Acceleration of Diffusion by Degradation

by Mr. Yoav Ironi

Dept. Of Physics, Ben-Gurion University Of The Negev

at Biological and soft-matter physics

Thu, 31 Dec 2020, 12:10
ZOOM only - Meeting ID: 841 9016 0947

Abstract

Contemporary research in the fields of embryonic development and immune responses had put a focus on the important role of signaling molecules, that control the development and physiological activity in these processes. Source cells induce relevant downstream responses in target cells by secreting signaling molecules. The target cells get stimulated by measuring the concentration of signaling molecules in their vicinity. Spatial and temporal variations in the concentration provide varying stimuli, thus creating variability between target cells that hold the same genetic information and are initially identical.

The concentration profile is established by several combined effects: cell secretion of signaling molecules from a source is followed by their spreading through diffusion and degradation. A fundamental question in the research of such systems is: how long does it take for the concentration profile to relax into its steady state solution? A long-lived theory assumed that the local relaxation times for the concentration profile scale quadratically with the distance from the source. It was only recently proven that this assumption is likely wrong. A new theory suggested that the local relaxation times should actually exhibit a linear dependence on the distance from the source, which means the relaxation to steady state is significantly quicker than traditionally assumed.

The purpose of this project was to design an experimental setup to model source-diffusion-degradation dynamics in a controlled in vitro environment. It turns out that fluorescent markers manifest a great analogy of a diffusion-degradation system. Our simplistic setup isolates the effect inside a pressure-controlled microfluidic chip, which we have designed and fabricated in our lab for the purpose of this project. Analysis of the experimental data collected so far supports the theory that local relaxation times exhibit linear dependence in the distance from the source. However, the data currently in our possession contains certain discrepancies with the theory, therefore it is not sufficient to conclude undoubtedly that the theory is valid.

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Meeting ID: 841 9016 0947

Created on 23-10-2020 by Granek, Rony (rgranek)
Updaded on 31-12-2020 by Granek, Rony (rgranek)