Made available in DSpace on 2014-06-11T19:25:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2006Bitstream added on 2014-06-13T19:53:30Z : No. of bitstreams: 1 aparecida_ah_me_araiq.pdf: 2281144 bytes, checksum: dea6a2f4d2dbe1a08aa508e8abc51b0d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A atividade biológica do titânio comercialmente puro - Ti c.p. em relação aos tecidos duros é melhorada mediante a modificação de sua superfície empregando-se recobrimento com material bioativo. Um dos materiais bioativos mais utilizados é a Hidroxiapatita - HA, uma das fases das apatitas (fosfatos de cálcio de variadas razões Ca/P), principal constituinte mineral do tecido ósseo. Contudo, além da HA, vários outros fosfatos de cálcio também ocorrem em sistemas biológicos, tais como fosfato de cálcio amorfo – ACP, fosfato octacálcico – OCP e o fosfato tricálcico – TCP, aumentando o interesse nas possibilidades de uso destes materiais como biocerâmicas. Uma técnica de recobrimento muito utilizada nos últimos anos tem sido o Método Biomimético. Seu sucesso deve-se à utilização de uma solução similar ao fluido corpóreo, denominada Synthetic Body Fluid – SBF, que propicia a mimetização do processo biológico realizado para a formação dos tecidos duros. O crescimento da HA e de outras apatitas, tanto no meio biológico quanto em SBF, ocorre em meio contendo, além de íons Ca2+ e PO4 3-, íons-traços essenciais tais como: Mg2+, HCO3 -, K+ e Na+. Alguns destes íons são conhecidos como inibidores do crescimento da HA, como Mg2+ e HCO3 -. Neste trabalho, estudou-se a influência dos íons K+, Mg2+, SO4 2- e HCO3 - na formação de apatitas, principalmente HA, sobre substratos metálicos de Ti c.p. previamente tratados com NaOH 5M. Os efeitos destes íons nos recobrimentos obtidos foram analisados antes e após tratamento térmico a 800ºC por microscopia eletrônica de varredura - MEV, espectroscopia de energia dispersiva de raios X - EDX, difratometria de raios X - DRX e espectroscopia no infravermelho com transformada de Fourier (FTIR). Os resultados mostraram que o crescimento de ACP foi favorecido pela presença dos íons Mg2+ e CO3 2- na solução... / The biological activity of commercially pure titanium - c.p. Ti in relation to hard tissues is improved by modifying its surface using coating with bioactive materials. One of the bioactive materials most used is Hydroxyapatite - HA, one of the phases of the apatites (calcium phosphates of varied Ca/P reasons), main mineral constituent of the bone tissue. However, beyond the HA, several other calcium phosphates also occur in biological systems, such as amorphous calcium phosphate - ACP, octacalcium phosphate - OCP and tricalcium phosphate - TCP, increasing the interest in the possibilities of use of these materials as bioceramics. One technique of coating very used in the last years has been the Biomimetic Method. Its success must it the use of a similar solution to the corporeal fluid, called Synthetic Body Fluid - SBF, that propitiates the imitation of the carried through biological process for the formation of hard tissues. The growth of the HA and other apatites, as much in the biological environment as in aqueous solution as the SBF, occurs environment containing, beyond calcium and phosphate ions, essential ion-traces such as: Mg2+, HCO3-, K+ and Na+. Some of these elements are known as inhibiting of the growth of the HA, as Mg2+ and HCO3-. In this work, it was studied it influence of íons K+, Mg2+, SO42- and HCO3- in the formation of apatites, mainly HA, on metallic substrate of Ti c.p. previously treated with NaOH 5M. The effects of these ions in the obtained coating, before and after the thermal treatment at 800ºC, were analyzed by scanning electron microscopy - SEM, energy dispersive X-rays - EDX, X-ray diffractometer - XRD and Fourier transformation infrared - FT-IR. The results had shown that the growth of ACP was favored by the presence of íons Mg2+ and CO32- in the solution, being also favored its transformation the OCP before the thermal treatment.

