Os componentes protéticos que fazem a união entre implante e prótese são importantes para a manutenção da saúde peri-implantar sendo responsáveis pela vedação permucosa e impedindo a penetração de agentes químicos ou bacterianos desencadeadores de processos destrutivos nas estruturas ao redor do implante. Assim faz-se importante o desenvolvimento de técnicas que preservando as características de citocompatibilidade dos componentes protéticos que incorporem a sua estrutura, agentes antibacterianos que assegurem a saúde peri-implantar e que não permitam o desenvolvimento de resistência dos micro-organismos sendo ainda inócuos aos tecidos circunjacentes e ao organismo como um todo. Este trabalho teve o objetivo de testar a citocompatibilidade de discos de titânio com uma cobertura revestida usando nanotecnologia de prata em cultura de fibroblastos gengivais humanos. Discos de titânio de 5,9 mm foram preparados para o ensaio, sendo compostos por disco controle ST (N=1) sem nenhuma espécie de tratamento e disco com tratamento CT (N=3) com 3 camadas de cobertura com filme carregado com partículas de prata. O aditivo antimicrobiano à base de prata foi obtido pelo método wet chemistry por impregnação de metal homogeneamente distribuída sobre a superfície do disco. Fragmentos de gengiva foram cortados e colocados em placas de petri com meio de cultura Eagle modificado por Dulbecco. Com aproximadamente 15 dias foram retirados os fragmentos de gengiva, seguido da tripsinização das células para sua expansão. O meio de cultura foi trocado a cada 2-3 dias e a progressão da cultura foi avaliada por microscópio de fase. Os FGHs (fibroblastos de gengiva humana) na terceira passagem (p3) foram contados em um hemocitômetro e plaqueados em placas de 96 e 24 poços. As análises foram feitas com 24, 48 e 72 horas após o plaqueamento. Após a solubilização, as soluções foram transferidas para uma nova placa de 96 poços, e efetuada a leitura. A citotoxicidade dos materiais foi avaliada por espectrofotometria no aparelho Leitor de Elisa, com comprimento de onda de 590 nm. As amostras foram metalizadas e o MEV foi usado para avaliar a morfologia das células. O comportamento da cultura de fibroblastos sobre os discos de titânio em um período de 24 horas mostrou-se mais favorável na superfície ST mesmo após 48 horas quando CT apresentou valores inferiores ao ST, porém estatisticamente não significantes ao tempo de armazenamento. A avaliação após 72 horas indica que CT apresentou queda no desenvolvimento da cultura de fibroblastos em relação a ST sendo o resultado estatisticamente significante o que sugere menor característica de citocompatibilidade do material utilizado no tratamento de superfície que se potencializa com o aumento do tempo de exposição visto que quando comparado aos demais espécimes com meio de cultura com nutrientes (CC), controle sobre a superfície da placa em H2O sem nutrientes (H2O) e controle sobre a superfície da placa com meio de cultura com nutrientes acrescido de fenol a 1 % (CM) o espécime CT somente teve valores absolutos superiores para presença das células quando comparado ao espécime CM. Nossos dados indicaram a necessidade de se promover aperfeiçoamento no complexo estrutural do material de cobertura dos discos de forma que se tornem mais citocompatíveis. / The prosthetic components that make the bond between implant and prosthesis are important for maintaining healthy peri-implant permucosal being responsible for sealing and preventing penetratíon of chemicals or bacterial triggers of destructive processes in the structures around the implant. So it is important to develop techniques that preserve the characteristics of cell compatibility of prosthetic components that incorporate its structure, antibacterial agents to ensure the peri-implant health and not allow the development of resistance of micro-organisms are harmless to the tissues even and surrounding the body as a whole. This study aimed to test the cell compatibility of titanium disks coated with a covering of silver using nanotechnology in cultured human gingival fibroblasts. Titanium disks of 5.9 mm were prepared for trial, being composed of hard control ST (N = 1) without any kind of treatment and treatment disc with CT (n = 3) with 3 layers of film cover loaded with silver particles. The additive antimicrobial silver-based was obtained by wet chemistry by impregnatíon of metal homogeneously distributed over the disk surface. Gingival fragments were distributed in petri dishes with culture medium Dulbecco\'s modified Eagle. With approximately 15 days they were removed, followed by trypsinizatíon of the cells for their expansíon. The culture medium were changed every 2-3 days of culture and progressíon was evaluated by phase microscopy. The FGHs (human gingival fibroblasts) in the third passage (p3) were counted in a hemocytometer and plated in a 96 