Determination of Abrin by Electrochemiluminescence Immunosensor Based on Phage-displayed Antibody

A new efficient immunoassay strategy for the determination of Abrin was developed.The assay consisted of a double antibody sandwich format in which immobilized polyclonal antibody(pcAb) was used for capture probe,and Ru(bpy)32+ labeled phage-displayed antibody for electrochemiluminescence(ECL) probe to amplify the ECL signal.A linear relationship between ECL intensity and the concentration of Abrin in the range of 0.005-100 μg/L was obtained.The linear regression equation was lgY=0.701lgX+1.767(R=0.9964,n=7,p0.0001) with a detection limit of 0.005 μg/L(S/N=3).In comparison with the ECL probe based on monoclonal antibody(mcAb),this method gave a 20-fold better sensitivity in Abrin detection.Due to the low detection limit,this method holds great promise in toxin trace detection.