Chitosan coated copper and cadmium hexacyanocobaltate nanocubes as immunosensing probes for the construction of multiple analytes platform

In this work, Cd3[Co(CN)6]2 and Cu3[Co(CN)6]2 (CdNCs and CuNCs) nanocubes were synthesized simply by a one-step process at room temperature in the presence of chitosan (CS). It was found that CdNCs and CuNCs produced obviously distinctive anodic peak currents at −0.7 V and −0.1 V (vs. Ag/AgCl), whose separation enabled differentiation between two analytes. They were used as novel electrochemical probes in multiplex electrochemical detection for carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) in a single run. The good performance of the new electrochemical probes was obtained. The linearity range was from 0.025 to 250 ng mL−1 for both CEA and AFP. The detection limit of CEA was 0.0175 ng mL−1 and that of AFP was 0.0109 ng mL−1 at a signal-to-noise of 3. Analysis of clinical serum samples using this immunosensor was well consistent with the data determined by the enzyme-linked immunosorbent assay (ELISA). The novel electrochemical probes could be generally used in multiplex protein detections.