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Behaviour of biomimetic particles under acoustophoretic conditions

par Iermano, Fabio
Président du jury Scheid, Benoît
Promoteur Hendrick, Patrick
Publication Non publié, 2023-10-26

Thèse de doctorat

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Résumé :

It is widely acknowledged within the scientific community that studying the physical properties of cells can serve as a valuable tool in gaining insight into various diseases and their progression. Across different pathological conditions, researchers have observed distinct variations in these properties. For instance, it has been well-documented that cancer cells are typically less rigid than their healthy counterparts. As such, the potential value of isolating, recovering and studying cells or extracellular vesicles that have undergone such changes for diagnostic and prognostic purposes is incredibly significant.This dissertation presents an exploration into the utilization of an acoustofluidic chip to analyse the density and compressibility of diverse biomimetic particles, and into the capability of the chip in manipulating and sorting the particles solely based on their compressibility. To achieve the research objectives, a rigorous methodology was developed that entailed validating a numerical model to forecast the particles' and cells' behaviour under different resonator designs. The numerical model was used to design a device that could produce half-wavelength resonance or an integer multiple of that, and apply an acoustophoretic field to manipulate and sort solutions of particles. Moreover, three types of biomimetic microparticle solutions with varying compressibility conditions were created, thus simulating diverse experimental scenarios.\In this thesis, it was conducted an analysis on the behaviour of biomimetic microparticles when subjected to acoustophoretic conditions. Specifically, the research involved the use of polyethylene microbeads and biomimetic microparticles, which included Alginate, Polydimethylsiloxane (PDMS), and Giant unilamellar vesicles. To carry out the experiments, the microparticles were exposed to acoustic radiation force within a specially designed acoustofluidic chip. The study relied on the known physical properties of polyethylene microbeads, such as size, density, and compressibility, to determine the acoustic energy density within the microchannel. This information was then utilized to estimate the unknown compressibility of the microparticles under investigation.Through the observations made in this work, it has been determined that microparticles of similar density yet different compressibility exhibit distinct responses to the acoustophoretic field. This phenomenon can be attributed to variations in their acoustic contrast factor, which spans from positive to negative. By conducting an analysis of both compressibility and acoustic contrast factors and observing microparticle behaviour, it can be concluded that the acoustofluidic chip developed in this thesis can be effectively employed for identifying particles with unknown mechanical properties and providing estimates thereof. This technology also holds potential for biomedical applications, such as screening and testing, and with further refinement, it may be used for sorting particles based on their compressibility.