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Publications

Cell-Derived Vesicles with Increased Stability and On-Demand Functionality by Equipping Their Membrane with a Cross-Linkable Copolymer

Cornell Affiliated Author(s)
Author
X. Huang
D. Hürlimann
H.T. Spanke
D. Wu
M. Skowicki
I.A. Dinu
E.R. Dufresne
C.G. Palivan
Abstract

Cell-derived vesicles retain the cytoplasm and much of the native cell membrane composition. Therefore, they are attractive for investigations of membrane biophysics, drug delivery systems, and complex molecular factories. However, their fragility and aggregation limit their applications. Here, the mechanical properties and stability of giant plasma membrane vesicles (GPMVs) are enhanced by decorating them with a specifically designed diblock copolymer, cholesteryl-poly[2-aminoethyl methacrylate-b-poly(ethylene glycol) methyl ether acrylate].

Journal
Advanced Healthcare Materials
Date Published
Research Area
Group (Lab)
Eric Dufresne Group

Elastic microphase separation produces robust bicontinuous materials

Cornell Affiliated Author(s)
Author
C. Fernández-Rico
S. Schreiber
H. Oudich
C. Lorenz
A. Sicher
T. Sai
V. Bauernfeind
S. Heyden
P. Carrara
L.D. Lorenzis
R.W. Style
E.R. Dufresne
Abstract

Bicontinuous microstructures are essential to the function of diverse natural and synthetic systems. Their synthesis has been based on two approaches: arrested phase separation or self-assembly of block copolymers. The former is attractive for its chemical simplicity and the latter, for its thermodynamic robustness. Here we introduce elastic microphase separation (EMPS) as an alternative approach to make bicontinuous microstructures. Conceptually, EMPS balances the molecular-scale forces that drive demixing with large-scale elasticity to encode a thermodynamic length scale.

Journal
Nature Materials
Date Published
Group (Lab)
Eric Dufresne Group

Multivalency ensures persistence of a +TIP body at specialized microtubule ends

Cornell Affiliated Author(s)
Author
S.M. Meier
A.-M. Farcas
A. Kumar
M. Ijavi
R.T. Bill
J. Stelling
E.R. Dufresne
M.O. Steinmetz
Y. Barral
Abstract

Microtubule plus-end tracking proteins (+TIPs) control microtubule specialization and are as such essential for cell division and morphogenesis. Here we investigated interactions and functions of the budding yeast Kar9 network consisting of the core +TIP proteins Kar9 (functional homologue of APC, MACF and SLAIN), Bim1 (orthologous to EB1) and Bik1 (orthologous to CLIP-170). A multivalent web of redundant interactions links the three +TIPs together to form a ‘+TIP body’ at the end of chosen microtubules.

Journal
Nature Cell Biology
Date Published
Group (Lab)
Eric Dufresne Group

The generalized Clapeyron equation and its application to confined ice growth

Cornell Affiliated Author(s)
Author
R.W. Style
D. Gerber
A.W. Rempel
E.R. Dufresne
Abstract

Most theoretical descriptions of stresses induced by freezing are rooted in the (generalized) Clapeyron equation, which predicts the pressure that a solid can exert as it cools below its melting temperature. This equation is central for topics ranging beyond glaciology to geomorphology, civil engineering, food storage and cryopreservation. However, it has inherent limitations, requiring isotropic solid stresses and conditions near bulk equilibrium. Here, we examine when the Clapeyron equation is applicable by providing a rigorous derivation that details all assumptions.

Journal
Journal of Glaciology
Date Published
Group (Lab)
Eric Dufresne Group

Liquid-liquid phase separation of proteins is modulated by amino acids in vitro and in vivo

Cornell Affiliated Author(s)
Author
Xufeng Xu
Aleksander Rebane
Laura Julia
Kathryn Rosowski
Eric Dufresne
Francesco Stellacci
Abstract

Liquid liquid phase separation (LLPS) of proteins is an intracellular process that is widely used by cells for many purposes. In living cells (in vivo), LLPS occurs in complex and crowded environments. Amino acids (AAs) are vital components of such environments, occupying a significant fraction of the cellular volume. In this work, we studied the effects of proline and other proteinogenic AAs on the LLPS of proteins, both in test tubes (in vitro) and in cells (in vivo).

