Polymers scaffolds with addition of ceramics for use in bone reconstruction

Orientadores: Antonio Celso Fonseca de Arruda, Cecília Amélia de Carvalho ZavagliaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: A engenharia tecidual, que tem como objetivo a reconstrução de tecidos de animais, enfrenta um desafio: a construção de suportes. Uma das propriedades relevantes desse eventual material é a sua taxa de absorção, que deve ser inversamente proporcional à taxa de crescimento tecidual. Nesse sentido, a poli ( -caprolactona) (PCL), que é um polímero biocompatível e bioreabsorvível, mostra-se ser um material promissor para reconstruções ósseas, já que possui uma taxa de reabsorção lenta. Esse polímero, por não ser capaz de atrair células osteoblásticas, deve ter a adição de cerâmicas bioativas com o propósito de fortalecer a estrutura do suporte. Adicionalmente, deve atuar como um condutor para a proliferação de células ósseas. O objetivo deste trabalho foi desenvolver suportes tridimensionais de poli ( -caprolactona) com fibras ou whiskers de hidroxiapatita. A estrutura deve ser porosa de modo a permitir a vascularização dessa área e consequentemente a osteocondução. Foram sintetizados reagentes primários tais como monetita e carbonato de cálcio, para a sinterização de fosfato tricálcico ( -TCP), que ao ser hidrolisado resultou em whiskers de hidroxiapatita. As fibras de hidroxiapatita foram obtidas pelo método de molten salt utilizando a hidroxiapatita precipitada. As cerâmicas foram caracterizadas por análises de difração de raios X (DRX), fluorescência de raios X (FRX) e microscopia eletrônica de varredura (MEV). Os suportes passaram por testes mecânicos de compressão e testes in vitro, além de MEV e DRX. Os resultados indicaram que os suportes poliméricos com adição de whiskers de hidroxiapatita apresentaram-se mais resistentes à compressão. A presença de whiskers, diferentemente das fibras, caracterizou-se como reforço na matriz polimérica. Os resultados do teste de imersão em fluído corpóreo mostraram que os suportes com whiskers de hidroxiapatita, diferentemente das fibras, resultaram em deposição de apatita em suas superfíciesAbstract: Tissue engineering, which aim is the reconstruction of animal tissues, faces a challenge: the building supports. One of the relevant properties of any material is its rate of absorption, which should be inversely proportional to the rate of tissue growth. Accordingly, to the poly ( -caprolactone) (PCL), which is a biocompatible polymer and bioresorbable shows to be a promising material for bone reconstruction since it has a slow rate of resorption. This polymer, for not being able to attract osteoblastic cells, should have the addition of bioactive ceramics in order to strengthen the supporting structure. Additionally, it should acts as an inducer for the proliferation of bone cells. The objective of this study was to develop three-dimensional scaffolds of poly ( -caprolactone) with fibers and whiskers of hydroxyapatite. The structure should be porous to allow vascularization of this area and consequently the osteoinduction. Were synthesized reagents such as monetita and calcium carbonate, for sintering of tricalcium phosphate ( -TCP), which when hydrolyzed results in hydroxyapatite whiskers. The fibers of hydroxyapatite were obtained by the method molten salt using precipitated hydroxyapatite. The ceramics were characterized by analysis of X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). The scaffolds were tested by mechanical compression and in vitro tests, in addition to SEM and XRD. The results indicated that the scaffolds with the addition of hydroxyapatite whiskers were more resistant to compression. The presence of whiskers, unlike fiber, characterized as reinforcement in polymer matrix. The test results of immersion in body fluid showed that the scaffolds with hydroxyapatite whiskers, unlike fiber, aimed to the deposition of apatite on their surfacesMestradoMateriais e Processos de FabricaçãoMestre em Engenharia Mecânic

