Vertically aligned carbon nanotube micropillars induce unidirectional chondrocyte orientation

Articular cartilage is a highly organized tissue with very limited regenerative capacities. One limitation to mimic cartilage structure in tissue engineering is due to specific orientation of chondrocytes. Here, we use vertically aligned multi-wall carbon nanotubes (VA-MWCNT) micropillars to achieve unidirectional orientation of chondrocytes. We demonstrate that the attachment, proliferation and extracellular matrix (ECM) production by the chondrocytes is enhanced on VA-MWCNT micropillars compared to controls. The nanostructures offered by the VA-MWCNT allow the chondrocytes to anchor at cellular structure level, while mechanical flexibility of the VA-MWCNT micropillars mimics the cartilage’s natural ECM Young’s modulus. We exploit these features to extrapolate the contractile forces exerted by the chondrocytes on the micropillars. Our findings will guide the design of VA-MWCNT templates to model cell’s contractile forces. Furthermore, the capability of VA-MWCNTs to induce unidirectional chondrocytes orientation open new perspectives in cartilage tissue engineering.