Pulsed Laser Deposition Derived Bioactive Glass-Ceramic Coatings for Enhancing the Biocompatibility of Scaffolding Materials

Abstract

The purpose of this work was to propose and evaluate a new composition for a bioactive glass-ceramic starting from the well-known 45S5 commercial product. Thus, we developed a modified version, including MgO, an oxide that turned out to induce superior mechanical properties and improved biological response. This had the following molar percentages: 46.1% SiO2, 2.6% P2O5, 16.9% CaO, 10.0% MgO, and 24.4% Na2O. The precursor alkoxides and nitrates were processed by a standard sol-gel technique, resulting in a glass-ceramic target, suitable for laser ablation experiments. Combeite (Na2Ca2Si3O9) was identified as a main crystalline phase within the calcined sol-gel powder, as well as in the case of the target sintered at 900 °C. The thin films were deposited on silicon substrates, at room temperature or 300 °C, being subsequently characterized from the material point of view, as well as in terms of bioactivity in simulated conditions and biocompatibility in relation to human fibroblast BJ cells. The investigations revealed the deposition of nanostructured glassy layers with a low proportion of crystalline domains; it was shown that a higher substrate temperature promoted the formation of surfaces with less irregularities, as a consequence of material arrangement into a shell with better morphological homogeneity. The complex elemental composition of the target was successfully transferred to the coatings, which ensured pronounced mineralization and a stimulating environment for the cell cultures. Thereby, both samples were covered with a thick layer of apatite after immersion in simulated body fluid for 28 days, and the one processed at room temperature was qualified to be the best in relation to the cells.

Osteoconductive and Osteoinductive Surface Modifications of Biomaterials for Bone Regeneration: A Concise Review

“…Precisely, the TiO 2 /ZnO coating enhanced bALP activity and secretion of main ECM proteins (collagen, OPN, OCN) in Saos-2 cells. In turn, Schitea et al [44] developed derivative bioactive glass-ceramics (SiO 2 /P 2 O 5 /CaO/MgO/Na 2 O) coating, which was deposited on silicon substrates by a pulsed laser deposition method at room temperature and at 300 • C substrate temperature. In vitro experiments using human skin fibroblasts (BJ cell line) showed that all prepared coatings were cytocompatible.…”

Composite Fiber Networks Based on Polycaprolactone and Bioactive Glass-Ceramics for Tissue Engineering Applications

“…The thermal processing must be conducted in such a way that the nucleation and growth of crystalline domains provide a balance between multiple aspects; however, the final three-dimensional porous structure should allow for cell proliferation, vascularization and nutrient diffusion [ 19 ]. Such materials, which are of an intrinsically composite character, can be shaped either as scaffolds [ 20 , 21 ] or as coatings [ 22 , 23 ].…”

Development of New Mg- or Sr-Containing Bioactive Interfaces to Stimulate Osseointegration of Metallic Implants

“…According to the SEM images captured after 28 days of immersion in SBF, the PLD-engineered layers present on their surface apatitic formations composed of spherical entities with diameters below 200 nm, lightly gathered in favoured areas; occasionally, hollow structures can be identified (Figure 5a-d). These types of appearance are typical of the products that arise during a mineralization process [6,8,36,42]. It is not clear if, apart from these micrometric and undefined agglomerations, a thin and continuous layer of apatite is nucleated on the entire exposed area.…”

“…Beyond the basic features of an implant, namely size, shape, mechanical strength, lack of cytotoxicity [4], current concerns are directed towards the design and fabrication of devices with superior characteristics, among which bioactivity and osseointegration potential are the most important [5]. By combining well-known and long-tested materials with bioactive coatings [6,7], antibacterial agents [8,9], antioxidant compounds [10] or biologically active molecules [11], novel systems that mimic the means of healing proper to the living body can be proposed, subsequently leading to bone regeneration and remodelling.…”

“…Our research group reported on several complex oxide systems, which were processed by sol-gel, spin coating and pulsed laser deposition as bioactive and biocompatible coatings [6,8,16,41,42], leading to considerable expertise in the field. In this work, novel compositions including Mg or Sr were tested in the form of thin films for providing suitable materials to coat the bioinert ceramic or metallic bone implants, ensure a biologically active interface and subsequently triggering speeded and superior osseointegration of them within the afflicted body.…”