Online Monitoring the Mechanical Remodeling of Hydrogels by Corneal Fibroblasts

Cell seeded hydrogels provide a useful model for examining cell behavior and matrix remodeling in-vitro. Fibroblasts are capable of manipulating the mechanical behavior of tissues by attaching to their surroundings matrix and applying strain. Any resulting change in the mechanical properties of the matrix can in turn affect the cells behavior. In this study, a non-destructive spherical indentation technique was used to examine the change in mechanical properties of collagen hydrogels seeded with either human corneal fibroblasts or human keratocytes over prolonged culture periods. Cell seeded hydrogels were clamped between two transparent circular rings and a sphere was placed on top of them, causing them to deform. The deformation displacement was measured using a CCD camera system and applied to a theoretical model to calculate the mechanical properties of each hydrogel. The non-destructive on-line nature of this technique enables repeated measurements the same hydrogels at several different time-points thus enabling the change in mechanical behavior of the hydrogels resulting from corneal fibroblasts remodeling to be examined. In this particular study, the effect of different culture medium on the cell behavior was investigated. The spherical indentation technique has also been used to examine the effect that different drugs and chemicals have on the cells ability to remodel of the hydrogels including MMP and actin inhibitors.