Desenvolvimento de estruturas compósitas de nanopartículas magnéticas encapsuladas em polímero para aplicações biomédicas

Dissertação de mestrado em Biofísica e BionanossistemasNos últimos anos, importantes avanços têm sido realizados no desenvolvimento de nanoestruturas para um grande leque de aplicações. Um exemplo passa pela crescente aplicação de nanopartículas magnéticas na área da biomedicina. O sucesso no uso destas nanopartículas depende de vários fatores, como é o caso do tamanho e das suas propriedades magnéticas, que podem ser controlados durante a sua síntese. No entanto, um problema inevitável das nanopartículas magnéticas é a sua baixa estabilidade em solução aquosa em longos períodos de tempo, podendo aglomerar ou mesmo oxidar. Esta barreira pode ser solucionada através do revestimento com diferentes materiais, incluindo surfactantes, polímeros ou materiais inorgânicos. Com o enquadramento acima descrito, nesta dissertação foi estudado o comportamento de diferentes estruturas compósitas de nanopartículas magnéticas encapsuladas para aplicação na biomedicina. Para o núcleo magnético foram utilizadas nanopartículas de ferrite de cobalto (CoFe2O4) e nanopartículas de óxido de ferro (Fe3O4), não só por possuírem elevada magnetização, mas também por apresentarem propriedades interessantes como a magnetostritividade e o superparamagnetismo, respetivamente. As nanopartículas de CoFe2O4 foram adquiridas comercialmente e as nanopartículas de Fe3O4 foram sintetizadas pelo método de coprecipitação. Em ambos os casos, as nanopartículas magnéticas sofreram um pós-processamento com ácido oleico de modo a aumentar a sua estabilidade em solução. De seguida, as nanopartículas magnéticas foram revestidas com dois materiais distintos, a sílica (SiO2), por uma adaptação do método de Stöber, e um polímero biocompatível e biodegradável, o poli (l-ácido lático) (PLLA), pelo método de microemulsão. Optou-se por estudar a viabilidade do revestimento com SiO2 por apresentar uma diversidade de vantagens para aplicações biomédicas. Os compósitos obtidos foram sujeitos a várias técnicas de caracterização de forma a determinar a morfologia, estrutura, propriedades magnéticas e estabilidade em solução. Por último, foram realizados ensaios de citotoxicidade para avaliar a viabilidade celular das partículas. O revestimento com SiO2 verificou-se apropriado tanto para as nanopartículas de CoFe2O4 como Fe3O4. Já para o revestimento com PLLA, este foi mais uniforme e eficiente para as nanopartículas de Fe3O4. De forma resumida, os resultados mostraram que as partículas produzidas apresentam um grande potencial para aplicação na biomedicina tendo em conta a sua fácil produção e de baixo custo.In recent years, important advances have been achieved in the development of nanostructures for a wide range of applications. An example is the increasing application of magnetic nanoparticles in the biomedical field. The successful use of these nanoparticles depends on several factors, such as their size and magnetic properties, which can be controlled during their synthesis. However, an unavoidable problem of magnetic nanoparticles is their low stability in aqueous solution over long periods of time, which may agglomerate or even oxidize. This problem can be overcome by coating with different materials, including surfactants, polymers or inorganic materials. Within the framework described above, this dissertation focussed on the study of the behaviour of different composite structures of encapsulated nanoparticles for application in biomedicine. Nanoparticles of cobalt ferrite (CoFe2O4) and iron oxide (Fe3O4) were used for the magnetic core, not only because of their high magnetization but also due to their interesting properties such as magnetostrictive response and superparamagnetism, respectively. CoFe2O4 nanoparticles were commercially acquired and Fe3O4 nanoparticles were synthetized by the coprecipitation method. In both cases, the magnetic nanoparticles were post processed with oleic acid in order to increase their stability in solution. Then, the magnetic nanoparticles were coated using two materials, porous and non-porous silica (SiO2) prepared by and adaptation of the Stöber method, and a biocompatible and biodegradable polymer, poly (l-lactic acid) (PLLA), prepared by the microemulsion method. In particular, coatings with SiO2 were studied as they present a variety of advantages for biomedical applications. The composites obtained were subjected to several characterization techniques in order to determine the morphology, structure, magnetic properties and stability in solution. Finally, cytotoxicity assays were performed. SiO2 was found to be suitable for coating both the CoFe2O4 and Fe3O4 nanoparticles. As for the PLLA coating, it was more uniform and efficient for the Fe3O4 nanoparticles. As a conclusion, results showed that the produced particles show a large potential for application in biomedicine, considering their easy production and low cost

