Improved adhesion and growth of human osteoblast-like MG 63 cells on biomaterials modified with carbon nanoparticles

Abstract

Three types of materials modified with carbon particles were prepared: (1) carbon fibre-reinforced carbon composites (CFRC), materials promising for hard tissue surgery, coated with a fullerene C 60 layer, (2) terpolymer of polytetrafluoroethylene, polyvinyldifluoride and polypropylene mixed with 4 wt.% of single- or multi-walled carbon nanotubes and (3) nanostructured or hierarchically micro- and nanostructured diamond layers deposited on silicon substrates. The materials were seeded with human osteoblast-like MG 63 cells (density from 8500 cells/cm 2 to 25,000 cells/cm 2). On the fullerene layers, the cells (day 2 after seeding) adhered in numbers from 2.3 to 3.5 times lower than those on control non-coated CFRC or polystyrene dishes. However, their spreading area was larger by 68% to 145% than that on the control surfaces. These cells also assembled numerous dot-like vinculin-containing focal adhesion plaques and a rich fine mesh-like beta-actin cytoskeleton. Similar results were obtained on the terpolymers mixed with carbon nanotubes. The cells were well spread and contained distinct beta-actin filament bundles, whereas the cells on the pure terpolymer were often rounded and clustered into aggregates. An enzyme-linked immunosorbent assay revealed that the cells on the material with single-walled carbon nanotubes contained a higher concentration of vinculin and talin, i.e. components of focal adhesion plaques (by 56% and 35%, respectively, compared to the pure terpolymer). However, the concentration of osteocalcin, a marker of osteogenic differentiation, was lower in cells on the terpolymer containing multi-walled nanotubes, which was probably due to more active proliferation of these cells (on day 7, they reached a 4.5 times higher population density than cells on the unmodified terpolymer). Adding both single-and multi-walled nanotubes to the terpolymer did not increase the concentration of ICAM-1, a marker of immune activation, in MG 63 cells. On diamond layers, the number of initially adhered cells was higher on the nanostructured layers, whereas the subsequent proliferation was accelerated on the layers with a hierarchical micro-and nanostructure. Thus, all tested carbon nanoparticle-containing materials gave good support to adhesion and growth of bone-derived cells, and they can be considered as promising for construction of bone implants and bone tissue engineering.