scholarly journals Investigation of Shape Transformations of Vesicles, Induced by Their Adhesion to Flat Substrates Characterized by Different Adhesion Strength

2021 ◽  
Vol 22 (24) ◽  
pp. 13406
Author(s):  
Jeel Raval ◽  
Aleš Iglič ◽  
Wojciech Góźdź
Keyword(s):  
Adhesion Strength ◽  
Flat Surface ◽  
Lipid Vesicles ◽  
Spontaneous Curvature ◽  
Reduced Volume ◽  
Vesicle Shape ◽  
Shape Transformations ◽  
The Stability

The adhesion of lipid vesicles to a rigid flat surface is investigated. We examine the influence of the membrane spontaneous curvature, adhesion strength, and the reduced volume on the stability and shape transformations of adhered vesicles. The minimal strength of the adhesion necessary to stabilize the shapes of adhered vesicles belonging to different shape classes is determined. It is shown that the budding of an adhered vesicle may be induced by the change of the adhesion strength. The importance of the free vesicle shape for its susceptibility to adhesion is discussed.

Nanoparticle wrapping at small non-spherical vesicles: curvatures at play

Nanoscale ◽  
2018 ◽  
Vol 10 (14) ◽  
pp. 6445-6458 ◽  
Author(s):  
Qingfen Yu ◽  
Sameh Othman ◽  
Sabyasachi Dasgupta ◽  
Thorsten Auth ◽  
Gerhard Gompper
Keyword(s):  
Particle Size ◽  
Spontaneous Curvature ◽  
Vesicle Size ◽  
Size And Shape ◽  
Reduced Volume ◽  
Vesicle Shape ◽  
Particle Size And Shape ◽  
Spherical Vesicles ◽  
Shape Transitions

Wrapping of nanoparticles that enter and exit vesicles depends on several important parameters, such as particle size and shape, vesicle size and reduced volume, and membrane spontaneous curvature. This implies complex wrapping behavior where particle wrapping transitions and vesicle shape transitions are intimately coupled.

Design of a wheeled wall climbing robot based on the performance of bio-inspired dry adhesive material

Robotica ◽  
2021 ◽  
pp. 1-14
Author(s):  
Hongkai Li ◽  
Xianfei Sun ◽  
Zishuo Chen ◽  
Lei Zhang ◽  
Hongchao Wang ◽  
...  
Keyword(s):  
Flat Surface ◽  
Thrust Force ◽  
Adhesion Force ◽  
Structure Design ◽  
Design Parameters ◽  
Climbing Robot ◽  
Adhesive Material ◽  
Ducted Fan ◽  
The Stability ◽  
Belt System

Abstract Inspired by gecko’s adhesive feet, a wheeled wall climbing robot is designed in this paper with the synchronized gears and belt system acting as the wheels by considering both motion efficiency and adhesive capability. Adhesion of wheels is obtained by the bio-inspired adhesive material wrapping on the outer surface of wheels. A ducted fan mounted on the back of the robot supplies thrust force for the adhesive material to generate normal and shear adhesion force whilemoving on vertical surfaces. Experimental verification of robot climbing on vertical flat surface was carried out. The stability and the effect of structure design parameters were analyzed.

Mechanics of membrane–membrane adhesion

2011 ◽  
Vol 16 (8) ◽  
pp. 872-886 ◽  
Author(s):  
Ashutosh Agrawal
Keyword(s):  
Lipid Vesicles ◽  
Spontaneous Curvature ◽  
Interface Conditions ◽  
Point Boundary ◽  
Lagrange Equations ◽  
Equilibrium Conditions ◽  
Numerical Studies ◽  
Curvature Elasticity ◽  
Equilibrium Shapes ◽  
Membrane Adhesion

Curvature elasticity is used to derive the equilibrium conditions that govern the mechanics of membrane–membrane adhesion. These include the Euler–Lagrange equations and the interface conditions which are derived here for the most general class of strain energies permissible for fluid surfaces. The theory is specialized for homogeneous membranes with quadratic ‘Helfrich’-type energies with non-uniform spontaneous curvatures. The results are employed to solve four-point boundary value problems that simulate the equilibrium shapes of lipid vesicles that adhere to each other. Numerical studies are conducted to investigate the effect of relative sizes, osmotic pressures, and adhesion-induced spontaneous curvature on the morphology of adhered vesicles.

Blocked Lipid Exchange in Bilayers and its Possible Influence on the Shape of Vesicles

1974 ◽  
Vol 29 (9-10) ◽  
pp. 510-515 ◽  
Author(s):  
W Helfrich
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Spontaneous Curvature ◽  
Lipid Exchange ◽  
Lipid Distribution ◽  
Shape Transformations ◽  
Curvature Elasticity ◽  
Possible Cause

Abstract The role of lipid exchange in the curvature elasticity of bilayers is studied theoretically. Blocking of exchange between the monolayers may give rise to a nonequilibrium lipid distribution going hand in hand with a spontaneous curvature. Some possible consequences for vesicular deformations are discussed. Lipid nonequilibrium is tentatively suggest as one possible cause for certain shape transformations of red blood cells

