The exploration of upconversion luminescence nanoprobes for tobramycin detection based on Förster resonance energy transfer

Tobramycin (TOB) is a broad-spectrum aminoglycoside extensively used as veterinary medicine to treat bacterial infections. However, TOB residue in food and environment may cause great threat to human health. Here, we report, for the first time, the upconversion nanoparticles (UCNPs) for TOB detection based on Förster resonance energy transfer (FRET). The upconversion (UC) luminescence from core-shell structured UCNPs was effectively quenched after addition of MnO₂ nanosheets due to the efficient energy transfer from the UCNPs to MnO₂ nanosheets. When interacting with TOB, the UC luminescence was restored and increased as a result of coupling between TOB and aptamer, with MnO₂ nanosheets dropping off the latter one. The UCNPs@SiO₂-MnO₂ aptasensors for TOB detection have a good selectivity and sensitivity in a linear range of 10–180 ng mL⁻¹ with a limit of detection (LOD) of 3.04 ng mL⁻¹. The sensors were tested for TOB detection in real samples of liquid milk and fishes and the results are very good and satisfactory. These type of aptasensors are promising for practical applications as they have a high sensitivity, selectivity, low LOD, and are autofluorescence-free.