Orientador: Prof. Dr. Arnaldo Rodrigues dos Santos Júnior / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biotecnociência, 2017. / Os fosfatos de calcio, tendo como principais componentes inorganicos de hidroxiapatita (HAp - Ca10(PO4)6(OH)2) e ¿À-Fosfato tricalcico (¿À-TCP-Ca3(PO4)2), vem sendo estudados como substitutos osseo, devido a constituicao mineral similar a dos ossos e dentes, apresentando elevada biocompatibilidade e baixa toxicidade. A substituicao dos ions Ca2+ por ions Mg2+ favorece o metabolismo da mineralizacao dos tecidos mineralizados e estimula a proliferacao osteoblastica. A dopagem com ion Eu3+ possibilita a obtencao de fosfatos de calcio fluorescentes, permitindo assim o bioimageamento das nanoparticulas nos testes in vitro. Neste trabalho, nanoparticulas de HAp, ¿À-TCP e bifasicas (50%HAp e 50%¿À-TCP) dopadas com europio (1,5%) e/ou magnesio (1%) foram sintetizadas pelo metodo de co-precipitacao e tratadas termicamente a 1000¿C por 10-20 minutos. O po foi caracterizado por microscopia eletronica de varredura (MEV), difracao de raios-X (DRX), FTIR e espectroscopia de fluorescencia. Todas as bioceramicas foram analisadas quanto a dissolucao, em meio simulado (pH 7,4) e meio extremo (pH 3,0) por 120 horas. Foi avaliada a citotoxidade in vitro dos extratos com celulas Vero pelo metodo do cristal violeta e por contraste de fase das celulas vivas. Essas celulas foram cultivadas em meio de cultura 199 com 10% de soro fetal bovino a 37o C com 5% de CO2, durante 24 horas. Por MEV caracterizou-se o tamanho e morfologia das particulas puras e dopadas com Mg+2 e/ou Eu+3. O DRX apresenta as fases cristalinas caracterizadas nas respectivas amostras de HAp, ¿À-TCP e HAp/¿ÀTCP com a incorporacao de seus dopantes Mg+2 e/ou Eu+3. Por FTIR identificou-se os grupos funcionais atraves da comparacao dos modos vibracionais nas amostras antes e apos os testes de dissolucao simulado e extremo. Pela tecnica de espectroscopia de fluorescencia obteve-se os espectros de emissao caracteristicos para as diferentes estruturas dos fosfatos de calcio (HAp, ¿À-TCP e bifasicas) dopados com Eu+3 e Mg+2/Eu+3 antes e apos os testes de dissolucao no meio simulado e extremo, por 120 horas. Por ICP OES determinou as concentracoes de ions dissolvidos das amostras apos os testes de dissolucao no meio simulado e extremo. Os ensaios citotoxicos mostraram que os biomateriais estudados nao apresentaram efeitos toxicos a viabilidade celular, sendo, portanto, materiais biocompativeis para aplicacoes in vitro. / Synthetic calcium phosphate bioceramics containing inorganic components hydroxyapatite (HAp-Ca10(PO4)6(OH)2) and â-phosphate tricalcium (â-TCP-Ca3(PO4)2) have been studied for bone repair applications because of their mineral constitution similar to that of bones and teeth, high biocompatibility and low toxicity. The substitution of Ca2+ by Mg2+ in the crystal structure of either the HAp or the â-TCP favors mineralization metabolism of mineralized tissues and stimulates osteoblast proliferation. The Eu3+ doping enables obtaining fluorescent calcium phosphates, thus allowing bioimaging of nanoparticles in vitro. In this work, HAp, â-TCP and biphasic (50% HAp and 50% â-TCP) nanoparticles doped with europium (1.5%) and / or magnesium (1%) were synthesized by the co-precipitation method and termically treated at 1000°C for 10-20 minutes. The powder was characterized by scanning electron microscopy (SEM), diffraction X-ray (XRD), FTIR and fluorescence spectroscopy. All bioceramics were analyzed on dissolution test in simulated (pH 7.4) and extreme (pH 3.0) during 120 hours. The bioceramic extracts were also used for cytotoxicity on vero cells in vitro by the crystal violet method and phase contrast microscopy of living cells. These cells were grown in culture medium 199 with 10% FBS at 37 °C with 5% CO2 for 24 hours. The particle size, and morphology characterized by SEM were compared with the ceramics without dopants and with incorporation of Mg+2 and / or Eu+3. The XRD shows the crystal phases characterized in their respective samples of HAp, â-TCP and HAp / âTCP with the incorporation of its dopants Mg2+ and / or Eu+3. With FTIR were identified functional groups by comparing the vibrational modes in the samples before and after the dissolution tests simulated and extreme. The fluorescence spectroscopy technique yielded the characteristic emission spectra for the different structures of calcium phosphates HAp, â-TCP and biphasic, dopants Mg+2 and / or Eu+3 before and after the dissolution test in simulated and extreme through time 120 hours. The ICP OES determined the dissolved ion concentrations of the samples after the dissolution tests in the medium simulated and extreme. Cytotoxic assays showed that the biomaterial studies showed no toxic effects on cell viability and, therefore, biocompatible materials in vitro applications.
| Identifer | oai:union.ndltd.org:IBICT/oai:BDTD:106547 |
| Date | January 2017 |
| Creators | Pereira, Rafael Francisco |
| Contributors | Santos Júnior, Arnaldo Rodrigues dos, Bonvent, Jean Jacques, Santos, Márcio Luiz dos |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf, 128 f. : il. |
| Source | reponame:Repositório Institucional da UFABC, instname:Universidade Federal do ABC, instacron:UFABC |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | http://biblioteca.ufabc.edu.br/index.php?codigo_sophia=106547&midiaext=74708, http://biblioteca.ufabc.edu.br/index.php?codigo_sophia=106547&midiaext=74707, Cover: http://biblioteca.ufabc.edu.brphp/capa.php?obra=106547 |
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