A multiple signal amplification based on PEI and rGO nanocomposite for simultaneous multiple electrochemical immunoassay

Abstract A novel electrochemical immunoassay platform for multi-signal amplification has been constructed and applied to the simultaneous detection of three tumor markers (TMs). The platform was successfully developed by polyethyleneimine (PEI)-polydopamine (PDA)/reduced graphene oxide (rGO) nanocomposites. PDA/rGO as the substrates can simultaneously load with detection antibodies (Ab2) and large amounts of PEI, which PEI were further used to immobilize different signal labels. Three TMs of carcinoembryonic antigen (CEA), prostate specific antigen (PSA) and alpha fetoprotein (AFP) were employed as potential factors. Ferrocenecarboxylic acid (Fc), anthraquinone-2-carboxylic acid (Aq) and acetylsalicylic acid (ASA) were employed as distinguishable signal labels. Electrochemical responses of designed sandwich-type immunosensor were successfully investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The multiplexed immunoassay displayed excellent linear response in the range of 0.102 pg/mL–112 ng/mL for CEA and PSA, 0.117 pg/mL–117 ng/mL for AFP. The detection limit of three TMs were 91 fg/mL, 101 fg/mL and 83 fg/mL for CEA, PSA and AFP, respectively. Moreover, this electrochemical immunoassay platform exhibited excellent reproducibility, sensitivity and selectivity for the simultaneous detection of multiple biomarkers.