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Projeto de investigação
Bioactive glass composition and macrophage polarization: towards a pro-regenerative response
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In Vitro Characterization of Doped Bioglass 45S5/HAp Coatings Obtained by CoBlastTM Deposition
Publication . Pádua, Ana Sofia; Gavinho, Sílvia Rodrigues; Vieira, Tânia; Hammami, Imen; Silva, Jorge Carvalho; Borges, João Paulo; Graça, Manuel Pedro Fernandes; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; DF – Departamento de Física; MDPI - Multidisciplinary Digital Publishing Institute
Bone replacement is one of the major medical procedures in the oral surgery field due to the progressive ageing population and to illness or trauma in younger age groups. The use of implants without biological activity and effective osseointegration increases the chances of implant failure. This work aims to improve the interaction between implants and bone by using Bioglass 45S5 (BG)/hydroxyapatite (HAp) mixtures, including copper-, zinc-, and cerium-doped BG, as well as co-doping by the mentioned metals, as coatings produced by the CoBlastTM technique. All coatings present a uniform coverage of the Ti-6Al-4V substrate. Furthermore, in vitro testing using human osteosarcoma Saos-2 cells indicated that BG/HAp coatings have no cytotoxic effect, and the used of doping agents did not alter cell adhesion, proliferation, or alkaline phosphatase (ALP) expression when compared to undoped coating. These results demonstrate that BG/HAp by CoBlastTM can be a solution to improve implants’ osseointegration.
Extensive Investigation on the Effect of Niobium Insertion on the Physical and Biological Properties of 45S5 Bioactive Glass for Dental Implant
Publication . Hammami, Imen; Gavinho, Sílvia Rodrigues; Pádua, Ana Sofia; Lança, Maria do Carmo; Borges, João Paulo; Silva, Jorge Carvalho; Sá-Nogueira, Isabel; Jakka, Suresh Kumar; Graça, Manuel Pedro Fernandes; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DF – Departamento de Física; DCM - Departamento de Ciência dos Materiais; UCIBIO - Applied Molecular Biosciences Unit; DCV - Departamento de Ciências da Vida; MDPI - Multidisciplinary Digital Publishing Institute
Dental implants have emerged as one of the most consistent and predictable treatments in the oral surgery field. However, the placement of the implant is sometimes associated with bacterial infection leading to its loss. In this work, we intend to solve this problem through the development of a biomaterial for implant coatings based on 45S5 Bioglass® modified with different amounts of niobium pentoxide (Nb2O5). The structural feature of the glasses, assessed by XRD and FTIR, did not change in spite of Nb2O5 incorporation. The Raman spectra reveal the Nb2O5 incorporation related to the appearance of NbO4 and NbO6 structural units. Since the electrical characteristics of these biomaterials influence their osseointegration ability, AC and DC electrical conductivity were studied by impedance spectroscopy, in the frequency range of 102–106 Hz and temperature range of 200–400 K. The cytotoxicity of glasses was evaluated using the osteosarcoma Saos-2 cells line. The in vitro bioactivity studies and the antibacterial tests against Gram-positive and Gram-negative bacteria revealed that the samples loaded with 2 mol% Nb2O5 had the highest bioactivity and greatest antibacterial effect. Overall, the results showed that the modified 45S5 bioactive glasses can be used as an antibacterial coating material for implants, with high bioactivity, being also non-cytotoxic to mammalian cells.
Polycaprolactone/Doped Bioactive Glass Composite Scaffolds for Bone Regeneration
Publication . Pádua, Ana Sofia; Graça, Manuel Pedro Fernandes; Silva, Jorge Carvalho; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; DF – Departamento de Física; MDPI - Multidisciplinary Digital Publishing Institute
Critical-size bone defects do not heal spontaneously and require external support, making bone regeneration a central challenge in tissue engineering. Polymeric/ceramic composite scaffolds offer a promising approach to mimic the structural and biological properties of bone. In this study, we aimed to evaluate the effect of different doping oxides in bioactive glass (BG) on the performance of polycaprolactone (PCL)-based composite scaffolds for bone tissue engineering applications. Composite scaffolds were fabricated using solvent casting, hot pressing, and salt-leaching techniques, combining PCL with 25 wt% of BG or doped BG containing 4 mol% of tantalum, zinc, magnesium, or niobium oxides, and 1 mol% of copper oxide. The scaffolds were characterized in terms of morphology, mechanical properties, and in vitro biological performance. All scaffolds exhibited a highly porous, interconnected structure. Mechanical compression tests indicated that elastic modulus increased with ceramic content, while doping had no measurable effect. Cytotoxicity assays confirmed biocompatibility across all scaffolds. Among the tested materials, the Zn-doped BG/PCL scaffold uniquely supported cell adhesion and proliferation and significantly enhanced alkaline phosphatase (ALP) activity—an early marker of osteogenic differentiation—alongside the Nb-doped scaffold. These results highlight the Zn-doped BG/PCL composite as a promising candidate for bone regeneration applications.
