MIL-101(Cr)-induced nano-optical sensor for ultra-sensitive detection of enrofloxacin in aquatic products using a fluorescence turn-on mechanism via upconversion nanoparticles

In this study, an ultra-sensitive and selective biosensor for the detection of enrofloxacin (ENR) in complex matrices has been established. The study intelligently converges the spectral properties of core-shell upconverted nanoparticles (UCNPs) and the excellent adsorption satiating aptitudes of metal organic frameworks (MOFs). The principle was based on the fluorescence resonance energy transfer (FRET) between aptamer-modified UCNPs as the donors and MOFs MIL-101(Cr) as the effective receptors. The spectral overlap between UCNPs fluorescence emission and MIL-101(Cr) absorption generated the FRET process under the action of pi-pi stacking interactions. The presence of ENR induced conformational changes in the aptamer via preferential binding, resulting in a decline in the nucleobase exposure on the surface of MIL-101(Cr) and eventually in the fluorescence recovery. The fluorescence intensity (FL) was enhanced as the ENR concentration was increased. The detection limit was 0.034 ng.mL(-1) and the linear calibration curve between logarithmic ENR concentration and FL was achieved in the range of 0.1-1000 ng.mL(-1). The applicability of the platform for ENR recognition was confirmed in real fish and shrimp samples and further validated by a standard HPLC technique with no significant difference (p > 0.05). The current UCNPs-MIL-101(Cr) aptasensor proposes a fast, sensitive and quantitative detection approach for ENR in aquatic products.

Automated summary

This study established an ultra-sensitive and selective biosensor for the detection of ENR in aquatic products by utilizing the spectral properties of UCNPs and the adsorption capabilities of MOFs, achieving accurate detection through the FRET process.