37ª RASBQ - Conferências

Hanne Christine Bertram
Aarhus University, Denmark

Metabolomics, which is defined as the description of the complete set of metabolites present in a given biomaterial, is a discipline gaining more and more applications in food and nutrition research. In this presentation examples of metabolomics applications in nutrition research will be given. This presentation aims at illustrating how metabolomics can be a valuable tool to obtain mechanistic insight in the metabolic response to dietary components when applied in animal and human intervention studies. By combining metabolomics analyses of different biofluids such as blood and urine with analyses on fecal samples, detailed information about endogenous effects related directly to the host as well as responses related to the gut microflora may be deciphered. NMR- as well as LC-MS-based metabolomics applications are presented, and advantages, disadvantages, limitations and potentials of the different analytical technologies are discussed.

Michele Aresta
CIRCC, Italy and NUS, Singapore

The capture and utilization of carbon dioxide (CCU) is considered today as a technology that may contribute to a better carbon-management coupled to environmental protection. For such technology may contribute to reduce the accumulation of CO₂ in the atmosphere, large volumes of CO₂ (few Gt/y) must be converted into useful products. To reach such objective, fuels must be targeted, not only chemicals.

The conversion of CO₂ occurs via two distinguished processes that imply the fixation of the entire moiety into a chemical (production of chemicals such as carboxylates, carbonates, urethanes) or its reduction to other energy rich C1 (CO, CH₃OH, CH₄) or Cn species (long chain alcohols, hydrocarbons). The latter process requires hydrogen and energy that must be derived from perennial energy sources such as solar, wind, geothermal (SWG).

This talk will make an analysis of the state of the art in CO₂ utilization, featuring the conversion of large volumes of CO₂, and timing the various options in the short-, medium-, long-term.

Opportunities, challenges and barriers will be discussed. A scenario for the potential of CCU will be outlined.

Marcos Nogueira Eberlin
Departamento de Química Orgânica, Instituto de Química - Universidade Estadual de Campinas
IQ-UNICAMP

A MS foi vista por décadas como altamente complexa, cheia de dificuldades e apreensões, e aplicável somente a moléculas voláteis e pequenas. Mas técnicas revolucionárias a transformaram em um modelo de simplicidade e amplitude de aplicações, fazendo-a hoje tão popular e abrangente como nunca ousamos sonhar. Como John Fenn (premio Nobel 2002) resumiu, com electrospray (ESI) a MS deu "asas aos elefantes moleculares ". Proteínas e mesmos formas de vida intactas, como bactérias e vírus, via ESI são hoje analisados por MS. Outras inovações como MALDI e as técnicas de dessorção/ionização ambientais, como EASI- permitem hoje a caracterização rápida e simples de bactérias, embriões, e fungos via verdadeiras impressões digitais químicas capazes ainda de caracterizar plantas, frutas e animais, carnes bovinas, presuntos Parma, caviar russo e azeite de oliva. A MS fornecer assim uma análise química ao nível molecular rápida e abrangente, seletiva e altamente sensível de muitas formas de vida geralmente sem qualquer pré - separação ou preparação da amostra. Embora a metáfora de Fenn ainda não é viável -a análise por MS de todo um elefante- muitas de suas partes já são hoje caracterizados por MS, por detecção de pools de biomoléculas. Em diagnósticos clínicos, a MS tem se destacado também, como nos testes do pezinho expandidos para dezenas de anomalias, e em bio-marcadores em cirurgias, como a de tumores de cérebro, aplicação revolucionária que deu a uma brasileira em 2013 o premio da ACS de melhor tese em Química. Esta palestra discutirá, portanto, os principais episódios dessa epopeia da MS, que permitiu à MS iniciar com os elétrons e chegar hoje às proteínas, e as células, e a Vida como um todo, oferecendo uma das ferramentas de maior abrangência e eficiência em Ciências. E o futuro, aonde nos levará? Ao infinito, e além!

Peter J. Schoenmakers
University of Amsterdam, Faculty of Science,
Science Park 904, 1098 XH Amsterdam, The Netherlands

Comprehensive two-dimensional separations offer some very attractive features. They allows the separation of very complex mixtures in a relatively short time and they yield structured, readily interpretable chromatograms if the separation dimensions (i.e. the retention mechanisms) match the dimensions (i.e. molecular structure) of the sample.

Comprehensive two-dimensional gas chromatography (GC×GC) is increasingly accepted as a high-performance separation technique. Several Brazilian groups have contributed significantly to advances in this field.