O crescimento de células em arcabouços tridimensionais porosos tem se tornado progressivamente ativo na engenharia de tecidos. Os arcabouços guiam o crescimento celular, sintetizam uma matriz extracelular e outras moléculas biológicas, e facilitam a formação de tecidos e órgãos funcionais. Um cimento deste tipo pode ser preparado misturando um sal de fosfato de cálcio com uma solução aquosa para que se forme uma pasta que possa reagir à temperatura corporal dando lugar a um precipitado que contenha hidroxiapatita (Ca10(PO4)6(OH)2). A similaridade química e morfológica entre este biomaterial e a parte mineral dos tecidos ósseos permite a osteocondução, sendo o cimento substituído por tecido ósseo novo com o tempo e com a vantagem de não desencadear processos inflamatórios e de corpo estranho, com eventual expulsão do material implantado. O objetivo do presente trabalho foi a obtenção e caracterização de suportes tridimensionais para a engenharia de tecido, com o uso de matérias-primas nacionais, por meio da utilização de microesferas de parafina como corpos geradores de poros. As microesferas foram produzidas por suspensão em solução aquosa de poli (álcool vinílico) (PVA) e sulfato de sódio (Na2SO4). Foram analisadas as fases presentes no cimento sintetizado e após a reação de cura do mesmo, a variação do tamanho de partícula e da resistência mecânica com o tempo de moagem. Foi analisada a porosidade dos suportes e a forma de extração da parafina daqueles que a utilizaram na sua formação. O tamanho de poro dos suportes gerados com a variação da quantidade de fase líquida ficou aquém do tamanho considerado ideal para o crescimento de tecido ósseo. A porosidade dos arcabouços fabricados com esferas de parafina foi observada por microscopia eletrônica de varredura (MEV), e seu comportamento foi analisado a partir de ensaios in vitro em solução SBF (simulated body fluid) e em cultura de células. A utilização de esferas de parafina permitiu a formação de poros com tamanho tal que possibilitam potencialmente o crescimento tecidual e celular. / The growth of cells in three-dimensional porous scaffolds has been extensively studied for use in tissue engineering. They guide grow of cells, synthesize extra cellular matrix and other biological molecules, and facilitate the formation of functional tissues and organs. Bone cements has been developed for biomedical applications for a decade approximately. This kind of cement can be prepared mixing a calcium phosphate salt with aqueous solution forming a paste that can react at body temperature generating a hydroxyapatite precipitated (Ca10(PO4)6(OH)2). The chemical and morphological similarity between the cement composition and the mineral part of the bones allows osteoconduction in the tissue with replacement of cement by new bone formed with the advantage to not unchain inflammatory processes and of strange body. The objective of this work was the use of the α-TCP cement for making these scaffolds, through the variation of the amount of liquid phase in the cement and of the use of paraffin spheres as pore source. These spheres were produced by suspension in water solution of poly (vinyl alcohol) and sodium sulphate (Na2SO4). The phases had been analyzed in the synthesized cement and after the reaction of cure of cement, beyond variation of the particle size and the resistance mechanics with the milling time. It was analyzed the porosity of the scaffolds and the extraction of the paraffin in that supports. The pore size of the supports generated with the variation of the amount of liquid phase was on this side of the size considered ideal for the bone tissue growth. The porosity of scaffolds manufactured with paraffin spheres was observed by Scanning Electron Microscopy (SEM), and its behavior was analyzed from test in vitro in SBF solution (simulated body fluid). The use of paraffin spheres allowed the formation of pores size able to permit tissue growth.

abstract: Presented below is the design and fabrication of prosthetic components consisting of an attachment, tactile sensing, and actuator systems with Fused Filament Fabrication (FFF) technique. The attachment system is a thermoplastic osseointegrated upper limb prosthesis for average adult trans-humeral amputation with mechanical properties greater than upper limb skeletal bone. The prosthetic designed has: a one-step surgical process, large cavities for bone tissue ingrowth, uses a material that has an elastic modulus less than skeletal bone, and can be fabricated on one system. FFF osseointegration screw is an improvement upon the current two-part osseointegrated prosthetics that are composed of a fixture and abutment. The current prosthetic design requires two invasive surgeries for implantation and are made of titanium, which has an elastic modulus greater than bone. An elastic modulus greater than bone causes stress shielding and overtime can cause loosening of the prosthetic. The tactile sensor is a thermoplastic piezo-resistive sensor for daily activities for a prosthetic’s feedback system. The tactile sensor is manufactured from a low elastic modulus composite comprising of a