Affinity chromatography (AC) is a chromatography method that uses specific biological affinities between biomolecules and AC media to separate samples. For example, the specific binding of enzymes to substrates, antibodies to their antigens, nucleic acids to their complementary chains, etc. The binding between different biological pairs is specific and reversible, so the separation and purification of proteins, polysaccharides, nucleic acids or cells can be carried out.The affinity chromatography medium consists of matrix, linker arm and ligand. Among them, the affinity ligand needs to have a specific interaction with the target molecule and can form a reversible complex, and the ligand-target molecular complex can be stable for a period of time in order to play a role in separation during chromatography.