(679d) Cell Migration Studies at the Interface of a Dual Chemical-Mechanical Gradient

Cell migration is crucial in numerous physiological and physiological processes, such as wound healing, response to inflammation and cancer metastasis. In recent years, accumulating evidence indicates that cell movement is regulated not only by chemical factors but also by mechanical signals. In living organisms, cell migration is directed by complex chemical and mechanical stimuli. Thus, understanding the cellular response to a combination of chemical and mechanical stimuli will be critical for in vivo applications. In this study, the main purpose is to understand whether a chemical or mechanical stimulus plays the major role in directing cell migration. A polyacrylamide hydrogel that exhibits chemical and mechanical gradients on either side of an interface was synthesized. The chemical gradient was created by varying the collagen (Type I) concentration and the mechanical gradient was introduced by changing the concentration of the cross-linker. One side of the interface exhibited a high value for Young's modulus and low collagen concentration while the other side of the interface was soft and exhibited a high collagen concentration. Balb/c 3T3 fibroblasts were cultured on the hydrogels and their cell motility patterns were studied. Cell migration was observed by time lapse microscopy over a 8 hour period. AFM measurements were used to determine values for Young's modulus at the interface. Our results indicate that cells close to the interface moved towards the high collagen/low Young's modulus regions of the substratum, indicating a greater role for chemotaxis.