A new rapid detection method for ricin based on tunneling magnetoresistance biosensor

Abstract In this research, the magnetic immuno-chromatographic test strip and TMR magnetic sensitive sensor signal detection were combined effectively, which displayed the multiple advantages of magnetic nanoparticles (MNPs) label technique, immunochromatography (IC) and tunneling magnetoresistance (TMR) sensing technology. Through detecting magnetic field intensity generated by functionalized magnetic signal probe on immuno-chromatographic test strip, a new method for ricin detection was established based on TMR biosensor. Compared with traditional labeled biosensor based on optical signal detection, this method can overcome the interference of background color and light of complex environmental samples, and has advantages of easy operation, high sensitive, accurate quantification, good reproducibility, specificity and interference-resistance. With this method, the selective separation and rapid quantitative detection of complex samples can be achieved. The linear range of quantitative detection for ricin was 1 ng/mL–200 μg/mL, the regression equation was Y = 0.2125 X + 0.5675 ( R = 0.9706, P N = 12), the limit of detection (LOD) was 1 ng/mL. This method can overcome the influence of complex environmental interferents in the toxin detection, and can meet the analysis requirements for simulated samples such as water, soil, food, blood and so on. The method showed good recovery ratio and reproducibility, with the recovery ratio of 90.1%–94.2% and the RSD of 2.43%–3.35%.