Made available in DSpace on 2014-06-11T19:27:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-24Bitstream added on 2014-06-13T18:56:30Z : No. of bitstreams: 1 ferreira_l_me_araca.pdf: 1328677 bytes, checksum: e8654f5c6e3eb77d8eb2d430f398667d (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Muito tem se avaliado a respeito das propriedades físicas e químicas dos selantes de fóssulas e fissuras, mas pouco sobre seus efeitos no biofilme dentário. O objetivo deste estudo foi analisar as características bioquímicas e microbiológicas do biofilme dentário formado in situ sobre materiais que liberam flúor ou cálcio e fosfato. Dez voluntários utilizaram dispositivo intrabucal palatino contendo corpos-de-prova de materiais (Fuji IX GP, Auralay XF e Aegis) ou blocos de esmalte bovino. A fase experimental consistiu de 4 etapas de 8 dias cada e a utilização de sacarose para formação do biofilme. No 7º dia dos períodos experimentais foi determinado o pH do biofilme e no 8º dia, o biofilme dentário formado foi coletado para determinação de flúor (F), cálcio (Ca), fósforo (P) e polissacarídeos extracelulares insolúveis (PEI) além da microbiota. Verificou-se a liberação de F, Ca e P de cada material e dos blocos de esmalte após ciclagem de pH. Após a verificação da homogeneidade dos dados, testes paramétricos e não-paramétricos foram realizados para análise dos resultados (p<0,05). O biofilme dentário formado sobre os materiais que liberam flúor apresentou maior presença de F, Ca e P e menor número de estreptococos do grupo mutans quando comparado ao bloco de esmalte. Após o uso da sacarose (7º dia), o pH do biofilme foi maior na presença do material ionomérico. O biofilme sobre o material que contém fosfato de cálcio amorfo mostrou similar concentração de Ca e P, quando comparado aos materiais que contém flúor, e uma ação tamponante no meio, sem efeito na microbiota. Concluiu-se que os materiais que liberam flúor aumentaram as concentrações de F, Ca e P e diminuíram a de PEI e a microbiota cariogênica do biofilme dentário; e o que contém fosfato de cálcio amorfo aumentou as concentrações de Ca e P / The chemical and physical properties of the pit and fissures sealants have been widely evaluated but rare researches focus on the effects on dental plaque. The aim of this study was to evaluate the biochemical and microbiological characteristics of the in situ dental plaque formed on materials that release fluoride or calcium and phosphate. Ten volunteers wore an intraoral palatal device containing specimens of materials (Fuji IX GP, Auralay XF and Aegis) or bovine enamel blocks. The experimental phase consisted of 4 stages with duration of 8 days each and use of sucrose to form the dental plaque. The dental plaque pH was determined at the 7th day of the experimental periods and the dental plaque was collected at the 8th day to determine the fluoride (F), calcium (Ca), phosphorus (P), insoluble extracellular polysaccharides (EPS) and microbiota. It was observed release of F, Ca and P from each material and from the enamel blocks after pH cycling. After verification of data homogeneity, parametric and non-parametric tests were performed (p<0.05). The dental plaque formed on the materials that release fluoride presented more F, Ca and P and reduced number of Streptococcus mutans in comparison to the enamel block. After use of sucrose (7th day), the dental plaque pH was higher with the presence of ionomeric material. The dental plaque on the material containing amorphous calcium phosphate exhibited similar Ca and P concentration compared to the ones on fluoride materials, and buffering action with no effect on the microbiota. It was concluded that the materials that release fluoride increased F, Ca and P concentrations, decreased EPS concentration and the cariogenic microbiota of the dental plaque; the amorphous calcium phosphate material increased concentrations of Ca and P

Made available in DSpace on 2016-12-08T15:56:17Z (GMT). No. of bitstreams: 1 Resumo LEVANDOWSKI.pdf: 475369 bytes, checksum: 6234f28eabf60dbad017c95e2d659f76 (MD5) Previous issue date: 2014-07-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nanotechnology involves creation, manipulation and exploitation of materials at the nanoscale. This Science has led to research and development of new materials consisting of molecules, particles and/or grains in the nanometer scale. The Research Group in Biomaterials of UDESC develops studies in the field of nanotechnology and nanomaterials for more than a decade with the goal of developing nanostructured biomaterials with different characteristics of conventional biomaterials, capable of promoting early bone formation and contributes significantly within the bone healing and