Fibrous PCL/PLLA Scaffolds Obtained by Rotary Jet Spinning and Electrospinning

Rotary jet spinning (RJS) and electrospinning are techniques to obtain fibrous scaffolds. RJS is a simple method, which fabricates three-dimensional fibers by exploiting a high-speed rotating nozzle, creating a polymer jet which stretches until solidification, and does not require high voltage. In opposite, electrospinning technique needs the presence of an external electric field to create fiber from the polymeric jet solution. This article investigates both processes using two different biocompatible polymers: Poly(L-lactic acid) (PLLA) and Poly(e-caprolactone) (PCL). Samples were characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimeter, and Fourier-transform infrared spectroscopy. Morphological observations showed the efficiency of both techniques in obtaining nanofibers. Thermal analyses of data indicate immiscible property of different blends and the total solvent evaporation. In vitro cytocompatibility test showed that RJS and electrospinning samples exhibited good cytocompatibility. Based on these results, it may be concluded that the fibers obtained with both technologies are non-cytotoxicity and with good biocompatibility, and might be suitable for applications as scaffold for cell growth.CAPESFAPESPBiofabris-INCTBiomaterials Laboratory PUC/SP SorocabaUniv Estadual Campinas, Fac Engn Mecan, Campinas, SP, BrazilPontificia Univ Catolica, Sao Paulo, SP, BrazilUniv Fed ABC, Ctr Ciencias Nat & Humanas, Santo Andre, BrazilUniv Fed Sao Paulo, Dept Ciencias Mar, Santos, SP, BrazilUniv Fed Sao Paulo, Dept Ciencias Mar, Santos, SP, BrazilFAPESP: 2013/19372-0Web of Scienc

Viability assays of PLLA fibrous membranes produced by rotary jet spinning for application in tissue engineering

Tissue engineering suggests different forms to reconstruct tissues and organs. One of the ways is through the use of polymeric biomaterials such as poly(L-lactic acid) (PLLA). PLLA is a recognized material in tissue engineering due to its characteristics as biocompatibility and bioresorbability. In this work PLLA fibrous membranes were produced by a simple technique known as rotary jet spinning. The rotary jet spinning consists of fibrous membranes production, with fibers of scale nano/micrometric, from a polymeric solution through the centrifugal force generated by the equipment. The membranes formed were subjected to preliminary in vitro assays to verify the cytotoxicity of the membranes made in contact with the cells. Direct cytotoxicity assays were performed through the MTT, AlamarBlue® and Live/Dead® tests, with fibroblastic and osteoblastic cells. The results obtained in this study showed that PLLA membranes produced by rotary jet spinning showed promising results in the 24-hours contact period of the cells with the PLLA fibrous membranes. The information presented in this preliminary study provides criteria to be taken in the future procedures that will be performed with the biomaterial produced, aiming at its improvement62COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2008/57680-

Development of three-dimensional matri composite of poly ('épsilon'-caprolactone) and bioative ceramic for use in tissue enginnering

