The Effect of Scaffold Pore Size in Cartilage Tissue Engineering

Abstract

Introduction: The effect of scaffold pore size and interconnectivity is undoubtedly a crucial factor for most tissue engineering applications. The aim of this study was to examine the effect of pore size and porosity on cartilage construct development in different scaffolds seeded with articular chondrocytes. Methods: We fabricated poly-L-lactide-co-trimethylene carbonate scaffolds with different pore sizes, using a solvent-casting/particulate-leaching technique. We seeded primary bovine articular chondrocytes on these scaffolds, cultured the constructs for 2 weeks and examined cell proliferation, viability and cell-specific production of cartilaginous extracellular matrix proteins, including GAG and collagen. Results: Cell density significantly increased up to 50% with scaffold pore size and porosity, likely facilitated by cell spreading on the internal surface of bigger pores, and by increased mass transport of gases and nutrients to cells, and catabolite removal from cells, allowed by lower diffusion barriers in scaffolds with a higher porosity. However, both the cell metabolic activity and the synthesis of cartilaginous matrix proteins significantly decreased by up to 40% with pore size. We propose that the association of smaller pore diameters, causing 3-dimensional cell aggregation, to a lower oxygenation caused by a lower porosity, could have been the condition that increased the cell-specific synthesis of cartilaginous matrix proteins in the scaffold with the smallest pores and the lowest porosity among those tested. Conclusions: In the initial steps of in vitro cartilage engineering, the combination of small scaffold pores and low porosity is an effective strategy with regard to the promotion of chondrogenesis

Development of biodegradable membranes for the delivery of a bioactive chitosan‐derivative on cartilage defects: A preliminary investigation

“…In fact, the results obtained by swelling tests pointed out that, when immersed in PBS, the membranes rapidly swell and adsorb considerable liquid amounts immediately after soaking (Figure a). These results are in line with recent research studies stressing the importance of the porosity of polymeric scaffolding materials for cartilage repair applications and pointing out the importance of porous materials to guide the regeneration of a functional tissue (Browe et al, ; Nava, Draghi, Giordano, & Pietrabissa, ; Song et al, ). One of the advantages of the proposed system is that membranes formulation can be tailored to deliver variable amounts of the bioactive polysaccharide CTL at the lesioned site.…”

Enhanced chondrogenic differentiation of bone marrow mesenchymal stem cells on gelatin/glycosaminoglycan electrospun nanofibers with different amount of glycosaminoglycan

“…In this study by adding the GAG to gelatin in scaffold composition we try to increase the attachment and proliferation. GAG in combination with gelatin in nanofiberous structure and highly porosity can have a great impact on attachment potential of the scaffolds . SEM images approve that G/GAG nanofiber structure is deferent from gelatin nanofibers.…”

Biomaterials-Induced Stem Cells Specific Differentiation Into Intervertebral Disc Lineage Cells

“…The pore size of a scaffold microarchitecture affects cell adhesion, which significantly influences cell interactions, migration, growth and differentiation. Both larger (>200 µm) and smaller (≤200 µm) pore sizes promote cell proliferation (Griffon et al, 2006;Nava et al, 2016;Kim et al, 2017), while larger pore sizes are more favorable for chondrogenesis (Oh et al, 2010).…”

“…Similarly, polycaprolactone (PCL) (Figure 5A) cylindrical scaffolds with larger pore size (370-400 µm) increased Collagen type II, sox-9, GAG content and GAG/DNA index, while inhibited Collagen type I and X expression in ADSC in vitro (Oh et al, 2010;Im et al, 2012; Figure 5B). However, scaffolds made from poly(urethane urea) showed contradictory outcome, in which larger pore size (300-500 µm) downregulated proteoglycan production and Collagen type II expression but promoted Collagen type I expression (Stenhamre et al, 2011;Nava et al, 2016). The well permeability of nutrients and oxygen of scaffold provides sufficient supply for stem cells and leads to better chondrogenic differentiation (Oh et al, 2010).…”