compressible thermoplastic elastomer and conductive carbon. Carbon is in graphite form and added in high filler ratios. The printed sensors were compared to sensors that were fabricated in a gravity mold to highlight the difference in FFF sensors to molded sensors. The 3D printed tactile sensor has a thickness and feel similar to human skin, has a simple fabrication technique, can detect forces needed for daily activities, and can be manufactured in to user specific geometries. Lastly, a biomimicking skeletal muscle actuator for prosthetics was developed. The actuator developed is manufactured with Fuse Filament Fabrication using a shape memory polymer composite that has non-linear contractile and passive forces, contractile forces and strains comparable to mammalian skeletal muscle, reaction time under one second, low operating temperature, and has a low mass, volume, and material costs. The actuator improves upon current prosthetic actuators that provide rigid, linear force with high weight, cost, and noise. / Dissertation/Thesis / Doctoral Dissertation Biomedical Engineering 2017

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-12T11:18:08Z No. of bitstreams: 1 ALYSSON ANTÔNIO RIBEIRO GOMES - DISSERTAÇÃO (PPGCEMat) 2015.pdf: 3273281 bytes, checksum: b71940c4b95418d315f4cfe0dfe1600a (MD5) / Made available in DSpace on 2018-07-12T11:18:08Z (GMT). No. of bitstreams: 1 ALYSSON ANTÔNIO RIBEIRO GOMES - DISSERTAÇÃO (PPGCEMat) 2015.pdf: 3273281 bytes, checksum: b71940c4b95418d315f4cfe0dfe1600a (MD5) Previous issue date: 2015-06-11 / Os implantes mamários são dispositivos médicos, empregados para aumentar, reconstrutir ou corrigir anomalis congênitas mamárias. Normalmente, são preenchidas por gel de silicone e/ou solução salina. Atualmente, têm sido utilizados com frequência implantes mamários com a superfície externa da membrana texturizada, por apresentar maior seguraça e reduzir complicações pós-operatórias como as contraturas capsulares. Desta forma, este trabalho teve como objetivo avaliar as propriedades físicas, químicas e biológicas de implantes mamários com membrana texturizada e preenchidas com gel de silicone. Portanto foram analisados quatro implantes mamários, de dois diferentes fabricantes, sendo uma marca nacional e outra importada. Os ensaios de caracterização foram realizados no lado da membrana interno que fica em contado com o gel e no lado externo que fica em contato com o meio biológico, através das seguintes técnicas: Microscopia Óptica – MO, Microscopia Eletrônica de Varredura – MEV, Espectroscopia por Energia Dispersiva de Raios X - EDS, Retilineidade, Ensaios Dimensionais - Espessura, Ensaio Mecânico - Tração, Citotoxicidade e Coesividade do Gel. Nos resultados do ensaio de avaliação morfológica (MO e MEV) foi observado que a superfície das membranas em contato com o gel apresenta-se com textura lisa e uniforme já o lado externo da membrana observou-se presença de poros com tamanhos e formas bastante distintas. Em relação aos ensaios mecânicos, todas as amostras atenderam aos requisitos normativos, porém uma das amostras apresentou valor muito próximo do limite de aprovação. Observou-se que a texturização das superfícies influencia nos desempenhos mecânicos das membranas. Os resultados do ensaio de coesividade do gel de preenchimento, citotoxicidade e de elementos químicos contaminantes foram semelhantes em todas as amostras e estão de acordo com as normas de certificação, sendo X2 muito próximo ao limite de aprovação. / Silicone breast implants are medical devices used to increase, reconstruct or correct mammary congenital deformities. Typically, they are filled with silicone gel and / or saline solutions. Currently, there is often used breast implants with the outer surface of the textured membrane to present maximum security and reduce post-operative complications such as capsular contracture. Thus, this study aimed to evaluate the physical, chemical and biological properties of textured silicone gel breast implants. Four breast implants were analyzed, two different manufacturers. The characterization tests were performed on the inner side of the membrane which is in contact with the gel, and the external side, in contact with the biological environment, through the following techniques: optical microscopy - MO, Scanning Electron Microscopy - SEM, Spectroscopy Energy Dispersive X-ray - EDS, Straightness, Dimensional Testing - Thickness, Mechanical Testing - Traction, Cytotoxicity and cohesiveness gel. The results of the morphological evaluation test (OM and SEM) it was observed that the surface of the membrane in contact with the gel appears with smooth and uniform texture, however, the external side of the membrane was observed pores with very different sizes and shapes . Regarding the mechanical tests, all samples met the regulatory requirements, but one of the samples showed a value close to approval limit. It was observed that the texturing of suferfícies influences the mechanical performances of the membranes. The cohesiveness filling gel test, cytotoxicity and chemical contaminants were similar in all samples and comply with certification regulations.