and 24 wells. Analyses from 24, 48 and 72 hours after plating were made. After solubilizatíon, the solutíons were transferred to a new 96-well plate, and made reading. The cytotoxicity of the materials were evaluated by spectrophotometric ELISA reader device with a wavelength of 590 nm. The samples were metallized and SEM was used to assess cell morphology. The behavior of cultured fibroblasts on titanium disks in a period of 24 hours was more favorable on the surface of ST even after 48 hours when the CT were lower than the ST but not statistically significant at the time of storage. The evaluatíon afetr 72 hours indicates that the CT fell in the development of cultured fibroblasts in relatíon to the ST and the result was statistically significant which suggests lower cell compatibility characteristic of the material used in surface treatment that enhances with increasing time exposure as compared to other disk with culture medium with nutrients (CC), control over the surface of the plate without nutrients H2O and control over the surface of the plate with culture medium with nutrients plus phenol 1 % (CM) the CT only had higher absolute values for the presence of cells when compared to CM. Our data indicated the need to promote improvement in the structural complex of the covering material so that the disks become more compatibility.

Os componentes protéticos que fazem a união entre implante e prótese são importantes para a manutenção da saúde peri-implantar sendo responsáveis pela vedação permucosa e impedindo a penetração de agentes químicos ou bacterianos desencadeadores de processos destrutivos nas estruturas ao redor do implante. Assim faz-se importante o desenvolvimento de técnicas que preservando as características de citocompatibilidade dos componentes protéticos que incorporem a sua estrutura, agentes antibacterianos que assegurem a saúde peri-implantar e que não permitam o desenvolvimento de resistência dos micro-organismos sendo ainda inócuos aos tecidos circunjacentes e ao organismo como um todo. Este trabalho teve o objetivo de testar a citocompatibilidade de discos de titânio com uma cobertura revestida usando nanotecnologia de prata em cultura de fibroblastos gengivais humanos. Discos de titânio de 5,9 mm foram preparados para o ensaio, sendo compostos por disco controle ST (N=1) sem nenhuma espécie de tratamento e disco com tratamento CT (N=3) com 3 camadas de cobertura com filme carregado com partículas de prata. O aditivo antimicrobiano à base de prata foi obtido pelo método wet chemistry por impregnação de metal homogeneamente distribuída sobre a superfície do disco. Fragmentos de gengiva foram cortados e colocados em placas de petri com meio de cultura Eagle modificado por Dulbecco. Com aproximadamente 15 dias foram retirados os fragmentos de gengiva, seguido da tripsinização das células para sua expansão. O meio de cultura foi trocado a cada 2-3 dias e a progressão da cultura foi avaliada por microscópio de fase. Os FGHs (fibroblastos de gengiva humana) na terceira passagem (p3) foram contados em um hemocitômetro e plaqueados em placas de 96 e 24 poços. As análises foram feitas com 24, 48 e 72 horas após o plaqueamento. Após a solubilização, as soluções foram transferidas para uma nova placa de 96 poços, e efetuada a leitura. A citotoxicidade dos materiais foi avaliada por espectrofotometria no aparelho Leitor de Elisa, com comprimento de onda de 590 nm. As amostras foram metalizadas e o MEV foi usado para avaliar a morfologia das células. O comportamento da cultura de fibroblastos sobre os discos de titânio em um período de 24 horas mostrou-se mais favorável na superfície ST mesmo após 48 horas quando CT apresentou valores inferiores ao ST, porém estatisticamente não significantes ao tempo de armazenamento. A avaliação após 72 horas indica que CT apresentou queda no desenvolvimento da cultura de fibroblastos em relação a ST sendo o resultado estatisticamente significante o que sugere menor característica de citocompatibilidade do material utilizado no tratamento de superfície que se potencializa com o aumento do tempo de exposição visto que quando comparado aos demais espécimes com meio de cultura com nutrientes (CC), controle sobre a superfície da placa em H2O sem nutrientes (H2O) e controle sobre a superfície da placa com meio de cultura com nutrientes acrescido de fenol a 1 % (CM) o espécime CT somente teve valores absolutos superiores para presença das células quando comparado ao espécime CM. Nossos dados indicaram a necessidade de se promover aperfeiçoamento no complexo estrutural do material de cobertura dos discos de forma que se tornem mais citocompatíveis. / The prosthetic components that make the bond between implant and prosthesis are important for maintaining healthy peri-implant permucosal being responsible for sealing and preventing penetratíon of chemicals or bacterial triggers