In vitro studies of the biomineralization in amorphous carbon films

Films of amorphous carbon (a-C) and amorphous carbon nitride (a-CN) were deposited on stainless steel substrates (AISI 316L) using a d.c. magnetron sputtering system. In vitro studies were carried out on the coated samples using human osteoblasts cells. Preliminary bio-activity of carbon films to promote bone growth was assessed by cellular adhesion and proliferation, as determined by a cellular count spectroscopic technique using a well-defined standard curve. Osteoblasts cells were also grown on uncoated steel and Ti coated steel samples for comparison. The degree of osteoblasts adhesion measured at 24 h attained maximum values for a-C films. Similarly, cellular proliferation evaluated at 1, 3 and 7 days showed an outstanding increase of osteoblasts cells for a-C and Ti coatings in contrast with uncoated steel. Bio-mineralization or mineral bone growth was evaluated by measuring the elemental composition and the substrate coverage of the mineral grown on the substrates after periods up to 14 days. Elemental composition analyses were performed by X-ray energy dispersion analysis (EDX) in a scanning electron microscope.