Three dimensional cell-scaffold constructs for application in bone tissue engineering

Dissertação de mestrado em Engenharia BiomédicaBone is a dynamic tissue with an amazing capacity of self-repair. However, when the defect reaches a critical size bone loses this capacity and medical intervention is needed. Bone is the second most transplanted tissue in the world and there is a huge need for bone grafts and substitutes and therefore leading to a decrease in bone banks donors. Scaffolds are of great importance for tissue engineering and orthopedic implants since they provide biological anchorage for the surrounding bony tissue via the ingrowth of tissue into pores. The pores of scaffolds have direct implications on their biofunctionality. Thus, a porous structure is critical for cell nutrition, proliferation, cell migration, and formation of newly vascularized tissue. Scaffold’s mechanical properties should also match that of bone in order to prevent stress shielding which is one of the main causes for implant’s failure. In this study, three-dimensional porous scaffolds with maximized mechanical strength capable for load-bearing applications and with elastic modulus near of the bone were produced. The porous scaffolds were made of: i) Ti6Al4V, ii) ZrO2 and iii) PEEK. Their microstructures were characterized by mean of performing SEM and Micro CT analyses. To assess the chemical composition of the scaffolds, XPS analysis was performed. The crystallographic phase of ZrO2 was investigated by XRD. Mechanical compressive tests were performed in order to evaluate the elastic modulus and compressive stress. Their efficacy as scaffold material for bone regeneration applications was evaluated in vitro by seeding SaOS-2 cells onto the scaffolds. The viability, proliferation and differentiation of SaOS-2 cells was analyzed. The cellular viability was assessed by Alamar blue test at day 1, day 3, day 7 and day 14. For the study of cell proliferation, DNA quantification was performed for the same time points. To assess the differentiation of SaOS-2 cells, alkaline phosphatase was qualitatively and quantitatively evaluated by performing the ALP quantification and staining with Fast violet B. Mechanical results showed an elastic modulus near of the bone which can minimize the phenomenon of stress shielding. The in vitro results revealed cytocompatibility with no cell alterations or death of SaOS-2 seeded on scaffolds surfaces. The proposed scaffolds showed great potential in vitro to be used in bone tissue engineering scaffolding applications.O osso é um tecido dinâmico com uma incrível capacidade de auto reparação. No entanto, quando o defeito ósseo ultrapassa um tamanho crítico, o osso perde essa capacidade e a intervenção médica torna-se necessária. O osso é o segundo tecido mais transplantado do mundo e existe uma grande necessidade de enxertos e substitutos ósseos, o que por sua vez levam a uma diminuição da disponibilidade de osso nos Bancos de Tecidos. As matrizes tridimensionais porosas são de grande importância para a engenharia de tecidos e implantes ortopédicos uma vez que servem de meio biológico para que tecido ósseo envolvente cresça para o interior dos poros. Uma matriz deve ser porosa por forma a possibilitar a nutrição, proliferação, e migração celular e formação de um novo tecido ósseo vascularizado As matrizes tridimensionais devem, ainda, possuir propriedades mecânicas próximas à do osso para evitar reabsorção óssea, a qual está associada à falha do implante. Neste estudo, foram produzidas matrizes tridimensionais com resistência mecânica máxima capazes de serem usadas em aplicações ortopédicas e com o módulo de Elasticidade semelhante ao módulo de Elasticidade do osso. As matrizes tridimensionais porosas foram produzidas com três materiais diferentes: i) Ti6Al4V; ii) ZrO2 e iii) PEEK. Para a caracterização da microestrutura das matrizes tridimensionais com estrutura celular SEM e Micro CT foi realizado. Para a avaliação da fase e composição química da superfície as matrizes tridimensionais porosas foram analisados por XRD e XPS. Testes mecânicos de compressão foram realizados para avaliar o módulo Elasticidade e a força máxima de compressão. A eficácia das matrizes tridimensionais como material para aplicações de engenharia de tecidos foi avaliada in vitro, recorrendo a uma linha celular SaOS-2 que foi cultivada na superfície das diferentes matrizes porosas. A sua viabilidade, proliferação e diferenciação foi analisada até 14 dias de cultura. A viabilidade celular foi estudada recorrendo ao teste de Alamar Blue para o dia 1, dia 3, dia 7 e dia 14 de cultura celular. A proliferação e diferenciação celular foi avaliada através da quantificação do DNA e a atividade da ALP para os mesmos tempos de cultura. As matrizes tridimensionais porosas cultivadas com células SaOS-2 foram, ainda, coradas com Fast Violet B para a observação da fosfatase alcalina. Os resultados obtidos sugerem o potencial das matrizes tridimensionais para aplicações na engenharia de tecido do osso. Estas matrizes apresentam um módulo Elasticidade perto do osso que pode minimizar o fenómeno da reabsorção óssea. Os resultados in vitro revelaram a não toxicidade das matrizes assim como apresentarem uma superfície favoráveis à adesão e à proliferação das células

