Characterization of magnesium doped sol-gel biomaterial for bone tissue regeneration: The effect of Mg ion in protein adsorption

Abstract

Magnesium is the fourth most abundant element in the human body with a wide battery of functions in the maintenance of normal cell homeostasis. In the bone, this element incorporates in the hydroxyapatite structure and it takes part in mineral metabolism and regulates osteoclast functions. In this study, sol-gel materials with increasing concentrations of MgCl2 (0.5, 1, and 1.5%) were synthesized and applied onto Ti surfaces as coatings. The materials were first physicochemically characterized. In vitro responses were examined using the MC3T3-E1 osteoblastic cells and RAW264.7 macrophages. Human serum protein adsorption was evaluated employing nLC-MS/MS. The incorporation of Mg did not affect the crosslinking of the sol-gel network, and a controlled release of Mg was observed; it was not cytotoxic at any of the tested concentrations. The cytoskeleton arrangement of MC3T3-E1 cells cultured on the Mg-doped materials changed in comparison with controls; the cells became more elongated, with protruded lamellipodia and increased cell surface. The expression of integrins (ITGA5 and ITGB1) was boosted by Mg-coatings. The ALP activity and expression of TGF-β, OSX and RUNX2 genes were also increased. In RAW264.7 cells, TNF-α secretion was reduced, while TGF-β and IL-4 expression rose. These changes correlated with the altered protein adsorption patterns. The Mg-doped coatings showed increased adsorption of anti-inflammatory (CLUS, IC1, CFAH, and VTNC), cell adhesion (DSG1, FILA2, and DESP) and tissue regeneration (VTNC and CYTA) proteins. This integrated approach to biomaterial characterization revealed the potential of Mg in bone tissue regeneration.

The effect of calcium–magnesium mixtures in sol–gel coatings on bone tissue regeneration

“…In vitro inflammatory response to Ca depends on the ion concentration in a material, 20 while Mg generally shows an antiinflammatory activity. 10 Here, the CaMg sol-gel coatings displayed increased TNF-α and TGF-β secretion and gene expression. However, these coatings decreased IL-10 expression in the Mg-dose-dependent manner.…”

“…The individual effects of these two ions on the protein adsorption on implant surfaces have been already examined. 10,20 It has been shown that Ca has a high affinity to proteins involved in coagulation and inflammatory responses, while the addition of Mg increases the material affinity to proteins related to cell adhesion. With these data in mind, designing and analysing a biomaterial to combine the regulatory properties of the two ions was a promising path to follow.…”

“…4,6 Naturally found in the bone, the Mg 2+ is essential for the metabolism of this tissue; it stimulates bone formation and resorption. 4 The Mg ions also enhance cell adhesion 10 via affecting all the cell adhesion machinery 11 and have an anti-inflammatory potential. 12,13 Therefore, the combined effect of these two metal cations might be the modulation of protein adsorption, blood clot formation, cell adhesion and differentiation, thus ensuring the success of the bone regeneration process.…”

Deciphering the role of faujasite-type zeolites as a cation delivery platform to sustain the functions of MC3T3-E1 pre-osteoblastic cells

“…Shen et al 49 showed that the surface of osteoblastic cells increases with a Mg 2+ concentration up to 8 mM (7.6 mM found at maximum in our study) prior to diminishing which is in accordance with another recent study that depicted the same dependence of the size on Mg 2+ ions, based on the argument that a lot of proteins, proteases, or apolipoproteins are prone to adsorb onto material surfaces in the presence of less than 10 mM Mg 2+ . 63 Likewise, protein adsorption may provide several sites to support cell adhesion and the establishment of focal contacts. Moreover, MC3T3-E1 cells in Mg 1% displayed the polygonal morphology whereas they appeared smaller and spindle-shaped in Mg 1.5%.…”

Insight into the antibacterial mechanism of Cu-enriched sol–gel coatings employing proteomics

“…17 Proteomics offers powerful tools for analysing complex mixtures of proteins, such as the protein layers formed on biomaterials. 18 Cerqueira et al 19 have studied the protein layers adsorbed onto magnesium-enriched surfaces. Many proteins associated with cell adhesion were found on these surfaces, explaining the improved osteoblast adhesion to these Mg-enriched materials.…”