Gold nanostars-based SERS-LFIA for the rapid and sensitive detection of group A rotavirus

Rotavirus (RV) infection is a zoonotic disease that primarily affects infants, young children, and young animals, with clinical manifestations including anorexia, vomiting, diarrhea, and dehydration. RV can be classified into seven groups (A-G), among which group A rotavirus (RVA) is the most prevalent and pathogenic. The high morbidity and mortality associated with RVA infection not only cause substantial economic losses to the livestock industry but also pose a serious threat to human health. Currently, the detection of RVA mainly relies on enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). However, these methods are limited by their complex procedures, long processing times, and high costs, making them unsuitable for rapid on-site diagnosis. In this study, a surface-enhanced Raman scattering-based lateral flow immunochromatographic assay (SERS-LFIA) employing gold nanostars (AuNS) as signal labels was developed for the rapid and sensitive detection of animal-derived RVA. AuNS were synthesized via a gold seed-mediated growth method. Mouse anti-RVA monoclonal antibodies and 5, 5'-Dithiobis ‌(2-nitrobenzoic acid) (DTNB) were conjugated to the surface of AuNS through AuS bonds to prepare SERS immunoprobes, which were then deposited onto the conjugate pad during test strip assembly. The unique star-shaped morphology of AuNS significantly enhanced the analytical signals, achieving a visual limit of detection (LOD) of 1.02 × 10³ copies/μL and a Raman signal-based LOD as low as 3.73 × 10² copies/μL. The method exhibited no cross-reactivity with other diarrhea-causing viruses or bacteria and showed an overall concordance rate of 95% (76/80) with RT-PCR when tested using 80 clinical samples. Furthermore, the RVA detection could be completed within 20 min without the need for complex instrumentation. Thus, the dual-signal-mode immunochromatographic assay demonstrates high sensitivity, specificity, and accuracy, making it highly suitable for the rapid on-site detection of RVA.