MgO nanoparticles obtained by Pulsed Laser Ablation in Liquid: a study on fabrication versatility aiming different applications

Apresentação efetuada em "Junior Euromat 2022", em Coimbra, 2022Nano and micro-sized metal particles are used in diverse fields, from electronics to biomedical. Among them, Magnesia, also known as magnesium oxide (MgO), is one of the most interesting metal oxides due to its unique properties, such as a large electrochemically active surface area and chemical stability. Although chemical routes such as chemical reactions, thermal evaporation,sol-gel, chemical vapor deposition and hydrothermal treatments are mainly used to fabricate metal oxide nanoparticles, they require the use of toxic reagents and long processing times. Thus, developing a simple green synthetic process for preparing MgO nanoparticles remains a challenging topic of investigation. Pulsed laser ablation in liquid (PLAL) has emerged as a potential alternative to chemical methods because it does not require chemicals, generates no waste, and produces high-purity particles. By changing some parameters such as the laser wavelength, laser fluence, and liquid media the size and shape of the particles produced can be tailored. The obtained particles can be added to act as anti-biofilm agents on coatings. Both influence of the liquid medium and the laser energy on nanoparticle composition and morphology are investigated in this work, as well as the effects of laser energy and different liquid media on the properties and characteristics of these nanoparticles.Acknowledgements: This work was supported by Fundação para a Ciência e Tecnologia through the grant 2020.07257.BD, the projects UIDB/04436/2020 and UIDP/04436/2020. PTDC/EME-EME/1442/2020(Add2MechBio). Additionally, this work was developed within the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC)

Relatório Anual 2013 - A Situação do País em Matéria de Drogas e Toxicodependências

É responsabilidade do SICAD a elaboração deste Relatório, a apresentar anualmente à Assembleia da República e ao Governo Português, fornecendo elementos de apoio à decisão política e ao planeamento da intervenção. Anexo: O volume anexo ao Relatório integra informação mais pormenorizada relativa à componente do Relatório: Parte A - Caracterização e Evolução da Situação.info:eu-repo/semantics/publishedVersio

revista de Ciências da Arte

Organizando-se agora no formato de número duplo, de modo a comportar dois números por ano, a revista digital Convocarte – Revista de Ciências da Arte mantém o mesmo propósito de promover o debate e edição de questões artísticas no espaço universitário, mantendo as coordenadas dominantes: convocar um número de especialistas em torno de um tema do mundo das artes, integrar trabalhos relevantes desenvolvidos nas fases curriculares e de projecto em mestrados e doutoramentos, sobretudo da FBAUL, e publicar trabalhos desenvolvidos em linhas de investigação do CIEBA. Assim, embora de funcionamento afecto à área científica de Ciências da Arte e do Património a Convocarte está aberta a outras especialidades interessadas em contribuir para a reflexão sobre as artes em geral, incorporando ensaios de predomínio teórico enraizado nos mais predominantes modos de discurso sobre arte, tais como História da arte, Crítica de Arte, Estética, Teorias da Arte ou Curadoria. (...) O nº2 organizou-se em torno de uma homenagem a uma figura importante das teorias da arte em Portugal, estratégia que Convocarte procurará manter nos próximos números. A intenção será deixar estudos sistematizados, entre o depoimento ou o ensaio, a memória e a reflexão, que estudem figuras marcantes da cultura portuguesa. (...) Neste número essa pasta foi dedicada a Rui Mário Gonçalves. Os textos são o resultado de uma sessão especial alargada a 2 de Maio no âmbito dos 2ºs Encontros com Críticos de Arte, com organização e coordenação de Fernando Rosa Dias, Cristina Tavares e Viviane Soares Silva, e decorridos ao longo das segundas do mês de Maio de 2016 na FBAUL (http://convocarte.belasartes.ulisboa.pt/index.php/2016/04/29/2o-encontros-com-criticos-de-arte/#more-325). A partir destes trabalhos reuniu-se um conjunto de estudos em torno de Rui Mário Gonçalves, com depoimentos e estudos sobre as mais diferentes facetas desta importante figura da cultura portuguesa: crítico de arte, historiador de arte, curador artístico, pedagogo e professor, político e activista, etc. A Convocarte orgulha-se de publicar os textos dessas comunicações, acrescentado de outros estudos, agradecendo a todos os colaboradores deste evento, que consideramos uma pasta que adianta contributos dando continuidade a estudos no catálogo de homenagem e no âmbito de apresentação da colecção do crítico de arte na SNBA, realizada pouco antes na SNBA.info:eu-repo/semantics/publishedVersio

MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio

Mammals in Portugal: a data set of terrestrial, volant, and marine mammal occurrences in Portugal

Mammals are threatened worldwide, with ~26% of all species being included in the IUCN threatened categories. This overall pattern is primarily associated with habitat loss or degradation, and human persecution for terrestrial mammals, and pollution, open net fishing, climate change, and prey depletion for marine mammals. Mammals play a key role in maintaining ecosystems functionality and resilience, and therefore information on their distribution is crucial to delineate and support conservation actions. MAMMALS IN PORTUGAL is a publicly available data set compiling unpublished georeferenced occurrence records of 92 terrestrial, volant, and marine mammals in mainland Portugal and archipelagos of the Azores and Madeira that includes 105,026 data entries between 1873 and 2021 (72% of the data occurring in 2000 and 2021). The methods used to collect the data were: live observations/captures (43%), sign surveys (35%), camera trapping (16%), bioacoustics surveys (4%) and radiotracking, and inquiries that represent less than 1% of the records. The data set includes 13 types of records: (1) burrows | soil mounds | tunnel, (2) capture, (3) colony, (4) dead animal | hair | skulls | jaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8), observation in shelters, (9) photo trapping | video, (10) predators diet | pellets | pine cones/nuts, (11) scat | track | ditch, (12) telemetry and (13) vocalization | echolocation. The spatial uncertainty of most records ranges between 0 and 100 m (76%). Rodentia (n =31,573) has the highest number of records followed by Chiroptera (n = 18,857), Carnivora (n = 18,594), Lagomorpha (n = 17,496), Cetartiodactyla (n = 11,568) and Eulipotyphla (n = 7008). The data set includes records of species classified by the IUCN as threatened (e.g., Oryctolagus cuniculus [n = 12,159], Monachus monachus [n = 1,512], and Lynx pardinus [n = 197]). We believe that this data set may stimulate the publication of other European countries data sets that would certainly contribute to ecology and conservation-related research, and therefore assisting on the development of more accurate and tailored conservation management strategies for each species. There are no copyright restrictions; please cite this data paper when the data are used in publications

High density HAp and β-TCP blocks for biomedical applications - fabrication strategy and resulting properties

Calcium phosphate compounds, such as HAp and β-TCP, are attractive biomaterials for implants due to a direct bonding to hard tissue owed to their chemical similarity to the inorganic components of human bone. In this study, hot pressing technique was used to produce fully dense HAp and β-TCP using two different approaches: a single holding time versus two holding times, aiming to compare their microstructure, porosity, and mechanical properties. Results showed that by using two holding times the densification was enhanced, which improved the flexural strength of both β-TCP and HAp.This work was supported by FCT (Fundação para a Ciência e a Tecnologia) through the project PTDC/EME-EME/1442/2020 (Add2MechBio). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC). Also, this work was supported by FCT national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020. Also, H. Pereira acknowledges FCT for her PhD scholarship (2020.07257.BD)

