Gold Nanoparticle Paper Immunoassays for Sensing the Presence of Vibrio parahaemolyticus in Oyster Hemolymph

Seafood contamination with Vibrio bacteria is a problem for aquaculture, especially with oysters,which are often consumed raw. Current methods for diagnosing bacterialpathogens in seafood involve lab-based assays such as polymerase chainreaction or culturing, which are time consuming and must occur ina centralized location. Detection of Vibrio in a point-of-care assay would be a significant tool for food safetycontrol measures. We report here a paper immunoassay that can detectthe presence of Vibrio parahaemolyticus (Vp) in buffer and oyster hemolymph. The test uses gold nanoparticlesconjugated to polyclonal anti-Vibrio antibodies in a paper-based sandwich immunoassay. A sample is addedto the strip and wicked through by capillary action. If Vp is present,it results in a visible color at the test area that can be read outby eyes or a standard mobile phone camera. The assay has a limit ofdetection of 6.05 x 10(5) cfu/mL and a cost estimateof $5 per test. Receiver operating characteristic curves with validatedenvironmental samples showed a test sensitivity of 0.96 and a specificityof 1.00. Because the assay is inexpensive and can be used on Vp directlywithout the requirement for culturing, or sophisticated equipment,it has the potential to be used in fieldable settings.

Automated summary

Seafood contamination with Vibrio bacteria is a problem for aquaculture, especially with oysters. Current methods for diagnosing bacterial pathogens in seafood involve lab-based assays, which are time-consuming and must occur in a centralized location. A point-of-care assay that can detect the presence of Vibrio in a quick and convenient manner would be valuable for food safety control measures.