Fabrication, ultra-structure characterization and in vitro studies of RF magnetron sputter deposited nano-hydroxyapatite thin films for biomedical applications

Thin Bioactive Zn Substituted Hydroxyapatite Coating Deposited on Ultrafine-Grained Titanium Substrate: Structure Analysis

“…Note, that this type of structure is rarely produced in magnetron sputtering systems due to the hexagonal structure of the HA and the deposition process being non-equilibrium. A preliminary growth of columnar-like grain has been reported by other authors (Surmeneva et al, 2014). In Figure 3B, SAD micrograph gathered from the thin film region confirms the high crystallinity level of the deposited HA-Zn coating.…”

“…Moreover, an amorphous sublayer of 8 nm thickness at the interface between the substrate and the coating is detected. As it was reported in Surmeneva et al (2014), the RF magnetron deposition process formed nano-scale grains, generating an amorphous layer of HA at the substrate/coating interface.…”

“…There are two major features of RF magnetron sputtering that are advantageous. First, good adhesion between coating and substrate and, second, the availability of sputtering targets with different chemical compositions which determine the composition of the synthesized coating (Surmeneva et al, 2014). In addition, RF magnetron sputtering is a highly controlled and reproducible process.…”

Testing the in vitro performance of hydroxyapatite coated magnesium (AZ91D) and titanium concerning cell adhesion and osteogenic differentiation

“…Although the wet-chemical methods are suitable for deposition of CaP coating on the magnesium alloys, all these methods suffer from weak adhesive strength [24]. HA coatings fabricated via RF magnetron sputtering on titanium and its alloys have been described as dense, uniform, non-porous films [29,30] and improved wear resistance compared to uncoated substrates [29,30]. Moreover, for NiTi substrates, the average nickel release rate from the samples with a dense crystalline 700 nm thick HA coating deposited via RF magnetron sputtering was reduced by 7-10 times relative to the uncoated substrates [36].…”

“…Moreover, it allows the preparation of the coatings < 1 μm thick with controlled microstructure which reduces the risk of third-body wear and subsequent osteolysis [24]. The adhesion of CaP-based coatings prepared via RF magnetron sputtering on metallic substrates is excellent; moreover, a beneficial biological response was observed both in vitro and in vivo in comparison with uncoated metals [26][27][28][29][30]. So far such thin coatings have not been applied on Mg alloys via RF magnetron sputtering and tested addressing osteoinductivity [15].…”