Effects of the surface characteristics of nanoporous titanium oxide films on Ti-24Nb-4Zr-8Sn alloy on the initial adhesion of osteoblast-like MG-63 cells

Abstract

The aim of the present study was to investigate the effects of the surface characteristics of nanoporous titanium oxide films, formed by anodization on Ti-24Nb-4Zr-8Sn (Ti2448) alloy, on the early adhesion of osteoblast-like MG-63 cells. Nanoporous titanium oxide films with two different pore sizes (30 and 90 nm) were formed by anodization in NH4F solution on Ti2448 alloy. The surface roughness of the nanoporous titanium oxide films was determined using a Surftest Formtracer and field emission scanning electron microscopy (FESEM). Cell viability was evaluated at different time points using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To investigate the regulatory mechanisms involved in the focal adhesion of osteoblasts to Ti2448 alloy, we quantified the expression levels of integrin β1 and paxillin mRNAs on the nanoporous titanium oxide films during early osteoblast adhesion using real-time RT-PCR. Samples with a 30-nm nanoporous film exhibited a greater number of overlapping microporous structures with microprojections compared with the 90-nm nanoporous film samples. The MTT assay indicated that cell viability on the 30-nm nanoporous surface following 24 and 48 h of cell culture was higher than those observed on the unanodized control and 90-nm nanoporous surfaces. Integrin β1 mRNA expression levels on the 30-nm nanoporous surface following cell culture for 48 h were also significantly higher compared with those on the unanodized control and 90-nm nanoporous surfaces. The results demonstrated that a 30-nm nanoporous titanium oxide film on Ti2448 alloy may provide the optimum bioactive implant surface for the initial adhesion of osteoblasts.

Nanoporous Anodic Alumina Surfaces Affect Fibro‐ and Osteoblasts in Opposite Ways

“…However, no superiority to Ti surfaces could be detected. These results coincide with previous studies that showed that bone cells have a better adhesion, growth, differentiation, and phenotypic maturation on surfaces with a roughness of tens of nanometers than on flat surfaces and surfaces with a submicron‐ or microscale roughness …”

Effect of TiO2 Nanotube Pore Diameter on Human Mesenchymal Stem Cells and Human Osteoblasts

“…Osteoblasts responses were rather conflicting in the literature, with some agreed on better cell viability found on nanotube less than 30 nm pore diameter (Group 1) [31,32] and some suggested greater osteoblastic functions found on pore diameter between 30 nm and 50 nm (Group 2) [13,[26][27][28][29][30], but only a few have proposed high osteogenic responses on the nanotube layer with pore diameter over 70 nm (Group 3) [33,35]. It is worth noting that the reports published in Group 1 and Group 3 were limited to only cell adhesion percentage [31], cell viability and proliferation rate [32], with a limited comparison between nanotube ranges [33] and generalised assumptions on osteoblastic responses [35], these studies were lacking a clear reasoning on osteogenic differentiation in general.…”

“…Previous work determining the relationship between nanotube diameter and mesenchymal stem progenitor cells suggested that a nanotube diameter below 30 nm led to enhanced mesenchymal osteogenic ability [14,[17][18][19][20][21][22], with a small number of reports proposing that 70 nm to 100 nm is more favourable for mesenchymal stem cells [14,23,24], and a single study that has reported that 30 and 50 nm stimulated early osteoblastic gene expression [25]. However, for in-vitro osteoblastic cell lines studies, greater bone mineralisation has been demonstrated on the surfaces of nanotubes with a diameter range of 30 to 50 nm [26][27][28][29][30], while others have suggested that nanotube diameters of 15 to 30 nm displayed higher cell viability and proliferation [13,31,32]. Other published works comparing the unilateral nanotube samples to that of non-anodised samples indicated that 70 to 80 nm exhibited greater osteogenic ability [33][34][35], but those results are not adequate as a more extensive sample size should be included to obtain a more precise conclusion.…”

Functional Studies of Anodic Oxidized β-Ti-28Nb-11Ta-8Zr Alloy for Mechanical, In-vitro and Antibacterial Capability

“…Such a NPTNTZO(c) layer demonstrates high corrosion resistance 33 , protecting this alloy in the corrosive environment during osteoblast culture. Another advantage of NPTNTZO(c) is its nanoporous morphology 34 , which is biomimetic with the extracellular matrix of bone tissue, which is mainly composed of nanoporous minerals 35 , 36 . Furthermore, the NPTNTZO(c) layer can also act as a reservoir to accommodate silver nanoparticles (AgNPs), providing an improved antibacterial capability.…”