Collagen matrix stiffness influencing on fibroblast contraction force

Fibroblast-seeded collagen gel which constructs a 3D bio-artificial extracellular matrix (ECM) has been widely used in wound healing, tissue engineering and regenerative medicine. Previous studies using fibroblast-populated collagen based assay to measure cell contractility were limited to examine the radius changes of gel and hence accurate determination of cell contraction force was difficult to achieve[1],[2]. Up to now, little has been known about how the stiffness of collagen matrix influences on cell contraction force. We have recently developed a novel nano-indentation device to measure the gel elasticity and in combination with a mathematical model, the cell contraction force can be determined accurately based on the measured gel thickness and area[3]. In this study, we apply the new technique to investigate the effect of gel stiffness on cell contraction force in a quantitative manner