CHAPTER 2
 BACKGROUND


 Contact Guidance

 The reaction of cells in vitro to the substrate they come into contact with has been

traditionally separated into two main features: topography and surface chemistry. Cells

adhere to surfaces via specific adhesion molecules that interact with proteins adsorbed

onto the surface of the substrate. Thus, if the surface chemistry is favorable to adhesive

protein adsorption, then the material should be favorable to cell adhesion. However, the

topography of the surface is also important not only in the adhesion of the cells to the

surface, but also in the behavior of the cells' metabolism and growth patterns after the

initial contact. The purpose of understanding and controlling cell and tissue growth on

artificial materials is to be able to design and implant medical devices that improve

biocompatibility and functionality.

Surface Topography

 The response of the cell to topography has been referred to as "contact

guidance."[6, 7] The first known reference to the effect of substrate topography on growth

characteristics comes from the growth of embryonic cells on plasma clots and spider

webs.81 Rovensky et al. used V-shaped grooves formed from copies of music records to

show that chick embryo fibroblasts migrated from the bottom of the groove to the top

over a period of hours and aligned along the texture.[9] Dunn and Heath examined chick

heart fibroblasts growing on glass fibers to examine the effect of radius of curvature on