A novel strategy of procalcitonin detection based on multi-nanomaterials of single-walled carbon nanohorns–hollow Pt nanospheres/PAMAM as signal tags

Abstract

Procalcitonin (PCT) is a common clinical biomarker of septicemia, and precise detection of PCT is critical to the treatment of septicemia. Conventional detection methods suffer various shortcomings that hinder precise PCT detection. An electrochemical immunosensor based on the antigen–antibody immune-reaction may provide a solution. We developed a novel electrochemical immunosensor for PCT using single-walled carbon nanohorns (SWCNHs)–hollow Pt nanospheres (HPtNPs) as signal tags. Given the high specific surface area of SWCNHs and the interesting catalytic properties of HPtNPs, the successful synthesis of SWCNHs–HPtNPs provided not only a high specific surface area for loading substantial antigen but also good catalytic properties to enhance the electrochemical signal with high sensitivity. In addition, to increase the quantity of the electrochemically active compound thionine immobilized on the surface, PAMAM, which is a class of hyper-branched polymers with a diamine core and an amido amine branching structure, was assembled on the SWCNH–HPtNP surface. A series of results demonstrated the higher sensitivity, improved stability and ideal selectivity of the novel immunosensor compared with a sensor prepared using traditional methods. Furthermore, a broad linear response from 10 pg mL−1 to 20 ng mL−1 with a detection limit of 1.74 pg mL−1 was observed under the optimized conditions of the assay. This immunosensor may provide a new option for clinical septicemia diagnosis through PCT detection.