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Nanotechnology offers a new strategy to develop novel bioactive materials, given that nano-scaled biomaterials exhibit an enhanced biocompatibility and bioactivity. In this work, we developed a method for the synthesis of spherical bioactive glass nanoparticles (BGNP) aimed at producing biomaterials for potential use in the repair of hard tissues. The BGNP were prepared using the sol-gel process based on the reaction of alkoxides and other precursors in aqueous media for obtaining the oxide-ternary system with the stoichiometric proportion of 60% SiO2, 36% CaO and 4% P2O5. The system was extensively characterized by Fourier transform infrared, x-ray diffraction and scanning electron microscope/energy-dispersive x-ray spectroscopy with regard to chemical composition, crystallinity and morphology. Moreover, the results suggested the BGNP to be highly bioactive, which was confirmed by the formation of a hydroxyapatite biomimetic layer on the material surfaces upon immersion in simulated body fluid solution. In addition, the bioactivity response toward the developed BGNPs was assessed by direct contact of osteoblast cells using resazurin and alkaline phosphatase assays. The new BGNP have presented a significant increase in the osteoblast in vitro cytocompatibility behavior as compared to similar micro-sized bioactive glass particles. Such improvement in the overall bioactive behavior of BGNP was attributed to the much higher surface area causing enhanced interactions at the cell-nanomaterial interfaces. Hence, based on the results, the BGNP produced are the biomaterials to be potentially utilized in hard tissue engineering applications.

The development of polymer/bioactive glass has been recognized as a strategy to improve the mechanical behavior of bioactive glass-based materials. Several studies have reported systems based on bioactive glass/biopolymer composites. In this study, we developed a composite system based on bioactive glass nanoparticles (BGNP), obtained by a modified Stöber method. We also developed a new chemical route to obtain aqueous dispersive biodegradable polyurethane. The production of polyurethane/BGNP scaffolds intending to combine biocompatibility, mechanical, and physical properties in a material designed for tissue engineering applications. The composites obtained were characterized by structural, biological, and mechanical tests. The films presented 350% of deformation and the foams presented pore structure and mechanical properties adequate to support cell growth and proliferation. The materials presented good cell viability and hydroxyapatite layer formation upon immersion in simulated body fluid.

Cementum is a mineralized tissue that lines the surface of the tooth root enabling attachment of the periodontal ligament to the root and surrounding alveolar bone. Studies examining the mechanisms involved in the formation of root cementum have been hindered by an inability to isolate and culture the cells required for cementum production (cementoblasts). This study isolated and characterized cementoblast cells derived from rat molar periodontal ligament. It was observed that the isolated cells expressed F-Spondin, a cementoblast marker, while F-Spondin expression was not observed in the cells of other tissues such as gingival fibroblasts and osteoblasts. As expected, the isolated cementoblast cells also expressed osteocalcin (OC), bone sialoprotein (BSP), alkaline phosphatase (ALP), and type I collagen, demonstrating the presence of mineralized tissues genes in cementoblast cells. These cells showed high ALP activity and calcified nodule formation in vitro. Since cementogenesis could be a critical event for regeneration of periodontal tissues, this study investigated whether bioactive glass particles could affect the proliferation of cementoblasts since they are known to enhance osteoblast proliferation. It was found that the ionic products from bioactive glass nanoparticles increased cementoblast viability, mitochondrial activity, and induced cell proliferation. Together, these results show the characterization of cementoblast cells from rat molar periodontal ligament. Additionally, it was shown that bioactive glass nanoparticles induced cementoblast to proliferate, indicating that they could be a potential material for use in cement regeneration through tissue engineering.

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Bioactive glass/polymer hybrids are promising materials for biomedical applications because they combine the bioactivity of these glasses with the flexibility of polymers. In this work it was evaluated the effect of increasing the PVA content of the on structural characteristics and mechanical properties of hybrid. The hybrids were prepared with 70 wt. (%) SiO 2 -30 wt. (%) CaO and PVA fractions of 20 to 60 wt. (%) by the sol-gel method. The structural and mechanical characterization was done by FTIR, SEM and compression tests. To reduce the acidic character of the hybrids due to the catalysts added, different neutralization solutions were tested. The calcium acetate alcoholic solution was the best neutralizing method, resulting in foams with final pH of about 7.0 and small sample contraction. The foams presented porosity of 60-85 wt. (%) and pore diameters of 100-500 µm with interconnected structure. An increase of PVA fraction in the hybrids improved their mechanical properties. The scaffolds produced provided a good environment for the adhesion and proliferation of osteoblasts.

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