An experiment on the stability of hypersonic laminar boundary layers

1960 ◽  
Vol 7 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Anthony Demetriades
Keyword(s):  
Boundary Layer ◽  
Flat Surface ◽  
Hypersonic Boundary Layer ◽  
Natural Disturbances ◽  
Hot Wire ◽  
Amplitude Variation ◽  
Laminar Boundary Layers ◽  
Boundary Layer Instability ◽  
The Stability ◽  
Maximum Amplification

An experimental investigation of the hydrodynamic stability of the laminar hypersonic boundary layer was carried out with the aid of a hot-wire anemometer. The case investigated was that of a flat surface at zero angle of attack and no heat transfer.The streamwise amplitude variation of both natural disturbances and of disturbances artifically excited with a siren mechanism was studied. In both cases it was found that such small fluctuations amplify for certain ranges of frequency and Reynolds number Rθ, and damp for others. The demarcation boundaries for the amplification (instability) zone were found to resemble the corresponding limits of boundary-layer instability at lower speeds. A ‘line of maximum amplification’ of disturbances was also found. The amplification rates and hence the degree of selectivity of the hypersonic layer were found, however, to be considerably lower than those at the lower speeds. The disturbances selected by the layer for maximum amplifications have a wavelength which was estimated to be about twenty times the boundary-layer thickness δ.

Shape transformations of vesicles: Phase diagram for spontaneous- curvature and bilayer-coupling models

1991 ◽  
Vol 44 (2) ◽  
pp. 1182-1202 ◽  
Author(s):  
Udo Seifert ◽  
Karin Berndl ◽  
Reinhard Lipowsky
Keyword(s):  
Phase Diagram ◽  
Spontaneous Curvature ◽  
Shape Transformations

A compact stair-climbing wheelchair with two 3-DOF legs and a 1-DOF base

2016 ◽  
Vol 43 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Chang-Hyuk Lee ◽  
Kyung-min Lee ◽  
Jehong Yoo ◽  
In-su Kim ◽  
Young-bong Bang
Keyword(s):  
Degrees Of Freedom ◽  
Flat Surface ◽  
Estimation Method ◽  
Stable Condition ◽  
Stair Climbing ◽  
Joint Power ◽  
Content Type ◽  
Flat Surfaces ◽  
Simple Estimation ◽  
The Stability

Purpose – The purpose of this paper is to describe a compact wheelchair, which has two 3-degrees of freedom (DOF) legs and a 1-DOF base (the total DOF of the leg system is 7) for stair-climbing, and wheels for flat surface driving. Design/methodology/approach – The proposed wheelchair climbs stairs using the two 3-DOF legs with boomerang-shaped feet. The leg mechanisms are folded into the compact wheelchair body when the wheelchair moves over flat surfaces. The authors also propose a simple estimation method of stair shape using laser distance sensors, and a dual motor driving system to increase joint power. Findings – The proposed wheelchair can climb arbitrary height and width stairs by itself, even when they are slightly curved. During climbing, the trajectory of the seat position is linear to guarantee the comfort of rider, and the wheelchair always keeps a stable condition to ensure the stability in an emergency stop. Originality/value – The wheelchair mechanism with foldable legs and driving wheels enables smooth stair climbing, efficient flat surface driving and additional useful motions such as standing and tilting.

Membrane Curvature Induced by Sugar and Polymer Solutions

1997 ◽  
Vol 489 ◽  
Author(s):  
H.-G. Döbereiner ◽  
A. Lehmann ◽  
W. Goedel ◽  
O. Selchow ◽  
R. Lipowsky
Keyword(s):  
Polymer Solutions ◽  
Lipid Vesicles ◽  
Membrane Curvature ◽  
Elastic Membrane ◽  
Spontaneous Curvature ◽  
Membrane Asymmetry ◽  
Bending Modulus ◽  
Bending Elasticity ◽  
Cellular Organelles

AbstractWe monitor the effect of transversal membrane asymmetry on the morphology of giant uni-lamellar vesicles in sugar and polymer solutions. The shapes of fluid lipid vesicles are governed by the bending elasticity of their membrane which is characterized by the bending modulus and the spontaneous curvature of the bilayer. We present a recently developed technique for the measurement of the spontaneous curvature using quantitative phase contrast microscopy. Different mechanisms for elastic membrane asymmetry and the role of the bending energy concept for the morphology of cellular organelles are discussed.

scholarly journals Diffuso-kinetic membrane budding dynamics

Soft Matter ◽  
2020 ◽  
Vol 16 (48) ◽  
pp. 10889-10899
Author(s):  
Rossana Rojas Molina ◽  
Susanne Liese ◽  
Haleh Alimohamadi ◽  
Padmini Rangamani ◽  
Andreas Carlson
Keyword(s):  
Energetic Cost ◽  
Spontaneous Curvature ◽  
Protein Diffusion ◽  
Wide Range ◽  
Shape Transformations ◽  
Membrane Budding ◽  
Membrane Bending ◽  
Protein Recruitment

A wide range of proteins create shape transformations of membranes. The remodeling is a coupling between the energetic cost of membrane bending, protein recruitment which induce local spontaneous curvature and protein diffusion on the membrane.

Sign in / Sign up

Export Citation Format

Share Document