Abstract
Tissue engineering techniques, combining autologous chondrocytes with biodegradable biomaterials, may offer significant advantages over current articular cartilage repair strategies. We present a series of experiments investigating the effect of 3D scaffold architecture and biomaterial composition on cartilage tissue formation in vitro and in vivo.
Porous polymer (PEGT/PBT) scaffolds with low (300/55/45) or high (1000/70/30) PEG molecular weight (MW) compositions were produced using novel solid free-form fabrication (3DF) techniques, allowing precise control over pore architecture, and conventional compression moulding (CM) foam techniques. Scaffolds were seeded with expanded human nasal chondrocytes, and cultured in vitro or implanted subcutaneously in vivo in nude mice for 4 weeks and cartilage tissue formation accessed.
3DF scaffolds contained highly accessible networks of large interconnecting pores (Ø525 μm) compared to CM scaffolds, containing complex networks of small interconnecting pores (Ø182 μm). 3DF scaffold architectures enhanced cell re-differentiation (GAG/DNA) and cartilaginous matrix accumulation compared to CM scaffolds, but only if 1000/70/30 compositions were used. Collagen type-II mRNA was significantly increased in 3DF architectures irrespective of scaffold composition. These effects were likely mediated by preferential protein adsorption to 1000/70/30 materials, promoting a spherical chondrocyte-like morphology, as well as efficient nutrient/waste exchange throughout interconnecting pores within 3DF architectures.
We observed synergistic effects of both composition and 3D scaffold architecture on human chondrocyte re-differentiation capacity, however, our data suggests that scaffold composition has a more significant influence than architecture alone. Such design criteria could be included in future scaffold architectures for repairing articular cartilage defects.
The abstracts were prepared by Editorial Secretary Jean-Claude Theis. Correspondence should be addressed to NZOA at Department of Orthopaedic Surgery, Dunedin Hospital, Private Bag 1921, Dunedin, New Zealand.