Orientadores: Cecília Amélia de Carvalho Zavaglia, Antonio Celso Fonseca de ArrudaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: A variedade de sítios anatômicos e diferentes propriedades mecânicas são essenciais para o êxito em cirurgias de reconstrução óssea, com isso tratamentos envolvendo fraturas complexas, perda óssea e próteses são beneficiadas com o uso dos biomateriais. Com o presente estudo, buscou-se uma proposta original no uso de um biomaterial compósito para implantes na região da mandíbula, a singularidade deste dispositivo é a estrutura física do material, que é composto por um núcleo denso em uma matriz porosa. As influências das estruturas e dos materiais utilizados foram analisadas por caracterizações físicas, químicas e as atividades celulares em ensaios in vitro, analisando o comportamento dessas em condições similares ao ambiente de implantação o que permitiu qualificar este biomaterial. Para tanto, foram sintetizados reagentes primários para a síntese de fosfato tricálcico (?-TCP), que ao ser hidrolisado resultou em whiskers de hidroxiapatita. As cerâmicas foram caracterizadas pelas análises de difração de raios X (DRX), fluorescência de raios X (FRX), microscopia eletrônica de varredura (MEV) e ensaio de citotoxicidade. As diversas composições poliméricas e compósitas foram analisadas utilizando os resultados obtidos pelos ensaios de ângulo de contato, calorimetria exploratória diferencial (DSC), microscópio de força atômica (MFA), microscopia óptica com luz polarizada (MO), ensaio mecânico de tração e ensaios in vitro com células U20S. Os suportes tridimensionais passaram por análises como de: ensaio mecânico de compressão e ensaios in vitro com células tronco mesenquimais. Os estudos foram realizados para a verificação do potencial de aplicação clínica desse material na engenharia tecidual óssea. As amostras que se apresentaram mais promissoras foram as de composições poli (?-caprolactona) / ácido oléico/ hidroxiapatita e poli caprolactona/ ácido oléico. Resistência mecânica, hidrofilicidade, rugosidade, cristalinidade, espraiamento celular e osteoindução foram os critérios utilizados neste trabalho. Os resultados obtidos demostraram-se promissores e irão incentivar pesquisas futuras envolvendo estes materiaisAbstract: The variety of anatomical sites and different mechanical properties are essential to the success of surgery bone reconstruction. Treatments involving this complex fractures, bone loss and prosthetics are benefited with the use of biomaterials. In the present study, we sought to an original use of a composite biomaterial for implants in the jaw area; the uniqueness of this device is the physical structure of the material, which is composed of a dense core in a porous matrix. The influences of structures and materials were analyzed by characterizing the physical, chemical and cellular activities in in vitro assays, analyzing the behavior of those in similar conditions to the deployment environment which would allow qualifying this biomaterial. Therefore, primers were synthesized reagents for the synthesis of tricalcium phosphate (?-TCP), which when hydrolyzed resulted in hydroxyapatite whiskers. The ceramics were characterized by analysis of X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and cytotoxicity assay. The various compositions were analyzed using the results obtained by contact angle tests, differential scanning calorimetry (DSC), atomic force microscope (AFM); optical microscopy with polarized light (OM), mechanical tests and in vitro assays with cells U20S. The scaffolds have undergone analyzes as: mechanical compression test and in vitro assays with mesenchymal stem cells. Studies were conducted to verify the potential clinical application of this material in bone tissue engineering. Because the analysis of the results of the characterizations, the samples which were the most promising compositions of poly (?-caprolactone) / oleic acid and poly(?- caprolactone)/ oleic acid/ hydroxyapatite. Mechanical strength, hydrophilicity, roughness, crystallinity, cell spreading and osteoinduction were the criteria used in this work. The results showed to be promising and will encourage future research involving these materialsDoutoradoMateriais e Processos de FabricaçãoDoutora em Engenharia Mecânic

Dispositivo Com Encaixe Para PrÓtese Em RegiÃo AtrÓfica Desdentada

DISPOSITIVO COM ENCAIXE PARA PRÓTESE EM REGIÃO ATRÓFICA DESDENTADA. A presente invenção trata de um dispositivo intra-oral que permite a reabilitação oral em pacientes com regiões ósseas atróficas, permitindo a realização de próteses em regiões, que anteriormente não poderiam ser reabilitadas. Este dispositivo se adapta ao local cirúrgico ficando justaposto ao osso e após sua osteointegração permite a fixação da parte protética.BR102012026428 (A2)A61C8/00BR20121026428A61C8/0

The importance of understanding differences in a critical size model: a preliminary in vivo study using tibia and parietal bone to evaluate the reaction with different biomaterials

