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You are here: Home / Seminars / Experimental physics and modelling / Bioclogging: a powerful approach to study soft porous media

Bioclogging: a powerful approach to study soft porous media

Olivier Liot (IMFT)
When Feb 18, 2025
from 11:00 to 12:00
Where Amphi H
Attendees Olivier Liot
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In this talk, I will try to show that microfluidics applied to bioclogging studies is indeed a powerful way to gain insights into the physics of soft porous media.

Membrane separation of solid particles suspended in a liquid is essential for many processes, but has a major drawback: the pores can become clogged by particle accumulation, leading to membrane fouling. Clogging is now relatively well understood for inert, rigid particles, but the study of bio-clogging - clogging by biological objects - opens up many research questions because living cells have unique properties: they are deformable, have specific adhesion mechanisms and can proliferate, consume nutrients and die. As a result, these cells can change both shape and volume, as well as rearrange themselves, thereby modifying the microstructure of a clog, which is actually a (potentially growing) soft porous media.

Numerous studies of bioclogging at the membrane scale report that the permeability of a clog composed of living particles is difficult to predict [3, 4]. In fact, there is a lack of microscale measurements to relate the macroscale permeability measurements to the displacements, cell deformations, and microstructure of a biological cell clog. The difficulty with microscale permeability measurements lies in the flow rates to be measured, which can be less than 10 nL/min, beyond the range of commercial flowmeters and without the benefit of the many existing metrology techniques applied to microfluidics [2]. We have developed an on-chip flowmeter (see Figure) that overcomes these limitations and opens up new perspectives for permeability studies in confined soft porous media.

The study of the mechanical response of a clog made of soft biological particles is also an area of disagreement, as some studies show that a clog can be compressible [6] or not [1]. Using microfluidic devices and appropriate modeling based on the poroelasticity framework [5], we have shown that confinement can induce a dominant effect of wall friction, even for slippery single objects.

References

[1] Ben Hassan, I., Lafforgue, C., Ayadi, A., & Schmitz, P. (2014). In situ 3D characterization of monodispersed spherical particle deposition on microsieve using confocal laser scanning microscopy. Journal of Membrane Science, 454, 283–297.
[2] Cavaniol, C., Cesar, W., Descroix, S., & Viovy, J.-L. (2022). Flowmetering for microfluidics. Lab on a Chip, 22(19), 3603–3617.
[3] Foley, G. (2006). A review of factors affecting filter cake properties in dead-end microfiltration of microbial suspensions. Journal of Membrane Science, 274(1-2), 38–46.
[4] Katagiri, N., Tomimatsu, K., Date, K., & Iritani, E. (2021). Yeast Cell Cake Characterization in Alcohol Solution for Efficient Microfiltration. Membranes, 11(2), 89.
[5] MacMinn, C. W., Dufresne, E. R., & Wettlaufer, J. S. (2016). Large Deformations of a Soft Porous Material. Physical Review Applied, 5(4).
[6] Valencia, A., LeMen, C., Ellero, C., Lafforgue-Baldas, C., F. Morris, J., & Schmitz, P. (2022). Direct observation of the microfiltration of yeast cells at the micro-scale: Characterization of cake properties. Separation and Purification Technology, 298, 121614.