Mechanical properties of collagen gels derived from rats of different ages.

In a previous study, we found that different collagen gels produced using collagen fibrils extracted from 1-, 4- and 8-month-old rat tails essentially influenced the morphogenesis of epithelial cells. More importantly, the youngest collagen gel induces the highest level of cell apoptosis. The objective of this study was to investigate mechanical properties of various collagen gels correlated to the rat ages. A rheometer and dynamic mechanical analyzer were used to measure shear and compressive properties of hydrated collagen gels. Experimental results obtained from both testing modes showed that older age-related collagen gels possessed a larger elastic modulus, possibly due to the enhanced cross-linking degree. The moduli obtained in shear mode were 1.4-2.7-times greater than those in compression. The results of shear test and compressive test consistently indicated the age of rats did have a statistically significant effect on mechanical properties of hydrated collagen gels.