Rapid detection of fish major allergen parvalbumin using superparamagnetic nanoparticle-based lateral flow immunoassay

Abstract A quantitative lateral flow immunoassay (LFIA) was developed based on superparamagnetic nanoparticle (SPMNP) probe for fish major allergen parvalbumin (Pa). The SPMNP probe was prepared by coupling monoclonal antibodies against allergen Pa onto the surface of SPMNP. Dispersibility of the obtained SPMNP probe was analyzed. Nitrocellulose membrane and test line coating concentration were optimized to construct the lateral flow system. Results showed that Sartorius CN 140 membrane, 0.8 mg/mL Pa was suitable for strip construction. Furthermore, a calibration curve with good linearity ( R 2  = 0.9949) was obtained by plotting magnetic signals against series concentrations of Pa. Signals of the T-line were linear in the range from 0.01 to 100 μg/mL Pa. LODs for qualitative and quantitative detection were 5 μg/mL and 0.046 μg/mL, respectively. The average recoveries in clam and peanut matrices ranged from 84.6% to 97.0%, within an acceptable level (80%–120%). 29 food extract samples were separately tested by LFIA and Western Blot assay. Comparative results indicated that the relative consistency between the two methods was 93.1% (27/29). On the other hand, the magnetic signal analysis results indicated that the detection time of the LFIA method was less than 20 min while Western Blot assay typically takes about 5 h. In conclusion, the LFIA method based on SPMNP probe for allergen Pa detection is rapid, specific and simple. It would significantly improve efficiency for large-scale screening and point-of-care detections of allergen Pa.