▎ 摘　　要

NOVELTY - Composite material in the form of a flat membrane comprises: a biocompatible polymer of polyacrylonitrile in the form of a flat membrane with a thickness of 198-208 μ m; and 33-60 wt.% many graphene nanoplatelets. The graphene nanoplatelets are located on the surface of the biocompatible polyacrylonitrile polymer forming clusters of graphene nanoplatelets in a random manner. The fraction of pores on the surface of the composite material is 1.1-2.3%. The fraction of pores in the cross-section of the composite material is 15.2-20.2%. USE - The composite material is useful as a substrate or scaffold for the in vitro culture of cancer cells, where those cancer cells are derived from a solid cancer removed from a subject suffering from cancer, and the solid cancer is breast cancer (all claimed). ADVANTAGE - None given. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for obtaining the composite material in the form of a flat membrane, comprising (a) dispersing graphene nanoplatelets in a solvent including N-methylpyrrolidone and/or dimethylacetamide by sonication, (b) adding polyacrylonitrile to the dispersion of graphene nanoplatelets and shaking resultant to obtain a homogeneous graphene nanoplatelets-polyacrylonitrile solution, where the solution comprises 5-15 wt.% graphene nanoplatelets, (c) degassing the polyacrylonitrile-graphene nanoplatelet solution for 8-24 hours at room temperature, (d) spreading the polyacrylonitrile-graphene nanoplatelet solution on a glass plate, (e) immersing the degassed polyacrylonitrile-graphene nanoplatelet solution in a first coagulation bath comprising water and/or the solvent, and (f) removing the remains of solvent from the product obtained in the step (e) in a second water bath.