A Hierarchical Au@PDA-PdCu Nanozyme for Signal-Amplified Immunochromatographic Detection of Carbofuran in Leafy Vegetables
Year: 2026
Type: article
Abstract: Carbofuran residues threaten food safety and public health, yet conventional instrumental methods require expensive equipment and complicated pretreatment, while traditional immunochromatographic assays still lack sufficient sensitivity. Herein, a hierarchical nanozyme composed of an Au core, a polydopamine (PDA) interlayer, and a PdCu shell (Au@PDA-PdCu) was developed as a signal probe for a competitive immunochromatographic assay (ICA) for rapid carbofuran detection. The Au core served as a stable nanoplatform, the PDA interlayer enabled antibody immobilization, and the PdCu shell provided strong peroxidase-like activity for post-assay signal amplification. Three probe formats, namely liquid, sprayed, and lyophilized probes, were constructed and optimized. After 3,3′-diaminobenzidine (DAB) enhancement, the detection limit of the liquid-format strip decreased from 0.055 to 0.016 ng/mL, while the working ranges of the sprayed-format and lyophilized-format strips expanded to 0–100 ng/mL. In Shanghai bok choy, Chinese chive, and spinach, all three formats exhibited good concentration-dependent responses. The visual limits of detection were 5 ng/mL for the liquid- and sprayed-format strips and 1 ng/mL for the lyophilized-format strip. Recoveries ranged from 70% to 119%, with coefficients of variation of 3.7–25.7%. Good specificity was observed, with cross-reactivity below 0.1% for most tested compounds except 3-hydroxycarbofuran. The ICA results agreed well with those obtained by LC–MS/MS. Overall, this method provides a rapid and sensitive proof-of-concept platform with potential for on-site carbofuran screening in leafy vegetables.
Source: Figshare
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7225241581