Ultrasensitive electrochemical immunosensor for procalcitonin with signal enhancement based on zinc nanoparticles functionalized ordered mesoporous carbon-silica nanocomposites

A novel and sensitive strategy for procalcitonin (PCT) determination was developed based on zinc nanoparticles-functionalized ordered mesoporous carbon-silica nano-composites (OMCSi-Zn). This strategy combined an effectively designed trace tag and a simple immunosensor. The large amount of OMCSi-Zn materials as label greatly amplified the detection signals for the electrochemical detection of proteins, while the good biocompatibility of graphene-chitosan as sensor matrix retained excellent stability and accelerated electron transfer for the sandwich-type immunoassay. Without metal preconcentration, the zinc nanoparticles loading on the ordered mesoporous carbon-silica nano-composites (OMCSi) could directly be detected through electrochemical voltammetries, while the immunoreaction had a close relationship with the distinct voltammetric peaks. The proposed method exhibited high sensitivity and good stability for PCT detection, possessing an improved linear response range from 0.05 pg/mL to 80 ng/mL, with a detection limit of 0.013 pg/mL (S/N = 3). Moreover, the serum samples from clinic were accurately detected with the proposed method, indicating that the developed immunoassay possessed excellent potential application in clinical diagnostics for PCT.