Bioinert article and its use

The invention relates to an article, comprising a substrate (2) and a polymer film (1) attached to the substrate (2), the polymer film (1) comprising a first layer (6) of a first polymer (5) functionalized by a first functionalization compound covalently bound to said first polymer (5) and bearing at least one catecholic group being present on a surface of the first layer (6). The article is characterized in that the polymer film (1) is a layered film, a top layer of which is formed by the first layer (6), the layered film comprising at least one further layer (3a, 3b, 9) of at least one further polymer (4, 7) functionalized by a further functionalization compound covalently bound to said further polymer (4, 7) and bearing at least one catecholic group being present on a surface of the at least one further layer (3a, 3b, 9), wherein an average ratio of catecholic groups per polymer molecule is equal to or less than 1 in case of the first polymer (5) and greater than 1 in case of the further polymer (4, 7).