Heat-treated carbon coatings on poly (l-lactide) foils for tissue engineering

Carbon-based materials have emerged as promising candidates for a wide variety of biomedical applications, including tissue engineering. We have developed a simple but unique technique for patterning carbon-based substrates in order to control cell adhesion, growth and phenotypic maturation. Carbon films were deposited on PLLA foils from distances of 3 to 7 cm. Subsequent heat-treatment (60 °C, 1 h) created lamellar structures with dimensions decreasing from micro- to nanoscale with increasing deposition distance. All carbon films improved the spreading and proliferation of human osteoblast-like MG 63 cells, and promoted the alignment of these cells along the lamellar structures. Similar alignment was observed in human osteoblast-like Saos-2 cells and in human dermal fibroblasts. Type I collagen fibers produced by Saos-2 cells and fibroblasts were also oriented along the lamellar structures. These structures increased the activity of alkaline phosphatase in Saos-2 cells. Carbon coatings also supported adhesion and growth of vascular endothelial and smooth muscle cells, particularly flatter non-heated carbon films. On these films, the continuity of the endothelial cell layer was better than on heat-treated lamellar surfaces. Heat-treated carbon-coated PLLA is therefore more suitable for bone and skin tissue engineering, while carbon-coated PLLA without heating is more appropriate for vascular tissue engineering.