In vitroevaluation of human fetal osteoblast response to magnesium loaded mesoporous TiO₂coating

Abstract

This work aimed to evaluate the in vitro response of Transfected Human Foetal Osteoblast (hFOB) cultured on a magnesium-loaded mesoporous TiO2 coating. The application of mesoporous films on titanium implant surfaces has shown very promising potential to enhance osseointegration. This type of coating has the ability to act as a framework to sustain bioactive agents and different drugs. Magnesium is the element that, after calcium, is the most frequently used to dope titanium implant surfaces, since it is crucial for protein formation, growth factor expression, and aids for bone mineral deposition on implant surfaces. Mesoporous TiO2 films with an average pore-size of 6 nm were produced by the evaporation-induced self-assembly method (EISA) and deposited onto titanium discs. Magnesium loading was performed by soaking the mesoporous TiO2 discs in a magnesium chloride solution. Surface characterization was conducted by SEM, XPS, optical interferometry, and AFM. Magnesium release profile was assessed at different time points using a Magnesium Detection kit. Cell morphology and spreading were observed with SEM. The cytoskeletal organization was stained with TRITC-conjugated Phalloidin and cell viability was evaluated through a mitochondrial colorimetric (MTT) assay. Furthermore, gene expression of bone markers and cell mineralization were analyzed by real time RT-PCR and alizarin-red staining, respectively. The surface chemical analysis by XPS revealed the successful adsorption of magnesium to the mesoporous coating. The AFM measurements revealed the presence of a nanostructured surface roughness. Osteoblasts viability and adhesion as well as the gene expression were unaffected by the addition of magnesium possibly due to its rapid burst release, however, were enhanced by the 3D nanostructure of the TiO2 layer.

Local release of magnesium from mesoporous TiO 2 coatings stimulates the peri-implant expression of osteogenic markers and improves osteoconductivity in vivo

“…It was observed that OC was heavily expressed in the hard callus, while it was not detected in the soft callus, displaying its action mainly during mineralization [30]. Similarly, it was observed in vitro that OC was significantly more expressed in osteoblasts cultured on disks coated with mesoporous TiO 2 and loaded with Mg ions than on non-loaded controls [12]. It was found that OC was almost four times more expressed on the implants with Mg addition than for the controls, attesting that in the Mg-containing group the mineralization process was further progressed.…”

“…In a previous in vitro study [12] some of the authors of the current paper tested the release kinetics of mesoporous surfaces loaded with physically adsorbed Mg, and they observed that release of Mg ions followed a sustained profile, with a stable release for the first 24 h, when most of the adsorbed Mg was mobilized from the surfaces.…”

“…Previous reports have shown that this nanoporous surface can provide a basis for physically absorbed magnesium, which upon in vivo release influences osteogenesis [11,12]. Magnesium is one of the inorganic components in bone tissue, and it plays a crucial role in skeletal development.…”

Osteogenic potential of human adipose-derived stromal cells on 3-dimensional mesoporous TiO2 coating with magnesium impregnation

“…In a previous study, we analyzed the cellular response of osteoblasts (human fetal osteoblasts) to mesoporous TiO 2 coatings generated by the evaporation-induced self-assembly method (EISA) [25,26] and chemically modified with magnesium [27]. We demonstrated that human fetal osteoblasts (hFOB) adhesion was significantly enhanced by the presence of the mesopores.…”

The effect of osteotomy dimension on osseointegration to resorbable media-treated implants: A study in the sheep

“…Besides surface topography, surface chemistry has been modified by incorporation of different bioactive substances, such as calcium, magnesium, phosphates or fluorides, to further promote bone regeneration, proteins adsorption and cell attachment on the implants [12][13][14][15][16] . One method to modify the texture of titanium surfaces while deposing hydroxyapatite or calcium phosphate (CaP) on them, is blasting with resorbable biocompatible bioceramics (resorbable blasting media or RBM) [17][18][19][20] (Coelho and Lemon 2009, Marin et al 2008.…”