Biomimetic approach to articular cartilage tissue engineering using carbon nanotube-coated and textured polydimethylsiloxane scaffolds.

There is a significant need to understand the complexity and heterogeneity of articular cartilage to develop more effective therapeutic strategies for diseases such as osteoarthritis. Here, we show that carbon nanotubes (CNTs) are excellent candidates as a material for synthetic scaffolds to support the growth of chondrocytes-the cells that produce and maintain cartilage. Chondrocyte morphology, proliferation, and alignment were investigated as nanoscale CNT networks were applied to macroscopically textured polydimethylsiloxane (PDMS) scaffolds. The application of CNTs to the surface of PDMS-based scaffolds resulted in an up to 10-fold increase in cell adherence and 240% increase in proliferation, which is attributable to increased nanoscale roughness and hydrophilicity. The introduction of macroscale features to PDMS induced alignment of chondrocytes, successfully mimicking the cell behavior observed in the superficial layer of cartilage. Raman spectroscopy was used as a noninvasive, label-free method to monitor extracellular matrix production and chondrocyte phenotype. Chondrocytes on these scaffolds successfully produced collagen, glycosaminoglycan, and aggrecan. This study demonstrates that introducing physical features at different length scales allows for a high level of control over tissue scaffold design and, thus, cell behavior. Ultimately, these textured scaffolds can serve as platforms to improve the understanding of osteoarthritis and for early-stage therapeutic testing.