluorescence lifetime of 55.5 ms and a quantum yield (QY) of 4.60 %, making them ideal for smart sensing applications. The novel aggregate exhibits an orthorhombic structure, with its photophysical properties elucidated through simulated modeling. Fluorescence quenching studies indicate dynamic interactions between TIPAs and dox in urine, achieving a limit of detection (LOD) of 13.77 μM, highlighting the method's sensitivity for real-time dox monitoring. The emission of TIPAs in the visible range (450–600 nm) overlaps with the absorption spectrum of dox , enabling efficient energy transfer and fluorescence quenching. These findings highlight the potential of TIPAs as stable, fluorescence-based sensors for drug monitoring, with promising applications in bioimaging and diagnostics within cancer therapy.