Yan Mao

and 6 more

Fluorescent molecular probes are commonly used to detect active substances. However, in variable living microenvironmental systems, most of conventional aromatic fluorescent probes often suffer from aggregation-caused quenching (ACQ) due to π-π stacking, which severely limit their selectivity and sensitivity. To tackle this challenge, a predictable supramolecular strategy, which offers significant spatial effects to prevent fluorophore’s intermolecular π-π stacking at the molecular level, was proposed to design fluorescent probes. Herein, supramolecular probe RAA@Q[8] was successfully integrated by loading an adamantane-modified Rhodamine derivative (RAA) into cucurbit[8]uril (Q[8]) via the host-guest recognition principle. Intriguingly, the original highly clustered RAA-agminated spheroids become discrete supramolecular organic framework octahedrons (RAA@Q[8]), suggesting that the molecular aggregation behavior is well-modulated. This encouraging result is important for precise detection of plant signaling molecules such as salicylic acid (SA) in various environments. Experimental investigations found that RAA@Q[8] was 2.2-fold more sensitive than RAA for detecting SA, with high selectivity and anti-interference, and a low detection limit of 3.0×10 -8 M. Importantly, in complicated living microenvironments, RAA@Q[8] achieved a precise recognition and imaging of SA on pea sprouts and HEK-293 cells. This study offers a guidance for future development of host-guest supramolecular fluorescent probes that are opposite to the intractable ACQ obstacle.