Natural Rutin-Based AIE Probes With Enhanced Fe3+ Recognition via Hydroxyl Group Engineering

Traditional fluorescent probes have challenges, including aggregation-induced quenching, biological incompatibility, and suboptimal selectivity. In this study, we developed a novel probe derived from natural rutin featuring an aggregation-induced emission (AIE) effect. Through hydroxy engineering of rutin, the optimized probe enables precise detection of Fe³⁺ via 2:1 stoichiometric coordination. The probe demonstrates remarkable analytical performance, with a detection limit as low as 0.22 μM. Concentration-dependent responses were observed within 0–20 μM, with significant linearity (R² > 0.99) in the 0–10 μM range. Density functional theory calculations reveal that the binding of Fe³⁺ effectively suppresses intramolecular charge transfer. The hydroxy-engineered modification plays a pivotal role in facilitating complexation for bond formation and providing appropriate steric hindrance. This research establishes a new benchmark for natural product-based AIE probes and deepens understanding of the structure–activity relationships governing flavonoid-metal recognition.