Chemotaxis is one of the essential mechanisms responsible for various
complex biological processes. For a crawling cell, the interface between the
cell and the substrate plays an important role in the chemotactic migration.
This paper presents a three-dimensional dynamic model to investigate the
effect of the interface between a crawling cell and a substrate on its
chemotaxis. The coupled mechanisms of chemotaxis, the surface energy of the
cell, and the interface between the cell and the substrate are incorporated
into a diffuse interface model. Simulations reveal rich dynamics of a
crawling cell associated with the interfacial condition, and confirm the
high possibility of adequate predictions.