Caracterização da liga Ti-Sn-Nb com Mg e seu potencial biotecnológico na consolidação óssea
Carregando...
Data
2021-03-01
Autores
Rossi, Mariana Correa
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A maioria dos materiais metálicos comercializados apresentam determinadas inconveniências, como toxicidade e módulo elástico distante com a do tecido ósseo. Estas características promovem diminuição da longevidade destes dispositivos quando implantados e podem levar a distúrbios respiratórios e neurológicos dependendo dos componentes presentes. Dessa maneira, materiais que utilizem elementos como Nb (estabilizador β) e Sn (elemento neutro), em ligas de titânio são estudados a fim de se conseguir características mais adequadas, pelo aumento da fase β e diminuição do módulo elástico. O objetivo foi a obtenção da liga de Ti-34Nb-6Sn, pela metalurgia do pó, e suas caracterizações físicas, químicas, mecânicas e biológicas. No processo foi adicionado um espaçador, Mg, a fim de conferir porosidade à liga. Foram realizadas sinterizações a 700ºC, 800ºC e 900ºC. A caracterização física foi feita por difratometria de raios X (DRX), microscopia eletrônica de varredura (MEV), análise composicional semi-quantitativa por energia dispersiva de raios X (EDX) e análise da molhabilidade por medidas dinâmicas de ângulo de contato. As características mecânicas como o módulo elástico, resistência a compressão e dureza de Vickers foram estudadas. A susceptibilidade à corrosão foi estudada pelo método eletroquímico em solução HANK e Fusayama que simula o fluído corpóreo e saliva. Nos ensaios biológicos, foram utilizadas as células tronco mesenquimais derivadas da medula óssea (MOCTMs) de eqüinos. Foram realizadas análises de citotoxicidade com os corpos de prova, bem como as análises do potencial de migração e diferenciação celular. Na presença de Nb e Sn, o material se torna mais rico em fase β à medida que se aumenta a temperatura de sinterização. Com o Mg, observou-se maior resistência a transformação alotrópica α→β, obtendo-se materiais com menor teor em fase β que aquele sem Mg. A porosidade foi maior para os materiais com Mg, assim como a molhabilidade superficial. O módulo elástico e a dureza foram menores para os materiais com Mg e quanto menor a temperatura de sinterização, mais próximos são do tecido ósseo. Já a resistência mecânica foi maior para a liga sem Mg. A liga sinterizada com Mg à 800ºC se mostrou mais resistente a corrosão comparada com a liga sem Mg. Ambos os materiais apresentaram boa biocompatibilidade, quando em contato com as MOCTMs, com capacidade de adesão na superfície e no interior dos poros. Além disso, as MOCTMs apresentaram processo de diferenciação osteogênica acentuada quando alimentada com o meio condicionado com a liga, possivelmente pela liberação de Mg no meio de cultivo. Após 24 horas, pelo ensaio de migração celular, as células que tiveram contato com a liga com Mg apresentaram um processo direcional significativo de migração comparado com o grupo controle.
