The Bending Rigidity of Phosphatidylcholine Bilayers: Dependences on Experimental Method, Sample Cell Sealing and Temperature

(Received 18 July 1994, accepted in final form 21 November 1994)

Abstract
The bilayer bending rigidities were measured for the same spherical vesicles with two methods, fluctuation mode analysis and electric deformation. In some of the sample cells the glue sealing the cell was in direct contact with the sample, in others the sample was shielded from the glue by a silicone grease. The values of the rigidity, while being lowest and practically equal for the unshielded samples, differed significantly between methods for the shielded ones. We also measured the temperature dependence of the bending rigidity. The dependence of the rigidity on method seems to suggest the existence of a membrane superstructure.