Repertório de jazz nas aulas de formação musical – um percurso complementar

No âmbito do Mestrado em Ensino de Música – ramo Formação Musical, foi instituída a realização de um relatório de estágio e de um projeto de investigação, nomeadamente um projeto de investigação-ação executado numa das escolas / turmas nas quais foi realizado um estágio de Prática Pedagógica no Ensino Vocacional da Música. Este relatório foi construído e organizado de forma gradual, ramificando-se em três capítulos, com o intuito de principiar com a descrição de conteúdos mais genéricos, particularizando-os até ao mais específico que consiste no artigo de investigação. Assim, ao longo do primeiro capítulo é efetuada uma pequena contextualização no ensino da música em Portugal e da disciplina de formação musical, integrada no currículo do ensino especializado da música. Posteriormente, é realizada uma contextualização do tema escolhido para abordagem nas aulas de Formação Musical, nomeadamente o Jazz e, as respetivas caraterísticas e, por fim, a descrição do Pólo de estágio. O capítulo dois consiste na reflexão de todo o processo desenvolvido ao longo da prática pedagógica e, tudo o que ela envolve, isto é, observações e planificações com a respetivas reflexões diárias. No capítulo três é apresentado o projeto de investigação intitulado “Repertório de Jazz nas aulas de Formação Musical – um percurso complementar”. Este foi motivado pelo interesse em descobrir se a utilização de um repertório diferente do atualmente utilizado (erudito), nomeadamente o jazz, pode ser uma mais-valia para a aprendizagem dos conteúdos da formação musical. Para finalizar é apresentado um breve pensamento de todo o processo desenvolvido ao longo do presente ano letivoUnder the Masters in Music Education - Musical Training branch, was established to carry out an internship report and a research project, consisting of a project action-research performed in one of the schools / classes in which we performed a Teaching Practice internship on Music’s Vocational Education. This report was constructed and arranged gradually branching into three sections, in order to begin with the description of more generic contents, particularising them to the more specific consisting of the research article. Thus, over the first chapter is made a little contextualization in music education in Portugal and discipline of the musical education, integrated in the curriculum of specialized music teaching. Subsequently, a contextualization is made on the theme chosen to approach in the musical training classes, in particular Jazz and their respective characteristics and, finally, the description of the Internship Center. Chapter two consists of a reflection on the whole process developed over the pedagogical practice and all that it involves; observations and lesson plans with the respective daily reflections. In chapter three it is presented, the research project titled "Jazz Repertory in Musical Training classes - an alternative route." This was motivated by the interest in whether the use of a different repertoire from the currently used (scholar) and in particular jazz, can be an asset towards learning the contents of the musical training. Finally, it is laid out a brief thought of the whole process developed throughout this school yea

Ionic liquid-based materials for biomedical applications

Ionic liquids (ILs) have been extensively explored and implemented in different areas, ranging from sensors and actuators to the biomedical field. The increasing attention devoted to ILs centers on their unique properties and possible combination of different cations and anions, allowing the development of materials with specific functionalities and requirements for applications. Particularly for biomedical applications, ILs have been used for biomaterials preparation, improving dissolution and processability, and have been combined with natural and synthetic polymer matrixes to develop IL-polymer hybrid materials to be employed in different fields of the biomedical area. This review focus on recent advances concerning the role of ILs in the development of biomaterials and their combination with natural and synthetic polymers for different biomedical areas, including drug delivery, cancer therapy, tissue engineering, antimicrobial and antifungal agents, and biosensing.The authors thank the FCT (Fundacao para a Ciencia e Tecnologia) for financial support under the framework of the Strategic Funding UID/FIS/04650/2019 and pro-jects PTDC/BTM-MAT/28237/2017, PTDC/EMD-EMD/28159/2017, and PTDC/FIS-MAC/28157/2017. Funds provided by FCT in the framework of EuroNano-Med 2016 call, Project LungChek ENMed/0049/2016 are also gratefully acknowledged. D.M.C., L.C.F., R.M.M., and M.M.F. also thank the FCT for the grants SFRH/BPD/121526/2016, SFRH/BD/145345/2019, and FRH/BD/148655/2019, SFRH/BPD/121464/2016, respectively and CR thanks the FCT for the contract under the Stimulus of Scientific Employment (2020.04163.CEECIND). S.L.M. and J.R. acknowledge the funding support from the Spanish State Research Agency (AEI) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Department under the ELKARTEK program.info:eu-repo/semantics/publishedVersio

