Copper as an alternative antimicrobial coating for implants-An in vitro study

AIM To investigate osteoconductive and antimicrobial properties of a titanium-copper-nitride(TiC uN) film and an additional BONIT~? coating on titanium substrates.METHODS For micro-structuring, the surface of titanium test samples was modified by titanium plasma spray(TPS). On the TPS-coated samples, the Ti Cu N layer was deposited by physical vapor deposition. The BONIT~? layer was coated electrochemically. The concentration of copper ions released from TiC uN films was measured by atomic absorption spectrometry. MG-63 osteoblasts on Ti Cu N and BONIT~? were analyzed for cell adhesion, viability and spreading. In parallel, Staphylococcus epidermidis(S. epidermidis) were cultivated on the samples and planktonic and biofilm-bound bacteria were quantified bycounting of the colony-forming units. RESULTS Field emission scanning electron microscopy(FESEM) revealed rough surfaces for TPS and TiC uN and a special crystalline surface structure on TiC uN + BONIT~?. TiC uN released high amounts of copper quickly within 24 h. These release dynamics were accompanied by complete growth inhibition of bacteria and after 2 d, no planktonic or adherent S. epidermidis were found on these samples. On the other hand viability of MG-63 cells was impaired during direct cultivation on the samples within 24 h. However, high cell colonization could be found after a 24 h pre-incubation step in cell culture medium simulating the in vivo dynamics closer. On pre-incubated TiC uN, the osteoblasts span the ridges and demonstrate a flattened, well-spread phenotype. The additional BONIT~?-coating reduced the copper release of the TiC uN layer significantly and showed a positive effect on the initial cell adhesion.CONCLUSION The Ti Cu N-coating inhibits the formation of bacterial biofilms on orthopedic implants by influencing the "race for the surface" to the advantage of osteoblasts.

Titanium allergy or not? “Impurity” of titanium implant materials

For patients suffering from allergies to nickel, chrome and cobalt, titanium implants are the implants of choice. Nevertheless, titanium implant sensitivity has been reported in the form of “allergies” and an increasing number of patients are confused. This paper aims to use spectral analysis as a diagnostic tool for analyzing different titanium implant alloys in order to determine the percentage of the alloy components and additions that are known to cause allergies. Different materials, such as sponge titanium, TiAl6Nb7, Ti21SRx, TiAl6V4 [forged alloy], TiAl6V4 [cast alloy], TMZF, pure titanium [c. p. 1] and iodide titanium were analyzed for the presence of the elements that have been associated with allergic reactions using spectral analysis. All the implant material samples contained traceable amounts of Be, Cd, Co, up to a maximum of 0.001 percent by weight [wt.%], Cr up to 0.033 wt.%, Cu up to 0.007 wt.%, Hf up to 0.035 wt.%, Mn up to 0.007 wt.%, Ni up to 0.031 wt.%, and Pd up to 0.001 wt.%. This paper demonstrates that all the investigated implant material samples contained a low but consistent percentage of components that have been associated with allergies. For example, low nickel contents are related to the manufacturing pro- cess and are completely dissolved in the titanium grid. Therefore, they can virtually be classified as “impurities”. Under certain circumstances, these small amounts may be sufficient to trigger allergic reactions in patients suffering from the corresponding allergies, such as a nickel, palladium or chrome allergy.