Encapsulation of Cells in a Collagen Matrix Surrounded by an Alginate Hydrogel Shell for 3D Cell Culture

Abstract

Numerous techniques for mammalian cell culture have been developed to mimic the complex in vivo three-dimensional structure of tissues and organs. Among them, the sole use of proteins to create a matrix where cells are embedded already gives rise to self-organized multicellular assemblies. Loading cells in a controlled extracellular matrix along with cell culture and monitoring through a strategy that is compatible with pipetting tools would be beneficial for high throughput screening applications or simply for a standardized method. Here, we design submillimeter compartments having a thin alginate hydrogel shell and a core made of a collagen matrix where cells are embedded. The process, using a microfluidic device, is based on a high speed co-extrusion in air, leading to a compound jet whose fragmentation is controlled. The resulting core–shell liquid drops are then collected in a gelling bath that triggers a fast hardening of the shell and is followed by a slower self-assembly of collagen molecules into fibers. We show how to formulate the core solution in order to maintain cell viability at physiological conditions that otherwise induce tropocollagen molecules to self-assemble, while being able to prevent flow disturbances that are detrimental for this jetting method. Encapsulated Caco-2 cells, mainly used to model the intestinal barrier, proliferate and form a closed polarized epithelial cell monolayer where the apical membrane faces the continuous medium.

Alginate Based Core–Shell Capsules Production through Coextrusion Methods: Recent Applications

“…In addition to oil and probiotic encapsulation, extrusion has been used for the encapsulation of various other ingredients. For instance, cells encapsulation using the coextrusion technology is one of the most promising methods for three-dimensional cell culture that mimics in vivo the three-dimensional structure of tissues and organs [87].…”

“…The core-shell structure appears to be superior to other bead structures for long-term cell culture and for three-dimensional self-assembled cellular structures formation [88]. A semipermeable shell is necessary to provide a favorable microenvironment for the cells, with excellent permeability for mass transfer [87][88][89]. It ensures minimal solute diffusion and peripheral cells' escape through the shell.…”

Calcium alginate elastic capsules for microalgal cultivation

“…These benecial features for cell growth has long rendered elastic capsules valuable for applications in human cell culture. [25][26][27] For instance, Nebel et al managed to encapsulate and grow mesenchymal stem cells (MSCs) inside alginate-based elastic capsules using simple inverse gelation for capsule formation. Proliferation measurement showed that the cell number increased 2.5 times aer four days.…”

Core–Shell Spheroid‐Laden Microgels Crosslinked under Biocompatible Conditions for Probing Cancer‐Stromal Communication

“…[4] Such models include cancer cell culture within porous scaffolds, hydrogels, and organ-in-a-chip devices among others. [7][8][9][10] These models, in particular many 3D models, enable the exploration of a broad range of biophysical or biochemical variables that affect tumor behaviors and TME. [11] Notably, the results obtained for in vitro models require validation for their biological relevance.…”

“…In many respects, embedding MCSs in hydrogels can be used to mimic many biophysical features of cancer niches in vivo, including certain mechanical support, strong cell-cell junctions, and gradients in nutrient concentration. [8,[12][13][14][15] Hydrogel-based artificial ECMs offer a spectrum of biophysical properties, such as chemical modifications, control over hydrogel mechanical properties, and the ability to design hydrogel shape and topography, whereby artificial cancer niches could be generated and easily modulated for cancer research and TME studies. [16] Nonadhesive surfaces, spin flasks, or rotational bioreactors are used for MCS culture.…”