of destructive processes in the structures around the implant. So it is important to develop techniques that preserve the characteristics of cell compatibility of prosthetic components that incorporate its structure, antibacterial agents to ensure the peri-implant health and not allow the development of resistance of micro-organisms are harmless to the tissues even and surrounding the body as a whole. This study aimed to test the cell compatibility of titanium disks coated with a covering of silver using nanotechnology in cultured human gingival fibroblasts. Titanium disks of 5.9 mm were prepared for trial, being composed of hard control ST (N = 1) without any kind of treatment and treatment disc with CT (n = 3) with 3 layers of film cover loaded with silver particles. The additive antimicrobial silver-based was obtained by wet chemistry by impregnatíon of metal homogeneously distributed over the disk surface. Gingival fragments were distributed in petri dishes with culture medium Dulbecco\'s modified Eagle. With approximately 15 days they were removed, followed by trypsinizatíon of the cells for their expansíon. The culture medium were changed every 2-3 days of culture and progressíon was evaluated by phase microscopy. The FGHs (human gingival fibroblasts) in the third passage (p3) were counted in a hemocytometer and plated in a 96 and 24 wells. Analyses from 24, 48 and 72 hours after plating were made. After solubilizatíon, the solutíons were transferred to a new 96-well plate, and made reading. The cytotoxicity of the materials were evaluated by spectrophotometric ELISA reader device with a wavelength of 590 nm. The samples were metallized and SEM was used to assess cell morphology. The behavior of cultured fibroblasts on titanium disks in a period of 24 hours was more favorable on the surface of ST even after 48 hours when the CT were lower than the ST but not statistically significant at the time of storage. The evaluatíon afetr 72 hours indicates that the CT fell in the development of cultured fibroblasts in relatíon to the ST and the result was statistically significant which suggests lower cell compatibility characteristic of the material used in surface treatment that enhances with increasing time exposure as compared to other disk with culture medium with nutrients (CC), control over the surface of the plate without nutrients H2O and control over the surface of the plate with culture medium with nutrients plus phenol 1 % (CM) the CT only had higher absolute values for the presence of cells when compared to CM. Our data indicated the need to promote improvement in the structural complex of the covering material so that the disks become more compatibility.

Surface modification is an extensively researched approach in order to overcomethe limitations, and improve the performance of orthopedic and dental implants. It is atthe surface of the implant materials that the initial interactions of tissues or body fluidstake place. Therefore, surface properties of biomaterials are the important factors that cancontrol these biological responses. Molecular imprinting is a surface modificationtechnique that creates specific recognition sites on the surface of biomaterials. Todevelop the recognition sites, a functional monomer is assembled with templatebiomolecule and then crosslinked. After removal of the template, the surface can rebindthe molecules. Therefore, desired reactions can be initiated at the interface between tissueand implants by modifying surfaces to selectively bind certain types of biomolecules,such as proteins. The objective of this project was to observe the potential of molecularimprinting technique for creating biomaterials that can recognize specific biomolecules.Fluorescently labeled lysozyme or RNase A was used as a template biomolecule and theprotein-imprinted scaffolds were fabricated by sol-gel processing. To interpret the densityof binding sites created, the quantity of surface-accessible protein was determined. Theamount of protein available on the surface was proportional to the amount loaded.Protein-imprinted scaffolds were evaluated for their ability to selectively recognize thetemplate biomolecule. Further, for these selectivity studies, a combination of theimprinted protein and a competitor protein were rebound to the polysiloxane scaffolds.The template protein rebound to the surface was measured more than twice as much ascompetitor. These scaffolds were then tested to understand their interaction with cells.The results of DNA and alkaline phosphatase activities indicate that the scaffolds thusdeveloped support growth and adhesion of osteoblastic cells. These initial selectivity andcytocompatibility studies show the potential of molecular-imprinted polysiloxanescaffolds to be used as tissue engineered materials for stable and controlled interactions atthe tissue-implant interface.