quality of life The first step of this Thesis research aimed to characterize six different granular microporous biomaterials divided into two groups. Group I was composed of hydroxyapatite (HAp), beta tricalcium phosphate (TCP), and biphasic calcium phosphate (BCP) at a concentration of 60% HAp and 40% TCP by volume. Group II consisted of three compositions of nanocomposites in hydroxyapatite matrix, with 5% by volume of the second nanometric phase, in the following compositions: HAp-SiO2n, HAp-TiO2n and HAp-Al2O3-&#945;n. The results of the characterization were related to X-ray diffraction analysis (XRD), Fourier transformed infrared spectroscopy (FTIR), morphological and microstructural characterization, specific surface area, hydrostatic density and open porosity. After characterization studies, the calcium phosphate biomaterials and nanocomposites were used for simultaneous comparative analysis of bone formation in a method of guided bone augmentation in rabbit calvaria. Blood clot (C) and bovine hydroxyapatite BioOss® (HAP-BOV) served as control. The results of histomorphometric analysis demonstrated that the biomaterial HAp-SiO2 showed the highest amount of mineralized bone tissue after 45 days (39.07%), followed by HAp (36.92%), TCP (31.3%), BCP (31.2%), HAp-Al2O3 (28.88%), HAp-BOV (26.45%), HAp-TiO2 (15.92%) and C (3.6%). After 90 days, analysis was performed only for Group I and the 14 HAp biomaterial had the highest amount of mineralized bone tissue (49.46%), followed by BCP (41.5%), TCP (35.18%) and C (6.26%). The results of the characterization and in vivo studies showed that calcium phosphates HAp, TCP, BCP and nanocomposite HAp-SiO2 were biocompatible and do not induced inflammatory tissue reactions. Their microstructural characteristics, with lower grain than 800nm and interconnected microporosity above 25%, provided better performance of bone formation in relation to commercial biomaterial used as control. / A nanotecnologia envolve a criação, manipulação e exploração de materiais na escala nanométrica. Esta Ciência tem levado à investigação e ao desenvolvimento de novos materiais constituídos por moléculas, partículas e/ou grãos na escala do nanômetro. O Grupo de Pesquisa em Biomateriais da UDESC desenvolve pesquisas na área de nanotecnologia e nanomateriais há mais de uma década com o objetivo de desenvolver biomateriais nanoestruturados com características diferenciadas dos biomateriais convencionais, capazes de promover a neoformação óssea precoce e contribuir significativamente dentro dos processos de reparação tecidual e com a qualidade de vida. A primeira etapa deste trabalho de Tese teve por objetivo realizar a caracterização de seis diferentes biomateriais microporosos granulados, divididos em dois grupos. O grupo I foi composto pelos biomateriais hidroxiapatita (HAp), fosfato tricálcico beta (TCP) e fosfato de cálcio bifásico (BCP) na concentração de 60% HAp e 40% TCP em volume. O grupo II foi formado por três composições de biomateriais nanocompósitos em matriz de hidroxiapatita, a 5% em volume da segunda fase nanométrica, nas seguintes composições: HAp-SiO2n, HAp-TiO2n e HAp-Al2O3-&#61537;n. Os resultados de caracterização obtidos relacionaram os dados referentes à análise por difratometria de raios X (DRX), espectroscopia de infravermelho com transformada de Fourier (FTIR), caracterização morfológica e microestrutural, área superficial, densidade hidrostática e porosidade aberta. Após a realização dos estudos de caracterização, os biomateriais fosfatos de cálcio e nanocompósitos foram utilizados para uma análise comparativa simultânea de formação óssea em um método de aumento ósseo guiado em calvária de coelhos. Como controle foram utilizados o coágulo sanguíneo (C) e a hidroxiapatita bovina BioOss® (HAP-BOV). Os resultados da análise histomorfométrica demonstraram que o biomaterial HAp-SiO2 apresentou a maior quantidade de tecido ósseo mineralizado aos 45 dias (39,07%), seguido da HAp (36,92%), TCP (31,3%), BCP (31,2%), HAp-Al2O3 (28,88%), HAp-BOV (26,45%), HAp-TiO2 (15,92%) e C (3,6%). A análise aos 90 dias foi realizada apenas para o grupo I e o biomaterial HAp apresentou a maior 12 quantidade de tecido ósseo mineralizado (49,46%), seguido por BCP (41,5%), TCP (35,18%) e C (6,26%). Os resultados obtidos dos estudos de caracterização e de formação óssea mostraram que os fosfatos de cálcio microporosos HAp, TCP, BCP e o nanocompósito microporoso HAp-SiO2 foram biocompatíveis e não induziram reações teciduais inflamatórias. Suas características microestruturais, com grãos inferiores a 800nm e microporosidade interconectada acima de 25%, proporcionaram um melhor desempenho de formação óssea em relação ao biomaterial comercial utilizado como controle.

Submitted by SABRINA FERREIRA null (sabrife@bol.com.br) on 2017-10-26T16:31:30Z No. of bitstreams: 1 TESE FINAL.docx: 68772200 bytes, checksum: f6722c6fe1365b9fe81b2aa5d5b01539 (MD5) / Rejected by Monique Sasaki (sayumi_sasaki@hotmail.com), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: A versão final da dissertação/tese deve ser submetida no formato PDF (Portable Document Format). O arquivo PDF não deve estar protegido e a dissertação/tese deve estar em um único arquivo, inclusive os apêndices e anexos, se houver. Por favor, corrija o formato do arquivo e realize uma nova submissão. Agradecemos a compreensão. on 2017-10-31T17:57:48Z (GMT) / Submitted by SABRINA FERREIRA null (sabrife@bol.com.br) on 2017-11-02T18:44:52Z No. of bitstreams: 1 TESE FINAL.pdf: 1299336 bytes, checksum: 6585035d2ca784a2d052292a49407084 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-11-10T18:05:35Z (GMT) No. of bitstreams: 1 ferreira_s_dr_araca.pdf: 1299336 bytes, checksum: 6585035d2ca784a2d052292a49407084 (MD5) / Made available in DSpace on 2017-11-10T18:05:35Z (GMT). No. of bitstreams: 1 ferreira_s_dr_araca.pdf: 1299336 bytes, checksum: 6585035d2ca784a2d052292a49407084 (MD5) Previous issue date: 2017-10-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A altura insuficiente do osso alveolar é um fator limitante para a reabilitação oral com próteses implantossuportadas. Taxas de sucesso clínico com uso de biomateriais à base de beta-tricálcio fosfato (b-TCP) para elevação do assoalho do seio maxilar (EASM) mostraram que são excelentes alternativas ao osso autógeno (OA). Portanto, objetivo foi avaliar a formação óssea do enxerto de b-TCP em bloco, seis meses após EASM, comparada ao OA por meio de análises tomográfica, microtomográfica e histomorfométrica. Para isso, Oito seios maxilares foram enxertados com b-TCF e sete OA. Após 6 meses, foram obtidas biópsias durante à instalação de implantes dentários. Não houve diferença significante (ANOVA) entre a contração do volume dos seios maxilares preenchidos por OA e b-TCP (p=0,113), bem como para todos os parâmetros microtomográfico (ANOVA) BV/TV (p=0.089), Tb.Th (p=1.000), Tb.Sp (p=0,989) e Tb.N (p=0.917). Na histomorfometria quando comparada a porcentagem ósseo em OA e b-TCP também não foi encontrada diferença estatística (ANOVA, p=0,794). Em conclusão, os resultados deste estudo indicam que ambos OA e b-TCP são adequados para o uso com segurança para o procedimento de EASM pela técnica da janela lateral. O material sintético apresenta boa estabilidade volumétrica com formação óssea semelhante ao OA suportada pelos parâmetros em análises 2D e 3D que se complementam. No entanto, a metodologia da análise volumétrica utilizada neste estudo parece representar a estabilidade volumétrica geral do procedimento, não somente do biomaterial, quando na técnica for utilizado o enxerto em bloco e não particulado. / The insufficient height of the alveolar bone is a limiting factor for oral rehabilitation with implants. Clinical success rates using beta-tricalcium phosphate (b-TCP) biomaterials for maxillary sinus floor elevation (MSFE) have been shown to be excellent alternatives to autogenous bone (AB). Therefore, the objective was to evaluate bone formation of the b-TCP graft in a block, six months after MSFE, compared to AB by means of tomographic, microtomographic and histomorphometric analyzes. For this, eight maxillary sinuses were grafted with b-TCF and seven AB. After 6 months, biopsies were obtained during the installation of dental implants. There was no significant difference (ANOVA) between the volume contraction of the maxillary sinus filled by AB and b-TCP (p = 0.113), as well as for all microtomographic parameters (ANOVA) BV/TV (p = 0.089), Tb.Th (p = 1.000), Tb.Sp (p = 0.989) and Tb.N (p = 0.917). In histomorphometry, when comparing bone percentage in AB and b-TCP, no statistical difference was found (ANOVA , p = 0.794). In conclusion, the results of this study indicate that both AB and b-TCP are suitable for safe use for the MSFE procedure by the side window technique. The synthetic material presents good volumetric stability with bone formation similar to AB supported by the parameters in 2D and 3D analyzes that complement each other. However, the volumetric analysis methodology used in this study seems to represent the general volumetric stability of the procedure, not only of the biomaterial, when in graft and non-particulate graft technique.

