Nanosurfacing Ti alloy by weak alkalinity-activated solid-state dewetting (AAD) and its biointerfacial enhancement effect.

Nanoscale manipulation of material surfaces can create extraordinary properties, holding great potential for modulating the implant-bio interface for enhanced performance. In this study, a green, simple and biocompatible nanosurfacing approach based on weak alkalinity-activated solid-state dewetting (AAD) was for the first time developed to nano-manipulate the Ti6Al4V surface by atomic self-rearrangement. AAD treatment generated quasi-periodic titanium oxide nanopimples with high surface energy. The nanopimple-like nanostructures enhanced the osteogenic activity of osteoblasts, facilitated M2 polarization of macrophages, and modulated the cross-talk between osteoblasts and macrophages, which collectively led to significant strengthening of in vivo bone-implant interfacial bonding. In addition, the titanium oxide nanopimples strongly adhered to the Ti alloy, showing resistance to tribocorrosion damage. The results suggest strong nano-bio interfacial effects, which was not seen for the control Ti alloy processed through traditional thermal oxidation. Compared to other nanostructuring strategies, the AAD technique shows great potential to integrate high-performance, functionality, practicality and scalability for surface modification of medical implants.

Potential of niobium-based thin films as a protective and osteogenic coating for dental implants: The role of the nonmetal elements.

An ideal dental implant coating should provide a highly protective interface and an osteogenic function. Inspired by the excellent biocompatibility and anti-corrosion of the Nb element, we produced Nb-based oxide, nitride and carbide films as well as the pure metal Nb film for surface enhancement of dental implants, and compare the impact of the nonmetal elements on the electrochemical, tribological, tribo-corrosion and biological performance of the coated implants. The NbC film, composed of a single-phased subniobium carbide, displays mechanical advantages and anticorrosion characteristics that are distinguished from the other composite films, highlighting its potential outstanding protective efficiency for dental implants against corrosion and wear. Rat bone marrow mesenchymal stem cells (rBMSCS) were found more readily to attach, grow and osteogenically differentiate on the NbC film compared to the Nb, NbO and NbN films, indicating the osteogenesis potential of the NbC film. Taken all the results together, it can be concluded that the NbC film have the highest potential for dental implant surface modification.

Nb-C nanocomposite films with enhanced biocompatibility and mechanical properties for hard-tissue implant applications.

One of the key challenges in engineering of orthopedic implants is to "bioactivate" their surface by using different surface techniques and materials. Carbon, especially amorphous (a-C) and diamond-like carbon down (DLC) films have attracted much attention in biomedical fields due to their biocompatibility and low coefficient of friction. However, they are unsuitable for uses as a "bioactivity enhancer" of orthopedic implants due to their bioinertness. In this work, we use the nonreactive magnetron sputtering technique to produce a-C films including the biocompatible niobium (Nb) element to alter the surface chemistry and nanotopography of the a-C films with the purpose of bioactivating the a-C film coated implants. Results show that the nanocomposite films (Nb-C) formed by the addition of Nb into the a-C films not only have improved corrosion resistance, but also possess enhanced mechanical properties (nanohardness, Young's modulus and superelastic recovery). Preosteoblasts (MC3T3-E1) cultured on the Nb-C films have enhanced adhesion and upregulated alkaline phosphatase (ALP) activity, compared to those cultured on the a-C film and TiO2 films used as a control, which are thought to be ascribed to the combined effects of the changes in surface chemistry and the refinement of the nanotopography caused by the addition of Nb.