Submitted by TULLIO HENRIQUE CANO DE HARO BARROS null (tullioharo@hotmail.com) on 2018-07-12T13:22:39Z No. of bitstreams: 1 Barros_Tullio_me_sjrp_int.pdf.pdf: 1544265 bytes, checksum: a6f5f0bd88b4957b4f0ca22899ec9aae (MD5) / Approved for entry into archive by Paula Torres Monteiro da Torres (paulatms@sjrp.unesp.br) on 2018-07-13T17:48:42Z (GMT) No. of bitstreams: 1 barros_thch_me_sjrp.pdf.pdf: 1544265 bytes, checksum: a6f5f0bd88b4957b4f0ca22899ec9aae (MD5) / Made available in DSpace on 2018-07-13T17:48:42Z (GMT). No. of bitstreams: 1 barros_thch_me_sjrp.pdf.pdf: 1544265 bytes, checksum: a6f5f0bd88b4957b4f0ca22899ec9aae (MD5) Previous issue date: 2018-06-28 / Este estudo teve como objetivo a síntese e caracterização de dietilaminoetilquitosana (QHdDEAE) e dodecil-dietilaminoetil-quitosana (QHdDEAEDOD) de baixa massa molar (Mw), para avaliar suas atividades antifúngicas contra os fungos Alternaria solani, Alternaria alternata e Penicilliun expansum, que provoca um grande impacto na produção e preservação de alimentos processados e minimamente processados. Os derivados de baixa massa molar (Mw) foram obtidos por reação de degradação de quitosana desacetilada com nitrito de sódio, seguido pela inserção de grupos DEAE e Dodecil na estrutura do polímero. O grau de desacetilação (DD) e de substituição (DS) por grupos dietilaminoetil (DEAE) e dodecil foram determinados usando ressonância magnética nuclear de hidrogênio (RMN-H) e caracterizados por infravermelho (IR). O grau de desacetilação e o grau de substituição por grupos DEAE foram de 94,8% 39,8%, respectivamente. Os derivados hidrofóbicos obtidos foram substituídos com 15% e 39,8% de grupos dodecil, conforme determinado por RMN-H. As massas molares foram determinadas usando Cromatografia de Permeação em Gel (GPC) e um Mw de 9,2 kDa foi obtido para quitosana desacetilada degradada. Ensaios in vitro contra os fungos Alternaria alternata, Peninicillium expansum e Alternaria solani foram realizados. Na concentração de 0,5g.L-1, QHdDEAEDOD e QHdDEAE foram mais eficazes que as quitosanas comercial e desacetilada e apresentaram inibições de 80% contra Alternaria alternata e Alternaria solani. A quitosana deacetilada degradada foi mais eficiente na inibição do crescimento fúngico de Penicillium expansum e para 0,5 g.L-1 atingiu cerca de 80% de inibição. Todos os derivados apresentaram viabilidade celular superior a 70% em células 3T3, demonstrando uma boa citocompatibilidade e potencial para aplicações na conservação de alimentos / This study aimed at the synthesis and characterization of Diethylaminoethyl-Chitosan (QHdDEAE) and Dodecyl-Diethylaminoethyl-Chitosan (QHdDEAEDOD) of low molar mass(Mw), to evaluate their antifungal activities against the fungi Alternaria solani, Alternaria alternata and Penicilliun expansum, which causes a great impact on the production and preservation of processed and minimally processed foods. The low Mw derivatives were obtained by degradation reaction with sodium nitrite, followed by the insertion of DEAE and Dodecyl groups on the polymer backbone. The degrees of deacetylation (DD) and substitution (DS) for DEAE and Dodecyl groups were determined using nuclear magnetic resonance of hydrogen (¹H-NMR) and characterized by FTIR. The degree of deacetylation and degree of substitution by DEAE gropus were 94,8% 39,8%, respectively. The obtained hydrophobicized derivatives were substituted with 15% and 39,8% of dodecyl groups as evaluated by ¹H-NMR. The molar masses were determined by using Gel Permeation Chromatography (GPC) and a Mw of 9,2kDa was obtained for deacetylated chitosan. In vitro assays against the fungi Alternaria alternata, Peninicillium expansum and Alternaria solani. At the concentration of 0.5 g.L-1 both, QHdDEAEDOD and QHdDEAE were more effective than commercial and deacetylated chitosans and exhibited inhibitions of 80% against Alternaria alternata and Alternaria solani. Degraded deacetylated chitosan was more efficient in inhibiting the fungal growth of Penicillium expansum and for 0.5 g.L-1 reached around 80% of inhibition. All the derivatives presented cell viabilities higher 70% on 3T3 demonstrated a good cytocompatibility and potential for applications in food preservation.