Development of poly(l-Lactic Acid)-based bending actuators

This work reports on the development of bending actuators based on poly(l-lactic acid) (PLLA)/ionic liquid (IL) blends, through the incorporation of 40% wt. of the 1-ethyl-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) IL. The films, obtained by solvent casting at room temperature and 50 °C, were subjected to several post-thermal treatments at 70, 90, 120 and 140 °C, in order to modify the crystallinity of the films. The influence of the drying temperature and of [Emim][TFSI] blending on the morphological, structural, mechanical and electrical properties of the composite materials were studied. The IL induced the formation of a porous surface independently of the processing conditions. Moreover, the [Emim][TFSI] dopant and the post-thermal treatments at 70 °C promoted an increase of the degree of crystallinity of the samples. No significant changes were observed in the degree of crystallinity and Young Modulus for samples with thermal treatment between 70 and 140 °C. The viability of the developed high ionic conductive blends for applications as soft actuators was evaluated. A maximum displacement of 1.7 mm was achieved with the PLLA/[Emim][TFSI] composite prepared at 50 °C and thermally treated at 140 °C, for an applied voltage of 10 Vpp, at a frequency of 100 mHz. This work highlights interesting avenues for the use of PLLA in the field of actuators.The authors thank the FCT—Fundação para a Ciência e Tecnologia—for financial support under the Strategic Funding UID/FIS/04650/2020, and PEST-C/QUI/UIO686/2019, the Associated Laboratory Research Unit for Green Chemistry, Technologies and Clean Processes, LAQV (financed by national funds from FCT/MEC, UID/QUI/50006/2020 and ERDF under the PT2020, POCI-01-0145-FEDER-007265) and projects PTDC/BTM-MAT/28237/2017 and PTDC/EMD-EMD/28159/2017. DMC and LCF also thank the grants SFRH/BPD/121526/2016 and SFRH/BD/145345/2019, respectively

Erratum: Development of Poly(l-Lactic Acid)-Based Bending Actuators. Polymers 2020, 12, 1187

The authors wish to make a change to their published paper [1]. In the original manuscript, there is a mistake in a sentence in Section 3.5, on page 10. Two words “anions and cations” were reverted by mistake. The corrected sentence is shown below: The strain developed as a response to the applied electrical field results from the diffusion of the ions and migration to the positive (anions) and negative (cations) electrode layers, and subsequent accumulation close to the electrodes. The authors apologize for any inconvenience caused, and the change does not affect the scientific results. The manuscript will be updated, and the original will remain online on the article webpage at https://www.mdpi.com/2073-4360/12/5/1187.(undefined

Multifunctional magnetoelectric sensing and bending actuator response of polymer-based hybrid materials with magnetic ionic liquids

With the evolution of the digital society, the demand for miniaturized multifunctional devices has been increasing, particularly for sensors and actuators. These technological translators allow successful interaction between the physical and digital worlds. In particular, the development of smart materials with magnetoelectric (ME) properties, capable of wirelessly generating electrical signals in response to external magnetic fields, represents a suitable approach for the development of magnetic field sensors and actuators due to their ME coupling, flexibility, robustness and easy fabrication, compatible with additive manufacturing technologies. This work demonstrates the suitability of magnetoelectric (ME) responsive materials based on the magnetic ionic liquid (MIL) 1-butyl-3-methylimidazolium tetrachloroferrate ([Bmim][FeCl4]) and the polymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE) for magnetic sensing and actuation device development. The developed sensor works in the AC magnetic field and has frequency-dependent sensitivity. The materials show voltage responses in the mV range, suitable for the development of magnetic field sensors with a highest sensitivity (s) of 76 mV·Oe−1. The high ME response (maximum ME voltage coefficient of 15 V·cm−1·Oe−1) and magnetic bending actuation (2.1 mm) capability are explained by the magnetoionic (MI) interaction and the morphology of the composites.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2020, UID/QUI/00686/2020, LA/P/0008/2020, UIDB/50006/2020 and UIDP/50006/2020. The authors are grateful for funds through FCT under the projects 2022.05932.PTDC, PTDC/BTM-MAT/28237/2017 and PTDC/EMD-EMD/28159/2017 and grant SFRH/BD/145345/2019 (L.C.F). D.M.C. and P.M. thank FCT—Fundação para a Ciência e Tecnologia for the contract under the Stimulus of Scientific Employment, Individual Support 2020.02915.CEECIND and CEECIND/03975/2017, respectively. This study forms part of the Advanced Materials programme and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and by the Basque Government under the IKUR program. Funding from the Basque Government Industry Departments under the ELKARTEK program is also acknowledged. Technical and human support provided by IZO-SGI, SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully acknowledged

Electrospun magnetic ionic liquid based electroactive materials for tissue engineering applications

