Includes bibliographical references (p. 111-115).

Thesis (Ph.D.)--University of Texas at Arlington, 2009.

Copper ions are widely reported to have pro-angiogenic properties and can be incorporated into bone substitute bioceramics as bio-instructive cues to stimulate infiltration of blood vessels into the material after implantation. By this, the viability of bone forming cells within the scaffold (which decreases rapidly with increasing depth from the surface) could be enhanced, and the healing process (resorption and replacement of the scaffold with new, natural bone) hastened. Pure-phase copper-doped hydroxyapatite (CuHA) materials with x = 0 - 1 in the nominal formula Ca10(PO4)6CuxOy(H)z were prepared by solid state synthesis at 1100 °C. Attempted preparation of compositions with y = 0.1 and 0.5 in the nominal formula Ca10−yCuy(PO4)6(OH)2 by an aqueous precipitation method led to formation of biphasic products containing considerable amounts of β-tricalcium phosphate. Dissolution tests in TRIS buffer, cell culture medium and citric acid buffer indicated that copper ions are released from CuHA materials at concentrations that increase with copper content in the materials and soaking time, and are in a physiologically-relevant range. This offers the potential to tune copper ion release by controlling the copper content of CuHA materials. In vitro in cultures of human osteoblast-like cells and human mesenchymal stem cells (hMSCs), copper ions released from CuHA downregulated ALP expression in both cell types and (particularly for hMSCs) upregulated VEGF expression. In vivo, the prepared copper-containing materials had pro-angiogenic and possible inflammatory effects in the chick embryo yolk sac membrane and chorioallantoic membrane angiogenesis assays. Copper ions released from beads grafted into the developing chick limb affected the integrity of developing blood vessels in the graft vicinity, causing haemorrhaging. The results suggest that the coupling of angiogenesis and osteogenesis, perhaps through the hypoxia and NO pathways, are important for copper's biological effects, and with further investigation and careful control of dose and timing these effects may be better understood and controlled.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 286-298). Available also in a digital version from Dissertation Abstracts.

No description available.

Thesis (M.S.)--Oregon Graduate Institute of Science and Technology, 1996.

No description available.

Bone consists of collagen/hydroxyapatite (HA) composites in which poorly crystalline carbonated calcium phosphate is intercalated within the fibrillar structure. Normal bone mineral is a carbonated-apatite, but there are limited data on the effect of mineral containing carbonate on cell response. Although the exact biological role of silicate in bone formation is unclear, silicate has been identified at trace levels in immature bone and is believed to play a metabolic role in new bone formation. To mimic the inorganic and organic composition of bone we have developed a variety of bone graft substitutes. In the present body of research, we characterized the surface composition of human cortical and trabecular bone. When then characterized the surface compositions of the following potential bone substitutes: carbonated hydroxyapatite (CO₃²-HA), silicated hydroxyapatite (Si-HA), and collagen sponges mineralized with calcium phosphate using the polymer-induced liquid-precursor (PILP) process. In the latter substitutes, the PILP process leads to type I collagen fibrils infiltrated with an amorphous mineral precursor upon which crystallization leads to intrafibrillar HA closely mimicking physiological bone mineral. We then determined the osteoblast-like cell response to each bone substitute to characterize the substrate’s effect on osteoblast differentiation. The observations collectively indicate that cells are sensitive to the formatting of the mineral phase of a bone substitute and that this format can be altered to modulate cell behavior.

