Method for continuous and batch purification of bacterial magnetic particles

Abstract

The invention provides a method for purifying a bacterial magnetosome at a large scale, which comprises the following steps: breaking magnetotactic bacterial cells by a high-pressure homogenizer, separating and cleaning the magnetosome by a magnetic chromatography system, digesting membrane protein with protease k, electroeluting, desalting by a magnetic stirring system, etc. The method has the advantages of continuous operations, and that the purification period is shortened from 2-3 months to less than one week, damage caused by ultrasonication to the plasma membrane of the magnetosome is effectively reduced, the membrane protein on the surface of the magnetosome is reduced and the immunogenicity of the purified magnetosome is lowered.

Description

technical field [0001] The invention relates to the field of nanobiology technology, in particular to a method for large-scale purification of bacterial magnetosomes. Background technique [0002] Bacterial magnetosomes (Magnetosomes) are natural nano-magnetic particles coated by magnetosome membranes synthesized by microorganisms such as magnetotactic bacteria. The particle size is between 40-50nm, and the main component is generally Fe. 3 o 4 and Fe 3 S 4 , has the characteristics of good dispersion, strong magnetism, and good biocompatibility. It is an ideal bionano material. , protein separation and other fields have broad application prospects. [0003] However, due to the limitations of separation and purification techniques, bacterial magnetosomes have not yet reached industrial application. At present, the classic magnetosome purification and extraction method (Li Xiang, Jiang Wei, Sun Jianbo et al, 2007, Lett.in Appl .Micro.45 (1): 75-81) includes the following...

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Problems solved by technology

[0003] However, due to the limitations of separation and purification techniques, bacterial magnetosomes have not yet reached industrial application. At present, the classic magnetosome purification and extraction method (Li Xiang, Jiang Wei, Sun Jianbo et al, 2007, Lett.in Appl .Micro.45 (1): 75-81) includes the following steps: 1) centrifuge to collect the bacteria; 2) resuspend with PBS buffer solution; 3) break the cells with a high-pressure homogenizer or a cell ultrasonic breaker; 4) Then place the broken cells in the container, place a magnet on the outer bottom of the container, and use the magnetism of the magnet to separate the magnetosomes from the cell fragments; 5) when the magnetosomes are separated, discard the supernatant, and weigh Suspend in PBS buffer solution, tap with low-power ultrasonic wave, then absorb with magnet, discard supernatant, repeat this step 80-100 times

Obviously, the treatment process of this classic method is discontinuous, and the purification period is long. Moreover, due to the use of physical methods for purification, there will generally still be a small amount of protein on the surface of the purified magnetosomes. If the magnetosomes are to be applied to animals or For the human body, if it is used for tumor targeting or gene therapy, the residual protein on its surface will cause an immune response and cause serious consequences

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