Most of the commercialized metallic materials have certain inconveniences, such as toxicity and discrepant elastic modulus compared to bone tissue. These characteristics promote a decrease in the longevity of them when implanted and can lead to respiratory and neurological disorders depending on the components present. In this way, materials that use elements such as Nb (stabilizer β) and Sn (neutral element), in titanium alloys are studied in order to achieve more appropriate characteristics, by increasing the β phase and decreasing the elastic modulus. The objective was to obtain the Ti-34Nb-6Sn alloy, by powder metallurgy, and its physical, chemical, mechanical and biological characterizations. In the process, a spacer, Mg, was added in order to impart porosity to the alloy. Sintering was carried out at 700ºC, 800ºC and 900ºC. The physical characterization was made by X-ray diffraction (XRD), scanning electron microscopy (SEM), semi-quantitative compositional analysis by X-ray dispersive energy (EDS) and analysis of wettability by dynamic contact angle measurements. The mechanical characteristics such as the elastic modulus, compressive strength and Vickers hardness were studied. The corrosion susceptibility was studied by the electrochemical method in HANK and Fusayama solution that simulates the body fluid and saliva. In biological assays, bone marrow-derived mesenchymal stem cells (BMMSCs) from horses were used. Cytotoxicity analyzes were performed with the specimens, as well as analyzes of the potential for cell migration and differentiation. In the presence of Nb and Sn, the material becomes richer in the β phase as the sintering temperature increases. With Mg, greater resistance to α → β allotropic transformation was observed, obtaining materials with lower β phase content than that without Mg. The porosity was higher for the materials with Mg, as well as the surface wettability. The elastic modulus and hardness were lower for the materials with Mg and the lower the sintering temperature and closer to bone tissue. The mechanical strength was higher for the alloy without Mg. The alloy sintered with Mg at 800ºC was more resistant to corrosion compared to the alloy without Mg. Both materials showed good biocompatibility when in contact with BMMSCs, with the ability to adhere to the surface and inside the pores. In addition, BMMSCs showed a marked osteogenic differentiation process when fed with the conditioned medium with the alloy, possibly due to the release of Mg in the culture medium. After 24 hours, through the cell migration test, cells that had contact with the alloy with Mg showed a significant directional migration process compared to the control group.
Most of the commercialized metallic materials have certain inconveniences, such as toxicity and discrepant elastic modulus compared to bone tissue. These characteristics promote a decrease in the longevity of them when implanted and can lead to respiratory and neurological disorders depending on the components present. In this way, materials that use elements such as Nb (stabilizer β) and Sn (neutral element), in titanium alloys are studied in order to achieve more appropriate characteristics, by increasing the β phase and decreasing the elastic modulus. The objective was to obtain the Ti-34Nb-6Sn alloy, by powder metallurgy, and its physical, chemical, mechanical and biological characterizations. In the process, a spacer, Mg, was added in order to impart porosity to the alloy. Sintering was carried out at 700ºC, 800ºC and 900ºC. The physical characterization was made by X-ray diffraction (XRD), scanning electron microscopy (SEM), semi-quantitative compositional analysis by X-ray dispersive energy (EDS) and analysis of wettability by dynamic contact angle measurements. The mechanical characteristics such as the elastic modulus, compressive strength and Vickers hardness were studied. The corrosion susceptibility was studied by the electrochemical method in HANK and Fusayama solution that simulates the body fluid and saliva. In biological assays, bone marrow-derived mesenchymal stem cells (BMMSCs) from horses were used. Cytotoxicity analyzes were performed with the specimens, as well as analyzes of the potential for cell migration and differentiation. In the presence of Nb and Sn, the material becomes richer in the β phase as the sintering temperature increases. With Mg, greater resistance to α → β allotropic transformation was observed, obtaining materials with lower β phase content than that without Mg. The porosity was higher for the materials with Mg, as well as the surface wettability. The elastic modulus and hardness were lower for the materials with Mg and the lower the sintering temperature and closer to bone tissue. The mechanical strength was higher for the alloy without Mg. The alloy sintered with Mg at 800ºC was more resistant to corrosion compared to the alloy without Mg. Both materials showed good biocompatibility when in contact with BMMSCs, with the ability to adhere to the surface and inside the pores. In addition, BMMSCs showed a marked osteogenic differentiation process when fed with the conditioned medium with the alloy, possibly due to the release of Mg in the culture medium. After 24 hours, through the cell migration test, cells that had contact with the alloy with Mg showed a significant directional migration process compared to the control group.
Descrição
Palavras-chave
Arcabouço, Biomateriais, Liga de Ti-Nb-Sn, Metalurgia do pó, Microestrutura, Scaffold, Biomaterials, Ti-Nb-Sn alloy, Powder metallurgy, Microstructure