Quantum dots (QDs) are increasingly attracting attention in recent years due to their potential in biological imaging and drug delivery applications. Despite their significant advantages over organic dyes and fluorescent proteins, cytotoxicity is still a major problem in live-cell QD labeling. In this work, in-vitro characterization of a novel CdTe/2MPA quantum dot capped with CdS-DMSA was conducted on human cervical cancer (HeLa) and mouse fibroblast (NIH/3T3) cell lines. Biocompatibility of this novel particle was evaluated in comparison to a commercial quantum dot (Qdot 565) and various QDs with CdTe core. Cytotoxicity of quantum dots was investigated using XTT and proliferation assays. Cellular internalization and localization of particles were studied using confocal laser scanning microscopy. For quantitative determination of internalization and intracellular QD stability, we also performed uptake and cadmium release assays. Optimal cell imaging concentration with CdTe-CdS/2MPA-DMSA was determined as 10-50 ug/mL in HeLa cells. Localization of the internalized QD particles was observed in the perinuclear region of the cells. XTT and proliferation assays provided identical viability results for the tested QDs. CdS-DMSA capping increased cytocompatibility of CdTe/2MPA by 15% in NIH/3T3 cells. Biocompatibility of this capped particle was further increased by 3-folds with pegylation. For pegylated CdTe-CdS/2MPA-DMSA and commercial Qdot 565, we have not observed QD-related cytotoxicity on NIH/3T3 cells following 24-hr QD exposure at 50 ug/mL. Our in-vitro characterization studies indicate that CdTe-CdS/2MPA-DMSA is a promising live-cell imaging probe which can be effectively excited in the visible range of the electromagnetic spectrum.

Quantum dots are fluorescent semiconductor nanocrystals that have unique optical properties such as high quantum yield and photostability. These nanoparticles are superior to organic dyes and fluorescent proteins in many aspects and therefore show great potential for both in vivo and in vitro imaging and drug delivery applications. However, cytototoxicity is still one of the major problems associated with their biological applications. The aim of this study is in vitro characterization and assessment of biological application potential of a novel silver sulfide quantum dot coated with mercaptopropionic acid (2-MPA). In vitro studies reported in this work were conducted on a mouse fibroblast cell line (NIH/3T3) treated with Ag2S/2-MPA quantum dots in 10-600 &mu / g/mL concentration range for 24 h. Various fluorescence spectroscopy and microscopy methods were used to determine metabolic activity, proliferation rate and apoptotic fraction of QD-treated cells as well as QD internalization efficiency and intracellular localization. Metabolic activity and proliferation rate of the QD treated cells were measured with XTT and CyQUANT&reg / cell proliferation assays, respectively. Intracellular localization and qualitative uptake studies were conducted using confocal laser scanning microscopy. Apoptosis studies were performed with Annexin V assay. Finally, we also conducted a quantitative uptake assay to determine internalization efficiency of the silver sulfide particles. Correlated metabolic activity and proliferation assay results indicate that Ag2S/2-MPA quantum dots are highly cytocompatible with no significant toxicity up to 600 &mu / g/mL treatment. Optimal cell imaging concentration was determined as 200 &mu / g/mL. Particles displayed a punctuated cytoplasmic distribution indicating to endosomal entrapment. In vitro characterization studies reported in this study indicate that Ag2S/2-MPA quantum dots have great biological application potential due to their excellent spectral and cytocompatibility properties. Near-infrared emission of silver sulfide quantum dots provides a major advantage in imaging since signal interference from the cells (autofluorescence) which is a typical problem in microscopic studies is minimum in this part of the emission spectrum. The results of this study are presented in an article which was accepted by Journal of Materials Chemistry. DOI: 10.1039/C2JM31959D.

