Apatite Forming Ability and Dissolution Behavior of Boron- and Calcium-Modified Silicon Oxycarbides in Comparison to Silicate Bioactive Glass

Abstract

The bioactivity of Ca and/or B modified silicon oxycarbides has been assessed in vitro upon immersion in SBF (simulated body fluid). In the context of the present work, bioactivity refers to the likeliness of hydroxyapatite crystallization (biomineralization) on the surface of a material when in contact with physiological fluids. The incorporation of Ca and B into the silicon oxycarbide glass network is found to increase its bioactivity, which seems to scale with the content of Ca; thus, SiOC glass with a relatively large Ca/Si molar ratio (i.e., 0.12) is shown to exhibit bioactive characteristics similar to those of the benchmark silicate bioactive glass of 45S5 composition. The release kinetics of the SiOC glasses modified with Ca and/or B during the SBF test was studied by inductively coupled plasma-optical emission spectroscopy. It has been observed that the Si release kinetics can be correlated with the Ca content in the SiOC glasses: SiOC based glasses modified with Ca exhibited low Si release activation energies (i.e., 0.07 eV), being comparable to that of 45S5 bioactive glass (i.e., 0.04 eV); whereas silicon oxycarbides without Ca modification showed higher activation energies for Si release (i.e., 0.27 eV).

Facile Preparative Access to Bioactive Silicon Oxycarbides with Tunable Porosity

“…Interestingly, although no hydroxyapatite-like precipitation was observed on SiCa0-T (Figure 9a), as also suggested by FTIR and XRD results, its surface shows a sort of coarsening compared to the surface before SBF soaking (see Figure 7a), indicating the occurrence of certain surface dissolution or leaching processes during SBF exposure. Indeed, Si release from ternary silicon oxycarbide takes place even though at a slow rate, according to our previous study [54]. The different shape and surface coverage of hydroxyapatite (HA) in Figure 9 shows clearly that SiCa50-T, with an almost complete HA surface covering, has the highest apatite forming ability among the investigated silicon oxycarbide samples.…”

Effect of Bone Morphogenic Protein-2-Loaded Mesoporous Strontium Substitution Calcium Silicate/Recycled Fish Gelatin 3D Cell-Laden Scaffold for Bone Tissue Engineering

“…Si ions were found to be excellent biological cues for induction of bone mineralization whilst the Ca ion served as a crucial factor for bone formation [12]. A previous study conducted by us further observed that CS-based materials had the ability to induce a layer of calcified bone-like apatite formation that could be used as a predictive marker for subsequent bone tissue formation [13]. In previous studies, it was shown that mesoporous molecules could be loaded onto CS and used in several biomedical applications, such as for molecule fluorescent labeling, as a drug carrier and as a genetic vector [14].…”

Effect of the Content and Ordering of the sp2 Free Carbon Phase on the Charge Carrier Transport in Polymer-Derived Silicon Oxycarbides

“…Moreover, studies concerning the network architecture of silicon oxycarbide glasses revealed a relatively low mass fractal dimension of those materials (typically in the range of 2.3–2.5) [ 2 ], which has been reflected for instance in a very low Poisson ratio (i.e., 0.11 as compared to 0.17 in silica-based glasses) [ 4 ] and highly promising bioactivity with respect to hydroxyapatite mineralization [ 5 , 6 , 7 ]. The glassy network of silicon oxycarbides can be easily altered via incorporating additional network formers (i.e., boron) [ 8 ] or modifiers (e.g., Li, Ca, Mg, etc.) [ 3 , 5 , 6 , 9 , 10 ], thus structural properties such as network connectivity and polymerization can be finely tuned [ 6 ].…”