A physical basis for red cell membrane elasticity

An estimate is made of the effect of lipid-water interactions at the membrane surface on observed membrane elasticity in the red blood cell. It is shown that elastic effects are expected to result from these interactions even in a completely fluid membrane. A simple statistical model is described and used to estimate the magnitude of the resultant elasticity. The estimate thus derived is compared with results of experiments during which a biaxial stress is applied to the membrane. The derived elasticity is sufficient to account for the results of these studies. Other properties of the red cell membrane are discussed in the light of this result.