The mechanics of axially symmetric liposomes.
Hotani has filmed morphological transformations in unilamellar liposomes, starting from a spherical shape, when the interior volume decreases steadily. Hotani's liposomes showed no evidence of general thermal fluctuations. We use a finite-deformation theory of axisymmetric, quasi-static thin shells to analyze theoretically bifurcations and changes of shape in liposomes under decreasing volume. The main structural action in a lipid bilayer is generally agreed to be its elastic resistance to bending, and it is usual to regard surface deformation as being like that of a two-dimensional liquid. We find, however, that some in-plane shear elasticity is also needed in order to produce the observed post-bifurcation behavior. Such an elasticity would be difficult to measure directly.
Pamplona
D C
DC
Department of Civil Engineering, PUC-RJ, Rio de Janeiro, Brasil.
Calladine
C R
CR
D001696:Biomechanical Phenomena; D055592:Biophysical Phenomena; D001703:Biophysics; D004548:Elasticity; D005069:Evaluation Studies as Topic; D008081:Liposomes; D008433:Mathematics; D008958:Models, Molecular; D009994:Osmolar Concentration; D011312:Pressure; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013816:Thermodynamics; D014743:Videotape Recording
D008081:Liposomes