Controlling the spatial relation between cells and host materials
Designing cell-containing materials is critical for a wide range of applications. From soil biodegradation to wound healing or bone regeneration, we rely heavily on the work provided by cellular entities.
One of our main research lines aims at designing radical new approaches to build cell-containing materials. Our efforts in rationalizing the spatial relations between cells and their host materials during fabrication have led to a double criteria that determines the possible cellularization pathways—fabrication process cytocompatibility and porosity.
Among these strategies, we focus mainly in ice templating, a technique initially develloped to design lightweight materials in ceramics, that is gathering increasing attention in the field of biomaterials.
Porous yet dense—new macroporous biomaterials to mimic the extracellular matrix
In multicellular organisms, tissues are structured as complex—often hierarchical—assemblies of biopolymers and living cells. The ability to reproduce the features of the native architecture of such biopolymer systems (the extracellular matrix, ECM) opens exciting perspectives in designing new, more relevant materials for 3D cell culture.
Using type I collagen, the main component of mammals’ ECM we have recently shown that freezing under carefully controlled conditions allows to design macroporous materials that can host primary cells in a 3D environment for extended periods of time.
The same approach has proven effective in mimicking other tissues such as plant stems, displaying remarkable mechanical and liquid transport properties.
Ice templating as a pathway for cell encapsulation
Ice templating (or directional freezing, freeze casting, etc…) allows for controlled phase separation events during freezing. We have shown that when controlled freezing is applied to biopolymer solutions with cells in suspension, it allows for the encapsulation of cells withing the biopolymer matrix.
These results shine a new light on cell cryopreservation, the single available technique to extend the lifespan of biological entities. Systematically used from research labs up to the clinic, cell cryopreservations relies on toxic cryoprotectants (such as DMSO or glycerol) to minimize the deletrious effects induced by ice crystals on living cells. Applying new strategies to control the freezing events (such as directional freezing) opens new avenues to maximise cell viability in absence of toxic cryoprotectants.
