Cell encapsulation in bio-polymers is a rapidly expanding field in bioproduction, encompassing organoid or spheroid maturation, drug screening, cellular therapies, and bioengineering. This thesis contributes to these applications through the multilayer encapsulation of cells in bio-polymers with a wide viscosity range. The inner layer (core) provides a more favorable environment for the maturation and survival of cells or organoids, while the outer layer ensures mechanical protection (shell) and acts as a filtering barrier against pathogens. Laden with selected biological agents, it allows controlled interaction with the core cells of the capsule.

The objective of this thesis is to develop an innovative ejection nozzle for forming high-frequency multilayer microcapsules using centrifugal force in a laboratory centrifuge. This new thesis builds upon a completed thesis in 2023 that studied, detailed, and developed a predictive model for generating single-layer microcapsules solely through centrifugal force.

The mechanisms of formation and ejection of multilayer capsules are complex, involving the rheological properties of bio-polymers, centrifugal force, surface tension, and interfaces. The design of the ejection nozzle must consider these properties. The first part of this thesis aims to better understand the multilayer formation and ejection mechanisms of microcapsules based on the selected ejection nozzle's geometry. This understanding will enable the prediction and control of formation based on the rheological properties of the bio-polymer(s). The second part involves developing an automated system for aseptic capsule production. Finally, biological validation will confirm the developed technology.

To achieve the study objectives, the candidate must initially conduct an analytical and numerical study, design ejection nozzles, and leverage the laboratory's expertise to manufacture them. Fluidic tests will be performed on models, and the design will be optimized to create and test a microcapsule formation prototype. The candidate should have a background in physics, engineering, and fluid mechanics, with a particular talent for experimental approaches. Prior experience in microfluidics/biology would be advantageous.