La surface naturelle des prothèses, tels que des implants métalliques, n'est pas idéale pour l'obtention d'une bonne ostéo-intégration. Par conséquent, l'amélioration des propriétés de surface pour les rendre ostéo-condutrices ou ostéo-inductrices est souhaitable. La délivrance contrôlée de protéines ostéo-inductrices de la famille des bone morphogenetic proteins (BMPs) par la surface des matériaux implantables permettrait une formation osseuse optimisée et plus rapide autour de l'implant. En particulier, la BMP-2 est importante dans la phase initiale de la différenciation vers l'os. En raison de leur similarité avec les tissus naturels, l'utilisation des revêtements de biopolymères qui ont une bonne affinité avec les molécules bioactives, semble prometteuse pour le chargement et la délivrance de BMP-2. L'équipe a déjà mis au point un film à base des biopolymères hyaluronane et de poly(L-lysine), en utilisant la technique d'assemblage couche par couche. Ce film constitue un réservoir qui permet de présenter la BMP-2 "liée à la matrice". La bioactivité in vitro et les propriétés ostéo-inductrices in vivo de ces films ont déjà prouvées. Dans ce travail, nous avons cherché à mieux comprendre l'interaction de la BMP-2 avec le film et l'interaction des cellules avec la BMP-2. Tout d'abord, nous avons étudié la structure de la BMP-2 piégée dans les films et l'avons comparé à celle en solution; puis nous avons évalué l'impact du séchage, du stockage à long terme et de la stérilisation sur la structure du film et sa bioactivité. Enfin, nous avons étudié l'internalisation de la BMP-2 par les cellules en fonction de la réticulation du film et avons étudié la relation entre internalisation et voies de signalisation. / The natural surface of bulk prostheses materials, such as metallic implants, is not suitable for successful osteointegration of implants. Therefore, improving the surface to render it osteoconductive and osteoinductive is needed. The controlled delivery of osteoinductive bone morphogenetic proteins (BMPs) from the surface of implantable materials would enable faster and better bone formation around the implant. In particular, BMP-2 plays an important role in the early phase of differentiation of stems cells in bone cells. The coating of natural polymers that have a high affinity for BMP-2 would enable BMP retention and localized delivery at the implant surface. Using the layer-by-layer technique, we have developed a coating made of the biopolymers hyaluronan and poly(L-Lysine), which acts as a reservoir to trap BMP-2 and to present them to cells in a "matrix-bound" manner. The in vitro bioactivity and in vivo osteoinductive properties of BMP-2-loaded films have previously been proved. In this work, the aim is to further understand the interaction of the BMP-2 with the film and the uptake of BMP-2 by the cells. First, the secondary structure of matrix-bound BMP-2 was studied and compared to its structure in solution. Second, the impact of drying, long term storage and sterilization on film structure and bioactivity were assessed. Finally, we investigated if and how matrix-bound BMP-2 is internalized by the cells from the different cross-linked films, the internalization route and its relation to BMP-2 signaling.

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-03-21T14:26:42Z No. of bitstreams: 1 arquivototal.pdf: 3600953 bytes, checksum: e3d3b68cddf291c4fb9c6bf44a515a2e (MD5) / Made available in DSpace on 2017-03-21T14:26:42Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3600953 bytes, checksum: e3d3b68cddf291c4fb9c6bf44a515a2e (MD5) Previous issue date: 2011-11-23 / The use of bone graft materials that promote the regeneration, it is a fact quite common in rehabilitation procedures. Various materials are used for this purpose, but among them, the plaster paris, which was one of the forerunners of this line fell into disuse at the expense of more elaborate materials. The objective of this study was a comparative analysis between the plaster paris and resorbable hydroxyapatite, to establish a degree of reliability of use for this material today as an option for low cost and easy handling. For this, an analysis was performed on 36 female Wistar rats with the use of these materials, for subsequent histological analysis of wound repair. This study demonstrated that in this situation, there was no difference in the potential of bone repair by comparing the two materials and the control group using only a blood clot, as well as the excellent biocompatibility of the same with the negative potential to produce unwanted reactions. / A utilização de materiais em enxertos ósseos, que favorecem a regeneração, é um fato bastante comum nos procedimentos reabilitadores. Diversos materiais são utilizados para este fim, mas dentre eles, o gesso paris, que foi um dos precursores desta linha, entrou em desuso em detrimento de materiais mais elaborados. O objetivo deste estudo foi fazer uma análise comparativa entre o gesso paris e a hidroxiapatita reabsorvível, visando estabelecer uma margem de confiabilidade de utilização para este material nos dias atuais como uma opção de baixo custo e fácil manuseio. Para isto, foi feito uma análise em 36 ratos Wistar fêmeas, com a utilização destes materiais, para uma posterior análise histológica da reparação da ferida cirúrgica. Este estudo demonstrou que nesta situação, não existiu diferença no potencial de reparação óssea se comparando os dois materiais e o grupo controle que utilizou apenas coágulo sanguíneo, como também a excelente biocompatibilidade dos mesmos com o potencial negativo de produzir reações indesejadas.

Made available in DSpace on 2014-10-09T12:42:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:58Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:48:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:12Z (GMT). No. of bitstreams: 1 09600.pdf: 6972887 bytes, checksum: 65b1043ea1de81f8d29ed5398e462257 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:52:44Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:05Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:52:55Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:50Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP