Improved adhesion, growth and maturation of human bone-derived cells on nanocrystalline diamond films

Nanocrystalline diamond (NCD) films were deposited on microscopic glass slides using the MW PECVD method (20 Tort, 710 degrees C, 0.8-1% CH4). After the growth period, the films were oxidized and subsequently hydrogenated, and some of them were doped with boron (NCD-B; 3,00030,000 ppm B : C; leading to rho similar to 10(-1) Omega cm for the highest doped films). The neutron depth profiling showed that in the near surface region (<800 nm) the boron (B-10 + B-11) content in the highest doped sample was about (1.9 +/- 0.3) x 10(21) B cm(-3) (i.e., 1.1 +/- 0.2 at% of B). The films were seeded with human osteoblast-like MG 63 cells (similar to 17,000 cells/cm(2)). On day 3 after seeding, the cell number on NCD (56,280 +/- 1,090 cells/cm(2)) was significantly higher than that on NCD-B (by 27 +/- 3%), glass slides (by 22 +/- 3%) and polystyrene wells (by 36 +/- 3%). On day 7, the cell numbers on both NCD and NCD-B films (351,170 +/- 16,530 cells/cm(2) and 310,020 +/- 10,410 cells/cm(2), respectively) became significantly higher than the values on glass slides and polystyrene dishes (218,800 +/- 12,340 cells/cm(2) and 223,400 +/- 9,290 cells/cm(2), respectively). Immunofluorescence staining showed that the cells on both NCD films assembled fine streak- or dot-like focal adhesion plaques containing alpha, integrins or talin, and a mesh-like beta-actin cytoskeleton. The cells on NCD-B were brightly stained for osteocalcin, an important marker of osteogenic differentiation. Thus, both tested nanocrystalline diamond films gave good support for the adhesion, growth and maturation of bone-derived cells. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.