▎ 摘　　要

NOVELTY - Method for preparing magnetic graphene oxide complex material modified by nucleic acid aptamer involves (a) synthesizing magnetic graphene oxide complex matrix material modified with polyethyleneimine (MagG-PEI) by solvothermal method, then using amide reaction to synthesize MagG-PEI-DSP on surface of the matrix material by modifying the homobifunctional crosslinking agent 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) (DSP) and connecting the 3 terminal modified NH2 nucleic acid aptamer to MagG-PEI-DSP to form the magnetic complex MagG-PEI-DSP-aptamer of surface-bonded nucleic acid aptamer. The particle size of the ferroferric oxide magnetic core dispersed on the graphene sheet with a diameter of 500 nm-5 mu m is 100-300 nm. The amount of nucleic acid aptamer immobilized on the magnetic complex is 1-93 nmol/mg. USE - The method is useful for preparing magnetic graphene oxide complex material modified by nucleic acid aptamer which is used as immunoaffinity material (claimed). ADVANTAGE - The method prepares magnetic graphene oxide complex material modified by nucleic acid aptamer with high specificity of target recognition by nucleic acid aptamers. The magnetic graphene oxide complex material separates exosomes from various biological samples such as urine, blood, and cell culture supernatant and has good practical value and application prospects in the research field based on exosomes. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for use of the magnetic graphene oxide complex material modified by nucleic acid aptamer as an immunoaffinity material.