Comprehensive two-dimensional liquid chromatography (LC×LC) is somewhat more involved, because the coupling ("modulation") between the two separation dimensions is less straightforward. On the other hand, the range of applications of LC×LC is potentially much greater than that of GC×GC, because many complex samples are non-volatile or contain non-volatile fractions.

To make full use of the potential of comprehensive two-dimensional separations it is tantamount that completely different ("orthogonal") mechanisms are employed in the two underlying dimensions.

In this lecture we will discuss the state-of-the-art of GC×GC and LC×LC, orthogonal separations, possible modulation principles and selected applications.

Lifeng Liu
International Iberian Nanotechnology Laboratory (INL), Braga, PT

Solar cells that convert solar energy into electrical energy have been extensively investigated and widely deployed around the world. Due to the intermittent nature, the electricity generated by solar cells usually has to be either immediately used or stored in a secondary device such as a battery. An emerging approach that allows for storing solar power more elegantly and potentially more practically is to convert solar energy directly into chemical energy in the simplest chemical bond, namely, H₂. This can be achieved by photoelectrolysis of water using semiconductors as both the light absorber and energy converter. In this presentation, basic concepts and working principles for photoelectrochemical water splitting using semiconductor/liquid junctions will be discussed, followed by an experimental demonstration of solar hydrogen evolution using rationally designed well-aligned p-type silicon nanobelt arrays and TiO₂/metal sulfide nanocomposite arrays. Besides, solar oxygen evolution based on well-defined manganese oxide nanostructures will also be presented. It will be shown that nanostructuring can greatly enhance the photoelectrochemical performance of semiconductors toward solar fuel generation.

Carlos Alberto L. Filgueiras
Departamento de Química, UFMG

Em 2013 completaram-se 250 anos do nascimento de José Bonifácio de Andrada e Silva, nascido em Santos, e o primeiro brasileiro a granjear renome internacional como cientista. José Bonifácio foi para a Europa aos 20 anos e só retornou ao Brasil aos 56 anos, depois de uma longa e produtiva carreira científica em vários países europeus, com trabalhos científicos publicados na França, na Alemanha, na Inglaterra e em Portugal. Ele foi químico, mineralogista, geólogo e metalurgista, além de atuar como professor e administrador de vários empreendimentos científicos. Sua carreira científica o tornou parte da cadeia de eventos que levou à descoberta do elemento lítio, e um pioneiro a desenvolver pesquisas na área de fitoquímica, estudando quimicamente componentes de plantas brasileiras. Indiretamente, ele veio a ter um papel no desenvolvimento da indústria de alumínio em larga escala, por ter sido o descobridor da criolita, mineral essencial no processo de eletrólise da alumina. Após sua aposentadoria como cientista ele iniciou a carreira política pela qual é muito mais conhecido no Brasil.

Kathryn Elizabeth Uhrich
Wright-Rieman Laboratories,
Rutgers University, NJ

The overall focus of my laboratory is the design, synthesis and characterization of biocompatible polymers for biomedical, cosmetic and food purposes. This lecture will focus on two different approaches in designing polymers with a purpose: polymers that are bioactives and polymers derived from bioactives.

Nanoscale amphiphilic macromolecules (AMs) were initially created to encapsulate hydrophobic drugs and improve drug water-solubility, which enhances bioactivity. These AMs can also be used to stabilize liposomes, a common drug delivery system, and increase their efficacy with anti-cancer agents. Related work has demonstrated that the AMs alone are bioactive – they actively coordinate with macrophage scavenger receptors to mitigate uptake of low-density lipoproteins (aka bad cholesterol).

As polymers derived from bioactives, PolymerDrugs are designed to hydrolytically degrade into biologically active molecules. PolyAspirin was the first example in which the polymer itself is a controlled-release system: the polymer backbone degrades into salicylic acid, an anti-inflammatory and analgesic compound. These polymers are currently in clinical trials as a biodegradable cardiac stent. This concept has been expanded to include PolyAntibiotics, PolyAntiseptics, PolyAntioxidants and PolyOpiates useful for localized, controlled delivery of bioactives

