Facile construction of ratiometric electrochemical immunosensor using hierarchical PtCoIr nanowires and porous SiO2@Ag nanoparticles for accurate detection of septicemia biomarker

Procalcitonin (PCT) is a sensitive and specific biomarker for sepsis diagnosis. In this study, a novel ratio typed electrochemical immunosensor was constructed for reliable and sensitive assay of PCT based on hierarchical PtCoIr nanowires/polyethylene polyamine-grafted-ferrocene (PtCoIr HNWs/PEPA-Fc) and porous SiO2@Ag nanoparticles-toluidine blue (porous SiO2@Ag NPs-TB). Importantly, the PtCoIr HNWs/ PEPA-Fc was first modified on the sensing interface, which harvested stable and strong electrochemical signals for readout of Fc due to the enriched anchoring sites created by the PtCoIr HNWs. Meanwhile, porous SiO2@Ag NPs-TB behaved as the label to conjugate with secondary antibody (Ab(2)), which also provided another strong detection signals originated from TB confined in such porous structures. The resulting immunosensor displayed a measurable output of procalcitonin (PCT) in the dynamic scope of 0.001 similar to 100 ng mL(-1) with a low limit of detection (LOD) of 0.46 pg mL(-1) (S/N = 3). Moreover, we exploited this strategy for PCT assay in a diluted human serum sample with acceptable results, exhibiting promising applications in the clinical analysis. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A novel ratio typed electrochemical immunosensor was successfully constructed for reliable and sensitive assay of PCT, utilizing PtCoIr HNWs/PEPA-Fc and porous SiO2@Ag NPs-TB for detection. The immunosensor showed a measurable output of PCT with a low limit of detection, demonstrating promising applications in clinical analysis.