Development of colloidal gold and carbon immunochromatographic strips for rapid detection of PDCoV

Porcine deltacoronavirus (PDCoV) is an enteric coronavirus that causes diarrhea in suckling piglets, leading to serious economic losses in the swine industry. In this study, we report the development of competitive immunochromatographic strips for PDCoV detection using both colloidal gold and carbon nanoparticles, which also represents the novel reported application of carbon nanoparticles in a viral immunochromatographic assay. The established strips had visual detection limits of 1:128 (gold) and 1:64 (carbon) at 1 × 10⁸ TCID₅₀/mL. Both assays showed excellent specificity, exhibiting no cross-reactivity with porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), or other viruses. Testing 137 clinical fecal samples showed that gold strips had 92.7% agreement with both RT-PCR and western blot, while carbon strips reached over 88%. These results demonstrate that gold- and carbon-nanoparticle-based immunochromatographic strips hold great potential for the rapid and sensitive detection of PDCoV, facilitating timely disease diagnosis and prevention.