Hierarchical CoCoPBA@PCN-221 nanostructure for the highly sensitive detection of deoxynivalenol in foodstuffs

An electrochemical impedimetric immunosensor was constructed based on a hierarchical nanostructured CoCo Prussian blue analogue entrapped by a Zr-based porphyrin MOF (denoted by CoCoPBA@PCN-221) for the sensitive detection of deoxynivalenol (DON). Given that CoCoPBA@PCN-221 demonstrated a hierarchical nanostructure, large specific surface area, and the synergistic effect between mixed metal valence states (Co2+/ Co3+) and Zr clusters, it thus displayed a high binding interaction with the DON-targeted antibody. Compared with CoCoPBA and PCN-221, CoCoPBA@PCN-221 showed a superior stabilization ability toward the antibody -antigen complex in aqueous solution. Under optimum conditions, the CoCoPBA@PCN-221-based impedimetric immunosensor exhibited a good linear range from 1 fg mL-1 to 1 ng mL-1, and an ultralow detection limit of 0.14 fg mL-1, accompanied by high selectivity, reproducibility, stability, and applicability in foodstuffs. This method allows the integration of MOFs with cascading properties for applications in the biosensing and food safety fields.