▎ 摘　　要

A one-step electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of carbohydrate antigen 19-9 (CA19-9) was developed based on multi-functionalized graphene oxide (GO), which was prepared with N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and CA19-9 antibody (anti-CA19-9) chemically bound to the surface of magnetic GO (nanoFe(3)O(4)@GO). ABEI and anti-CA19-9 acted as the electrochemiluminophore and the capture device for CA19-9 respectively. NanoFe(3)O(4)@GO enabled all the ABEI immobilized molecules electrochemically active due to its good conductivity, and brought multifunctionalized GO attracted on the surface of magnetic glass carbon electrode through magnetism. Thus the ECL immunosensor could be prepared through a one-step process that facilitates ultrasensitive detection of CA19-9. Under optimal conditions, the ECL intensity of the immunosensor decreased proportionally to the logarithmic concentrations of CA19-9 in the range of 0.001-5 U/mL with a detection limit of 0.0005 U/mL. This one-step ECL immunosensor showed good performance in specificity, stability, reproducibility, regeneration and application. It opened a new avenue to apply multi-functionalized bionanomaterials in ECL immunoassay. (C) 2014 Elsevier B.V. All rights reserved.