Abstract: Disclosed in the present invention is a method for preparing and certifying a novel coronavirus nucleocapsid protein (nCOV N protein) reference material, the method including: purification and dilution of a raw material of the nCOV N protein; preliminary uniformity test and packaging of solution of a candidate nCOV N protein reference material; characterization of physicochemical properties of the solution of the candidate nCOV N protein reference material in the packaging units; uniformity and stability test of the nCOV N protein reference material in the packaging unit; measurement of standard N protein content of the nCOV N protein reference material, determination and statistical test of standard value of the nCOV N protein reference material; and uncertainty assessment of certified result of the standard value of the nCOV N protein reference material.

Abstract: A composite magnetic nanomaterial based on a DNA tetrahedron, preparation therefor and use thereof are provided. The preparation method include the steps of synthesizing a DNA tetrahedron by means of a self-assembly reaction of single-stranded DNA chains, loading magnetic nanoparticles on the surfaces of molybdenum disulfide particles, modifying gold nanoparticles on exposed active sulfur atoms of the molybdenum disulfide particles, modifying the DNA tetrahedron on the gold nanoparticles, and bonding a protein antibody on the DNA tetrahedron. The composite magnetic nanomaterial is used for enriching and detecting low-abundance proteins in serum, and specific low-abundance proteins in the serum can be efficiently and selectively enriched by means of the specific reaction between an antigen and an antibody.