Patent ID: 8227415

Claim:
A non-porous film having an average pore size of less than 1 μm as determined by scanning electron microscope, comprising on at least one side thereof a layer comprising living or viable cells, wherein the non-porous film comprises a collagen polypeptide comprising at least one GXY domain having a length of at least 5 consecutive GXY triplets, wherein X and Y each represent any amino acid and wherein at least 20% of the amino acids of said collagen polypeptide are present in the form of consecutive GXY triplets and wherein the film thickness when placed in demineralized water of 37° C. for 24 hours is at most 10 times its initial thickness, and wherein said film is crosslinked by: (i) adding between 0.02 mmol and 5.0 mmol of a crosslinking compound per gram collagenous polypeptide; or (ii) exposure to radiation so that the degree of crosslinking is the equivalent of adding between 0.02 mmol and 5.0 mmol of a crosslinking compound per gram collagenous polypeptide.