Orientador: Cecilia Amelia de Carvalho Zavaglia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T21:15:57Z (GMT). No. of bitstreams: 1 Leal_ClaudeneteVieira_M.pdf: 5685507 bytes, checksum: 57585e6d19469dc1898123b62c967679 (MD5) Previous issue date: 2006 / Resumo: Os cimentos ósseos a base de fosfato de cálcio são materiais cerâmicos que apresentam biocompatibilidade devido a sua composição química semelhante à dos ossos, e bioatividade, promovendo a osteocondução. Com essas características, é possível a utilização desses materiais como implantes ósseos ou como preenchimento. Os cimentos de fosfato de cálcio são materiais constituídos por um pó e um líquido, que, ao serem misturados formam uma pasta que endurece espontaneamente à temperatura ambiente ou corpórea como resultado da precipitação de um ou vários fosfatos de cálcio. O pó pode ser composto por um ou vários fosfatos de cálcio, outros sais de cálcio e aditivos orgânicos. O líquido pode ser água ou soluções aquosas de compostos de cálcio ou fosfato. A proposta desse trabalho foi estudar a síntese de monólitos de fosfatos de cálcio baseado no sistema ß-Fosfato Tricálcio/Ácido Fosfórico (ß-TCP/H3PO4), que produz hidrogeno fosfato de cálcio dihidratado (DCPD), um cimento de fosfato de cálcio que possui como principal vantagem baixo custo e a desvantagem de possuir pH ácido, podendo causar necrose em tecidos. Para contornar esse problema, o DCPD foi convertido em apatita pela hidrólise em solução alcalina. O estudo envolveu a síntese do ß-TCP, a preparação do cimento, caracterizações físicas e químicas e o estudo do cimento em Fluido Corpóreo Simulado (FCS), solução que simula o plasma sanguíneo humano, para avaliar seu comportamento in vitro / Abstract: Calcium phosphate bone cements are ceramics materials that present biocompatibility because of their chemical composition similar to the human bone, and bioactivity, promoting osteocunduction. Due to these characteristics, it is possible the use of these materials as bone implants. Calcium phosphate cements are composed of a powder and liquid phases, which, when mixed form a paste that hardens spontaneously as result of the precipitation of one or more calcium phosphates. The powder may be composed of one or some calcium phosphates, others salts and organics additives. The liquid may be water or calcium phosphates aqueous solutions. The purpose of this work is the synthesis of calcium phosphate monoliths based on ß-tricalcium phosphate/ortho-phosphoric acid (ß-TCP, Ca3(PO4)2/H3PO4), that produce dicalcium phosphate dehydrate (DCPD, CaHPO4.2H2O) as phase precipitated as a result of the setting reaction. DCPD is inexpensive, but is quite soluble and has an acidic hydrolysis, which may cause necrosis in vivo. To resolve this problem, DCPD was converted in apatite phase by hydrolysis in NaOH aqueous solution. This study included ß-TCP synthesis, cement preparation, chemical and physical characterizations and the study of the cement in Simulated Body Fluid (SBF), with ion concentrations nearly equal to those of human blood plasma, to evaluate the in vitro behavior / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Orientadores: Maria Clara Filippini Ierardi, André Luiz Jardini Munhoz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T11:48:55Z (GMT). No. of bitstreams: 1 Zavaglia_FelipedeCarvalho_M.pdf: 14473856 bytes, checksum: 25fac84e52ec20bec15f8b33d830a26a (MD5) Previous issue date: 2011 / Resumo: Os biomateriais vêm sendo desenvolvidos e utilizados há muito tempo, e, uma questão relevante a se observar, é a conformação destes materiais para a confecção de produtos. Um novo conceito surge com a prototipagem rápida. Como os componentes do organismo humano são únicos e distintos, as tecnologias modernas de prototipagem rápida e personalização de implantes se destacam em importância. O uso de prototipagem rápida está relacionado normalmente à produção indireta de próteses e outras soluções médicas; no entanto, estudos recentes tem sido feitos com o objetivo de se utilizar as técnicas de prototipagem rápida diretamente com os biomateriais. O objetivo do presente pesquisa foi sintetizar e caracterizar a biocerâmica de beta fosfato tricálcico (ß-TCP) para aplicações em três tipos de casos de implantes. O procedimento experimental constou da síntese do ß-TCP e caracterização através de microscopia eletrônica de varredura, avaliação da distribuição granulométrica, espectroscopia de fluorescência de raios X e difração de raios X. Foram preparados, com essa biocerâmica, implantes de formatos simples (como pequenos discos), através da conformação por prensagem uniaxial e sinterização. A preparação dos grânulos de ß-TCP e ligantes foi feita de duas maneiras: manualmente e através de equipamento spray dryer. Após essa preparação dos grânulos foi realizada a prototipagem rápida, com sucesso, de pequenos corpos de prova em equipamento 3D Printer. O ß-TCP sinterizado também foi utilizado, através da técnica PVD (deposição física a vapor) para revestir implantes macro porosos de titânio metálico, obtidos por outro equipamento de prototipagem rápida (sinterização de metais direta a laser). Os resultados obtidos neste trabalho foram satisfatórios, demonstrando que as técnicas desenvolvidas de utilização do ß-TCP pode levar a obtenção de implantes úteis no tratamento de pessoas com problemas de pequenos defeitos ósseos / Abstract: Biomaterials have been developed and used for a long time, and a relevant question is about conformation of these materials for products confectioning. A new concept arises with rapid prototyping. Due to the components of human organism being single and distinct, modern techniques of rapid prototyping and implants personalization stand highly. The use of Rapid prototyping is usually related to indirect production of prosthesis and other medical solutions, however, recent studies have been done with the goal to use rapid prototyping techniques directly with biomaterials. The present research goal was to synthesize and characterize beta tricalcium phosphate (ß-TCP) for application in three types of implants. The experimental procedure consisted in the synthesis of ß-TCP and its characterization by scanning electronic microscopy, granulometric distribution evaluating, x-ray fluorescence spectroscopy and X-ray diffraction. Simple structures were prepared with this bioceramic by axial pressing and sintering. The preparation of ß-TCP granules with binder was done in two ways: manually and by spray drying equipment. After granules preparation, rapid prototyping was performed with success of small specimens with a Zcorp 3D Printer equipment. The sintered ß-TCP was also used for coating macro porous metallic titanium implants obtained by other rapid prototyping equipment, (direct metal laser sintering) using PVD technique (physical vapor deposition). The present results were satisfactory, showing that the techniques developed for ß-TCP can lead to useful implants for small bone defects / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica