The present invention refers to a biomaterial film comprising a protein component, in a concentration comprised between 2 and 8 % by weight, monosaccharides/disaccharides, in a concentration comprised between 0.5 and 2 % by weight, agar, in a concentration comprised between 0.1 and 1 % by weight, and glycerol, in a concentration comprised between 0.2 and 1.5 % by weight, wherein the film has a thickness comprised between 70-150 μm and a rugosity lower than 70 GU. The invention also refers to a method for preparing said biomaterial film. The use of the biomaterial film in medicine, in particular, in the treatment of chronic tympanic membrane perforation is also contemplated. Finally, the present invention refers to an implant comprising the biomaterial film of the invention.