Humberto Osório Stumpf
Departamento de Química do ICEX da UFMG

A área de Magnetismo Molecular estuda sistemas que vão desde uma molécula simples até um material no estado sólido, em construções planejadas ou descobertas ao acaso, através de sínteses baseadas na química orgânica e de compostos de coordenação. A Química Supramolecular nem sempre é a diretora nos desenhos planejados, mas invariavelmente se encontra nos edifícios moleculares resultantes. Magnetismo Molecular é uma área caracterizada pela interdisciplinaridade. Conceitos de física teórica se juntam a imaginativos - às vezes artísticos - argumentos químico-topológicos para o planejamento de 'blocos construtores'. Estas unidades construtivas são geralmente íons ou moléculas a partir dos quais se busca uma determinada propriedade magnética resultante de uma montagem; ou auto-montagem, quando o sistema se forma por si mesmo, regido por forças de ligação muitas vezes fracas e desprezadas no planejamento racional de partida. Quando se utiliza um complexo metálico como bloco construtor referimo-nos ao termo "complexo como ligante" e, geralmente, as reações químicas de catenação ou polimerização acabam se enquadrando em uma estratégia metalosupramolecular.

Os sistemas de maior interesse atual são os nanomateriais magnéticos, os quais são alvo de intensa pesquisa visando-se propriedades como superparamagnetismo, ferromagnetismo, tunelamento quântico/relaxação lenta da magnetização, transporte eletrônico/spintrônica, magneto-ópticas, etc. Na construção racional de edifícios moleculares, novas propriedades surgem com potenciais aplicações em materiais nanoporosos (MOF's, Metal–Organic Frameworks), armazenamento, leitura ou gravação de informação, refrigeração magnética, processamento quântico de informação, catálise, biotecnologia, entre outras. Vários destes aspectos serão abordados nesta apresentação.

Irene Cristina de Mello
Universidade de Federal do Mato Grosso, Cuiabá, MT

A educação superior no Brasil nas últimas décadas tem se consolidado em um modelo de diversificação, internacionalização, centrado na lógica expansionista, com aumento expressivo no número de instituições, cursos de graduação e de estudantes. Com o foco constante na democratização do acesso, cresce também o número de profissionais contratados para o exercício da docência nas instituições de ensino superior. A discussão sobre a docência neste nível de ensino não raramente nos remete à polêmica, pautada em uma perspectiva ética e institucional, que tem atraído o interesse de pesquisadores da área de Educação em âmbito nacional e internacional. No Brasil, trata-se de um debate que, também, mobiliza as administrações superiores das universidades. Uma análise sobre a universidade brasileira nos permite observar que para muitos professores, para ensinar Química basta saber o conteúdo, sendo o exercício contínuo da docência, o verdadeiro lócus para se aprender a ensinar. Por não haver uma exigência legal de formação para a docência no ensino superior, como ocorre na educação básica, o entendimento sobre a docência parece que se tornou um não-lugar e, por vezes, cenário conflituoso. Muitos exercem sua função de formador a partir de concepções alternativas sobre ensino-aprendizagem desenvolvidas ao longo de sua trajetória, seja como estudantes ou como professores em situações eventuais, muitas das quais compartilhadas com profissões correlatas à Química e, quase sempre, com maior status que a docência. Neste sentido, esta conferência pretende abordar a docência no ensino superior de Química apresentando alguns desafios e perspectivas, mediante estudos e experiências desenvolvidas em um programa de formação docente na Universidade Federal de Mato Grosso.

Peter H. Seeberger
Max-Planck Institute for Colloids and Interfaces, Potsdam, Germany,
Free University of Berlin, Germany, University Potsdam, Germany and The Burnham Institute, La Jolla, CA USA; Arnimallee 22 14195 Berlin (Germany)

Most pathogens including bacteria, fungi, viruses and protozoa carry unique glycans on their surface. Currently, several vaccines against bacteria are marketed very successfully. Since many pathogens cannot be cultured and the isolation of pure oligosaccharides is extremely difficult, synthetic oligosaccharide antigens provide now a viable alternative. Based on the automated synthesis platform,¹ that has now been completely overhauled, ² we are currently developing multiple vaccine candidates against bacterial infections, fungi, and protozoan parasites. In addition to their function as antigens, the synthetic oligosaccharides serve as tools to create monoclonal antibodies, and to establish glycan microarrays to map vaccine epitopes. ³ In this lecture B. anthracis, C. difficile, S. pneumonia, N. meningitides and malaria will be used as examples to illustrate the approach. ^4-6

Traditionally, chemists have performed reactions in a batch-wise mode. In recent years continuous flow systems have become increasingly interesting to practitioners of synthetic chemistry. ⁷ Described is the use of a continuous flow system to produce the anti-malaria drug artemisinin in large quantities. ⁸

