Kreplak, Laurent
Permanent URI for this collectionhttps://hdl.handle.net/10222/22077
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Item Open Access Item Open Access Item Open Access Item Open Access Effect of out of plane orientation on polarization second harmonic generation of single collagen fibrils(2023) Harvey, MacAulay; Cisek, Richard; Tokarz, Danielle; Kreplak, LaurentItem Open Access An interferometric-based tensile tester to resolve damage events within reconstituted multi-filaments collagen bundles(2024) Yaghoobi, Hessameddin; Tremblais, Chloe; Gareau, Alex; Cointe, Matthieu; Tikhomorov, Alexey; Kreplak, Laurent; Labrie, DanielItem Open Access Anisotropic swelling due to hydration constrains anisotropic elasticity in biomaterial fibers(2024) Gouws, Xander; Mastnak, Ana; Kreplak, Laurent; Rutenberg, AndrewItem Open Access Formation of linear arrays of holes in self-assembled collagen films(2024) Melis, Erkan; Blakney, Kaitlyn; Andrews, Emily; Leslie, Reagan; Ozsan, Eda; Kreplak, LaurentCollagen is one of the main constituents of mammalian extracellular matrix and is used extensively as a coating for tissue culture dishes and medical implants to promote cell growth and proliferation. By modulating the topography of the collagen coating at the nanometer to micrometer length scales, it is possible to achieve spatial control over cell growth and morphology. In this work, we are exploring the self-assembly of a thin collagen film on a glass substrate as a way to create new nanoscale surface features. By controlling the collagen concentration and adding an oscillatory flow, we are able to enrich the collagen film surface with a localized pattern of ripples oriented perpendicular to the flow direction. We propose that these ripples are the result of dewetting of the collagen film that leads to the formation of adjacent holes. We observe that individual holes form with an anisotropic rim due to the microstructure of the deposited collagen fibril network. This intrinsic anisotropy and the oscillatory flow yield new holes being formed in the film next to existing rims. As holes keep growing deeper, the rims extend along the flow direction, and the holes appear rectangular in shape, which gives the linear array of holes the apparent morphology of a ripple. Overall, we are able to create localized ripples at the surface of collagen films that would be difficult to produce via standard nanofabrication techniques.Item Open Access Multifilament Collagen Fiber Bundles with Tendon-like Structure and Mechanical Performance(2023) Yaghoobi, Hessameddin; Clarke, Alison; Kerr, Gavin; Frampton, John; Kreplak, LaurentItem Open Access Nanoscale Strain-Hardening of Keratin Fibres(2012-07) Fortier, Patrick; Suei, Sandy; Kreplak, LaurentNo abstract available.Item Open Access Forced desorption of polymers from interfaces(2011-01) Staple, Douglas B.; Geisler, Michael; Hugel, Thorsten; Kreplak, Laurent; Kreuzer, Hans JuergenNo abstract available.Item Open Access Hierarchical Structure Controls Nanomechanical Properties of Vimentin Intermediate Filaments(2009-10) Qin, Zhao; Kreplak, Laurent; Buehler, Markus J.No abstract available.Item Open Access Forced desorption of polymers from interfaces(Institute of Physics Publishing, 2011) Staple, Douglas B.; Geisler, Michael; Hugel, Thorsten; Kreplak, Laurent; Kreuzer, Hans JurgenIn the past decade it has become possible to directly measure the adsorption force of a polymer in contact with a solid surface using single-molecule force spectroscopy. A plateau force in the force-extension curve is often observed in systems of physisorbed or noncovalently bonded polymers. If a molecule is pulled quickly compared to internal relaxation, then nonequilibrium effects can be observed. Here we investigate these effects using statistical mechanical models and experiments with a spider silk polypeptide. We present evidence that most experiments showing plateau forces are done out of equilibrium. We find that the dominant nonequilibrium effect is that the detachment height hmax() increases with pulling speed . Based on a nonequilibrium model within a master-equation approach, we show the sigmoidal dependence of the detachment height on the pulling speed of the cantilever, agreeing with experimental data on a spider silk polypeptide. We also show that the slope with which the plateau forces detach is given by the cantilever force constant in both theory and experiment. IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.Item Open Access Stretching, Unfolding, and Deforming Protein Filaments Adsorbed at Solid-Liquid Interfaces Using the Tip of an Atomic-Force Microscope(2009-03) Staple, Douglas B.; Loparic, Marko; Kreuzer, Hans Juergen; Kreplak, LaurentNo abstract available.Item Open Access Structural analysis of DNA complexation with cationic lipids(2009-02) Marty, Regis; N'soukpoe-Kossi, Christophe N.; Charbonneau, David; Weinert, Carl Maximilian; Kreplak, Laurent; Tajmir-Riahi, Heidar-AliNo abstract available.Item Open Access Structural characterization of cationic lipid-tRNA complexes(2009-08) Marty, Regis; N'soukpoe-Kossi, Christophe N.; Charbonneau, David M.; Kreplak, Laurent; Tajmir-Riahi, Heidar-AliNo abstract available.Item Open Access Plasticity of Intermediate Filament Subunits(2010-08) Kirmse, Robert; Qin, Zhao; Weinert, Carl M.; Hoenger, Andrea; Buehler, Markus J.; Kreplak, LaurentNo abstract available.