Novel sandwich-typed electrochemical immunosensing of C-reactive protein using multiply twinned AuPtRh nanobead chains and nitrogen-rich porous carbon nanospheres decorated with Au nanoparticles

C-reactive protein (CRP) is commonly utilized as a significant biomarker for inflammation and infection, whose sensitive detection is of importance for early diagnosis of such diseases as a greatly reliable prediction. In this work, a novel sandwich-typed electrochemical immunosensor was built based on mono-dispersed nitrogen-rich porous carbon nanospheres decorated with Au nanoparticles (Au-N-CNSs) for such determination, coupled with multiply twinned AuPtRh nanobead chains (AuPtRh NBCs) as a label material. The AuPtRh NBCs were synthesized by a simple solvothermal method with micelles of a block copolymer poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO (10500) -b-PMMA (18000) ), which can enlarge the loading capacity, significantly catalyze the oxidation of potassium ferricyanide (K 3 [Fe(CN) 6 ]), and increase the conductivity, ultimately amplifying the signals. The obtained sandwich-typed immunosensor showed a broad linear range of 0.01 ng mL −1 –100 μg mL −1 , and a low limit of detection (LOD = 7.70 pg mL −1 ). This strategy offers certain constructive insights for both bioanalysis and early clinical diagnosis of inflammation or tissue damage. • Au-N-CNSs and AuPtRh NBCs were prepared by wet-chemical and solvothermal methods, respectively. • The Au-N-CNSs worked as desirable matrix for immobilizing the Ab 1 . • The AuPtRh NBCs showed great effects on signal magnification as the Ab 2 label. • The sandwich-like immunosensor was fabricated for ultrasensitive assay of CRP.