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 functionalized upconversion nanoparticles (UCNPs) based turn-on aptasensor for ENR detection is presented. Efficient Fӧrster resonance energy transfer (FRET) from aptamer modified core-shell UCNPs with highly enhanced upconversion (UC) luminescence to MnO 2 nanosheets occurs. Based on the UC luminescence recovery of the UCNPs-MnO 2 aptasensor caused by ENR, this luminescence turn-on UCNPs-MnO 2 aptasensor shows highly sensitive and selective detection of ENR in linear range of 0.5–3000 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 background 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.