A novel electrochemical immunosensor for dibutyl phthalate based on Au@Pt/PEI-rGO and DNA hybridization chain reaction signal amplification strategy

Herein, a sensitive immunosensor for the rapid detection of Dibutyl phthalate (DBP) small molecules was developed. Its principle is based on Au@Pt/Polyethyleneimine (PEI)-rGO and hybridization chain reaction signal amplification system. First, Au@Pt/PEI-rGO modified electrode is used as a signal amplification platform and the antibody is fixed. In the presence of target DBP, it competes with DBP-bovine serum albumin-S0 for binding antibody. Finally, the DNA concatemer carrying a large number of signal molecules methylene blue combines with its S0 to produce a reduced electrochemical signal. Under the most reasonable conditions, this immunosensor showed a good linear range from1 pg mL-1 to 0.1 μg mL-1with a low detection limit of 0.276 pg mL-1. It has been verified that this immunosensor has good selectivity, reproducibility and stability. The designed biosensing solution will open up a new path for DBP monitoring and other small molecule targets in the food field.