Label-free electrochemical biosensor for determination of procalcitonin based on graphene-wrapped Co nanoparticles encapsulated in carbon nanobrushes coupled with AuPtCu nanodendrites

A new label-free electrochemical immunosensor was constructed for quantitative detection of procalcitonin (PCT), by employing AuPtCu nanodendrites (AuPtCu NDs, prepared by a one-pot solvothermal method) and graphene-wrapped Co nanoparticles encapsulated in 3D N-doped carbon nanobrushes (G-Co@ NCNBs), obtained by self-catalyzed chemical vapor deposition as immune-sensing platform. Impressively, the home-made nanocomposite enlarged the highly accessible active sites and promoted the mass/electron transport, in turn showing the efficient synergistic catalysis towards H2O2 reduction, combined by greatly increasing the loading capacity of the PCT antibody (Ab). The as-constructed sensor displayed a dynamic linear range of 0.0001 similar to 100 ng mL(-1) along with an ultra-low limit of detection (LOD = 0.011 pg mL(-1), S/N= 3) and was further explored for determination of PCT in a diluted serum sample with acceptable results. The sensor provides some valuable guidelines for bioassay and early diagnosis of sepsis.

Automated summary

A label-free electrochemical immunosensor was developed for quantitative detection of procalcitonin using AuPtCu nanodendrites and graphene-wrapped Co nanoparticles. The sensor exhibits efficient catalysis and low detection limit, providing valuable guidance for bioassays and early diagnosis.