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4.Tamborrini, M.; Werz, D. B.; Frey, J.; Pluschke, G.; Seeberger, P.H.; Angew. Chem. Int. Ed. 2006, 45, 6581.
5.Oberli, M.A.; Tamborrini, M.; Tsai, Y.-H.; Werz, D.B.; Horlacher, T.; Adibekian, A.; Gauss, D.; Möller, H.M.; Pluschke, G.; Seeberger, P.H.; J. Am. Chem. Soc. 2010, 132, 10239-10241.
6. Martin, C.E.; Weishaupt, M.W.; Seeberger, P.H.; Chem. Comm. 2011, 47, 10260.
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Elsa Reichmanis
School of Chemical and Biomolecular Engineering
Georgia Institute of Technology
Atlanta, GA 30332, USA

The performance of devices fabricated using polymeric semiconductors depends critically upon alignment of the polymer chains at the nano- through macro-scales. Significant structure-process-property relationships that allow for enhancement of long-range order will be described. For instance, a lyotropic liquid crystalline (LC) phase has been observed in poly-(3-hexylthiophene) (P3HT) via solvent-evaporation induced self-assembly. In-situ polarized Raman spectroscopy facilitated investigation of the evolution of structure that eventually was found to undergo a phase transition from an isotropic solution to LC phase. The insights gained through these investigations were applied to the design of an alternative, donor-acceptor (D-A) benzothiadiazole oligothiophene based copolymer material. For one family of copolymers, structural elements were found to provide for a span in hole mobility of approximately 3 orders of magnitude. Samples annealed at moderate temperatures exhibited mobilities in excess of 1 cm²/Vs. The lessons learned through these studies may allow for simple, controllable, and cost-effective methodologies for achieving high performance plastic electronic devices.

Bradley D. Miller
American Chemical Society - ACS

Paulo Cezar Vieira
Universidade Federal de São Carlos - UFSCar

Paulo Cezar Vieira earned his Ph.D. from the University of São Paulo in 1982. He is currently Associate Professor 4 in the Department of Chemistry, Federal University of Sao Carlos (UFSCar). He has published over 180 papers in peer reviewed journals and over 500 papers in conference proceedings. He has also published 5 book chapters, organized 3 books and co-authored 1 book. He has directed 11 dissertations and 26 PhD theses. His professional activities involve collaborations with several institutions in Brazil and abroad. In his career, he has served as vice-chair in the Department of Chemistry at UFSCar, and coordinator of the graduate program in the same department. He was secretary general, vice president and president (two terms) of the Brazilian Chemical Society, and also the president of the Latin American Federation of Chemical Associations (FLAQ). More recently he was the secretary general for international relations of Federal University of São Carlos. His research has been focused in Chemistry with emphasis in Chemistry of Natural Products. His recent research interests involve isolation and identification of natural products with biological activity with an emphasis on parasitic diseases and search for specific inhibitors of particular enzymes cathepsins.

Bradley D. Miller holds a Ph.D. from the University of Arizona. He is currently Director, American Chemical Society (ACS) Office of International Activities, where he has worked since 1999 developing programs to advance chemical sciences through exchange and collaborations in Africa, Asia, Europe, Latin America and the Middle East. Miller serves on the US National Commission for UNESCO and in 2011 and 2012, he received the ACS Catalyst Award for ACS' contributions to global and domestic International Year of Chemistry celebrations and the International Chemistry Olympiad. In 2006 Miller was recipient of an NSF Discovery Corps Fellowship fostering US/Brazil collaboration in the chemistry of biomass conversions to biofuels. He has worked for university-based international programs, for a higher education association focused on principles of quality assurance for transnational education, and for a private voluntary organization dedicated to international allied health sciences. He has published nine articles and book chapters and is a frequent invited speaker on topics related to international aspects of non-profit S&T association management, and scientific, professional and academic mobility.

Wilson de Figueiredo Jardim
Universidade Estadual de Campinas – UNICAMP, Campinas, SP

Vivemos numa sociedade que se caracteriza por um elevado grau de consumo, o que implica na demanda exacerbada de matéria prima e energia. Calcula-se hoje que convivemos rotineiramente com algo como 100 mil substâncias, sendo que a cada ano mais de mil novas moléculas são registradas. Também é sabido que conhecemos muito pouco sobre a toxicidade tanto das novas como das antigas substâncias que nos rodeiam, o que faz com que tenhamos que adotar mecanismos claros e protocolos para avaliar os riscos da exposição humana e possíveis danos que estas substâncias possam causar na biosfera. Nesta busca, temos vários inimigos, como a pressão econômica, o pouco tempo de testes antes do lançamento de um produto e as interpretações e extrapolações dos ensaios de toxicidade realizados com diferentes animais. Em especial, quanto aos danos causados pela exposição crônica a estas substâncias. Estes temas serão abordados com exemplos ilustrativos das dificuldades encontradas e das consequências já observadas no nosso planeta.

