Mechanical properties of pore-spanning lipid bilayers probed by atomic force microscopy.
We measure the elastic response of a free-standing lipid membrane to a local indentation by using an atomic force microscope. Starting point is a planar gold-coated alumina substrate with a chemisorbed 3-mercaptopropionic acid monolayer displaying circular pores of very well defined and tunable size, over which bilayers composed of N,N,-dimethyl-N,N,-dioctadecylammonium bromide or 1,2-dioleoyl-3-trimethylammonium-propane chloride were spread. Centrally indenting these "nanodrums" with an atomic force microscope tip yields force-indentation curves, which we quantitatively analyze by solving the corresponding shape equations of continuum curvature elasticity. Since the measured response depends in a known way on the system geometry (pore size, tip radius) and on material parameters (bending modulus, lateral tension), this opens the possibility to monitor local elastic properties of lipid membranes in a well-controlled setting.
Steltenkamp
Siegfried
S
Institute of Physical Chemistry, University of Mainz, 55128 Mainz, Germany.
Müller
Martin Michael
MM
Deserno
Markus
M
Hennesthal
Christian
C
Steinem
Claudia
C
Janshoff
Andreas
A
D003198:Computer Simulation; D004548:Elasticity; D006244:Hardness; D006245:Hardness Tests / Q000379:methods; D008051:Lipid Bilayers / Q000737:chemistry*; D019563:Mechanics; D008560:Membrane Fluidity; D018625:Microscopy, Atomic Force / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D010316:Particle Size; D016062:Porosity; D013314:Stress, Mechanical
D008051:Lipid Bilayers