Autofluorescence free functionalized upconversion nanoparticles-based turn-on aptasensor for highly sensitive and selective sensing of antibiotics

Overuse of antibiotics such as enrofloxacin (ENR) can lead to their residues in environment and food and ultimately endanger human health. It's essential to build a rapid, sensitive and selective biosensor to detect the antibiotics residues. Herein, an autofluorescence free near-infrared (NIR) laser excited func-tionalized upconversion nanoparticles (UCNPs) based turn-on aptasensor for ENR detection is presented. Efficient Forster resonance energy transfer (FRET) from aptamer modified core-shell UCNPs with highly enhanced upconversion (UC) luminescence to MnO2 nanosheets occurs. Based on the UC luminescence recovery of the UCNPs-MnO2 aptasensor caused by ENR, this luminescence turn-on UCNPs-MnO2 aptasensor shows highly sensitive and selective detection of ENR in linear range of 0.5e300 0 ng mL-1 with a limit of detection (LOD) at 0.0642 ng mL-1 in diluted commercially available milk solution without pretreatment. The proposed aptasensor demonstrates high sensitivity, excellent selectivity, no back-ground autofluorescence for high signal-to-noise ratio and low LOD for the fast detection of antibiotics residue, holding great potential for environmental and food safety detection of antibiotics.& COPY; 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).