Visual and Ultrasensitive Detection of a Coronavirus Using a Gold Nanorod Probe under Dark Field

Biosensors (Basel). 2022 Dec 8;12(12):1146. doi: 10.3390/bios12121146.


Porcine epidemic diarrhea virus (PEDV), a coronavirus that causes highly infectious intestinal diarrhea in piglets, has led to severe economic losses worldwide. Rapid diagnosis and timely supervision are significant in the prophylaxis of PEDV. Herein, we proposed a gold-nanorod (GNR) probe-assisted counting method using dark field microscopy (DFM). The antibody-functionalized silicon chips were prepared to capture PEDV to form sandwich structures with GNR probes for imaging under DFM. Results show that our DFM-based assay for PEDV has a sensitivity of 23.80 copies/μL for simulated real samples, which is very close to that of qPCR in this study. This method of GNR probes combined with DFM for quantitative detection of PEDV not only has strong specificity, good repeatability, and a low detection limit, but it also can be implemented for rapid on-site detection of the pathogens.

Keywords: dark field microscopy (DFM); gold-nanorod probe (GNR probe); low detection limit; on-site detection; porcine epidemic diarrhea virus (PEDV).

MeSH terms

  • Animals
  • Coronavirus Infections* / diagnosis
  • Coronavirus*
  • Gold
  • Porcine epidemic diarrhea virus*
  • Swine
  • Swine Diseases* / diagnosis


  • Gold