Abstract: A method for producing a plastic packaging container (10) in which a plastic packaging container (10) is formed by injection moulding, deep drawing and/or blow moulding, wherein the plastic packaging container (10) is coated and/or able to be coated with a barrier layer (40), and is produced with a cavity (12) suitable for accommodating a filling material, in particular a food product, and having a sealing zone (20), wherein in order to improve sealability with a sealing material, the surface of the sealing zone (20) is produced in such manner that an area of at least 50% of the surface thereof has a greater average surface roughness Ra according to DIN EN ISO 4288:1998 than the average surface roughness Ra according to DIN EN ISO 4288:1998 of an area of at least 50% of the inner surface (14) of cavity (12), and/or an area of at least 50% of the outer surface, particularly the lateral surface, of the plastic packaging container, and wherein the sealing zone (20) is produced having an average surface roughness

Abstract: A polysaccharide coated carrier having a coating of at least two successive layers of polysaccharide. The first polysaccharide layer spontaneously associates with a second polysaccharide layer and, optionally, the carrier. Each successive layer of polysaccharide spontaneously associates with a preceding layer. Spontaneous association occurs due to the presence of oppositely charged functional groups on each layer of polysaccharide or due to a spontaneous reaction between the functional groups the layers. The carrier may be any surface such as a tube, microtitration plate, bead, particle or the like and is suitable for use in diagnostic or therapeutic methods.