Fabrication, Structural and Biological Characterization of Zinc-Containing Bioactive Glasses and Their Use in Membranes for Guided Bone Regeneration
Publication . Gavinho, Sílvia R.; Pádua, Ana Sofia; Sá-Nogueira, Isabel; Silva, Jorge C.; Borges, João P.; Costa, Luís C.; Graça, Manuel Pedro F.; DF – Departamento de Física; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UCIBIO - Applied Molecular Biosciences Unit; DCV - Departamento de Ciências da Vida; DCM - Departamento de Ciência dos Materiais; Molecular Diversity Preservation International (MDPI)
Polymeric membranes are widely used in guided bone regeneration (GBR), particularly in dentistry. In addition, bioactive glasses can be added to the polymers in order to develop a matrix that is osteoconductive and osteoinductive, increasing cell adhesion and proliferation. The bioactive glasses allow the insertion into its network of therapeutic ions in order to add specific biological properties. The addition of zinc into bioactive glasses can promote antibacterial activity and induce the differentiation and proliferation of the bone cells. In this study, bioactive glasses containing zinc (0.25, 0.5, 1 and 2 mol%) were developed and structurally and biologically characterized. The biological results show that the Zn-containing bioactive glasses do not present significant antibacterial activity, but the addition of zinc at the highest concentration does not compromise the bioactivity and promotes the viability of Saos-2 cells. The cell culture assays in the membranes (PCL, PCL:BG and PCL:BGZn2) showed that zinc addition promotes cell viability and an increase in alkaline phosphatase (ALP) production.
Biocompatibility, Bioactivity, and Antibacterial Behaviour of Cerium-Containing Bioglass®
Publication . Gavinho, Sílvia R.; Pádua, Ana Sofia; Sá-Nogueira, Isabel; Silva, Jorge C.; Borges, João P.; Costa, Luís C.; Graça, Manuel Pedro F.; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UCIBIO - Applied Molecular Biosciences Unit; DCV - Departamento de Ciências da Vida; MDPI AG
The main reason for the increased use of dental implants in clinical practice is associated with aesthetic parameters. Implants are also presented as the only technique that conserves and stimulates natural bone. However, there are several problems associated with infections, such as peri-implantitis. This disease reveals a progressive inflammatory action that affects the hard and soft tissues surrounding the implant, leading to implant loss. To prevent the onset of this disease, coating the implant with bioactive glasses has been suggested. In addition to its intrinsic function of promoting bone regeneration, it is also possible to insert therapeutic ions, such as cerium. Cerium has several advantages when the aim is to improve osseointegration and prevent infectious problems with dental implant placement. It promotes increased growth and the differentiation of osteoblasts, improves the mechanical properties of bone, and prevents bacterial adhesion and proliferation that may occur on the implant surface. This antibacterial effect is due to its ability to disrupt the cell wall and membrane of bacteria, thus interfering with vital metabolic functions such as respiration. In addition, its antioxidant effect reverses oxidative stress after implantation in bone. In this work, Bioglass 45S5 with CeO2 with different percentages (0.25, 0.5, 1, and 2 mol%) was developed by the melt-quenching method. The materials were analyzed in terms of morphological, structural, and biological (cytotoxicity, bioactivity, and antibacterial activity) properties. The addition of cerium did not promote structural changes to the bioactive glass, which shows no cytotoxicity for the Saos-2 cell line up to 25 mg/mL of extract concentration for all cerium contents. For the maximum cerium concentration (2 mol%) the bioactive glass shows an evident inhibitory effect for Escherichia coli and Streptococcus mutans bacteria. Furthermore, all samples showed the beginning of the deposition of a CaP-rich layer on the surface of the material after 24 h.
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Fundação para a Ciência e a Tecnologia
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UI/BD/151287/2021