Supramolecular Coassembly Activated Dual-Excitation Fluorescent Sensing Platform for Precise Detection of Aflatoxin...

The development of a sensory signal amplification approach is very crucial for rapid and precise detection of aflatoxin B₁ (AFB₁). However, such approaches remain scarce due to the weak interactions between AFB₁ and the sensing probes. Herein, the first example of a dual-excitation fluorescent platform for antibody-free AFB₁ detection is reported, which is assembled by an ordered π-π stack of cationic perylene derivative (PTHA) and tris(2,2'-bipyridine)ruthenium(II) [Ru(bpy₃)²⁺]. Taking advantage of stepwise assembly and multiple binding sites of the nanoprobe, its ability for capturing AFB₁ is significantly improved driven by multiple noncovalent interactions. Interestingly, dual-excitation fluorescent sensing mode with signal superposition and self-calibration is activated in the supramolecular coassembly process. Under excitation of 365 nm and 440 nm, the platform exhibits specific recognition toward AFB₁ and the limit of detection is determined to be 0.12 ng mL^-1. Notably, the dual-excitation platform demonstrates exceptional sensitivity enhancements of 106-fold, revealing that the self-calibrated reference improves the sensitivity and accuracy of analytical method significantly. The applications of our platform not only crack the problem of precise AFB₁ detection via supramolecular coassembly strategy but also provide a universal sensitization strategy for ultrasensitive analysis in complex environments.