Limits...
Mechanics of lipid bilayer junctions affecting the size of a connecting lipid nanotube.

Karlsson R, Kurczy M, Grzhibovskis R, Adams KL, Ewing AG, Cans AS, Voinova MV - Nanoscale Res Lett (2011)

Bottom Line: An electrochemical method monitoring diffusion of electroactive molecules through the nanotube has been used to determine the radius of the nanotube R as a function of nanotube length L for the two configurations.The data show that the LNT connected in the TVC constricts to a smaller radius in comparison to the tube-only mode and that tube radius shrinks at shorter tube lengths.In particular, this model allows us to estimate the surface tension coefficients from R(L) measurements.

View Article: PubMed Central - HTML - PubMed

Affiliation: BioNano Systems Laboratory, Institute for Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg, Sweden. marina.voinova@chalmers.se.

ABSTRACT
In this study we report a physical analysis of the membrane mechanics affecting the size of the highly curved region of a lipid nanotube (LNT) that is either connected between a lipid bilayer vesicle and the tip of a glass microinjection pipette (tube-only) or between a lipid bilayer vesicle and a vesicle that is attached to the tip of a glass microinjection pipette (two-vesicle). For the tube-only configuration (TOC), a micropipette is used to pull a LNT into the interior of a surface-immobilized vesicle, where the length of the tube L is determined by the distance of the micropipette to the vesicle wall. For the two-vesicle configuration (TVC), a small vesicle is inflated at the tip of the micropipette tip and the length of the tube L is in this case determined by the distance between the two interconnected vesicles. An electrochemical method monitoring diffusion of electroactive molecules through the nanotube has been used to determine the radius of the nanotube R as a function of nanotube length L for the two configurations. The data show that the LNT connected in the TVC constricts to a smaller radius in comparison to the tube-only mode and that tube radius shrinks at shorter tube lengths. To explain these electrochemical data, we developed a theoretical model taking into account the free energy of the membrane regions of the vesicles, the LNT and the high curvature junctions. In particular, this model allows us to estimate the surface tension coefficients from R(L) measurements.

No MeSH data available.


Related in: MedlinePlus

Schematics of the geometry of the tube-junctions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211838&req=5

Figure 2: Schematics of the geometry of the tube-junctions.

Mentions: We assume that the shape of LNT can be approximated by a cylindrical surface of radius R and length L. Since radii of both vesicles are much larger than the tube radius, the junctions between the cylinder and vesicles are modelled by toroidal surfaces with the inner radius R + r and crossection radius r (Figure 2). In the TOC, when the inner vesicle is not present, only one junction is considered. Although the junction between the micropipette and the tube contributes to the total free energy, it is assumed that this contribution does not depend on the tube radius R and, thus, the corresponding term vanishes after the variation. In these settings, the radius-dependent part of the free energy is given by the expression:(4)


Mechanics of lipid bilayer junctions affecting the size of a connecting lipid nanotube.

Karlsson R, Kurczy M, Grzhibovskis R, Adams KL, Ewing AG, Cans AS, Voinova MV - Nanoscale Res Lett (2011)

Schematics of the geometry of the tube-junctions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211838&req=5

Figure 2: Schematics of the geometry of the tube-junctions.
Mentions: We assume that the shape of LNT can be approximated by a cylindrical surface of radius R and length L. Since radii of both vesicles are much larger than the tube radius, the junctions between the cylinder and vesicles are modelled by toroidal surfaces with the inner radius R + r and crossection radius r (Figure 2). In the TOC, when the inner vesicle is not present, only one junction is considered. Although the junction between the micropipette and the tube contributes to the total free energy, it is assumed that this contribution does not depend on the tube radius R and, thus, the corresponding term vanishes after the variation. In these settings, the radius-dependent part of the free energy is given by the expression:(4)

Bottom Line: An electrochemical method monitoring diffusion of electroactive molecules through the nanotube has been used to determine the radius of the nanotube R as a function of nanotube length L for the two configurations.The data show that the LNT connected in the TVC constricts to a smaller radius in comparison to the tube-only mode and that tube radius shrinks at shorter tube lengths.In particular, this model allows us to estimate the surface tension coefficients from R(L) measurements.

View Article: PubMed Central - HTML - PubMed

Affiliation: BioNano Systems Laboratory, Institute for Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg, Sweden. marina.voinova@chalmers.se.

ABSTRACT
In this study we report a physical analysis of the membrane mechanics affecting the size of the highly curved region of a lipid nanotube (LNT) that is either connected between a lipid bilayer vesicle and the tip of a glass microinjection pipette (tube-only) or between a lipid bilayer vesicle and a vesicle that is attached to the tip of a glass microinjection pipette (two-vesicle). For the tube-only configuration (TOC), a micropipette is used to pull a LNT into the interior of a surface-immobilized vesicle, where the length of the tube L is determined by the distance of the micropipette to the vesicle wall. For the two-vesicle configuration (TVC), a small vesicle is inflated at the tip of the micropipette tip and the length of the tube L is in this case determined by the distance between the two interconnected vesicles. An electrochemical method monitoring diffusion of electroactive molecules through the nanotube has been used to determine the radius of the nanotube R as a function of nanotube length L for the two configurations. The data show that the LNT connected in the TVC constricts to a smaller radius in comparison to the tube-only mode and that tube radius shrinks at shorter tube lengths. To explain these electrochemical data, we developed a theoretical model taking into account the free energy of the membrane regions of the vesicles, the LNT and the high curvature junctions. In particular, this model allows us to estimate the surface tension coefficients from R(L) measurements.

No MeSH data available.


Related in: MedlinePlus