Development of collagen condensation method to improve mechanical strength of tissue engineering scaffolds

A major drawback of collagen sponges regarding their use in tissue engineering scaffolds is their weak mechanical properties under wet conditions. To overcome this problem without the use of other skeletal materials, the exhaustive condensation technique of reconstituted collagen fibrils was developed to fabricate high-density collagen sponges using freeze drying. The density linearly increased with an increase in the concentration of collagen fibrils. The compression tests under wet conditions demonstrated that the toughness and stiffness of the collagen sponges increased with an increase in the density. The collagen sponge with a density of 129 mg/cm3 showed a compressive strength (to a strain of 30%) of 8.88 kPa and a modulus of 332 kPa. These results suggested the possibility that the mechanical properties of collagen sponges can increase significantly while retaining the sponges' inherent bioresorbability.