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Biomechanics of collagenous scaffolds

Collagen scaffold materials are being investigated for their advantageous features in tissue engineering and regenerative medicine. To date, porous collagen sponges have been used to support in vitro growth of many types of tissues, including cancerous tissue. Also, bioreactors used to control in vitro perfusion within a medium and to apply hydrostatic fluid pressure has been explored; they have shown to provide enhanced support for histogenesis in collagen scaffolds. As such, and to further aid the in vitro efforts, we are developing tissue-specific models of porous collagen scaffold (PCS) materials – tailored to the needs of our experimental collaborators.

One example involves a project concerning the synthesis of 3D superparamagnetic collagen-based hydrogels with tunable swelling, mechanical and magnetic properties. We interrogated experimentally the deposition of hydrophilic magnetite nanoparticles (OA.OA.Fe3O4) within the matrix of the hydrogels, and we tested their mechanical properties (under confined compressive loading conditions). Moreover, nanoparticles’ deposition in the collagenous matrix was modelled mathematically with respect to the swelling of the gel and the effective stiffness of the matrix. Our model recapitulated nanoparticle diffusion and deposition as well as hydrogel swelling, in terms of nanoparticles’ size and concentration of OA.OA.Fe3O4 aqueous solution. This work culminated in a Materials Science and Engineering: C paper, jointly with Profs Krasia-Christoforou and Stylianopoulos (UCY) and their groups.

Another example, is Mr Lopez’s MSc project that is in collaboration with Prof D. Tzeranis. This project aims to develop multiscale models that span from a millimetre scale to the cell-scale and up to the nanoscale, of dry-state PCS appropriate to facilitate neuro cell recovery (after injury, subcutaneous wound). Thus, one aspect to the project is develop models encompassing the contractile behaviour of cells that is relevant in understanding wound healing and scar formation, as well as models that could model cell—matrix biomechanics. This will help us to interrogate and propose optimised PCS designs by elucidating on neurons mechano-biology and the cells/matrix interactions, towards providing the cells the best microenvironment conditions for enhanced tissue regeneration outcomes (in the laboratory setting).

Relevant work:

Karagiorgis et al. 2020. Materials Science and Engineering: C, doi: 10.1016/j.msec.2020.11108

 

Biomechanical characterization of engineered magnetoactive collagen hydrogels (MCH) with tunable and predictable properties. We have employed a combination of experimental and mathematical modelling procedures to investigate the effect of the nanoparticle content on the mechanical, swelling and magnetic properties of MCHs (Source: https://doi.org/10.1016/j.msec.2020.111089).
Agent-based model (ABM) simulation demo of Α172-Η4 cell invasion inside a porous matrix represented through a tetrakaidecahedron lattice (see here: https://doi.org/10.1016/j.ijsolstr.2007.10.028). Cells migrate following spherically distributed gradients of biochemical cues, while they adhere and crawl through the scaffold (fibres) or/and the wall structures (represented as grey obstacles) inside an in vitro device.

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