Sophie Marbach

CNRS, Sorbonne University, Paris

I am a theoretical physicist interested in soft problems. I just moved to Sorbonne University in Paris, in the Phenix physical chemistry Lab, to work there as a permanent researcher (CNRS). I obtained my PhD in Physics at the Ecole Normale Superieure in Paris, studying nanofluidic transport related to filtration questions. I then moved to the Courant Institute of New York University (NY), where I studied sticky feet particle systems, that I will discuss at the venue! I am now building a new research activity inspired by soil physics. As a researcher, I am engaged in diversity representation in science, as well as sustainability issues (check out my blog http://sciriousgecko.com/ on carbon footprints).


Tuesday April 18th

The Nanocaterpillar's Random Walk: or how to move precisely with random sticky feet?

Particles with sticky feet - or nanoscale caterpillars - in biological or artificial systems, beat the paradigm of standard diffusion to achieve complex functions. Some cells (like leucocytes) use ligand-receptor contacts (sticky feet) to crawl and roll along vessels. Sticky DNA (another type of sticky feet) is coated on colloids to design programmable interactions and self-assembly. Predicting the dynamics of such sticky motion is challenging since sticky events (attaching/detaching) often occur on very short time scales compared to the overall motion of the particle. Even understanding the equilibrium statistics of these systems (how many feet are attached in average) is largely uncharted. Yet, controlling the dynamics of such particles is critical to achieve these advanced functions -- for example facilitating rolling is critical for long-range alignment of DNA coated-colloids in crystals. Here we present advanced theory and experimental results on a model system. We rationalize what parameters control average feet attachment and how they can be compared to other existing systems. We investigate furthermore how various motion modes (rolling, sliding or skipping) may be favored over one another.