▎ 摘　　要

NOVELTY - Low-field nuclear magnetic resonance homogeneous immunological detection based on superparamagnetic two-dimensional material comprises (i) synthesizing functionalized superparamagnetic two-dimensional materials GO@SPIONs&Ab, and (ii) taking 0.1 ml GO@SPIONs&Ab dispersion and 1.0-1.4 ml test samples containing different concentrations of food-borne pathogens into sample bottles and mixing, shaking and incubating for 30 minutes, placing in a low-field NMR contrast agent relaxation analyzer, collecting T2 at 35℃, and using CPMG pulse sequence to measure transverse relaxation time difference ΔT2 of water protons corresponding to a series of food-borne pathogens with different concentrations, establishing quantitative relationship between the lateral relaxation time difference of water protons and the concentration of food-borne pathogens, and determining concentration of food-borne pathogens in unknown samples according to the quantitative relationship. USE - The method is useful for low-field nuclear magnetic resonance homogeneous immunological detection based on superparamagnetic two-dimensional material. ADVANTAGE - The method ensures the concentration of foodborne pathogens in unknown samples can be determined, and has high sensitivity and accuracy, strong specificity, and simple and rapid operation, and is not for the purpose of diagnosis or treatment. DETAILED DESCRIPTION - Low-field nuclear magnetic resonance homogeneous immunological detection based on superparamagnetic two-dimensional material comprises (i) synthesizing functionalized superparamagnetic two-dimensional materials GO@SPIONs&Ab by (a) centrifuging 15-25 ml 0.5-1.5 mg/ml graphene oxide dispersion at 12000 revolutions/minute for 5 minutes, discarding the supernatant, re-dispersing in 15-25 ml absolute ethanol, ultrasonically processing for 6 minutes, adding 15-25 μl 0.0426 M 3-aminopropyltriethoxysilane solution, magnetically stirring at 65-75℃ for 3-5 hours, washing repeatedly with ethanol and water, and dispersing in 20 ml water to obtain an aminated monolayer graphene oxide dispersion, and (b) adding 1-3 ml 25 wt.% glutaraldehyde solution into 8-12 ml amino-graphene oxide dispersion, stirring magnetically for 2-5 h at room temperature, centrifuging at 5000 revolutions/minute, and washing with ethanol, dispersing in 8-12 ml water, adding 150-250 μl 0.5 mg/ml superparamagnetic iron oxide nanoparticles and 150-250 μl 100 μg/ml foodborne pathogenic polyclonal antibody solution to the dispersion, shaking for 4 hours to obtain functionalized GO@SPIONs&Ab, adding 150-250 μl 2 wt.% bovine serum albumin solution to block non-specific binding sites, washing with pH 7.4, 0.01 M phosphate-buffered saline solution to remove unbound bovine serum albumin and antibody, and dispersing in 2 ml phosphate-buffered saline solution, centrifuging at 1737 revolutions/minute for 3 minutes to remove free SPIONs, and dispersing the obtained product in 10 ml phosphate-buffered saline solution to obtain the functionalized superparamagnetic two-dimensional material GO@SPIONs&Ab dispersion, and (ii) taking 0.1 ml GO@SPIONs&Ab dispersion and 1.0-1.4 ml test samples containing different concentrations of food-borne pathogens into sample bottles and mixing, shaking and incubating for 30 minutes, placing in a low-field NMR contrast agent relaxation analyzer, collecting T2 at 35℃, and using CPMG pulse sequence to measure the transverse relaxation time difference ΔT2 of water protons corresponding to a series of food-borne pathogens with different concentrations, establishing quantitative relationship between the lateral relaxation time difference of water protons and the concentration of food-borne pathogens, and determining concentration of food-borne pathogens in unknown samples according to the quantitative relationship.