Functional electrospun fibers incorporating ionic liquids (ILs) present a novel approach in the development of active microenviroments due to their ability to respond to external magnetic fields without the addition of magnetic particles. In this context, this work reports on the development of magnetically responsive magneto-ionic fibers based on the electroactive polymer poly(vinylidene fluoride) and the magnetic IL (MIL), bis(1-butyl-3-methylimidazolium) tetrathiocyanatocobaltate ([Bmim]2[(SCN)4Co]). The PVDF/MIL electrospun fibers were prepared incorporating 5, 10 and 15 wt.% of the MIL, showing that the inclusion of the MIL increases the polar β-phase content of the polymer from 79% to 94% and decreases the crystallinity of the fibers from 47% to 36%. Furthermore, the thermal stability of the fibers decreases with the incorporation of the MIL. The magnetization of the PVDF/MIL composite fibers is proportional to the MIL content and decreases with temperature. Finally, cytotoxicity assays show a decrease in cell viability with increasing the MIL content.This research was funded by FCT—Fundação para a Ciência e Tecnologia (FCT) under the scope of the strategic funding of UID/FIS/04650/2020, and project PTDC/BTM-MAT/28237/2017. Moreover, the authors thank FCT for the research grant SFRH/BD/145345/2019 (LMC), SFRH/BD/148655/2019 (RMM), and D.M.C. and CR thank the FCT for the contract under the Stimulus of Scientific Employment 2020.02915.CEECIND and 2020.04163.CEECIND, respectively.The authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program. Technical and human support provided by IZO-SGI, SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) is gratefully acknowledged

Environmentally friendly carrageenan-based ionic-liquid driven soft actuators

UID/FIS/04650/2020 UID/QUI/0686/2020 LA/P/0008/2020 PID2019-106099RB-C43/AEI/10.13039/501100011033A naturally derived polymer based on iota carrageenan and different ammonium and imidazolium based ionic liquids (ILs) are used for the development of environmentally friendly soft actuators. The influence of IL content and type and solvent evaporation temperature on the morphological and physico-chemical properties of the materials was evaluated, together with the effect on actuator functional response. Independently of the IL content and type, and the solvent evaporation temperature, a non-porous structure is obtained. The incorporation of the IL within the polymer matrix does not affect the thermal stability but leads to a decrease in the Young modulus for the different IL/carrageenan samples. The highest influence was observed by using the [Ch][DHP] IL at a filler content of 40% w/w with a decrease in the Young modulus from 748 MPa for the neat polymer to 145 MPa for the [Ch][DHP]/carrageenan sample. Furthermore, the ionic conductivity of the samples increases with increasing IL content, with the highest values being 2.9 × 10-6 S cm-1 and 1.2 × 10-6 S cm-1 for the samples with 40% w/w of [Bmim][FeCl4] and [Ch][DHP], respectively. Regarding the soft actuator performance, the maximum displacement was obtained for the [Ch][DHP]/carrageenan sample with an IL content of 40% w/w, showing a maximum displacement of 5.8 mm at a DC applied voltage of 9 V.publishersversionpublishe

Determinants of HIV late presentation among men who have sex with men in Portugal (2014–2019): who’s being left behind?

Introduction: HIV late presentation (LP) remains excessive in Europe. We aimed to analyze the factors associated with late presentation in the MSM population newly diagnosed with HIV in Portugal between 2014 and 2019. Methods: We included 391 newly HIV-1 diagnosed Men who have Sex with Men (MSM), from the BESTHOPE project, in 17 countrywide Portuguese hospitals. The data included clinical and socio-behavioral questionnaires and the viral genomic sequence obtained in the drug resistance test before starting antiretrovirals (ARVs). HIV-1 subtypes and epidemiological surveillance mutations were determined using different bioinformatics tools. Logistic regression was used to estimate the association between predictor variables and late presentation (LP). Results: The median age was 31 years, 51% had a current income between 501-1,000 euros, 28% were migrants. 21% had never been tested for HIV before diagnosis, with 42.3% of MSM presenting LP. 60% were infected with subtype B strains. In the multivariate regression, increased age at diagnosis, higher income, lower frequency of screening, STI ever diagnosed and higher viral load were associated with LP. Conclusion: Our study suggests that specific subgroups of the MSM population, such older MSM, with higher income and lower HIV testing frequency, are not being targeted by community and clinical screening services. Overall, targeted public health measures should be strengthened toward these subgroups, through strengthened primary care testing, expanded access to PrEP, information and promotion of HIV self-testing and more inclusive and accessible health services.info:eu-repo/semantics/publishedVersio

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit