Abstract One of the major health security challenges of the 21st century is the occurrence of microbial infections and bacterial complications that could affect 10 million people by 2050. On the biomaterial field, implant metallic currently replaces partial or total body parts and can fail to be integrated into the body due to infections. This study performs two combined surface modifications on Ti-30Ta alloy, in order to obtain an infection-resistance and osseointegration surface on metallic implants to be tested within bacterial biofilm. The Group 1 investigated surface modifications by the anodization process in the electrolyte glycerol + NH4F 0.25% at 30V- 9 hours and annealed in 530°C (5°C/min). The Group 2 underwent the same process as Group 1 and, additionally, the samples were immersed in 0.3 M CaCl2 and 0.5 M Na2HPO4 solutions for hydroxyapatite growth. The substrate was characterized using scanning electron microscopy (SEM), X-ray diffractometer (XRD) and dynamic contact angle. S. epidermidis bacterial adhesion and biofilm formation. The results indicated that the Group 1 shows a higher antimicrobial activity, hydrophilic behavior and potential to be used for metallic implant applications. The Group 2 with the hydroxyapatite film coating did not have an improvement in the antimicrobial response.

RESUMO A cerâmica à base de fosfato de cálcio hidroxiapatita (Hap) é muito utilizada para reparos ósseos por ser um biomaterial biocompatível e apresentar propriedades osteocondutoras e osteoindutoras. No entanto, a baixa resistência mecânica da Hap pode limitar sua aplicabilidade. Assim, o presente trabalho tem como objetivo melhorar as propriedades mecânicas da Hap, associando-a à alumina (Al2O3), pela técnica de metalurgia do pó, que consiste na moagem dos pós precursores em moinho planetário, prensagem uniaxial e sinterização. A microestrutura e a resistência mecânica das amostras sinterizadas foram avaliadas através dos testes de densidade, microdureza, resistência à compressão e molhabilidade. Concluiu-se que o uso de Al2O3 no compósito melhora as propriedades mecânicas da Hap, enquanto diminui seu potencial hidrofílico. Assim, a composição com 40% de Hap / 60% de Al2O3 foi considerada a melhor para aplicações biomédicas.

ABSTRACT The hydroxyapatite calcium phosphate based ceramic (Hap) is widely used for bone repair, as it is a biocompatible biomaterial and because it has osteoconductive and osteoinductive properties. However, the low mechanical strength of Hap may limit its applicability. Thus, the present work aims to improve the mechanical properties of Hap, associating it with alumina (Al2O3), using the powder metallurgy technique, which consists in the milling of the precursor powders in a planetary ball mill, uniaxial pressing and sintering. The microstructure and mechanical strength of the sintered samples were evaluated using density, microhardness, compressive strength and wettability tests. It was concluded that the use of Al2O3 in the composite improves the mechanical properties of Hap, while decreases its hydrophilic potential. Thus, the composition with 40% Hap / 60% Al2O3 was considered the best for biomedical applications.

Several studies have been carried out to develop new materials for biomedical applications. Material surfaces that present biomimetic morphology like nanotubes or nanofibers that provides nanoscale architectures have been shown to alter cell/biomaterial interactions. The coated surface biomaterial with biocompatible polymers and nanotubes of TiO2 is an alternative to improve osseointegration. The anodization process was performed to obtain nanotubes of TiO2 covering the Ti-30Ta alloy surface and the electrospinning process has been used for producing polymer fibers. Characterization techniques such as scanning electron microscopy (SEM - FEG), X-ray diffraction analysis (X-rays), thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and contact angle were used for samples analyses. Adult human adipose-derived stem cells (ADSCs) were used to investigate the cellular response and S. aureus antimicrobial activity on these coated surfaces. The results indicated that both surface modification treatment showed a favorable micro-environment for cells growth and proliferation such as adhesion, viability and morphology which is a desire property for an implant. In addition, the antimicrobial activity study presented both materials with similar growth of S. aureus. So, it can conclude nanotubes and nanofibers can be used at biomedical field and both present similar cell evaluation and antimicrobial activity results.

Abstract The 316L stainless steel (316L SS) is one of the most used metallic materials for implants, due to its high mechanical properties and low cost. However, it is bioinert. One possibility to improve its biocompatibility is the production of a composite with b-tricalcium phosphate (β-TCP) addition. This study investigated the mechanical behavior of 316L SS/β-TCP composites through powder metallurgy. For this, used were 3 compositions, with 0 %, 5 % and 20 % of β-TCP. The compositions with 5% and 20% were milled during 10 hours with a mass/sphere ratio of 1:10 and 350 rpm. All compositions were uniaxially pressed with 619 MPa and sintered during 1 hour at 1100ºC. The microstructural and mechanical evaluations were performed through scanning electron microscopy, density and compressive strength. The results indicated that, by increasing the percentage of β-TCP in the compositions, the mechanical resistance decreases, as a consequence of its low load support.

Abstract The use of alumina as a reinforcement in metallic and ceramic matrix is well-known. The purpose of this study was to investigate the effect of alumina addition according to its amount on the microstructural and mechanical behavior of tricalcium phosphate ceramic (TCP), more specifically the β-TCP. Although β-TCP has excellent bioactive and biocompatible properties, it presents low fracture resistance and load bearing capacity, which limits its use in the monolithic form. The route used for the β-TCP/alumina composite production was powder metallurgy. The powders were milled in a high energy ball mill with the following parameters: 5, 10, 15 and 20 hours, mass/sphere relation of 1:20 and speed of 150 rpm. After the milling process, the powders of both compositions were uniaxially pressed and sintered. Two of the compositions were processed containing 90% and 50% of β-TCP, respectively. The results indicated that composition 1 with a smaller percentage of alumina in its microstructure presented 62.4 % smaller particle size after the high energy ball milling process, which provided higher densification after pressing and sintering. These results implied in increased mechanical resistance, with 4.6 GPa of elastic modulus and 140 MPa of compressive strength, against 3.6 GPa of elastic modulus and 117 MPa of compressive strength obtained in composition 2.

INTRODUÇÃO: Dor é uma manifestação importante em pacientes com esclerose múltipla (EM), mas que tem sido negligenciada na pesquisas clínica e experimental. OBJETIVO: Investigar a resposta nociceptiva de camundongos com encefalomielite autoimune experimental (EAE) induzida por MOG35-55. MÉTODO: A EAE foi induzida em camundongos C57BL/6 fêmeas de 8-10 semanas com emulsão contendo MOG35-55, Adjuvante Completo de Freund, Mycobacterium tuberculosis cepa H37 RA e toxina pertussis. A nocicepção foi medida pelo método de filamentos de von Frey. Uma escala clínica variando de 0 a 15 foi utilizada para avaliar a debilidade motora dos animais. RESULTADOS: Os sinais clínicos da doença iniciaram-se no dia 10 e a gravidade máxima foi alcançada no dia 14 após a imunização. Não houve piora dos sintomas até o dia 26. Os camundongos induzidos com EAE apresentaram diminuição do limiar de pressão nos dias 7 e 10 após a imunização e antes do início dos sinais motores. CONCLUSÃO: A hipernocicepção verificada valida a EAE induzida por MOG35-55 como um modelo para estudos de dor em esclerose múltipla.

BACKGROUND: Pain is an important clinical manifestation in multiple sclerosis (MS) patients, though it has been neglected in clinical and experimental researches. OBJECTIVE: To investigate the nociceptive response in MOG35-55 experimental autoimmune encephalomyelitis (EAE)-induced mice. METHOD: EAE was induced in 8 to 10 week old C57BL/6 female mice with an emulsion of MOG35-55, Complete Freund Adjuvant, Mycobacterium tuberculosis H37 RA and pertussis toxin. Nociception was evaluated by the von Frey filaments method. A clinical scale ranging from 0 to 15 was used to assess motor impairment. RESULTS: Clinical evidence of disease started at day 10 and peaked at day 14 after immunization. Thereafter, there was no worsening of symptoms until day 26. The EAE-induced mice presented reduced pressure threshold at days 7th and 10th after immunization and before the onset of clinical motor signs. CONCLUSION : The hypernociception found validates MOG35-55 EAE as a model for the study of pain in multiple sclerosis.