Schematic representation of collagen gel mechanical testing. Collagen gels were clamped on each end at the mesh, and creep testing was performed in tension by using hanging weights. An initial weight of 1.5 g was added, followed by increments of 0.5 g at 2-minute intervals until failure. The cross-sectional area, measured before loading, was used to calculate applied engineering stress, and analysis of deformations in individually captured frames was used to calculate the engineering strain. Mechanical viscoelastic behavior was quantified by fitting data to the standard linear viscoelastic solid-model equation for creep loading.
Rastogi et al. Arthritis Research & Therapy 2013 15:R57 doi:10.1186/ar4224