Thermoelasticity of red blood cell membrane.
The elastic properties of the human red blood cell membrane have been measured as functions of temperature. The area compressibility modulus and the elastic shear modulus, which together characterize the surface elastic behavior of the membrane, have been measured over the temperature range of 2-50 degrees C with micropipette aspiration of flaccid and osmotically swollen red cells. In addition, the fractional increase in membrane surface area from 2-50 degrees C has been measured to give a value for the thermal area expansivity. The value of the elastic shear modulus at 25 degrees C was measured to be 6.6 X 10(-3) dyne/cm. The change in the elastic shear modulus with temperature was -6 X 10(-5) dyne/cm degrees C. Fractional forces were shown to be only on the order of 10-15%. The area compressibility modulus at 25 degrees C was measured to be 450 dyne/cm. The change in the area compressibility modulus with temperature was -6 dyne/cm degrees C. The thermal area expansivity for red cell membrane was measured to be 1.2 X 10(-3)/degrees C. With this data and thermoelastic relations the heat of expansion is determined to be 110-200 ergs/cm2; the heat of extension is 2 X 10(-2) ergs/cm2 for unit extension of the red cell membrane. The heat of expansion is of the order anticipated for a lipid bilayer idealized as twice the behavior of a monolayer at an oil-water interface. The observation that the heat of extension is positive demonstrates that the entropy of the material increases with extension, and that the dominant mechanism of elastic energy storage is energetic. Assuming that the red cell membrane shear rigidity is associated with "spectrin," unit extension of the membrane increases the configurational entropy of spectrin by 500 cal/mol.
D004548:Elasticity; D004910:Erythrocyte Membrane / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D006358:Hot Temperature; D006801:Humans; D008051:Lipid Bilayers; D008433:Mathematics; D008954:Models, Biological; D013499:Surface Properties
D008051:Lipid Bilayers
Blood. 1975 Jan;45(1):29-43
803108
J Biol Chem. 1977 Apr 25;252(8):2753-63
15998
Biophys J. 1977 Dec;20(3):307-13
922122
J Biomech. 1977;10(4):211-21
858727
J Membr Biol. 1977 Jan 28;30(4):351-62
839527
Microvasc Res. 1976 Nov;12(3):291-304
1004241
J Cell Biol. 1974 Jul;62(1):1-19
4600883
Biophys J. 1974 Dec;14(12):923-31
4429770
Biophys J. 1973 Aug;13(8):747-62
4726877
Biophys J. 1973 Sep;13(9):941-54
4733701
Biophys J. 1973 Sep;13(9):926-40
4733700
Biophys J. 1973 Mar;13(3):245-64
4697236
Biophys J. 1976 Jun;16(6):585-95
1276386
Biophys J. 1975 Nov;15(11):1095-100
1201326
Blood. 1975 Oct;46(4):611-24
1174695