Cell contact with solid surfaces

Abstract

It is my intention to outline the main biophysical studies on cell-to-substratum contact which have been done in this laboratory during the past few years. A brief explanation of the way in which the topics to be discussed are connected may be helpful. In the dark ages, when it was suspected that cell adhesion could be understood solely as a long-range balance of intermolecular attractive and repulsive forces, without direct molecular contact, I joined Dr.V.A.Parsegian to learn how to calculate the size of these forces (Parsegian & Gingell, 1973) and went on to devise several ways of measuring them for cell contacts. Since the idea of a long-range force balance implies a gap between the cell membrane and the substratum, it was natural to try to visualize it optically and measure it if possible. This led to an interest in interferometry which eventually culminated in a quantitative theory of interference reflection microscopy, IRM, (Gingell & Todd, 1979; Gingell et al., 1982). Cell-to-substratum water gaps were indeed detected in certain situations for aldehyde-fixed red blood cells (Gingell & Todd, 1980) and for free living amoebae (Gingell & Vince, 1982b). The theory helped us to understand why IRM images could sometimes be very hard to interpret, and our attention turned to total internal reflection fluorescence as an alternative and superior method of visualizing and measuring cell-to substratum contacts. The success of this technique has exceeded our most optimistic predictions.