Publications by authors named "Iaroslava Golovkova"

3 Publications

  • Page 1 of 1

Adhesion as a trigger of droplet polarization in flowing emulsions.

Soft Matter 2021 Apr 16;17(14):3820-3828. Epub 2021 Mar 16.

Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire Jean Perrin (LJP), F-75005, Paris, France.

Tissues are subjected to large external forces and undergo global deformations during morphogenesis. We use synthetic analogues of tissues to study the impact of cell-cell adhesion on the response of cohesive cellular assemblies under such stresses. In particular, we use biomimetic emulsions in which the droplets are functionalized in order to exhibit specific droplet-droplet adhesion. We flow these emulsions in microfluidic constrictions and study their response to this forced deformation via confocal microscopy. We find that the distributions of avalanche sizes are conserved between repulsive and adhesive droplets. However, adhesion locally impairs the rupture of droplet-droplet contacts, which in turn pulls on the rearranging droplets. As a result, adhesive droplets are a lot more deformed along the axis of elongation in the constriction. This finding could shed light on the origin of polarization processes during morphogenesis.
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http://dx.doi.org/10.1039/d1sm00097gDOI Listing
April 2021

Depletion attraction impairs the plasticity of emulsions flowing in a constriction.

Soft Matter 2020 Apr;16(13):3294-3302

Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire Jean Perrin (LJP), F-75005, Paris, France.

We study the elasto-plastic behavior of dense attractive emulsions under a mechanical perturbation. The attraction is introduced through non-specific depletion interactions between the droplets and is controlled by changing the concentration of surfactant micelles in the continuous phase. We find that such attractive forces are not sufficient to induce any measurable modification on the scalings between the local packing fraction and the deformation of the droplets. However, when the emulsions are flowed through 2D microfluidic constrictions, we uncover a measurable effect of attraction on their elasto-plastic response. Indeed, we measure higher levels of deformation inside the constriction for attractive droplets. In addition, we show that these measurements correlate with droplet rearrangements that are spatially delayed in the constriction for higher attraction forces.
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http://dx.doi.org/10.1039/c9sm02343gDOI Listing
April 2020

Quantifying the Performance of Micro-Compartmentalized Directed Evolution Protocols.

Life (Basel) 2020 Feb 13;10(2). Epub 2020 Feb 13.

Laboratoire Gulliver, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France.

High-throughput, in vitro approaches for the evolution of enzymes rely on a random micro-encapsulation to link phenotypes to genotypes, followed by screening or selection steps. In order to optimise these approaches, or compare one to another, one needs a measure of their performance at extracting the best variants of a library. Here, we introduce a new metric, the Selection Quality Index (SQI), which can be computed from a simple mock experiment, performed with a known initial fraction of active variants. In contrast to previous approaches, our index integrates the effect of random co-encapsulation, and comes with a straightforward experimental interpretation. We further show how this new metric can be used to extract general protocol efficiency trends or reveal hidden selection mechanisms such as a counterintuitive form of beneficial poisoning in the compartmentalized self-replication protocol.
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http://dx.doi.org/10.3390/life10020017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175308PMC
February 2020
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