Colorimetric immunoassay for rapid detection of Vibrio parahaemolyticus

Vibrio parahaemolyticus (V. parahaemolyticus) is one of the most common food-borne pathogens. The authors describe a rapid colorimetric assay for V. parahaemolyticus that is based on a combination of a magnetic bead-based sandwich immunoassay and signal amplification via an enzmye mimic. MnO2 nanoparticles are used as an artificial oxidase that oxidizes 3,3', 5,5'-tetramethylbenzidine in the presence of oxygen to form a blue (and readily visible) product with an absorption maximum at 652 nm. By combining the superior capture efficiency ofmagnetic beads with the high catalytic activity of the enzmye mimic, this method can detect V. parahaemolyticus concentration in the range between 10 to 10(5) cfu.mL(-1) without pre-enrichment, and the limit of detection is as low as 10 cfu.mL(-1). Recoveries ranging from 87.5% to 106.0% are found when analyzing spiked oyster samples. The assay is rapid, sensitive, and specific and specific. In our perception, it shows promise in rapid instrumental and on-site visual detection of V. parahaemolyticus.