A Sandwich-Type Immunosensor Based on Pd NPs@DSHSs-Cu2O and Au NPs Functionalized Graphene Oxide Doped Poly(3,4-ethylenedioxythiophene) Nanorod for Quantitative Detection NSE

Changes in the concentration of neuron-specific enolase (NSE) can be used as an indicator for many diseases. Electrochemical immunosensor is a reliable tool for early diagnosis, but achieving ultrasensitive analysis is a pressing problem. In this work, graphene oxide doped poly (3,4-ethylenedioxythiophene) (PEDOT/GO) spindle-like nanorods prepared by liquid/liquid interface polymerization method have good stability and high conductivity. The sulfur atoms on the thiophene ring combine with gold nanoparticles (Au NPs) to further improve the efficiency of interface electron transfer. Besides, the exposed carboxyl groups and Au NPs on the surface of PEDOT/GO can effectively couple with the capture antibody (Ab 1 ). Double-shelled Cu 2 O hollow spheres (Pd NPs@DSHSs-Cu 2 O) modified with palladium nanoparticles (Pd NPs) are used as signal markers. The abundant catalytic active sites and detection antibody (Ab 2 ) binding sites rely on the double-shell hollow spheres to increase the specific surface area. The combined effect of Cu 2 O and Pd NPs can efficiently catalyze H 2 O 2 to realize the amplification of electrical signals. The detection range of the immunosensor prepared by the above-mentioned sensing strategy was 50.0 fg ml −1 ∼ 100.0 ng ml −1 , and the detection limit was 7.54 fg ml −1 , which provides potential reference value for early clinical diagnosis.