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A visual on-site biosensor for low-cost detection of chloramphenicol based on aptamer and split DNAzyme.

Chloramphenicol (CAP) is a kind of broad-spectrum antibiotic, which has been forbidden in food by most countries because of its side effects. In this study, a simple and low-cost biosensor for CAP detection in food was developed. The biosensor consisted of an aptamer specific to CAP and a pair of split probes that could self-assemble as DNAzyme. The detection result could be identified by the naked eye and the visual limit was 10 nM CAP. The absorbance of final reaction products at 417 nm had a linear relationship with the logarithm of the CAP concentration in a range from 10 to 200 nM, and the limit of detection was 87.3 pM. The visual analysis by imageJ also showed a linear detection range between 25 and 200 nM. The entire detection procedure could be completed in about 1.5 h at a cost of about 0.16 dollars per reaction. We believe that the biosensor shows great potential in the rapid and sensitive detection of CAP in food.