Sintese e caracterização de revestimentos de titanato de cálcio e apatita sobre subtrato de titânio
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Data
2023-02-06
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Universidade Estadual Paulista (Unesp)
Resumo
O presente projeto objetiva sintetizar filmes de hidroxiapatita sobre o titânio comercialmente puro (Ti-c.p.) modificado com o titanato de cálcio, estabelecendo-se as melhores condições para isso, bem como caracterizá-los por técnicas físicas e realizar ensaios biológicos do conjunto. Os materiais biocerâmicos à base de fosfato de cálcio como a hidroxiapatita (HAp) é importante por ser o principal componente mineral ósseo e desempenha um papel importante na biomineralização. Ao recobrir a superfície do titânio, material utilizado como implante, oferece condições que auxiliam a promover a osseointegração, conexão entre o osso neoformado e a superfície do implante. Para assegurar a boa ancoragem mecânica da HAp o titânio foi previamente recoberto com uma camada intermediária de titanato de cálcio pelo método sol-gel associado à tecnica de imersão. O sol precursor de apatita foi preparado inicialmente em duas condições diferentes para encontrar a condição que proporciona melhor revestimento ao titânio modificado com o titanato de cálcio. Quando preparados na forma de pó, ambos resultaram em materiais compostos de duas fases de apatita, HAp e pirofosfato de cálcio. Com a condição definida, as amostras de titânio comercialmente puro (Ti-c.p.), contendo ou não uma camada intermediaria de titanato de cálcio, foram revestidas com apatita e caracterizadas pelas seguintes técnicas: difratometria de raios X (DRX), microscopia eletrônica de varredura (MEV), energia dispersiva de raios X (EDX), molhabilidade da superfície, potencial zeta de superfície, testes eletroquímicos e ensaio biológico (contato indireto). Os resultados da caracterização não mostraram claramente o papel do titanato de cálcio na adesão da apatita sobre o titânio, porém proporcionou tanto maior resistência à corrosão como biocompatibilidade, sendo que a combinação dos filmes apresentou indícios de melhor biocompatibilidade ao material.
This project aims to synthesize hydroxyapatite films on commercially pure titanium (c.p.-Ti) modified with calcium titanate, establishing the better conditions for coating it. It was characterized by physical techniques as well as biological assays of the set were carried out. Bioceramic materials based on calcium phosphate such as hydroxyapatite (HAp) are important in the interaction with bone because it is the main mineral component of the bone and plays an important role in biomineralization process. By covering the surface of titanium, a material used as an implant, it offers conditions to promote osseointegration, the connection between newly formed bone and the surface of the implant. To ensure good mechanical adhesion of the HAp, the titanium was previously coated with an intermediate layer of calcium titanate using the sol-gel method associated with the dip-coating technique. The precursor sol of apatite was initially synthesized under two different conditions to find the condition that provides the better coating of titanium which was previously modified with calcium titanate. Both conditions resulted in materials composed of two phases of apatite: HAp and calcium pyrophosphate. After, the c.p-Ti coated with apatite, containing or not an intermediate layer of calcium titanate, were characterized by the following techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive (EDX), surface wettability, surface zeta potential, electrochemical tests and biological assay (non direct contact). The characterization results did not clearly show the role of calcium titanate for apatite adhesion to titanium, however, it provided both greater resistance to corrosion and biocompatibility, and the combination of films gives evidence of better biocompatibility for the material.
This project aims to synthesize hydroxyapatite films on commercially pure titanium (c.p.-Ti) modified with calcium titanate, establishing the better conditions for coating it. It was characterized by physical techniques as well as biological assays of the set were carried out. Bioceramic materials based on calcium phosphate such as hydroxyapatite (HAp) are important in the interaction with bone because it is the main mineral component of the bone and plays an important role in biomineralization process. By covering the surface of titanium, a material used as an implant, it offers conditions to promote osseointegration, the connection between newly formed bone and the surface of the implant. To ensure good mechanical adhesion of the HAp, the titanium was previously coated with an intermediate layer of calcium titanate using the sol-gel method associated with the dip-coating technique. The precursor sol of apatite was initially synthesized under two different conditions to find the condition that provides the better coating of titanium which was previously modified with calcium titanate. Both conditions resulted in materials composed of two phases of apatite: HAp and calcium pyrophosphate. After, the c.p-Ti coated with apatite, containing or not an intermediate layer of calcium titanate, were characterized by the following techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive (EDX), surface wettability, surface zeta potential, electrochemical tests and biological assay (non direct contact). The characterization results did not clearly show the role of calcium titanate for apatite adhesion to titanium, however, it provided both greater resistance to corrosion and biocompatibility, and the combination of films gives evidence of better biocompatibility for the material.
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Palavras-chave
Biomateriais, Hidroxiapatita, Sol-gel, Titanato de cálcio, Titânio