Hydrodynamic trapping of molecules in lipid bilayers

Jönsson, Peter; Clarke, R.N.; Ostanin, Victor P.; Jönsson, Bengt; Klenerman, David

doi:10.1073/pnas.1202858109

Cited by 37 publications

(63 citation statements)

References 20 publications

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“…One is to use this knowledge to determine the interaction between molecules in a lipid bilayer using hydrodynamic trapping. 25 By relating the hydrodynamic force from a liquid flow out of a pipette to the accumulation of macromolecules in a lipid bilayer makes it possible to measure the force between these molecules as a function of intermolecular distance.…”

Section: Discussionmentioning

confidence: 99%

“…We have also previously used hydrodynamic trapping of streptavidin molecules bound to an SLB to estimate the effect of hydrodynamic shielding at different surface coverage. 25 These experiments gave a decrease in A hydro of 23% going from  = 11% to  = 16% and a decrease of 11% in A hydro going from  = 16% to  = 19%. This can be compared to a decrease of 21% going from  = 11% to  = 16% and a decrease of 12% going from  = 16% to  = 19%, when using Eq.…”

Section: Redistribution Of Molecules In a Lipid Bilayermentioning

confidence: 99%

“…Thus, even though A hydro changes with  as expected from theory, the absolute values for A hydro from the hydrodynamic trapping experiments will appear lower due to intermolecular repulsion. 25 This effect is avoided when performing the measurements at constant surface coverage as done in this work, which allows us to measure only the hydrodynamic force.…”

Section: Redistribution Of Molecules In a Lipid Bilayermentioning

confidence: 99%

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Hydrodynamic Forces on Macromolecules Protruding from Lipid Bilayers Due to External Liquid Flows

Jönsson

2015

Langmuir

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It has previously been observed that an externally applied hydrodynamic shear flow above a fluid lipid bilayer can change the local concentration of macromolecules that are associated with the lipid bilayer. The external liquid flow results in a hydrodynamic force on molecules protruding from the lipid bilayer, causing them to move in the direction of the flow.However, there has been no quantitative study about the magnitude of these forces. We here use finite element simulations to investigate how the magnitude of the external hydrodynamic forces varies with the size and shape of the studied macromolecule. The simulations show that the hydrodynamic force is proportional to the effective hydrodynamic area of the studied molecule, A hydro , multiplied by the mean hydrodynamic shear stress acting on the membrane surface,  hydro .The parameter A hydro depends on the size and shape of the studied macromolecule above the lipid bilayer and scales with the cross-sectional area of the molecule. We also investigate how hydrodynamic shielding from other surrounding macromolecules decreases A hydro when the surface coverage of the shielding macromolecules increases. Experiments where the protein streptavidin is anchored to a supported lipid bilayer on the floor of a microfluidic channel were finally performed at three different surface concentrations, Φ = 1%, 6%, and 10%, where the protein is being moved relative to the lipid bilayer by a liquid flow through the channel. From photobleaching measurements of fluorescently labeled streptavidin we found the experimental drift data to be within good accuracy of the simulated results, less than 12% difference, indicating the validity of the results obtained from the simulations. In addition to giving a deeper insight into how a liquid flow can affect membrane-associated molecules in a lipid bilayer, we also see an interesting potential of using hydrodynamic flow experiments together with the obtained results to study the size and the intermolecular forces between macromolecules in membranes and lipid bilayers.3

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Section: Discussionmentioning

confidence: 99%

Section: Redistribution Of Molecules In a Lipid Bilayermentioning

confidence: 99%

Section: Redistribution Of Molecules In a Lipid Bilayermentioning

confidence: 99%

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Hydrodynamic Forces on Macromolecules Protruding from Lipid Bilayers Due to External Liquid Flows

Jönsson

2015

Langmuir

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“…Purified proteins attached to the upper-lipid leaflet of a fluid SLB are highly mobile with diffusion coefficients on the order of 1 μm 2 /s, the force required to move molecules laterally of ~5 fN (Jonsson et al, 2012) and a vertical force of ~10 pN needed to extract a lipid from the SLB. When these highly mobile ligands are fluorescently labeled they accumulate in adhesive interfaces in proportion to interactions with cell surface receptors.…”

Section: Measuring 2d Interactions With Ligands Within a Supported LImentioning

confidence: 99%

Force and affinity in ligand discrimination by the TCR

Depoil

Dustin

2014

Trends in Immunology

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T cell recognition of antigen is a physical process that requires formation of a cell-cell junction that is rich in active force generation. Recently, a biomolecular force probe was used to examine how the TCR-pMHC interaction responds to force and the consequences of force dependent interactions for T cell activation. While adhesion and co-stimulatory molecules in the immunological synapse impact the overall force of the interaction, these results suggest that the TCR uses a force-dependent bond – a catch bond – and that it may therefore be important to consider the TCR-pMHC interaction in isolation in the early phases of the decision process. Here we discuss these findings in the context of other work on the impact of forces on the TCR and quantification of interaction in interfaces.

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“…5e show the start and end positions of a particle pulled over 1.6 mm and then released by lifting the nanopipette, while the graph displays its full trajectory. We point out that Jönsson et al 21 have recently also presented a nanopipette-based trap that operates by attracting molecules attached to membranes under a negative pressure. This interesting approach is complementary to our method in that it is nonspecific in its selection of the molecules to be trapped.…”

Section: Experimental Considerationsmentioning

confidence: 99%

Scanning-aperture trapping and manipulation of single charged nanoparticles

2014

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Although trapping and manipulation of small objects have been of interest for a range of applications and many clever techniques have been devised, new methods are still in great demand for handling different materials and geometries. Here, we report on an electrostatic trap that is created in an aqueous medium between the aperture of a nanopipette and a glass substrate without the need for external potentials. After a thorough characterization of the trapping conditions, we show that we can displace or release a particle at will. Furthermore, we demonstrate trapping and manipulation of nanoparticles and lipid vesicles attached to lipid bilayers, paving the way for controlled studies of forces and diffusion associated with biological membranes. We expect the technique to find interesting applications also in other areas such as optonanofluidics and plasmonics.

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Hydrodynamic trapping of molecules in lipid bilayers

Cited by 37 publications

References 20 publications

Hydrodynamic Forces on Macromolecules Protruding from Lipid Bilayers Due to External Liquid Flows

Hydrodynamic Forces on Macromolecules Protruding from Lipid Bilayers Due to External Liquid Flows

Force and affinity in ligand discrimination by the TCR

Scanning-aperture trapping and manipulation of single charged nanoparticles

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