Rapid on-site diagnosis of PEDV and PoRV co-infection by gold magnetic nanoparticles-based SERS immunochromatography.

Porcine epidemic diarrhea virus (PEDV) and porcine rotavirus (PoRV) are the two main pathogens causing porcine diarrhea, which are characterized by high morbidity and mortality. Most of the diagnostic methods available are limited to the laboratory or fail to highlight their advantages in terms of target species, detection time, sensitivity, and stability. To meet the demand for rapid on-site diagnosis of PEDV and PoRV co-infection, a surface-enhanced Raman scattering (SERS) immunochromatographic sensor based on gold magnetic nanoparticles (MNPs) was developed. The sensor is dual-mode, detecting on the basis of color signals by the naked eye and Raman signals. After a series of optimizations, the constructed sensor could perform simultaneous qualitative and quantitative detection of PEDV and PoRV in just 18 min, with visualized (color signals observed by the naked eye) limits of detection (LOD) of 3.13 × 102 TCID50/mL and 4.69 × 102 copies/μL, respectively. The LOD based on Raman signal analysis was as low as 4.63 × 101 TCID50/mL and 3.30 × 102 copies/μL for PEDV and PoRV, respectively. In addition, the sensor exhibited excellent specificity without cross-reactivity with common pathogens. The overall compliance rate with RT-PCR was 92.1 % (35/38) for 38 clinical samples. Therefore, the sensor is characterized by high sensitivity, specificity, reproducibility, and accuracy, making it suitable for the simultaneous rapid on-site detection of PEDV and PoRV.