The Nanomechanics of Lipid Multibilayer Stacks Exhibits Complex Dynamics

Abstract

The nanomechanics of lipid membranes regulates a large number of cellular functions. However, the molecular mechanisms underlying the plastic rupture of individual bilayers remain elusive. This study uses force clamp spectroscopy to capture the force‐dependent dynamics of membrane failure on a model diphytanoylphosphatidylcholine multilayer stack, which is devoid of surface effects. The obtained kinetic measurements demonstrate that the rupture of an individual lipid bilayer, occurring in the bilayer parallel plane, is a stochastic process that follows a log‐normal distribution, compatible with a pore formation mechanism. Furthermore, the vertical individual force‐clamp trajectories, occurring in the bilayer orthogonal bilayer plane, reveal that rupturing process occurs through distinct intermediate mechanical transition states that can be ascribed to the fine chemical composition of the hydrated phospholipid moiety. Altogether, these results provide a first description of unanticipated complexity in the energy landscape governing the mechanically induced bilayer rupture process.

Unveiling a Hidden Event in Fluorescence Correlative Microscopy by AFM Nanomechanical Analysis

“…For instance, after adding Nile red to the solution, the adhesion increases noticeably in agreement with the presence of a weakly bound overlayer that can trap the AFM probe after closing the layer during the retract phase (see adhesion map Figures 6F,I compared with control Figure 6C ). Also in agreement with idea of weakly bounded overlayer of Nile red, the breakthrough force threshold slightly increases, in fact, similar to multilayer structures, more force is required to displace laterally the overlayer before final breakthrough event ( Relat-Goberna et al, 2017 ).…”

“…6C). Also in agreement with idea of weakly bounded overlayer of Nile red, the breakthrough force threshold slightly increases, in fact, similar to multilayer structures, more force is required to displace laterally the overlayer before final breakthrough event (Relat-Goberna et al, 2017). After 30 min laser irradiation, the effect on layer mechanics is very noticeable, exhibiting a decrease of force required to breakthrough (−40%, Figures 6G, 7A,G decrease of Young's modulus (−31%, Figures 6H, 7H).…”

Insights into the structure and nanomechanics of a quatsome membrane by force spectroscopy measurements and molecular simulations

“…Local characterization of these membrane properties can be widely explored with techniques that allow working at nanometric resolution and preserving the physiological membrane environment. In this context, atomic force microscopy (AFM), 35 AFM-based force spectroscopy (AFM-FS) 14,36 and force clamp (AFM-FC) 37,38 are essential tools to locally study the physical properties of supported membranes at the nanoscale with high spatial range sensitivity and versatility while giving the possibility to control the environmental conditions. Lateral interactions between the molecules can be directly evaluated with AFM-FS, by measuring the maximum vertical force a membrane is able to resist before its rupture, the breakthrough force F b , when indented by the AFM tip.…”

The Insertion Mechanism of a Living Cell Determined by the Stress Segmentation Effect of the Cell Membrane during the Tip–Cell Interaction

“…The molecules were coated on the surface of the nanoneedle, which could be transferred into the cell after the nanoneedle was successfully inserted into the cell membrane. However, the living cell is highly challenging to be inserted due to the complex internal structure and the interaction between the tip and the cell membrane, which is the main obstacle in the practice of cell transfection and intracellular studies by using the AFM‐nanotip technology . The insertion efficiency varies from 20 to 80% for different types of the cells, different nanofilms on the cell surface, and different environmental temperatures .…”

“…However, the living cell is highly challenging to be inserted due to the complex internal structure and the interaction between the tip and the cell membrane, which is the main obstacle in the practice of cell transfection and intracellular studies by using the AFM-nanotip technology. [20][21][22] The insertion efficiency varies from 20 to 80% for different types of the cells, [23] different nanofilms on the cell surface, [24] and different environmental temperatures. [25] In order to obtain a high efficient and controllable insertion approach, some efforts have been done.…”