A spherical nucleic acid-based colorimetric and fluorescent dual-responsive sensor for rapid and sensitive detection of neomycin in environmental water samples

The widespread application of neomycin (NEO) has raised pollution problem caused by the accumulation of its residues, which poses potential risk to human health and ecological safety. Therefore, the development of sensitive and reliable approaches is crucial for detecting and monitoring low levels of NEO in complex samples. In this study, an innovative spherical nucleic acid (SNA) based sensor was designed for the selective detection of NEO. The colorimetric response was attributed to hydrogen bonding, electrostatic interaction, and coordination between the SNA and NEO. Meanwhile, the fluorescence of FAM-labeled SNA was quenched by NEO due to fluorescence resonance energy transfer (FRET) effect. By integrating visual colorimetry and fluorescence analysis, the dual-responsive sensor enabled rapid, selective, and sensitive determination of NEO, with detection limits of 40.0 nM and 3.3 nM, respectively. Furthermore, the SNA exhibited good salt tolerance, maintaining stability without aggregation even in high-salt conditions. The average recoveries for detecting NEO in water samples analysis ranged from 97.6 % to 108.7 %, confirming its reliability and accuracy in practical applications. This work provides an effective strategy for NEO detection and expands the potential applications of SNA in environmental monitoring and pollution control.