Journal
arXiv e-prints
Date Published
Group (Lab)
Eric Dufresne Group

Dehydration drives damage in the freezing of brittle hydrogels

Cornell Affiliated Author(s)
Author
Shaohua Yang
Dominic Gerber
Yanxia Feng
Nicolas Bain
Matthias Kuster
Laura de Lorenzis
Ye Xu
Eric Dufresne
Robert Style
Abstract

It is widely known that freezing breaks soft, wet materials. However, the mechanism underlying this damage is still not clear. To understand this process, we freeze model, brittle hydrogel samples, while observing the growth of ice-filled cracks that break these apart. We show that damage is not caused by the expansion of water upon freezing, or the growth of ice-filled cavities in the hydrogel. Instead, local ice growth dehydrates the surrounding hydrogel, leading to drying-induced fracture.

Journal
arXiv e-prints
Date Published
Research Area
Group (Lab)
Eric Dufresne Group

Polycrystallinity Enhances Stress Buildup around Ice

Cornell Affiliated Author(s)
Author
D. Gerber
L.A. Wilen
E.R. Dufresne
R.W. Style
Abstract

Damage caused by freezing wet, porous materials is a widespread problem but is hard to predict or control. Here, we show that polycrystallinity significantly speeds up the stress buildup process that underpins this damage. Unfrozen water in grain-boundary grooves feeds ice growth at temperatures below the freezing temperature, leading to fast stress buildup. These stresses can build up to levels that can easily break many brittle materials.

Journal
Physical Review Letters
Date Published
Group (Lab)
Eric Dufresne Group

Surface Passivation Method for the Super-repellence of Aqueous Macromolecular Condensates

Cornell Affiliated Author(s)
Author
A. Testa
H.T. Spanke
E. Jambon-Puillet
M. Yasir
Y. Feng
A.M. Küffner
P. Arosio
E.R. Dufresne
R.W. Style
A.A. Rebane
Abstract

Solutions of macromolecules can undergo liquid-liquid phase separation to form droplets with ultralow surface tension. Droplets with such low surface tension wet and spread over common surfaces such as test tubes and microscope slides, complicating in vitro experiments. The development of a universal super-repellent surface for macromolecular droplets has remained elusive because their ultralow surface tension requires low surface energies.

Journal
Langmuir
Date Published
Group (Lab)
Eric Dufresne Group

Structural color from pigment-loaded nanostructures

Cornell Affiliated Author(s)
Author
T. Sai
L.S. Froufe-Pérez
F. Scheffold
B.D. Wilts
E.R. Dufresne
Abstract

Color can originate from wavelength-dependence in the absorption of pigments or the scattering of nanostructures. While synthetic colors are dominated by the former, vivid structural colors found in nature have inspired much research on the latter. However, many of the most vibrant colors in nature involve the interactions of structure and pigment. Here, we demonstrate that pigment can be exploited to efficiently create bright structural color at wavelengths outside its absorption band.

Journal
Soft Matter
Date Published
Group (Lab)
Eric Dufresne Group

Strain stiffening elastomers with swelling inclusions

Cornell Affiliated Author(s)
Author
S. Heyden
R.W. Style
E.R. Dufresne
Abstract

Inhomogeneously swollen elastomers are an emergent class of materials, comprising elastic matrices with inclusion phases in the form of microgel particles or osmolytes. Inclusion phases can undergo osmotically driven swelling and deswelling over orders of magnitude. In the swollen state, the inclusions typically have negligible Young's modulus, and the matrix is strongly deformed. In that regime, the effective mechanical properties of the composite are governed by the matrix.

Journal
Soft Matter
Date Published
Group (Lab)
Eric Dufresne Group