Abstract: Provided is biological magnetic microsphere, comprising magnetic microsphere body. Magnetic microsphere body comprises, on outer surface thereof, at least one polymer having linear backbone and side chain. End of linear backbone fixes to outer surface of magnetic microsphere body, other ends of polymer unattach to outer surface of magnetic microsphere body. Biotin links to terminal end of side chain of polymer of biological magnetic microsphere. Further provided are modification to, preparation method for, use of biological magnetic microsphere. Biological magnetic microsphere can be handled and used conveniently, rapidly disperse and rapidly precipitate in solution without need to use large-scale experimental equipment such as high-speed centrifuge, can be connected via biotin with purification element having selectivity (such as avidin, affinity protein, polypeptide/protein tag, etc.

Abstract: A biomagnetic microsphere and a preparation method and a method for protein isolation and purification therefor. The outer surface of a magnetic microsphere body of the biomagnetic microsphere has at least one liner polymer with a branched chain; one end of the linear polymer with a branched chain is covalently coupled to the outer surface of the magnetic microsphere body, and other parts are free on the outer surface of the magnetic microsphere body; a backbone of the linear polymer is a polyolefin backbone, and no cross-linking agent is required in the backbone forming process of the linear polymer. The prepared biomagnetic microsphere can implement efficient elution of target proteins and effectively reduce the retention time and retention ratio of the target proteins, and it is easy to operate and widely used.