Scaffolds and cells for tissue regeneration: different scaffold pore sizes—different cell effects

Abstract

During the last decade biomaterial sciences and tissue engineering have become new scientific fields supplying rising demand of regenerative therapy. Tissue engineering requires consolidation of a broad knowledge of cell biology and modern biotechnology investigating biocompatibility of materials and their application for the reconstruction of damaged organs and tissues. Stem cell-based tissue regeneration started from the direct cell transplantation into damaged tissues or blood vessels. However, it is difficult to track transplanted cells and keep them in one particular place of diseased organ. Recently, new technologies such as cultivation of stem cell on the scaffolds and subsequently their implantation into injured tissue have been extensively developed. Successful tissue regeneration requires scaffolds with particular mechanical stability or biodegradability, appropriate size, surface roughness and porosity to provide a suitable microenvironment for the sufficient cell-cell interaction, cell migration, proliferation and differentiation. Further functioning of implanted cells highly depends on the scaffold pore sizes that play an essential role in nutrient and oxygen diffusion and waste removal. In addition, pore sizes strongly influence cell adhesion, cell-cell interaction and cell transmigration across the membrane depending on the various purposes of tissue regeneration. Therefore, this review will highlight contemporary tendencies in application of non-degradable scaffolds and stem cells in regenerative medicine with a particular focus on the pore sizes significantly affecting final recover of diseased organs.

An nMgO containing scaffold: Antibacterial activity, degradation properties and cell responses

“…The scaffold showed a well ordered and interconnected porous structure. It was considered that the pore size of scaffolds should be large enough to ensure nutrient delivery and tissue ingrowth but not too large to prevent cell migration [30] . Roosa et al [31] found all of the polycaprolactone scaffolds with pore size from 350 to 800 μm could promote bone regeneration and there were no significant differences in new bone formation between them.…”

Optimal bovine collagen concentration to achieve tracheal epithelial coverage of collagen sponges

“…It is well accepted that the degrees of cell migration and sprouting of blood vessels into three‐dimensional (3D) porous scaffolds depend on the pore size of scaffolds . Although the pore size most suitable for subepithelial tissue formation and angiogenesis in the tracheal mucosa is unknown, many reports have suggested that 3D scaffolds enriched with >100‐μm pore diameters are beneficial for cell invasion . In our study, it was difficult to measure the pore sizes of the bovine collagen sponges, but the intermembrane spaces in the 0.7% sponge appeared to be larger than those in the 0.5% and 1.0% sponges.…”

Load‐bearing biodegradable polycaprolactone‐poly (lactic‐co‐glycolic acid)‐ beta tri‐calcium phosphate scaffolds for bone tissue regeneration

“…This is required to maintain the structural integrity and the length of the affected limb. The newly formed pore channels in the PCL skeleton will help in the formation of the vascular network and therefore, facilitate the supply of oxygen and nutrients to the cells growing deep inside the scaffolds …”