Label-free electrochemiluminescent immunosensor for detection of prostate specific antigen based on mesoporous graphite-like carbon nitride

In this paper, mesoporous graphite-like carbon nitride (mpg-C3N4) combined with gold nanoparticles (Au NPs) was conducted to construct a luminol-hydrogen peroxide (H2O2) based electrochemiluminescent (ECL) immunosensor for prostate specific antigen (PSA) detection. The mpg-C3N4 exhibited large specific surface area and high porosity was synthesized from a simple precursor, which possessed abundant active sites to load Au NPs and luminol (mpg-C3N4/Au-luminol). After that, Au NPs linked mpg-C3N4 (mpg-C3N4/Au) could hatch with the primary antibody (Ab1) via Au-NH2 bond, which reinforced the sensitivity of immunosensor. The mpg-C3N4 and Au shows excellent catalytic enhancement effect on the ECL intensity of luminol. Under optimal conditions, the constructed ECL immunosensor exhibited sensitive response to PSA in a wide linear range of 0.001 ~ 15 ng mL-1 with a lower detection limit of 0.927 pg mL-1. Meanwhile, the proposed ECL immunosensor endows the good reproducibility and stability. Therefore, the results could open another avenue for detection of PSA and other biomarkers.