Nanocellulose has received considerable interest during the last decade because it is renewable and biodegradable, and has excellent mechanical properties, nanoscale dimensions and wide functionalization possibilities. It is considered to be a unique and versatile platform on which new functional materials can be based. This thesis focuses on nanocellulose from wood (NFC) and from Cladophora algae (CNC), functionalized with surface charges or coated with the conducting polymer polypyrrole (PPy), aiming to study the influence of synthesis processes on structural and electrochemical properties of such materials and assess their biocompatibility. The most important results of the work demonstrated that 1) CNC was oxidized to the same extent using electrochemical TEMPO-mediated oxidation as with conventional TEMPO processes, which may facilitate easier reuse of the reaction medium; 2) NFC and CNC films with or without surface charges were non-cytotoxic as assessed by indirect in vitro testing. Anionic TEMPO-CNC films promoted fibroblast adhesion and proliferation in direct in vitro cytocompatibility testing, possibly due to its aligned fibril structure; 3) Rinsing of PPy-coated nanocellulose fibrils, which after drying into free-standing porous composites are applicable for energy storage and electrochemically controlled ion extraction, significantly degraded the PPy coating, unless acidic rinsing was employed. Only minor degradation was observed during long-term ambient storage; 4) Variations in the drying method as well as type and amount of nanocellulose offered ways of tailoring the porosities of nanocellulose/PPy composites between 30% and 98%, with increments of ~10%. Supercritical CO2-drying generated composites with the largest specific surface area yet reported for nanocellulose/conducting polymer composites (246 m2/g). The electrochemical oxidation rate was found to be controlled by the composite porosity; 5) In blood compatibility assessments for potential hemodialysis applications, heparinization of CNC/PPy composites was required to obtain thrombogenic properties comparable to commercial hemodialysis membranes. The pro-inflammatory characteristics of non-heparinized and heparinized composites were, to some extent, superior to commercial membranes. The heparin coating did not affect the solute extraction capacity of the composite. The presented results are deemed to be useful for tuning the properties of systems based on the studied materials in e.g. energy storage, ion exchange and biomaterial applications.

<div>Wounds are created in soft and hard tissue through surgery or disease. As the wound heals, the tissue is held in place using sutures or staples for soft tissue or plates, pins, or screws for hard tissues. These fixation methods inherently damage the surrounding healthy tissue. Surgical adhesives are a non-damaging alternative to these methods. In order to be effective, surgical adhesives must be biocompatible,</div><div>adhere strongly in a moist environment, and have mechanical properties similar to those of the native tissue.</div><div><br></div><div><div>To address the design criteria for surgical adhesives, we look to nature to find inspiration from compounds that provide these properties. Mussels use catechol-based</div><div>molecules to adhere to surfaces in wet and turbulent environments. Incorporating catechols into polymer systems can provide adhesion even in moist biological environments.</div><div>Mimics of elastomeric proteins from soft tissue can be used as backbones for soft and flexible adhesive systems. In particular, elastin-inspired proteins have a well-defined modular sequence that allows for a range of design choices. In this work, we explored the behavior of elastin- and mussel-inspired natural and synthetic polymers in biologically relevant environments.