Portable fluorescent film and gel microspheres for sensitive multi-color detection and efficient adsorption of tetracycline

Drug-resistant bacteria and resistance genes caused by tetracycline (TC) antibiotic residues seriously threaten the ecological balance and human health and have become a significant public health concern. Therefore, it is crucial to construct multifunctional nanomaterials that can simultaneously detect concentration levels and remove TCs. Here, the CdTe QDs@ZIF-8 nanoprobe, prepared by encapsulating the fluorescent guest of cadmium telluride quantum dots (CdTe QDs) with red light emission in the cavity of ZIF-8, was a bifunctional nanomaterial that integrates multi-color fluorescence detection and removal. Through the interaction between Zn2+ in the ZIF-8 skeleton and TC, the yellow fluorescence emission increased conspicuously, resulting in the evolution of the fluorescence color from red to yellow. The CdTe QDs@ZIF-8@SA film was prepared by SA post-modification, which not only enhanced its water stability and fluorescence detection accuracy (with LOD as low as 19.66 nM in the TC range of 0–50 μM) but also prevented secondary contamination from powder materials, making it more suitable for on-site fluorescence detection. In addition, the TC adsorption capacity of CdTe QDs@ZIF-8 reached 101.05 mg g−1. The TC removal efficiency of the CdTe QDs@ZIF-8@SA gel microspheres reached 82.69 % within 4 h. It exhibited noticeable color and fluorescence changes before and after TC adsorption, facilitating the widespread use of TC detection and removal.