Marrow‐Derived stem cell motility in 3D synthetic scaffold is governed by geometry along with adhesivity and stiffness

Abstract

Design of 3D scaffolds that can facilitate proper survival, proliferation, and differentiation of progenitor cells is a challenge for clinical applications involving large connective tissue defects. Cell migration within such scaffolds is a critical process governing tissue integration. Here, we examine effects of scaffold pore diameter, in concert with matrix stiffness and adhesivity, as independently tunable parameters that govern marrow-derived stem cell motility. We adopted an “inverse opal” processing technique to create synthetic scaffolds by crosslinking poly(ethylene glycol) at different densities (controlling matrix elastic moduli or stiffness) and small doses of a heterobifunctional monomer (controlling matrix adhesivity) around templating beads of different radii. As pore diameter was varied from 7 to 17 µm (i.e., from significantly smaller than the spherical cell diameter to approximately cell diameter), it displayed a profound effect on migration of these stem cells—including the degree to which motility was sensitive to changes in matrix stiffness and adhesivity. Surprisingly, the highest probability for substantive cell movement through pores was observed for an intermediate pore diameter, rather than the largest pore diameter, which exceeded cell diameter. The relationships between migration speed, displacement, and total path length were found to depend strongly on pore diameter. We attribute this dependence to convolution of pore diameter and void chamber diameter, yielding different geometric environments experienced by the cells within.

Independent regulation of tumor cell migration by matrix stiffness and confinement

“…Moreover, most of these systems require retrospective determination of pore size based on empirical correlations and do not, in general, permit prospective imposition of some pore size of interest. As a way of addressing these limitations, "bead templating" approaches have recently been developed to yield hydrogels of defined stiffness containing a communicating network of pores whose characteristic size is dictated by the particles around which the scaffold is formed (24). In practice, the conduits between pores are so short that cells are observed to "jump" discontinuously between void chambers, offering limited opportunity to observe and characterize cells in confined geometries.…”

Electrotaxis of lung cancer cells in ordered three-dimensional scaffolds

“…III A, 3D scaffolds composed of gelatin are softer (stiffness $ kPa) than 2D gelatin-coated glasses (stiffness $ 100 kPa) and bare glass or PMMA substrates (stiffness $ GPa), and this difference in stiffness might affect cell attachment and subsequent electrotaxis and motility. [83][84][85] From the current result, stiffer substrates result in more prominent electrotactic response of the cells. However, the effect of the steric hindrance cannot be ruled out.…”

Fabrication of a multi-layer three-dimensional scaffold with controlled porous micro-architecture for application in small intestine tissue engineering

“…The variation in material thickness that results from pore structure may impact mechanical properties of the substrate. 34 The mechanism by which these factors influence cell migration involves modulation of signal transduction pathways leading to rearrangement of the cell cytoskeleton. 33 Taken together, these data demonstrate the inter-relatedness of cell migration, speed, scaffold mechanical properties and pore structures.…”