Magnetic bead, preparation method thereof and application of magnetic bead in extracellular vesicle extraction

The invention provides a magnetic bead, a preparation method of the magnetic bead and application of the magnetic bead in extracellular vesicle extraction. The defects that an existing extracellular vesicle separation method is high in cost, tedious in step, long in consumed time, low in yield and low in purity are overcome. The micro-nano magnetic bead prepared by the invention is a magnetic graphene oxide nano material combined with a polyethyleneimine/polylysine salt material PEI/Plys, the material can adsorb extracellular vesicles with specific sizes in a sample by utilizing a confinement effect under a nano scale, and the extracellular vesicles can be adsorbed by the material under the action of an external magnetic field. According to the method, the directional movement of the compound of the micro-nano magnetic beads and the extracellular vesicles can be induced, the compound of the magnetic beads and the extracellular vesicles is separated from a sample by utilizing magnetic adsorption and can be sep