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Background Next generation of coating materials on the surface of implants is designed with a paradigm shift from an inert material to an osteoimmunomodulatory material. Regulating immune response to biomedical implants through influencing the polarization of macrophage has been proven to be an effective strategy. Methods Through anodization and hydrothermal treatment, magnesium ion incorporated TiO2 nanotube array (MgN) coating was fabricated on the surface of titanium and it is hypothesized that it has osteoimmunomodulatory properties. To verify this assumption, systematic studies were carried out by in vitro and in vivo experiments. Results Mg ion release behavior results showed that MgN coating was successfully fabricated on the surface of titanium using anodization and hydrothermal technology. Scanning electron microscopy (SEM) images showed the morphology of the MgN coating on the titanium. The expression of inflammation-related genes (IL-6, IL-1β, TNF-α) was downregulated in MgN group compared with TiO2 nanotube (NT) and blank Ti groups, but anti-inflammatory genes (IL-10 and IL-1ra) were remarkably upregulated in the MgN group. The in vitro and in vivo results demonstrated that MgN coating influenced macrophage polarization toward the M2 phenotype compared with NT and blank-Ti groups, which enhanced osteogenic differentiation of rat bone mesenchymal stem cells rBMSCs in conditioned media (CM) generated by macrophages. Conclusion MgN coating on the titanium endowed the surface with immune-regulatory features and exerted an advantageous effect on osteogenesis, thereby providing excellent strategies for the surface modification of biomedical implants.

Titanium is a primary metallic biomaterial widely used in dental implants because of its favorable mechanical properties and osseointegration capability. Currently, increasing interests have been taken in the interaction between titanium implant surface and surrounding bone tissue, particularly in surface topographical aspect. There are currently several techniques developed to modify surface topographies in the world market of dental implant. In this review, state of titanium implant surfaces in topographical aspect is presented from relatively smooth surfaces to rougher ones with microtopographies and/or nanotopographies. Each surface is summarized with basic elaborations, preparation methods, mechanisms for cellular responses and current availabilities. It has been demonstrated that rough surfaces evolving from micro- to nano-scale, especially hierarchical micro-and nanotopographies, are favorable for faster and stronger osseointegration. Further experimental and clinical investigations will aid in the optimization of surface topography and clinical selection of suitable implants.

The ligands 1-H6 and 2-H6 are prepared by condensation of the triangular triamines 5 and 2,3-dihydroxybenzoic acid hydrazide 7. The ligands form container-type tetrahedral coordination compounds Mx [(1 or 2)4M′4] (M = Li, Na, K; M′ = Ti, x = 8; M′ = Ga, x = 12). The complexes are characterized by NMR spectroscopy and ESI mass spectrometry. Despite the relatively labile acyl hydrazone unit, the complexes show high stability in water. Ligand 3-H6 is prepared from the trisacyl hydrazide 8 and 2,3-dihydroxybenzaldehyde 9 but does not form well-defined coordination compounds with gallium(III) or titanium(IV) ions.

Triangular triscatechol ligands are prepared in facile reaction sequences. The catechol units are either bound to the triangular backbone through their 3- or 4-position. With titanium(IV) ions, the ligands form metallosupramolecular M(4)L(4) tetrahedra which are characterized by ESI MS and proton NMR. Quantum-chemical calculations reveal that connectivity at the catechol in the 3-position results in highly condensed structures while attachment in the 4-position affords container molecules providing huge internal cavities.