Aggregation-induced emission carbon dots as Al³⁺-mediated nanoaggregate probe for rapid and selective detection of tetracycline

Worldwide abuse of tetracycline (TC) seriously threatens environmental safety and human health. Metal-TC complexes formed by residual TC in the environment can also contribute to the spread of antibiotic resistance. Therefore, monitoring of TC residues is still required. Here, we report novel aggregation-induced emission carbon dots (AIE-Cdots) as nanoaggregate probes for the rapid and selective detection of TC residue. Riboflavin precursors with rotational functional groups led to the development of AIE-Cdots. The aggregation of AIE-Cdots was induced selectively for Al³⁺, amplifying the fluorescence signals owing to the restricted rotation of the side chains on the AIE-Cdot surface. The fluorescence signal of such Al³⁺-mediated nanoaggregates (Al³⁺-NAs) was further triggered by the structural fixation of TC at the Al³⁺ active sites, suggesting the formation of TC-coordinated Al³⁺-NAs. A linear correlation was observed in the TC concentration range of 0–10 μM with a detection limit of 42 nM. In addition, the strong Al³⁺ binding affinity of AIE-Cdots produced similar NAs and enhanced fluorescence signals in Al³⁺–TC mixtures. These AIE-Cdots-based nanoplatforms have a rapid response, good selectivity, and reliable accuracy for detecting TC or aluminum complexes, meeting the requirements for hazardous substance monitoring and removal in environmental applications.