Corona-Structured Magnetic Nanozymes Enable Dual-Mode Immunochromatographic Analysis for Flexible and Ultrasensitive Detection of Emerging Viruses.

Real-time and highly sensitive monitoring of pathogens in environmental and host-derived samples is critical for controlling emerging and acute infectious diseases, yet remains technically challenging. Here, we report a multifunctional nanozyme-based immunochromatographic assay (ICA) that enables rapid, universal, and multiplex detection in different scenarios through visual readouts. We constructed a corona-structured magnetic nanozyme (CSMN) with a triple signal-amplification mechanism involving "magnetic enrichment-synergistic enhancement-multiple catalytic sites," enabling efficient enrichment of trace pathogens in complex matrices and generation of dual visual outputs (colorimetric and catalytically enhanced signals) on ICA. The CSMN-based nanozyme ICA requires only 2 min of catalysis to achieve a ≥92.65-fold increase in sensitivity and a 100-fold expansion of the detection range. Based on this platform, dual-mode detection strategies were developed for SARS-CoV-2 and monkeypox virus. The direct mode enables rapid screening within 12 min, with detection limits as low as 19.4 and 22.5 pg/mL for the two targets, respectively. The enrichment mode enables ultrasensitive detection within 20 min, with detection ranges of 0.0012-1000 ng/mL and 0.0026-1000 ng/mL, respectively, while mitigating interference from the hook effect, making it suitable for detecting low-abundance targets in complex samples. The method demonstrated high accuracy and reliability across environmental and clinical samples, with a detection time approximately one-sixth that of qPCR and ELISA, indicating strong potential for infectious disease surveillance and outbreak control.