Le développement de matériaux biocompatibles permettant la vectorisation de principes actifs est particulièrement souhaitable dans le cadre de la réparation osseuse liée à certaines pathologies. Dans la première partie de ce mémoire, nous décrivons la synthèse et la caractérisation de verres de phosphates de calcium dopés avec du gallium qui est un agent inhibiteur de la résorption osseuse. Les modifications du réseau phosphate sont étudiées par RMN du 31P et les différents environnements locaux du Ga3+ sont mis en évidence par RMN du 71Ga en utilisant des conditions expérimentales spécifiques (très haut champ magnétique de 20T et rotation de l’échantillon ultra-rapide). Le comportement en solution de ces verres a été étudié par RMN et par ICP-AES. Les résultats obtenus indiquent qu’ils sont soumis à une dissolution quasi-congruente et que l’ajout de Ga3+ augmente leur durabilité chimique. La seconde partie de ce travail est dédiée à l’étude d’un verre bioactif utilisé en chirurgie réparatrice osseuse : le Bioglass® 45S5 (système SiO2-CaO-Na2O-P2O5). L’utilisation d’expériences RMN de double résonance a permis d’apporter des éléments de réponse sur le type d’association entre les groupements phosphates et le réseau silicate. Après immersion de ce verre dans un fluide physiologique simulé (SBF), un suivi quantitatif des espèces, initiales et formées à la surface du verre, a été réalisé par RMN. Les résultats obtenus par RMN et par d’autres techniques de caractérisation montrent que l’hydroxyapatite carbonatée se formant en surface du verre présente de grandes similitudes avec les apatites biologiques. / The development of biocompatible materials allowing the local delivery of specific drugs is of high interest to repair pathological bone defects. The first part of this manuscript describes the synthesis and the characterisation of calcium phosphates glasses doped with gallium, which is a bone resorption inhibitor. The nature of the phosphate network is probed by 31P NMR and the Ga3+ local environments are studied 71Ga NMR at very high magnetic field (20T) and ultra-fast spinning frequency. The leaching behaviour of these glasses is investigated by NMR and ICP-AES. The obtained results indicate that the glass dissolution is nearly congruent and that Ga3+ doping improves the chemical durability. The second part of this work is dedicated to the study of the Bioglass® 45S5 which is a bioactive glass (SiO2-CaO-Na2O-P2O5 glassy system) used in bone repair surgery. Double-resonance NMR experiments are used to obtain information about the association between the phosphate units and the silicate network. NMR analyses are also used to characterize quantitatively the various species formed at the glass surface after immersion into a simulated body fluid for varying periods. Results obtained from NMR and other characterization methods revealed that the carbonated hydroxyapatite formed at glass surface shows strong similarities with biological apatites.

The design and selection of a biomaterial will depend on its specific application and the required properties for that application, both mechanical physicochemical properties. Biomaterials can be extremely helpful in order to treat and help the human body to heal and repair faster any kind of fracture produced in bones. Calcium phosphate scaffolds produced by sol-gel procedures have been used for this purpose with a great success regarding mechanical properties and biocompatibility. This is the reason why new techniques needs to be developed to be able to produce scaffolds in a faster way and to reach a personalized treatment to each patient. By using 3D printing techniques, a new and promising scope is open for bone tissue engineering due to the possibility of printing scaffolds with any shape and complexity through CAD design and modelling. In this project 3D printed scaffolds with a matrix combination of polymers and calcium phosphate will be produced and studied for bone tissue regeneration. Self-setting alpha tricalcium phosphate (α-TCP) based cement inks combined with polycaprolactone (PCL) were optimized, and 3D printed structure scaffolds were successfully generated by direct ink writing. Afterwards, the scaffolds were subjected to different hardening processes in order to obtain different hydroxyapatite microstructure morphologies and were characterised by different methodologies. It was demonstrated the important effect of obtaining a complete transformation from the α-TCP into hydroxyapatite in the mechanical properties. An improvement in the mechanical properties at compression was achieved with the addition of PCL within the scaffold ́s structure and a different fracture mode of the scaffolds was observed.

