A highly sensitive and flexible magnetic nanoprobe labeled immunochromatographic assay platform for pathogen Vibrio parahaemolyticus

• A highly sensitive and flexible magnetic nanoprobe labeled immunochromatographic assay (MNP/ICTS) platform for pathogen.
• A simple (naked-eye observation) and rapid (~ 10 min) system.
• Be able to detect 1.58 × 102 CFU/g Vibrio parahaemolyticus in seafood by flexibly combining with pre-incubation.
• The total sample pre-treatment plus MNP/ICTS assay only needs about 4.5 h.

A magnetic nanoprobe labeled immunochromatographic test strip (MNP/ICTS) was developed to detect food-borne pathogen Vibrio parahaemolyticus. Specific antibody against V. parahaemolyticus was used as test line by coating onto the nitrocellulose membrane. Magnetic nanoprobe was prepared by immobilizing the specific antibody onto the surface of superparamagnetic nanoparticles. Specificity and sensitivity of the MNP/ICTS system were verified by artificially contaminated shrimp homogenate samples. Reliability and application feasibility of the MNP/ICTS system were demonstrated by using seafood samples (n = 36). Comparing with polymerase chain reaction (PCR) and traditional culture methods, the MNP/ICTS system is found to be not only a rapid qualitative analysis (~ 10 min), but also an accurately quantitative detection platform. Through its rapid magnetic separation property, the MNP/ICTS system is capable to flexibly combine with a sample enrichment and pre-incubation process. This combination makes the qualitative sensitivity for the food samples surged more than 100-fold. A naked-eye observation of 1.58 × 102 CFU/g V. parahaemolyticus was realized. This sensitivity could meet the V. parahaemolyticus test threshold value in many countries. Also, the total sample pre-treatment plus MNP/ICTS assay only needs about 4.5 h. Namely, we can get test results in a day. Hence, the developed MNP/ICTS assay platform is simple, rapid and highly sensitive. It is a flexible test platform for pathogen detection. The favorable comparison with PCR and culture methods further proves that the developed MNP/ICTS is applicable into food-borne pathogen or other areas where a simple, rapid, sensitive and point-of-care analysis is desirable.

Scheme of a sample pre-incubation combined with MNP/ICTS assay platform for bacteria V. parahaemolyticus. Seafood homogenate was firstly pre-incubated in SPB media for 3–4 h. Subsequently the enriched samples were mixed well with magnetic nanoprobe, and applied to ICTS assay. V. parahaemolyticus could be qualitatively judged by a naked-eye observation and quantitatively detected by a Magnetic Assay Reader.Figure optionsDownload as PowerPoint slide