Abstract:

Objective To establish an electrochemical immunosensor for the determination of human epididymis-specific protein 4 （HE4） based on Graphene sheet and Au nanoparticle nanocomposite. Methods Firstly,Graphene sheet and Au nanoparticle nanocomposite was coated onto screen printed electrode（SPE） with an enhanced electrochemical active area and good electronic transfer property. HE4 antibody was adsorbed on the nanocomposite,which aimed at assembling more HE4 antigen. Following the immunoreaction with HE4,a double-antibody sandwich immunoassay was performed on SPE using horseradish peroxidase labeled HE4 antibody. Electrochemical detection was carried out for HE4 level in the presence of hydrogen dioxide（H₂O₂）. Results The immunosensor showed broad linear response to the HE4 level comprised between 0 pmol/L and 400 pmol/L with a limit of detection（LOD）of 0.5 pmol/L. Conclusions The electrochemical immunosensor allows the identification of patients at risk of ovarian cancer,providing a new,fast and simple approach for early diagnosis in daily clinical practice.

Key words: Electrochemical immunosensor, Double-antibody sandwich immunoassay, Human epididymis-specific protein 4, Screen printed electrode, Graphene sheet