<p>Zn-Incorporated TiO2 Nanotube Surface Improves Osteogenesis Ability Through Influencing Immunomodulatory Function of Macrophages</p>

Abstract

Purpose: Zinc (Zn), an essential trace element in the body, has stable chemical properties, excellent osteogenic ability and moderate immunomodulatory property. In the present study, a Zn-incorporated TiO 2 nanotube (TNT) was fabricated on titanium (Ti) implant material. We aimed to evaluate the influence of nano-scale topography and Zn on behaviors of murine RAW 264.7 macrophages. Moreover, the effects of Zn-incorporated TNT surface-regulated macrophages on the behaviors and osteogenic differentiation of murine MC3T3-E1 osteoblasts were also investigated. Methods: TNT coatings were firstly fabricated on a pure Ti surface using anodic oxidation, and then nano-scale Zn particles were incorporated onto TNTs by the hydrothermal method. Surface topography, chemical composition, roughness, hydrophilicity, Zn release pattern and protein adsorption ability of the Zn-incorporated TiO 2 nanotube surface were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), surface profiler, contact angle test, Zn release test and protein adsorption test. The cell behaviors and both pro-inflammatory (M1) and pro-regenerative (M2) marker gene and protein levels in macrophages cultured on Zn-incorporated TNTs surfaces with different TNT diameters were detected. The supernatants of macrophages were extracted and preserved as conditioned medium (CM). Furthermore, the behaviors and osteogenic properties of osteoblasts cultured in CM on various surfaces were evaluated. Results: The release profile of Zn on Zn-incorporated TNT surfaces revealed a controlled release pattern. Macrophages cultured on Zn-incorporated TNT surfaces displayed enhanced gene and protein expression of M2 markers, and M1 markers were moderately inhibited, compared with the LPS group (the inflammation model). When cultured in CM, osteoblasts cultured on Zn-incorporated TNTs showed strengthened cell proliferation, adhesion, osteogenesis-related gene expression, alkaline phosphatase activity and extracellular mineralization, compared with their TNT counterparts and the Ti group. Conclusion: This study suggests that the application of Zn-incorporated TNT surfaces may establish an osteogenic microenvironment and accelerate bone formation. It provided a promising strategy of Ti surface modification for a better applicable prospect.

Impact of exogenous metal ions on peri-implant bone metabolism: a review

“…102 Zn-containing titanium nanotubes show that the size of nanotubes can affect the release of zinc ions and further affect the osteogenic differentiation of MC3T3-E1 cells by regulating the function of macrophages. 103 In the process of zinc ion deposition on the titanium surfaces, longer deposition times and higher zinc contents decrease of the levels E. coli and S. aureus. These data proved that Zn-containing titanium surfaces can inhibit the adhesion and growth of bacteria and reduce the inammatory response around the implant.…”

Silver-Deposited Nanoparticles on the Titanium Nanotubes Surface as a Promising Antibacterial Material into Implants

“…In addition to NP silver and NP copper, zinc, fluorine can be incorporated into TiO 2 nanotubes for biomedical applications. For example, zinc can be easily incorporated hydrothermally into nanotubes [46]. Moreover, in situ, other anodizing possibilities were made for gold (TiAu) [47] and platinum (TiPt) alloys [48].…”

Nano-Modified Titanium Implant Materials: A Way Toward Improved Antibacterial Properties

“…It was known that Zn can enhance the expression of M2 marker genes and proteins in macrophages. The adhesion, proliferation, and expression of osteoblast-related genes are increased by Zn ( Zhang et al, 2018c ; Chen et al, 2020 ). Zinc NPs are non-toxic and have a higher affinity to bacteria than ordinary zinc, which can lead to better antibacterial effect.…”