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The immunomodulatory role of monocytes is essential for tissue healing and can influence the osseointegration of implanted materials. Properties such as the surface structure, hydrophilicity, and roughness of the implanted materials can modulate monocyte–macrophage function. In this study, we characterized material-hydrogenated TiO2 nanotubes (H-TNT) with superhydrophilic surfaces to investigate the effect of H-TNT on macrophage polarization and osseointegration. H-TNT were prepared by anodic oxidation and hydrogenation and used in the experimental group, while TNT and smooth pure Ti were employed in the control groups. RAW264.7 cells were selected to observe the immunomodulatory effect of these samples. The cell morphology was observed via scanning electron microscopy, and cytokine expression was detected using an enzyme-linked immunosorbent assay and immunofluorescence staining. After 24 hr of cultivation, the macrophage-conditioned medium was collected and used for indirect coculture with MC3T3-E1 cells. The morphology of MC3T3-E1 cells was observed using fluorescence staining. Cell adhesion and proliferation were measured using the Cell Counting Kit-8 assay. Alkaline phosphatase activity measurement, alizarin red staining, calcium quantification, and reverse transcription polymerase chain reaction were performed to assess the osteogenic differentiation of MC3T3-E1 cells. The results showed that H-TNT promoted the M2-type polarization of macrophages, which in turn influenced the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. These materials can serve as useful candidates for bone implants because they activate macrophages to produce a favorable osteoimmunomodulatory microenvironment. [ABSTRACT FROM AUTHOR]

Titanium-based implants are often utilized in oral implantology and craniofacial reconstructions. However, the biological inertness of machined titanium commonly results in unsatisfactory osseointegration. To improve the osseointegration properties, we modified the titanium implants with nanotubular/superhydrophilic surfaces through anodic oxidation and thermal hydrogenation and evaluated the effects of the machined surfaces (M), nanotubular surfaces (Nano), and hydrogenated nanotubes (H-Nano) on osteogenesis and osseointegration in vitro and in vivo. After incubation of mouse bone marrow mesenchymal stem cells on the samples, we observed improved cell adhesion, alkaline phosphatase activity, osteogenesis-related gene expression, and extracellular matrix mineralization in the H-Nano group compared to the other groups. Subsequent in vivo studies indicated that H-Nano implants promoted rapid new bone regeneration and osseointegration at 4 weeks, which may be attributed to the active osteoblasts adhering to the nanotubular/superhydrophilic surfaces. Additionally, the Nano group displayed enhanced osteogenesis in vitro and in vivo at later stages, especially at 8 weeks. Therefore, we report that hydrogenated superhydrophilic nanotubes can significantly accelerate osteogenesis and osseointegration at an early stage, revealing the considerable potential of this implant modification for clinical applications. [ABSTRACT FROM AUTHOR]

The soft tissue sealing at the transmucal portion of implants is vital for the long-term stability of implants. Hydrogenated titanium nanotubes (H2-TNTs) as implant surface treatments were proved to promote the adhesion of human gingival fibroblasts (HGFs) and have broad usage as drug delivery systems. Bovine serum albumin (BSA) as the most abundant albumin in body fluid was crucial for cell adhesion and was demonstrated as a normal loading protein. As the first protein arriving on the surface of the implant, albumin plays an important role in initial adhesion of soft tissue cells, it is also a common carrier, transferring and loading different endogenous and exogenous substances, ions, drugs, and other small molecules. The aim of the present work was to investigate whether BSA-loaded H2-TNTs could promote the early adhesion of HGFs; H2-TNTs were obtained by hydrogenated anodized titanium dioxide nanotubes (TNTs) in thermal treatment, and BSA was loaded in the nanotubes by vacuum drying; our results showed that the superhydrophilicity of H2-TNTs is conducive to the loading of BSA. In both hydrogenated titanium nanotubes and non-hydrogenated titanium nanotubes, a high rate of release was observed over the first hour, followed by a period of slow and sustained release; however, BSA-loading inhibits the early adhesion of human gingival fibroblasts, and H2-TNTs has the best promoting effect on cell adhesion. With the release of BSA after 4 h, the inhibitory effect of BSA on cell adhesion was weakened. [ABSTRACT FROM AUTHOR]

• Superhydrophilic nanostructure was fabricated for improving soft tissue sealing. • The properties of the surface regulate the behavior of human gingival fibroblasts. • FAK/integrin-mediated adhesion seemed to be induced by the hydrogenated surface. Soft tissue integration is critical for the long-term retention of dental implants. The surface properties including topography and wettability can impact soft tissue sealing. In our work, a thermal hydrogenation technique was applied to modify anodized titanium dioxide nanotubes (TNTs). However, the effects of the hydrogenated surface on soft-tissue cells remain unclear. The aim of the present study was to investigate the bioactivities of human gingival fibroblasts (HGFs) on structured surfaces, which determine the early formation of soft tissue sealing. Three groups were examined: commercially pure titanium (Ti), anodized TNTs (air-TNTs) and hydrogenated TNTs (H 2 -TNTs). Scanning electron microscopy showed the nanotubular topography on the titanium surfaces after anodization. Then, hydrogenation ensured that the H 2 -TNTs were superhydrophilic with a contact angle of 3.5 ± 0.8°. In vitro studies such as cell adhesion assays, cell morphology, immunocytochemistry, wound healing assays, real-time PCR and enzyme-linked immunosorbent assays displayed enhanced adhesion, migration, relative gene expression levels, and extracellular matrix synthesis of the HGFs on H 2 -TNTs. Interestingly, focal adhesion kinase activation and integrin-mediated adhesion seemed to be induced by the H 2 -TNT surface. Our results revealed that a superhydrophilic nanostructure modified by anodization and hydrogenation can improve the bioactivity of HGFs and connective tissue regeneration, which will further promote and expand the application of titanium dioxide nanotubes in dental implants. [ABSTRACT FROM AUTHOR]