Magnetic-Fluorescent Nanocluster Lateral Flow Assay for Rotavirus Detection

Rotavirus is a leading cause of death in young children worldwide. Although vaccines are currently available and reduce the disease burden, most low-income countries rely on diagnosis by point-of-care testing owing to its rapidity, simplicity, and affordability; however, its sensitivity remains a problem. Magnetically assisted antigen enrichment improves the sensitivity with increased fluorescence intensity. However, magnetic nanoparticles (NPs) strongly absorb ultraviolet light, limiting the combination of magnetic NPs and quantum dots (QDs). Therefore, this study aimed to establish a magnetic-fluorescent nanocluster composed of magnetite (Fe 3 O 4 ) NPs and CdSe–CdS core–shell QDs for a high-sensitivity lateral flow assay (LFA). Inducing a solvophobic interaction mediated by solvent polarity increased the interparticle distance. Consequently, the self-assembled nanoclusters exhibited a QD-embedded structure with Fe 3 O 4 NPs on the outer layer. The magnetic enrichment enhanced the detection limit of the rotavirus antigen up to 1.0 × 10 1 TCID 50 /mL, where TCID 50 represents the median tissue culture infectious dose. The clinical trial results showed that the established LFA platform outperformed commercial test kits. Thus, this study provides a nanotechnology-based LFA platform with increased sensitivity for inhibiting the propagation of viruses.