A one-step electrochemiluminescence immunosensor preparation for ultrasensitive detection of carbohydrate antigen 19-9 based on multi-functionalized graphene oxide

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 (nanoFe3O4@GO). ABEI and anti-CA19-9 acted as the electrochemiluminophore and the capture device for CA19-9 respectively. NanoFe3O4@GO enabled all the ABEI immobilized molecules electrochemically active due to its good conductivity, and brought multi-functionalized 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.