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Influence of surface pinning points on diffusion of adsorbed lipid vesicles

Simon Klacar (Institutionen för teknisk fysik, Kemisk fysik) ; Kristian Dimitrievski (Institutionen för teknisk fysik, Kemisk fysik) ; Bengt Kasemo (Institutionen för teknisk fysik, Kemisk fysik)
Journal Of Physical Chemistry B (1520-6106). Vol. 113 (2009), 17, p. 5681-5685.
[Artikel, refereegranskad vetenskaplig]

Using a simple model of a vesicle and a substrate, we have studied surface diffusion of an adsorbed vesicle. We show that the experimentally observed but unexplained fact, that a neutral (POPC) vesicle adsorbed to a SiO2 or mica surface does not diffuse but can be moved laterally by an atomic force microscope (AFM) t, without rupture, can be explained by transient (i.e., temporary) pinning of lipid head groups to surface charges. We studied the surface diffusion for different vesicle adsorption strengths (without any pinning taking place), with the observation that stronger vesicle-surface attraction leads to slower surface diffusion. However, the surface diffusion was still significant and too high to explain the experimentally observed immobility. When allowing transient lipid pinning between the vesicle and the , a 1-2 orders of magnitude decrease in the surface diffusion coefficient was observed. For a lipid adsorption potential of around 20 kB-T and a lipid pinning potential of about 25 kB-T, the vesicle is found to be practically immobile on the surface.

Nyckelord: Temperature-dependence, computer-simulation, molecular-dynamics, QCM-D, bilayer, membranes, AFM, adsorption



Denna post skapades 2009-10-15. Senast ändrad 2013-10-29.
CPL Pubid: 100225

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Kemisk fysik (1900-2015)

Ämnesområden

Kemisk fysik
Beräkningsfysik

Chalmers infrastruktur