Ultrasensitive signal-on electrochemiluminescence immunosensor for prostate-specific antigen detection based on novel nanoprobe and poly (indole-6-carboxylic acid)/flower-like Au nanocomposite

A novel signal-on electrochemiluminescence (ECL) immunosensor is constructed by using Au nanoparticle/graphene quantum dots-poly(etherimide)-graphene oxide (AuNP/GQDs-PEI-GO) composite as a probe to detect prostate-specific antigen (PSA). GQDs and AuNP are modified onto the PEI-GO through amide bond and electrostatic interaction sequentially. Poly(indole-6-carboxylic acid)/flower-like Au nanoparticles (PICA/FGNs) composites with satisfactory conductivity are used as a good substrates for the immobilization of the primary antibody (Ab1). ECL signal of the fabricated ECL immunosensor is greatly amplified by the synergistic action of PICA, FGNs, AuNP, GQDs and PEI-GO. This designed ECL sensor greatly broadens the linear response range for PSA detection. The detection range is ranging from 0.001 ng mL(-1) to 100 ng mL(-1) and the detection limit is as low as 0.44 pg mL(-1). In addition, this ECL immunosensor shows good stability, reproducibility, selectivity and good accuracy in actual human serum sample detection, indicating that this developed sensor has the prospect as a universal platform for detection of cancer biomarkers.