Surface micromorphology and cellular interactions.

Contact guidance induced by the topographical properties of the underlying substratum is of great importance in morphogenesis and also influences the interaction of tissue cells with implanted material. A large body of evidence has accumulated since the first detection of this phenomenon in 1910. Several major hypotheses have been developed to explain the observed cell behaviour. The technological progress enabled researchers to produce pure substrata with a defined and controlled surface microgeometry. Based on these specimens, it could be demonstrated that cytoskeletal structures and receptors forming focal adhesions most likely are involved in contact guidance. In a study using human gingival fibroblasts, the reaction of these cells to a regular surface microstructure of 1 micron pitch and 1 micron depth was tested. After two days on the microstructured samples, all the cells showed a strong alignment to the topography of the surface. Transmission electron microscopy revealed that the cells either bridged the grooves or conformed to the surface structures. The latter confirms earlier investigations with porous subcutaneous implants, where the inflammatory reaction and the formation of a fibrous tissue capsule was reduced due to enhanced tissue adhesion.