Hierarchical Mesochannel-Confined Nanozyme Reactors Propelling Gold Amplification Immunoassays for Ultrasensitive Point-of-Care Diagnostics.

Ultrasensitive, rapid, stable, and user-friendly point-of-care (POC) diagnostic technologies are imperative for disease screening and home healthcare. Herein, we propose a novel hierarchically mesoporous channel-confined nanozyme reactor (FeMPPt) as an enrichment-confinement nanoreactor to enhance gold plasmonic signal amplification, significantly boosting the sensitivity and stability of visual lateral flow immunoassays (vLFIAs) for ultrasensitive dual-mode (qualitative/quantitative) detection of multiplex disease biomarkers. The FeMPPt with high colorimetric signal brightness was synthesized through a spatially controlled assembly of polydopamine flexible scaffolds and platinum nanozymes within the hierarchical mesochannels of 3D magnetically core-shelled dendritic mesoporous silica. Through electrostatic adsorption, high-specific-surface-area interception, and mesoporous confinement catalysis, 125- and 5-fold enhancements were achieved compared to conventional gold nanoparticles (AuNPs) and nonporous nanozymes of almost equivalent size, respectively. The limit of detection for FeMPPt-labeled vLFIA for qualitative/quantitative detection of cardiac troponin I and alpha-fetoprotein was 125/230-fold and 1300/1300-fold lower than that for AuNP-labeled vLFIA, respectively. In addition, clinical practicality was validated using 234 serum samples from clinical laboratories and 34 samples from emergency departments, with quantitative performance comparable/superior to standard/miniaturized chemiluminescence immunoassay systems, demonstrating its considerable potential for real-time disease biomarker detection in both clinical and POC settings.