A dual-mode PCT electrochemical immunosensor with CuCo2S4 bimetallic sulfides as enhancer

A method for the detection of procalcitonin (PCT) with improved accuracy is urgently needed. A dual-mode electrochemical immunosensor with CuCo 2 S 4 –Au bimetallic sulfides as enhancer for accurate detection of PCT was fabricated in this work. The immunosensor not only displays a heavy square wave voltammetry (SWV) signal due to the electron transfer of Cu 2+ and Cu + but not the addition of electron mediators. But also presents high electrocatalytic activity towards H 2 O 2 redox reactions and enhances the detection sensitivity of the amperometric i-t curve ( i-t ). The introduction of Au nanoparticles, not only improves the conductivity but also has synergistic effects between Au NPs and CuCo 2 S 4 , which promote the detection sensitivity by SWV and i-t . To firmly immobilize antibodies, electrolytic gold was used as the matrix for the immunosensor. Based on a CuCo 2 S 4 –Au dual-signal indicator and electrolytic gold as the matrix, the developed immunosensor for PCT detection in this study demonstrates a wide linear response (0.0001–50 ng/mL) and a low detection limit (SWV: 82.6 fg/mL and i-t : 95.4 fg/mL). Additionally, the fabricated immunosensor exhibited an outstanding analytical approach for PCT and broad application for other biomarkers in clinical diagnosis and treatment. • A dual-mode electrochemical immunoassay was designed for PCT. • CuCo 2 S 4 –Au was first used as a dual-signal indicator of the immunosensor. • PCT detection results were established by F-test and t-test. • It achieved an excellent result in human serum sample analysis.