| With the improvement of living standards, People’s diet structure is more and more diversified, and people pay more attention to food safety problems. Outbreak rates of foodborne disease rise sharply, while the malignant food safety accidents frequently outbreak around the world,which has brought great pain and loss to people. So, how to detect food-borne pathogens fast and accurately has become the key to food safety control.In recent years, nanotechnology has developed rapidly. Due to the unique physical and chemical properties of nano-materials, nano-technology is widely used in the biological area, including Biochemistry,Cell biology, Molecular biology, Genomics, Proteomics, medical diagnostics, drug screening and so on. More and more food poisoning events has been brought by Listeria monocytogenes,LM,which makes people suffer from listeriosis. The patientsis manifest sepsis and meningitis to miscarry, gastroenteritis, etc. Especially,Pregnancy women, newborns and immunocompromised patients are more likely to be infected.Combining Nuclear magnetic resonance, NMR and magnetic nanoparticles, MNPs. The paper built a rapid detection method oghf LM. The first part studied the optimum medium of LM and counting method. Throu the growth curve drawing, it was concluded that the optimal culture medium was listeria richment broth. By comparing the dilution plate counting method and MPN counting method, the MPN method counting effected better. The second part successfully synthesized biological functionalization manganese oxide nanoparticles. First through high temperature pyrolysis,the manganese oxide as the core of magnetic nanoparticles was prepared.Through reverse microemulsion method,manganese oxide was coated by silicon dioxide,and modified with amino.Thus, amination manganese oxide nanoparticles is synthesized successfully. The particle size waas about 30 nm. EDC · HCL and NHS activated antibody. Activated antibody immunized amination manganese oxide nanoparticles,which formed immunized nanoparticles, with protein immobilized ability. The third part built a rapid detection method of LM with high specificity,and high sensitivity. Immunized nanoparticles can specifically recognize LM. This specific binding leaded to change of nanoparticle dispersion degree in the reaction system. Meanwhile, Longitudinal relaxation time of solution system changed. In order to improve the sensitivity of detection, the response parameter of the detection system has been optimized, and finally The optimal concentration of reaction magnetic beads is 0.08 mg/m L, the best stabilizer is 2% skimmed milk powder, optimum p H value is 7.0 and optimal reaction incubation time is 30 min in between magnetic beads and LM. Under the optimum reaction parameters, the linear range of detecting LM is 10 ~ 103 cfu/m L. Testing samples with LM, the result showed that the IMS-LF-NMR detection method can be used for the sample with high specificity.In short, this paper developed a kind of rapid and specific method for detecting foodborne pathogenic, LM. It is a theoretical foundation, so that nanoparticles is further applied to the detection of foodborne pathogens. |
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