Simultaneous electrochemical detection of multiple tumor markers based on dual catalysis amplification of multi-functionalized onion-like mesoporous graphene sheets

In this work, a sandwich-type electrochemical immunosensor for simultaneous sensitive detection of prostate specific antigen (PSA) and free prostate specific antigen (fPSA) is fabricated. Gold nanoparticles (AuNPs) modified Prussian blue and nickel hexacyanoferrates nanoparticles were firstly prepared, respectively, and then decorated onion-like mesoporous graphene sheets (denoted as Au@PBNPs/O-GS and Au@NiNPs/O-GS) as distinguishable signal tags to label different detection antibodies. Subsequently, streptavidin and biotinylated alkaline phosphatase (bio-AP) were employed to block the possible remaining active sites. With the employment of the as prepared nanohybrids, the dual catalysis amplification can be achieved by catalysis of the ascorbic acid 2-phosphate to in situ produce AA in the presence of bio-AP, and then AA was further catalyzed by Au@PBNPs/O-GS and Au@NiNPs/O-GS nanohybrids, respectively, to obtain the higher signal responses. The experiment results show that the linear range of the proposed immunosensor for simultaneous determination of fPSA is from 0.02 to 10 ng mL−1 with a detection limit of 6.7 pg mL−1 and PSA is from 0.01 to 50 ng mL−1 with a detection limit of 3.4 pg mL−1 (S/N = 3). Importantly, the proposed method offers promise for rapid, simple and cost-effective analysis of biological samples.

Graphical abstractIn this work, we developed a novel multiple-label method and dual catalysis amplification for simultaneous detection of multiple tumor markers. Firstly, AuNPs modified Prussian blue nanoparticles and AuNPs modified nickel hexacyanoferrates nanoparticles decorated onion-like mesoporous graphene sheets, respectively (denoted as Au@PBNPs/O-GS and Au@NiNPs/O-GS) as distinguishable signal tags were utilized to label different detection antibodies. Subsequently, streptavidin and biotinylated alkaline phosphatase (bio-AP) were employed to block the possible remaining active sites. With the bio-AP, the amplification signals could be achieved by catalysis of the ascorbic acid 2-phosphate to in situ produce AA. Then, AA was further catalyzed by Au@PBNPs/O-GS and Au@NiNPs/O-GS nanocomposites, respectively, to obtain the higher signal responses. (A) Preparation procedure of Ab2 bioconjucates (bio-AP/SA/anti-fPSA/Au@PBNPs/O-GS and bio-AP/SA/anti-PSA/Au@NiNPs/O-GS). (B) Fabrication process of the immunosensor and the dual catalysis amplification mechanism.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A novel strategy for simultaneous determination of fPSA and PSA has been constructed. ► The Au@PBNPs/O-GS and Au@NiNPs/O-GS hybrids were employed as distinguishable signal tags. ► With the SA and bio-AP, the dual signal amplifications could be achieved. ► The proposed method offers promise for rapid and simple analysis of biological samples.