Pre regeneráciu a rast poranených nervových vlákien bolo preskúmaných mnoho postupov, no výsledný rast axónov je často náhodný až dezorganizovaný a odráža sa na zložitejšom zotavovaní pacienta. V tejto práci boli vyrobené nové skafoldy s mikroštruktúrnymi a mechanickými vlastnosťami nervového skafoldu pomocou metódy freeze-casting. Konkrétne boli vyrobené biokeramické skafoldy na báze fosforečnanov vápenatých, oxidu titaničitého alebo oxidu zirkoničitého. Pomocou kontrolovaného rastu ľadu v jednom smere bola pripravená orientovaná mikroštruktúra. Pozorovanie pomocou skenovacej elektrónovej mikroskopie potvrdilo lineárne orientované póry (lamelárny systém), v ktorých priemerná veľkosť pórov klesala so zvyšujúcou sa rýchlosťou mrazenia. Skafoldy pripravené pomocou mrazenia v tekutom dusíku vykazovali vynikajúce mechanické vlastnosti, kde pevnosť v ohybe bola získaná v rozmedzí 10–17 MPa. Tie isté skafoldy mali vzdialenosť medzilamelamelárnych priestorov 10–30 µm, ktorých parametre sú vhodné pre nervové skafoldy. Biokompatibilita bola vyhodnotená pomocou Schwannových buniek in vitro, kde bola pozorovaná adhézia a rast v lamelárnom smere. Cytotoxické testy odhalili negatívny vplyv vyššej koncentrácie vápnika na prežitie Schwannových buniek. Pripravené skafoldy mali schopnosť tvorby apatitu na povrchu v podobe embryonálnych a nukleačných centier a apatitu samotného. Skafoldy na báze fosforečnanov vápenatých a oxidu titaničitého vykazovali sľubné regeneračné vlastnosti, konkrétne adhéziu a rast prostredníctvom pórovitej štruktúry a taktiež vynikajúce mechanické vlastnosti.

Indiana University-Purdue University Indianapolis (IUPUI) / Calcium phosphate-filled restorative materials were developed to provide calcium (Ca) and phosphate (PO4) ions, which have been proposed to enhance remineralization of demineralized tooth structure. Recently, tricalcium phosphate (TCP)-filled restorative materials were introduced as an alternative to amorphous calcium phosphate. The TCP filler has a more crystalline structure than ACP and is therefore potentially stronger. The aim of the present study was to examine TCP-filled restorative resins at different concentration levels at different time intervals to characterize the concentrations of Ca and PO4 ions released, and to measure the water sorption (WS) of these resins. An in vitro study was conducted by formulating resin composite using TCP as the filler mixed with EBPADMA, HmDMA, and HEMA as the resin matrix. One-hundred- sixty samples were prepared, 40 samples of each filler concentration (30 percent, 40 percent, 50 percent, and 60 percent) by weight. From each filler concentration, 5 samples of each of the 8 time points (time intervals of 4 h, 8 h, 12 h, 24 h, 3 d, 7 d, 14 d, and 21 d) were immersed in 100-ml deionized water. Calcium and PO4 ions were measured using atomic absorption spectroscopy and light spectroscopy, respectively. Water sorption (WS) was measured according to ISO 4049 specification and then the WS and the diffusion coefficient were calculated. The significance level was set at p = 0.001. The results indicated that Ca and PO4 ion release increased with increasing filler level at a rate faster than being linear. In addition, WS results were very high and failed to meet the ISO 4049 specification requirement. Diffusion coefficient results were also high. One-way ANOVA test for only 21-day data revealed that there is a statistically significant difference in filler level percent, and two-way ANOVA testing revealed that there is a statistically significant interaction between time and filler level percent on the Ca, PO4 released and WS. It can be concluded that the concentrations of Ca and PO4 released and WS were affected by composition of the monomers, filler level and type, dispersion, and the absence of coupling agent. Although this TCP-filled restorative material may release Ca and PO4, it cannot serve as a restorative material due to high WS values. Further study is needed to improve the material and evaluate its ability in promoting remineralization of the tooth structure in order for it to serve its purpose.

