A label-free fluorescent biosensor based on specific aptamer-templated silver nanoclusters for the detection of tetracycline

Abstract

Tetracycline (TET) is a broad-spectrum antibiotic commonly used in the treatment of animals. TET residues in food inevitably threaten human health. High-performance analytical techniques for TET detection are required in food quality assessment. The objective of this study was to establish a label-free fluorescent biosensor for TET detection using specific aptamer-templated silver nanoclusters (AgNCs). An aptamer with a high specific binding ability to TET was used to synthesize a novel DNA-templated AgNCs (DNA-AgNCs). When TET is present, the aptamer’s conformation switched from an antiparallel G-quadruplex to a hairpin structure, altering the connection between AgNCs and the aptamer. Following the transformation of AgNCs into large sized silver nanoparticles (AgNPs), a fluorescence decrease was detected. When used to detect TET in milk, the proposed biosensor displayed high sensitivity and selectivity, with a limit of detection of 11.46 ng/mL, a linear range of 20 ng/mL−10 g/mL, and good recoveries of 97.7–114.6% under optimized conditions. These results demonstrate that the proposed biosensor was successfully used to determine TET quantitatively in food samples, suggesting that our method provides an efficient and novel reference for detecting antibiotics in food while expanding the application of DNA-AgNCs in related fields.

A whole‐cell hypersensitive biosensor for beta‐lactams based on the AmpR‐AmpC regulatory circuit from the Antarctic Pseudomonas sp. IB20

“…Biosensors have emerged as a promising alternative for quick and cost‐effective antibiotic measurement. While biosensors for aminoglycosides, macrolides, and tetracyclines are developed (Mehlhorn et al., 2018 ; Naseri et al., 2023 ; Yang et al., 2023 ), progress in detecting beta‐lactam antibiotics is limited. Detecting penicillins and cephalosporins is until now addressed through enzymatic methods, aptamers and whole‐cell biosensors (Au et al., 2020 ; Chinnappan et al., 2020 ; Lautenschläger et al., 2020 ; Valtonen et al., 2002 ; Xiao et al., 2016 ), but detecting carbapenems is challenging due to their complex structure, limited stability and low abundance (Codjoe & Donkor, 2017 ), presenting an ongoing challenge for accurate and affordable measurement.…”