Agradecimentos: We thank Dr. Dario Campana, St Jude Children’s Research Hospital for kindly providing the hTERT + bone marrow mesenchymal cell line. We also acknowledge Prof. Dr. Antonio Riul Junior and Dr. Mawin Javier Martinez Jimenez from DFA-IFGW, UNICAMP, for their support in the electrochemical tests. This work was supported by the São Paulo Research Foundation (FAPESP), grants #2019/18460-4, #2019/04943-3 and #2018/24461-0 and FAPERGS, grant #19/2551-0002288-3. FC and LLA are FAPESP fellows. VP is CAPES fellow (grant #88887.475264/2020-00). JAY, CAF and FA are CNPq fellows Ver menos

Abstract: This study combines the brand new concept of high-entropy designed materials with the superior properties of metallic glasses to obtain a NbTaTiVZr high-entropy metallic glass (HEMG) coating for biomedical applications. The amorphous structure is achieved by a room temperature magnetron sputtering deposition, whereas a bcc crystalline phase, typical of high-entropy alloys (HEA), is obtained at 400 degrees C. X-ray photoelectron spectroscopy showed that the oxygen concentration on the coatings surface is > 50% and significantly higher than in the bulk (similar to 5%). The NbTaTiVZr(O) HEMG surface is completely passivated, in contrast to the metallic + oxide outermost layer found for the HEA. Potentiodynamic polarization tests attested an improved corrosion resistance of the HEMG surface, which showed also increased hydrophilicity compared to the crystalline sample. In vitro biocompatibility investigations using both the hTERT-immortalized bone marrow mesenchymal cells and MG-63 osteosarcoma cells showed excellent viability (similar to 98% and similar to 96%, respectively) and adhesion onto the HEMG coating after 96 h of incubation, indicating the integrity and biosafety of this surface. The cell viability and proliferation on the HEA and Ti (used as a benchmark) surfaces were much inferior. The enhanced surface protection and the superior biocompatibility makes the HEMG promising to be employed as a biocoating on orthopedic implants Ver menos