Functional role of scaffold geometries as a template for physiological ECM formation: evaluation of collagen 3D assembly

Abstract

Bone tissue regeneration involves different healing stages and the resulting final hard tissue is formed from natural templates such as fibrous collagen, soft and hard callus and capillary bed. This work aims to evaluate the efficiency of different scaffold geometries with a novel approach: exploring the relationships among scaffold morphologies, cell activity and collagen 3D organization, which serves as a natural template for subsequent mineralization. Among the possible systems to fabricate scaffolds, solvent casting with particulate leaching and microfabrication were used to produce random vs ordered structures from poly(D,L-lactic acid). In vitro biological testing was carried out by culturing a human osteosarcoma-derived osteoblast cell line (MG63) and measuring material cytotoxicity, cell proliferation and migration. Assemblage of collagen fibres was evaluated. A preliminary study of collagen distribution over the two different matrices was performed by confocal laser microscopy after direct red 80 staining. Both of the scaffolds were seen to be a good substrate for cell attachment, growth and proliferation. However, it seems that random, rather than regular, well-ordered porosity induces a more proper collagen fibre distribution and organization, similar to the natural one formed in the early stages of bone repair.

Influence of scaffold properties on the inter-relationship between human bone marrow derived stromal cells and endothelial cells in pro-osteogenic conditions

“…In previous studies we assessed the role of PDLLA scaffold morphology in its support of human osteoblast-like cell culture [27,28]. We further established that fibroin fiber addition to these scaffolds did not alter porosity and mechanical properties and better supported endothelial cell cultures and promoted vascularization in vivo [29].…”

“…To overcome this problem, we used a previously developed multicomponent scaffold composed of a synthetic porous scaffold and a silk fibroin fibrous structure. The baseline scaffold was made using poly(D,L-lactic acid) (PDLLA), designed to promote mineralization [27,28], while silk fibroin was incorporated as the fibrous structure to trigger endothelial cell activity [29].…”

Effects of silk fibroin fiber incorporation on mechanical properties, endothelial cell colonization and vascularization of PDLLA scaffolds

“…Silk fibroin fibers were incorporated into salt-leached sponge without modifying scaffold porosity. The baseline scaffold, composed of poly-D,L-lactic acid (PDLLA), was specifically designed to promote ECM production and mineralization providing a perfect 3D porous structure as support [47,48]. Silk fibroin fibers were selected for their ability to support endothelial cell attachment and growth.…”

Test system for evaluating the influence of polymer properties on primary human keratinocytes and fibroblasts in mono- and coculture

“…Besides the chemical composition of the substrate and the topography (roughness and geometry) (Jiang et al, 2011;Stoppato et al, 2013), the apparent Young´s modulus can influence cell adherence, viability and function (Georges and Janmey, 2005).…”