</div></div><div><br></div><div><div>First, the cytocompatibility of a catechol-containing poly(lactic acid) (cPLA) hard tissue adhesive was studied. The cPLA polymer was reacted with iron- or periodatebased</div><div>crosslinkers and compared to PLA. Fibroblasts grown directly on cPLA or cultured with leachate from cPLA had high viability but slower growth than cells on PLA. The periodate crosslinker was significantly cytotoxic, and cells grown on cPLA crosslinked with periodate had reduced metabolism and slowed growth. Cells grown on or in leachate from iron-crosslinked cPLA had similar viability, metabolism, and growth to cells on or in leachate from cPLA. The iron-crosslinked cPLA is a promising</div><div>cytocompatible adhesive for hard tissue applications.</div></div><div><br></div><div><div>Second, two elastin-like proteins (ELP) were developed that had pH-sensitive properties in solution and when crosslinked into hydrogels. Both ELPs had a large number of ionizable tyrosine and lysine residues, and one design also had a large number of ionizable histidine and aspartic acid residues. The stiffness of the hydrogels was maximized at pH values near the isoelectric point of the protein. The stoichometric ratio of crosslinker used affected hydrogel stiffness but did not significantly alter the pH-sensitivity of the gel. The crosslinked gel shrank when swelled at physiological pH. The pH-sensitive mechanical properties of hydrogels made from the two ELPs did not vary significantly. The tyrosine and lysine residues in one ELP were also</div><div>chemically blocked through acetylation to lower the isolectric point of the protein. The acetylated hydrogels had maximum stiffness at a pH near the isoelectric point of the acetylated ELP. The stiffness of both the native and acetylated gels were within the range of soft tissue. Through a combination of crosslinker ratio and chemical modification, the pH-responsive properties of the elastin-inspired hydrogels could be tuned.</div></div><div><br></div><div><div>Finally, adhesive proteins were created that were inspired by both elastin and mussels. An ELP was modified to include catechol groups (mELP). The ELP and mELP were optimized for adhesive use in a soft tissue system. A warm and humid environment was used to study the adhesion of these proteins on pig skin. Iron and (hydroxymethyl) phosphine crosslinkers increased the adhesive strength of both proteins, and periodate increased the adhesive strength of mELP. The adhesive strengths of the proteins were maximized when mELP was mixed with iron or when either protein were mixed with (hydroxymethyl)phosphine crosslinkers. These maximized adhesives were 12-17 times stronger than a commercially available sealant. In addition,</div><div>the iron and mELP adhesive formulation achieved high adhesive strengths even when cured for only ten minutes. This adhesive formula shows promise for adhesive</div><div>applications on soft tissue.</div></div>

Nanotrubičky oxidu titaničitého v průběhu posledních let nabyly na významu v poli biomedicíny. Jakožto biokompatibilní nanostrukturovaný povrch nachází potenciál pro své uplatnění především v oblasti implantačních aplikací. Teoretická část této práce je tak věnována různým přístupům pro syntézu TiO2 nanotrubiček, jejich modifikacím a aplikacím v biomedicíně. Experimentální část pak pojednává o nanotrubičkách oxidu titaničitého, které jsou připraveny z titanu metodou jednokrokové anodické oxidace v organickém elektrolytu. Jako výchozí materiály jsou používány křemíkové disky s naprášenou vrstvou titanu a titanové folie. Zprvu amorfní nanotrubičky jsou žíháním převedeny na svou krystalickou podobu, a následně modifikovány selenovými a stříbrnými nanočásticemi. Připravené struktury jsou zkoumány z hlediska povrchových vlastností a biologických interakcí s vybranými tkáňovými kulturami (MG-63, NIH-3T3) a bakteriemi (E. coli, P. aeruginosa, S. aureus). V závěru experimentální práce jsou stručně porovnány výsledky selenových a stříbrných nanočástic. Hlavním cílem této práce je rozšířit znalosti týkající se bio-rozhraní tvořeným adherentními buněčnými liniemi, bakteriálními buňkami a nanostrukturovaným povrchem tvořeným TiO2 nanotrubičkami dekorovanými selenovými a stříbrnými nanočásticemi.