Innovative, Sugar-Free Oral Hydrogel as a Co-administrative Vehicle for Pediatrics: a Strategy to Enhance Patient Compliance

Palatability and swallowability in the pediatric population are perceived as true challenges in the oral administration of medication. Pediatric patients have high sensitivity to taste and reduced ability to take solid dosage forms, which can often lead to a poor therapeutic compliance. It is crucial to find new strategies to simplify the oral administration of drugs to children. The present paper reports the development of a new hydrogel vehicle adapted to the pediatric population. Several polymers with similar properties were selected and adjustments were made to obtain the desired characteristics of the final product. The developed formulations were studied for organoleptic properties, rheology, mucoadhesion properties, preservative efficacy, and stability. Physical and chemical compatibilities between the vehicle and several drugs/medicines, at the time of administration, were also studied. Six final formulations with different polymers, odor, and color were chosen, and no known interactions with medications were observed. The proposed new oral vehicles are the first sugar-free vehicle hydrogels designed to make the intake of oral solid forms a more pleasant and safer experience for pediatric patients.This research was funded by FCT (Fundação para a Ciência e a Tecnologia) through iMed.ULisboa UID/DTP/04138/2020 and UIDB/04138/2020). Joana Marto is financed through FCT, I.P., under the Scientific Employment Stimulus—Institutional Call (CEECINST/00145/2018).info:eu-repo/semantics/publishedVersio

Pure magnesium laser surface modification using Nd:YAG laser

Magnesium (Mg) and its alloys are promising materials for a wide range of biomedical applications due to its biodegradability. Nevertheless, their rapid corrosion dictates the need to develop strategies to control these materials' corrosion rate. In fact, several surface modification techniques have been used to retard the corrosion of Mg and its alloys. Laser technology can be used to tailor Mg surfaces aiming to modify exposed area/roughness and thus control the biocorrosion process. This work presents a detailed study on pure Mg surface texturing by an Nd:YAG laser and their morphological characterisation, aiming to create either localised texturing or remelted areas. The characterisation of the textured and remelted surfaces was carried out by scanning electron microscopy and analysed using image analysis software (Image J) for obtaining their depth and width. Results show that higher scan speed (400 mm/s) and lower laser power (1.5 W) were unsuitable for machining pure Mg. The parameters to perform texturing and remelting are discussed herein.This work was supported by FCT (Fundação para a Ciência e a Tecnologia) through the project PTDC/EMS-TEC/5422/ 2014_ADAPTPROSTHESIS and also by project NORTE 01- 0145_FEDER-000018-HAMaBICo. Additionally, this work was supported by FCT with the reference project UID/EEA/ 04436/201

3D-scaffolds for bone replacement

Bone is the world's second most transplanted tissue, and there is a high demand for bone substitutes, which leads to a decrease in bone bank donors. Three-dimensional scaffolds based on Ti6Al4V, ZrO2, and PEEK were developed and characterized in this study. The mechanical performance of the scaffolds was investigated using experimental mechanical compressive tests and finite element analysis. Also, their in vitro cytocompatibility and osteogenic ability were tested, revealing that the scaffolds were non-cytotoxic and capable of host cells for the duration of the culture.UID/EEA/04436/2019, B-FABULUS (PTDC/BBB-ECT/2690/2014, 3BioMeD (FCT/4773/May 4, 2017/S), DL 57/ 2016 (CTTI-57/18-I3BS(5), FCT/MCTES, SFRH/BD/99555/2014, IF/01285/2015, 2020.07257.BD. e Foundation for Science and Technology (FCT) through the projects: UID/EEA/04436/2013, NORTE-01-0145-FEDER-000018-HAMaBICo, B-FABULUS (PTDC/BBB-ECT/2690/2014), 3BioMeD (FCT/4773/May 4, 2017/S), DL 57/ 2016 (CTTI-57/18-I3BS(5)). FCT/MCTES, (SFRH/BD/99555/2014), IF/01285/2015 and 2020.07257.BD