Abstract:
:Biological membranes are constantly exposed to forces. The stress-strain relation in membranes determines the behavior of many integral membrane proteins or other membrane related-proteins that show a mechanosensitive behavior. Here, we studied by force spectroscopy the behavior of supported lipid bilayers (SLBs) subjected to forces perpendicular to their plane. We measured the lipid bilayer mechanical properties and the force required for the punch-through event characteristic of atomic force spectroscopy on SLBs as a function of the interleaflet coupling. We found that for an uncoupled bilayer, the overall tip penetration occurs sequentially through the two leaflets, giving rise to two penetration events. In the case of a bilayer with coupled leaflets, penetration of the atomic force microscope tip always occurred in a single step. Considering the dependence of the jump-through force value on the tip speed, we also studied the process in the context of dynamic force spectroscopy (DFS). We performed DFS experiments by changing the temperature and cantilever spring constant, and analyzed the results in the context of the developed theories for DFS. We found that experiments performed at different temperatures and with different cantilever spring constants enabled a more effective comparison of experimental data with theory in comparison with previously published data.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Alessandrini A,Seeger HM,Caramaschi T,Facci Pdoi
10.1016/j.bpj.2012.05.039subject
Has Abstractpub_date
2012-07-03 00:00:00pages
38-47issue
1eissn
0006-3495issn
1542-0086pii
S0006-3495(12)00619-4journal_volume
103pub_type
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