Highly sensitive detection of lipopolysaccharide based on collaborative amplification of dual enzymes

In this work, a novel electrochemical biosensor is developed for facile and highly sensitive detection of lipopolysaccharide (LPS) based on collaboration of dual enzymes for multiple-stages signal amplification. Through ingenious design, the specific recognition of target LPS is transformed to the exonuclease III (Exo III)-assisted interface DNA cycling collaborated with the terminal deoxynucleotidyl transferase (TdT)-catalyzed DNA extension, finally inducing significant electrochemical signal concerned with the concentration of LPS. This paper mainly discusses the detection principle, optimization of key factors, and the analytical performance of the biosensor. With the efficient signal amplification, the biosensor shows high sensitivity with a good linearity and a low limit of detection of 1 pg mL(-1) for LPS. Moreover, the developed biosensor can clearly discriminate LPS from interferents and show high specificity for LPS detection. This biosensor has also been successfully employed to measure LPS in real food samples, suggesting potential opportunity for application in food safety detection. (C) 2020 Elsevier B.V. All rights reserved.