Bone is a remarkable multifunctional tissue with the ability to regenerate and remodel without generating any scar tissue. However, bone loss due to injury or diseases can be a great challenge and affect the patient significantly. Autologous bone grafting is commonly used throughout the world. Autograft both fills the void and is bone inductive, housing the particular cells that are needed for bone regeneration. However, a regenerative complement to autograft is of great interest as the use of biomaterials loaded with bioactive molecules can avoid donor site morbidity and the problem of a limited volume of material. Two such regenerative products that utilise bone morphogenetic protein (BMP)-7 and -2 have been used for more than a decade clinically. Unfortunately, several side effects have been reported, such as severe swelling due to inflammation and ectopic bone formation. Additionally, the products require open surgery and use of supra physiological doses of the BMPs due to poor localisation and retention of the growth factor. The purpose of this thesis was to harness the strong inductive capacity of the BMP-2 by optimising the carrier of this bioactive protein, thereby minimising the side effects that are associated with the clinical products and facilitating safe and localised bone regeneration. We focused on an injectable hyaluronan-based carrier developed through polymer chemistry at the University of Uppsala. The strategy was to use the body’s own regenerative pathway to stimulate and enhance bone healing in a manner similar to the natural bone-healing process. The hyaluronan-based carrier has a similar composition to the natural extracellular matrix and is degraded by resident enzymes. Earlier studies have shown improved properties when adding hydroxyapatite, a calcium phosphate that constitutes the inorganic part of the bone matrix. In Paper I, the aim was to improve the carrier by adding other forms of calcium phosphate. The results indicated that bone formation was enhanced when using nano-sized hydroxyapatite. In Paper II, we discovered the importance of crushing the material, thus enhancing permeability and enlarging the surface area. We wished to further develop the carrier system, but were lacking an animal model with relatively high throughput, facilitated access, paired data, and we were also committed to the 3Rs of refinement, reduction, and replacement. To meet these challenges, we developed and refined an animal model, and this is described in Paper III. In Paper IV, we sought to further optimise the biomaterial properties of the hydrogel through covalent bonding of bisphosphonates to the hyaluronan hydrogel. This resulted in exceptional retention of the growth factor BMP-2. In Paper V, SPECT/PET/µCT was combined as a tri-modal imaging method to allow visualisation of the biomaterial’s in situ action, in terms of drug retention, osteoblast activity and mineralisation. Finally, in Paper VI the correlation between existing in vitro results with in vivo outcomes was observed for an array of biomaterials. The study identified a surprisingly poor correlation between in vitro and in vivo assessment of biomaterials for osteogenesis.

Bone is a remarkable multifunctional tissue with the ability to regenerate and remodel without generating any scar tissue. However, bone loss due to injury or diseases can be a great challenge and affect the patient significantly. Transplanting bone graft from one site in the patient to the site of fracture or bone void, i.e. autologous bone grafting is commonly used throughout the world. The transplanted bone not only fills voids, but is also bone inductive, housing the particular cells that are needed for bone regeneration. Nevertheless, a regenerative complement to autograft is of great interest and importance because the benefits from an off-the-shelf product with as good of healing capacity as autograft will circumvent most of the drawbacks with autograft. With a regenerative-medicine approach, the use of biomaterials loaded with bioactive molecules can avoid donor site morbidity and the problem of limited volume of material. Two such regenerative products that utilize bone morphogenetic protein 7 and 2 have been used for more than a decade in the clinic. However, some severe side effects have been reported, such as severe swelling due to inflammation and ectopic bone formation. Additionally, the products require open surgery, use of supra physiological doses of the BMPs due to poor localization and retention of the growth factors. The purpose of this thesis was to harness the strong inductive capability of the BMP-2 by optimizing the carrier of this bioactive protein, thereby minimizing the side effects that are associated with the clinical products and facilitating safe and localized bone regeneration at the desired site. We focused on an injectable hyaluronan-based carrier. The strategy was to use the body’s own regenerative pathway to stimulate and enhance bone healing in a manner similar to the natural bone-healing process. The hyaluronan-based carrier has a similar composition to the natural extracellular matrix and is degraded by resident hyaluronidase enzymes. Earlier studies have shown a more controlled release and improved mechanical properties when adding a weight of 25 percent of hydroxyapatite, a calcium phosphate that constitutes the inorganic part of the bone matrix. In Paper I, the aim was to improve the carrier by adding other forms of calcium phosphate. The results indicated that the bone formation was enhanced when using nano-sized hydroxyapatite. We wished to further develop the carrier system but were lacking an animal model with high output and easy access. We also wanted to provide paired data and were committed to the 3 Rs of refinement, reduction and replacement. To meet these challenges, we developed and refined an animal model, and this is described in Paper II. In Paper III, we characterized and optimized the handling properties of the carrier. In Paper IV, we discovered the importance of crushing the material, thus enhancing permeability and enlarging the surface area. In Paper V, we sought to further optimize biomaterial properties of the hydrogel through covalently bonding of bisphosphonates to the hyaluronan hydrogel. The results demonstrated exceptional retention of the growth factor BMP-2. In Paper VI, the in vivo response related to the release of the growth factor was examined by combining a SPECT/PET/µCT imaging method to visualize both the retention of the drug, and the in-vivo response in terms of mineralization.

