Ultra-Stable 2D Magneto-Fluorescent Probe-Mediated Multiplex Immunochromatographic Assay for Precise Bedside Detection of Sepsis.

Abstract

Accurate bedside diagnosis of sepsis is essential for timely treatment and reducing mortality, yet technical limitations persist. Here, we present a multiplex-compatible lateral flow immunoassay (LFIA) that integrates a universal click-chemistry conjugation strategy with highly dispersible, film-like magnetic fluorescent probes (GFDQD@Si) to enable precise diagnosis through concurrent monitoring of pathogens and protein biomarkers. GFDQD@Si combines a two-dimensional high-area reactive interface; a magnetic interlayer for target enrichment and signal amplification; a multilayer of quantum dots for fluorescence enhancement; and an outer silica shell that suppresses background fluorescence and confers superior flowability. This architecture overcomes the size disparity between bacteria and proteins, enabling efficient cocapture of multiple proteins/bacteria and achieving faster, more sensitive detection on an LFIA platform. The platform quantitatively detects two key sepsis biomarkers─procalcitonin (PCT) and interleukin-6 (IL6)─as well as the pathogen <i>Pseudomonas aeruginosa</i>, with limits of detection of 4.44 pg mL^-1 for PCT, 0.94 pg mL^-1 for IL6, and 7 CFU mL^-1 for bacteria. Validation in 75 clinical whole-blood samples demonstrated high sensitivity, ease of operation, and robustness, underscoring its potential for real-time bedside sepsis diagnosis. By simultaneously providing dual readouts of host-response biomarkers and pathogen detection, the GFDQD@Si-LFIA platform is expected to accelerate and improve clinical decision-making for sepsis.