Cytosine compounds-modulated fluorescent CuNCs for fingerprint discrimination of tetracyclines antibiotics based on host-guest pattern recognition.

Multiple CuNCs with modulable spectra were obtained by selecting nucleoside molecules as ligands. C-series CuNCs showed strong and discrepant emission intensities which were selected as the recognition elements of a three-channel fluorescent sensor array after surface modification with SH-β-cyclodextrin. Leveraging differences in host-guest recognition between various tetracyclines and the β-cyclodextrin cavity, the array generated distinct fluorescence response fingerprint patterns, enabling high-throughput discrimination of six structurally similar tetracycline antibiotics at different concentrations. Linear discriminant analysis revealed a linear relationship between the most influential discrimination factor and the antibiotic concentrations, allowing for highly sensitive and specific detection. And we obtained the satisfactory detection limits for tetracycline, aureomycin, oxytetracycline, doxycycline hydrochloride, minocycline and methacycline and they were 0.61 µM, 0.48 µM, 0.53 µM, 0.51 µM, 1.2 µM and 1.4 µM, respectively. Furthermore, the sensor array successfully identified spiked six antibiotics at different concentrations in environmental water and commercial milk samples, and achieved 100% accuracy in double-blind screening of unknown samples. This work provides an efficient sensing strategy for detecting structural analogs in complex matrices, with promising potential in environmental monitoring and food safety.