Ce travail a consisté à élaborer un biomatériau hybride constitué d’un tissu de fibres de carbone (TFC) revêtu de phosphates de calcium (CaP) déposés par un procédé de sono-électrodéposition et à étudier l’influence des paramètres expérimentaux sur la composition chimique, la microtexture et la structure des revêtements phosphocalciques, ainsi que la biocompatibilité in vitro du biomatériau hybride. La densité de courant s’est avérée être un paramètre important. Pour de fortes densités de courant (≥ 100 mA/g), un régime d’électrolyse rapide de l’eau entraîne la formation d’un dépôt aciculaire d’hydroxyapatite déficitaire en calcium (CaD-HAP) carbonatée avec la présence éventuelle d’une phase de calcite. Pour de faibles densités de courant (≤ 50 mA/g), un régime d’électrolyse lent de l’eau entraîne la formation d’un dépôt plaquettaire de CaD-HAP carbonatée issu de l’hydrolyse in situ du phosphate octocalcique plaquettaire préalablement précipité. Pour l’ensemble des dépôts, les particules sont constituées d’un coeur de CaD-HAP carbonatée de structure ordonnée et d’une surface hydratée de CaD-HAP carbonatée de structure désordonnée qui résulte de l’existence d’une zone de sursaturation lors de la précipitation des CaP. La sono-électrodéposition se révèle être un procédé versatile capable d’orienter la synthèse des phases de CaP, avec pour une faible densité de courant appliquée l’obtention d’un dépôt biomimétique comparable à la partie minérale du tissu osseux obtenue par le processus d’ostéogénèse naturelle. Des tests de viabilité in vitro réalisés avec des ostéoblastes humains primaires ont montré que la nanoporosité et le caractère hydrophile des TFC n’impactent pas la biocompatibilité et que les paramètres tels que le précurseur des fibres, l’ensimage et/ou la forme lobée des fibres semblent favoriser l’adhésion et la prolifération des cellules. / This work is focused on the synthesis of a novel hybrid biomaterial made of carbon fibers cloth (CFC)/ calcium phosphates (CaP) using the sono-electrochemical technique and the study of the influence of experimental parameters on the chemical composition, microtexture and structure of CaP deposits and on in vitro biocompatibility. Current density is shown to be a crucial parameter. Specifically, at high current densities ((≥ 100 mA/g), the fast water electrolysis rate leads to a needle-like deposit consisting in a major phase of carbonated calcium deficient hydroxyapatite (CaD-HAP) mixed with a calcium carbonate phase. At low current densities (≤ 50 mA/g), the slow water electrolysis rate generates a plate-like carbonated CaD-HAP phase, coming from the in situ hydrolysis of a former octacalcium phosphate phase. Whatever the experimental conditions, particles of the deposits consists in a carbonated CaD-HAP core showing an ordered structure, surrounded by a hydrated and disordered carbonated CaD-HAP surface layer which results of the formation of oversaturated domains during CaP precipitation. Sono-electrodeposition is shown to be a versatile process able to control the nature of CaP phases. Especially, at low current density a biomimetic CaP deposit is obtained, similar to the mineral part of bones produced during natural osteogenesis. In vitro biologic tests using primary human osteoblasts showed that the nano-porosity and hydrophilicity of the carbon fibers do not affect the biocompatibility and that fiber precursor, sizing and lobe shaped fibers seems to favor adhesion and proliferation of human cells.