Abstract: Provided is a structure composed of a cell population comprising endothelial cells, astrocytes and pericytes, and a 3D (three dimensional) cell growth material within which the cell population is located. The structure has a TEER value of at least 450 ?/cm2. The cells of the structure may be derived from the brain. The cells may be human cells, and in particular may be primary derived non-immortalised cells. The structure is particularly suited for use in a model of the blood brain barrier, and the invention also provides such a model. The structure is located in a container, in which it separates a first chamber located on a first side of the structure and a second chamber located on a second side of the structure. The first and second chambers respectively contain first and second liquids in contact with first and second sides of the structure. The liquids mimic the brain extracellular fluid and the blood.

Abstract: Provided is a structure composed of a cell population comprising endothelial cells, astrocytes and pericytes, and a 3D (three dimensional) cell growth material within which the cell population is located. The structure has a TEER value of at least 450 ?/cm2. The cells of the structure may be derived from the brain. The cells may be human cells, and in particular may be primary derived non-immortalised cells. The structure is particularly suited for use in a model of the blood brain barrier, and the invention also provides such a model. The structure is located in a container, in which it separates a first chamber located on a first side of the structure and a second chamber located on a second side of the structure. The first and second chambers respectively contain first and second liquids in contact with first and second sides of the structure. The liquids mimic the brain extracellular fluid and the blood.