Aptamer-Functionalized Hydrogel Biosensor Targeting Trace Antibiotics via UV Detection

The abuse of antibiotics has given rise to a huge threat to human health and life; thus, quantitative detection of residual antibiotics in food, drugs, and the environment is of great significance. Although various detection methods and detectors have been developed and applied, designing a detector with convenient operation, high sensitivity, strong selectivity, and a low detection limit is a daunting task. In this work, a sensitive and exquisite hydrogel biosensor is designed based on the self-assembly of graphene oxide (GO) and physical crosslinking, in which an antibiotic aptamer is employed as the UV indicator (260 nm). When used for antibiotic detection, the aptamer quickly diffuses from the gel network and binds with the antibiotic; thereby, the aptamer–antibiotic combination can be measured by a UV spectrophotometer. Notably, the obtained biosensor exhibits a low detection limit (1.89 nM) and a wide linear concentration range (LCR, up to 10 μM). In spike-and-recovery experiments for water samples in an actual environment, all recovery rates were within the acceptable range. Significantly, excellent versatility of the biosensor can be achieved by simply replacing the specific aptamer. In brief, this hydrogel biosensor combines the advantages of low cost, simple operation, and short detection time, promising to protect our lives from the risk of antibiotic pollution.