Many researches aim to develop different biomaterials that are compatible with natural tissues. In vitro and in vivo tests are used to evaluate this potential. Our aim was to report the importance of the critical defect's location for in vivo assays, to evaluate this approach; in vivo studies were performed, using different compositions of biomaterials in two critical size defects: tibia and parietal bone. Polycaprolactone was used as the main polymeric matrix with and without addition of hydroxyapatite. In vivo studies on the standard critical size defect in tibia and parietal bone were performed using Wistars models: 3x2 and 5x1 dimensions, respectively. The animals were sacrificed after 32 days; neobone formation was assessed with the histological data. The in vivo data demonstrated differences between the tibia and parietal bone groups: the influence of the bone on the neobone's formation was notable. All the tibia defect samples had greater neobone volume when compared to the parietal data. Indeed, these bones have distinct embryology, influence of mechanical forces and vascularization rate that are well known; moreover, these characteristics were demonstrated to be critical for neobone formation221FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2009/54546-9; 2013/19472-

PLLA synthesis and membrane production through rotary jet spinning process poly (L-lactic acid) synthesis and physico-chemical analysis

Poly (L-lactic acid) (PLLA) is a well-established polymer, which is widely used in a wide range of fields; however, it is a high cost material, presenting great difficulties for its purchase. Therefore, the present work proposes PLLA synthesis in the laboratory, as an alternative to turn this more feasible; its processing through rotary jet spinning to obtain fibrous membranes; its physico-chemical analyses for material characterization; and, in vitro cell viability analyses with osteoblasts and fibroblasts. Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Energy Dispersive Spectroscopy (EDS), and Live/Dead® assays were the characterization analyzes of the obtained membrane. PLLA membranes had initial degradation at 200 °C, and none harmful chemical elements were present. In vitro test verified the compatibility of the membranes with two cell lines, indicating a possible and potential application of these membranes in the medical field71050345043COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçã

Fibrous PCL/PLLA Scaffolds Obtained by Rotary Jet Spinning and Electrospinning

<div><p>Rotary jet spinning (RJS) and electrospinning are techniques to obtain fibrous scaffolds. RJS is a simple method, which fabricates three-dimensional fibers by exploiting a high-speed rotating nozzle, creating a polymer jet which stretches until solidification, and does not require high voltage. In opposite, electrospinning technique needs the presence of an external electric field to create fiber from the polymeric jet solution. This article investigates both processes using two different biocompatible polymers: Poly(L-lactic acid) (PLLA) and Poly(ε-caprolactone) (PCL). Samples were characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimeter, and Fourier-transform infrared spectroscopy. Morphological observations showed the efficiency of both techniques in obtaining nanofibers. Thermal analyses of data indicate immiscible property of different blends and the total solvent evaporation. In vitro cytocompatibility test showed that RJS and electrospinning samples exhibited good cytocompatibility. Based on these results, it may be concluded that the fibers obtained with both technologies are non-cytotoxicity and with good biocompatibility, and might be suitable for applications as scaffold for cell growth.</p></div

Fibrous PCL/PLLA Scaffolds Obtained by Rotary Jet Spinning and Electrospinning

<div><p>Rotary jet spinning (RJS) and electrospinning are techniques to obtain fibrous scaffolds. RJS is a simple method, which fabricates three-dimensional fibers by exploiting a high-speed rotating nozzle, creating a polymer jet which stretches until solidification, and does not require high voltage. In opposite, electrospinning technique needs the presence of an external electric field to create fiber from the polymeric jet solution. This article investigates both processes using two different biocompatible polymers: Poly(L-lactic acid) (PLLA) and Poly(ε-caprolactone) (PCL). Samples were characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimeter, and Fourier-transform infrared spectroscopy. Morphological observations showed the efficiency of both techniques in obtaining nanofibers. Thermal analyses of data indicate immiscible property of different blends and the total solvent evaporation. In vitro cytocompatibility test showed that RJS and electrospinning samples exhibited good cytocompatibility. Based on these results, it may be concluded that the fibers obtained with both technologies are non-cytotoxicity and with good biocompatibility, and might be suitable for applications as scaffold for cell growth.</p></div