Dans un contexte de démarche écoresponsable et pour répondre aux exigences de biocompatibilité notamment dans les applications cosmétiques et biomédicales, nous avons développé de nouveaux hydrogels à base de polysaccharides neutres et anioniques en utilisant deux voies originales. La 1ère approche est biomimétique et a consisté à mimer un phénomène d’élaboration naturelle d’hydrogels que l’on retrouve chez certains végétaux pour lesquels une enzyme, la laccase, permet de créer des liens de réticulation par dimérisation des composés phénoliques (en l’occurrence de l’acide férulique FA) présents sur les arabinoxylanes des mucilages des graines de céréales par exemple. Notre travail a ainsi consisté à greffer de l’acide férulique via deux chimies différentes de type imidazole et carbodiimide respectivement pour des polysaccharides neutres ou anioniques. Nous avons ainsi fonctionnalisé trois polysaccharides : le pullulane ou PUL (neutre modèle), le carboxyméthylpullulane ou CMP (anionique modèle) et l’acide hyaluronique ou HA (anionique d’intérêt). Des taux de greffage compris entre 2 et 25% ont été obtenus. L’étude physicochimique en régimes dilué et semi-dilué a permis de mettre en évidence un comportement associatif lié au caractère amphiphile des polysaccharides fonctionnalisés. La réticulation en présence de laccase, suivie in situ en rhéologie, a été réalisée avec succès sur les différents systèmes envisagés avec des contrôles possibles de la cinétique, des propriétés mécaniques finales ou encore du gonflement des hydrogels en fonction du caractère neutre ou chargé des polysaccharides, du degré de substitution en acide férulique, de la concentration en polymère ou de l’activité enzymatique fixée. Les dérivés synthétisés ont globalement démontré des activités biologiques (antioxydante et cytocompatible) intéressantes. La deuxième approche repose sur la photoréticulation possible de polysaccharides (PUL, CMP et HA) fonctionnalisés par le greffage d’amine/acide gras mono ou polyinsaturé (oleylamine, acide oléique et linoléique) via la chimie des imidazoles. Si le pullulane modifié par l’acide linoléique à 2% s’est avéré non hydrosoluble en raison de son caractère neutre, tous les autres dérivés avec des taux de greffages de 3 et 10% ont démontré une bonne solubilité dans l’eau. Les études physicochimiques mettent en évidence un très fort caractère associatif de ces dérivés amphiphiles avec la formation de gels physiques en régime semi-dilué. La photoréticulation a été démontrée en rhéologie sous irradiation UV in situ en présence d’un photoamorceur de type Darocur 1173®. Les résultats préliminaires obtenus selon cette approche en photoréticulation ouvrent ainsi des perspectives intéressantes. / In the framework of an eco-responsible context and to take advantage of biocompatibility, notably in cosmetic and biomedical applications, we have developed new hydrogels based on neutral and anionic polysaccharides using two original routes. The first approach is biomimetic and consists of mimicking a natural development of hydrogels that is found in certain plants for which an enzyme, laccase, allows to create crosslinks by dimerization of phenolic compounds, in occurrence of ferulic acid (FA) present on arabinoxylans mucilage of cereal seeds for example. Thus, our work consisted in grafting ferulic acid via two different chemical ways that means imidazole and carbodiimide respectively for neutral or anionic polysaccharides. We functionalized three polysaccharides: pullulan or PUL (neutral model), carboxymethylpullulane or CMP (model anionic) and hyaluronic acid or HA (anionic of interest) with grafting rates of between 2 and 25%. The physicochemical study in diluted and semi-diluted regimes evidenced an associative behavior due to the amphiphilic character of the functionalized polysaccharides. The crosslinking in the presence of laccase, followed in situ thanks to rheology, has been successfully performed on the various envisaged systems with possible controls of kinetics, the final mechanical properties or the swelling of the hydrogels as a function of the neutral or charged nature of the polysaccharides, the degree of substitution in FA, the polymer concentration or the enzymatic activity. The synthesized derivatives have generally demonstrated interesting biological activities (antioxidant and cytocompatibility). The second approach is based on the possible photocrosslinking of polysaccharides (PUL, CMP and HA) functionalized by the grafting of mono or polyunsaturated fatty amine/acid (oleylamine, oleic acid and linoleic acid) via imidazole chemistry. If pullulan grafted with 2% of linoleic acid was found to be water-insoluble due to its neutral character, all other derivatives (i.e. anionic ones) with grafting rates of 3 and 10% showed good solubility in water. The physicochemical studies show a very strong associative character of these amphiphilic derivatives with the formation of physical gels in semi-diluted regime. Photocrosslinking has been demonstrated in situ thanks to rheology/UV irradiation in the presence of a Darocur 1173® photoinitiator. The preliminary results according to this photocrosslinking approach thus open interesting perspectives.