The measurement of cell adhesion.

Abstract Some of the theoretical physical aspects of the measurement of cell adhesion by distractive techniques have been discussed. It is suggested that when adherends are separated by distraction, the tensile strengths of the adherend surfaces may be measured instead of the adhesive forces holding them together. Elementary rheological considerations strongly suggest that the final estimate of adhesive strength may vary not only with the magnitude of the distractive force but also with the rate at which it is applied. An experimental approach to the problem is described, in which accurately determined shearing forces are transmitted through fluid to detach cells adherent to discs of various materials in vitro. The experimental results confirm the predictions that when the strength of adhesion is estimated by distraction, this estimate will always tend to vary considerably with the method used to obtain it.