The present invention relates to a method for improving the biocompatibility of a surface (1) in particular the surface of a solid and to a device (3) for example an implant sensor or cell culture vessel which is brought into contact with biological systems via a biocompatible surface. In order to improve the biocompatibility of surfaces in particular with respect to cell cultures and tissues in a simple way and for a large number of different surfaces provision is made according to the invention for the surface (1) to be brought into contact with reactive radicals (2). The device (3) according to the invention has a biocompatible surface (1) that has been treated by the method according to the invention.
