Method for magnetically separating yersinia enterocolitica (YE)

Abstract

The invention relates to the technical field of biology and discloses a method for enriching and separating yersinia enterocolitica (YE). The method comprises the following steps: performing covalent coupling on a dendrimer and an antibody; coating the antibody modified dendrimer with a long-chain biotin molecule; capturing a target bacterium in a sample liquid by the antibody and long-chain biotin comodified dendrimer; identifying and coupling the long-chain biotin dendrimer in the sample liquid by using streptavidin modified nano-magnetic beads; and carrying out separation and weight suspending on the captured bacterium, wherein the weight suspending solution can be directly used for subsequent analysis. Compared with a traditional bacterium magnetic separation method, the method is more suitable for magnetically separating bacteria in a complex matrix, so that the target bacterium separation efficiency in a sample can be improved.

Description

technical field [0001] The invention relates to the field of biotechnology, in particular to a method for isolating food-borne pathogenic bacteria based on nano magnetic beads. Background technique [0002] Foodborne pathogen contamination is one of the major problems of food safety in my country. According to WHO statistics, about one-third of people in developed countries are infected with food-borne diseases every year, and 2.2 million people in the world die every year due to food-borne diseases. In my country, the number of cases of food poisoning is between 200,000 and 400,000 per year, most of which are caused by food-borne pathogens except for accidents. Yersinia enterocolitica ( Yersinia enterocolitica, YE ) is a class of zoonotic pathogens, first discovered in New York State, USA. In the mid-1980s, there were two major outbreaks in my country, causing more than 500 people to be infected, which were confirmed to be caused by food contamination Yersinia enterocoli...

AI Technical Summary

Problems solved by technology

However, the current separation technology based on micron-scale immunomagnetic beads has many limitations: 1) The specific surface area of ​​micron-sized magnetic beads is relatively small, which reduces the capture efficiency of magnetic beads; Bacterial cells are combined through a multiphase reaction, and it usually takes longer to specifically capture the bacterial cells in the food matrix; 3) Micron magnetic beads have poor monodispersity and are prone to occur in food matrix liquids Self-aggregation or precipitation; 4) The traditional immunomagnetic separation technology often directly couples antibody molecules to immunomagnetic beads. steric hindrance effect, which reduces the capture efficiency of antibodies; 5) The food matrix has complex properties and the concentration of non-target pathogenic bacteria is large, and micron magnetic beads are prone to non-specific adsorption, making it difficult to achieve the target in food sample liquid. 6) Excessive concentration of micron magnetic beads will cause damage to bacterial cells (the magnetic field causes the magnetic beads on the surface of the cells to attract each other, causing the cells to be squeezed or even ruptured), resulting in failure of separation; 7) Magnetic beads even When linking antibodies, hydrophobic adsorption or chemical coupling is generally used to link active antibodies on the surface of magnetic beads

If the distance between the antibody and the surface of the magnetic bead is too close, due to the nature of the magnetic bead itself and the hydrophobic or strong hydrophilic groups remaining on the surface, it is easy to cause changes in the spatial conformation of the antibody, resulting in a decrease in the biological activity of the antibody

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