Daniel Mario Ugarte
(IF-UNICAMP)

The novel physical and chemical properties of nanosystems place them as one of the most promising elements to develop new technologies. However, the detailed assessment of atomic structure and chemical modifications of nanomaterials still represents a serious challenge, rendering difficult the development of basic understanding and technological use. We will present the application of electron microscopy techniques to analyze in detail the structural and electronic properties of individual nanowires and nanotubes by in-situ dynamic experiments. We will describe different application to analyze chemical composition modifications, structural distortions and, also, mechanical behavior. In particular, we will address, the atomistic aspects associated with the deformation and rupture of noble metal nanorods as function of temperature when observed by real-time atomic resolution transmission electron microscopy (HRTEM). Our results indicate that surface energy (ex. steps) overrule staking fault energetics, indicating that both size and shape determines the nanoscale mechanical behavior during the deformation process. Finally, we will discuss the status and perspectives for electron microscopy characterization methods and the challenging point associated with human resource formation in this field.

Maria Laura Bolognesi
Department of Pharmacy and Biotechnology
Università di Bologna, Italy

Scientific interest in prion diseases has increased dramatically in recent years, transforming them from rare, puzzling diseases to a sort of emblem of neurodegeneration.

Initially, what made them so unique and fascinating was the fact that the key pathogenic event was identified in the conversion of the normal cellular prion protein (PrP^C) into a toxic scrapie isoform (PrP^Sc), rich in β–strands. Then, through an autocatalytic replication, PrP^Sc accumulates in proteinaceous aggregates, resulting in the diffuse neuronal degeneration and the spongiform brain lesions typical of the disease. Currently, an even more fascinating finding is that the amyloidogenic proteins underlying more common neurodegenerative diseases, such as Aβ andα-synuclein, promote the formation of pathogenic isoforms in a process that is analogous to the propagation of classic prions. Thus, it is highly realistic that the inhibition of common proteostatic cellular pathways may influence the pathogenesis of neurodegenerative disorders representing the largest unmet clinical needs of the developed societies [1].

Regrettably, despite the impressive advances occurred so far and the potential impact of future therapies, prion diseases remain incurable and a challenging endeavor for medicinal chemists. The growing reliance on target-based and structure-guided approaches to drug discovery, combined with a still uncertain pathogenesis, has led to consider screening approaches the method of election when looking for new drugs against prion.

In my opinion, in the med chem toolbox there is still a multitude of intriguing ideas on how to potentially target prion diseases that may prove to be of benefit in the near future. One such option is a multitarget drug discovery approach, which is being successfully pursued in the therapy of other complex diseases, such as depression and cancer. Here, creating a multitarget ligand that selectively engages a predefined set of molecular targets involved in the neurotoxic cascade is of high therapeutic potential [2]. Another possibility is the exploitation of theranostics, i.e. single agents with concomitant therapeutic and diagnostic properties. The general purpose of theranostics is to optimize the efficacy and safety of therapy, as well as to streamline the whole drug discovery process. Along these lines, they are particularly suitable towards prion diseases [3]. In this lecture, I will illustrate the use of both strategies with different examples taken from my own research.

[1] Legname G, Bolognesi ML. Curr Top Med Chem. 2013;13(19):2395-6.
[2] Bongarzone S, Tran HN, Cavalli A, Roberti M, Rosini M, Carloni P, Legname G, Bolognesi ML. ChemMedChem. 2011;6(4):601-5.
[3] Staderini M, et al. ACS Med Chem Lett. 2013;4(2):225–9.

Timothy J. Donohoe
Department of Chemistry
University of Oxford, Oxford, UK

José A. S. Cavaleiro
Department of Chemistry
University of Aveiro, 3810-193 Aveiro, Portugal

Respiration, photosynthesis and drug detoxification are examples of vital functions which are played in nature by macrocycles which are porphyrin-type derivatives. Several research groups, mainly during the last century, have considered, as target studies, the synthesis, biosynthesis, mode of action and catabolism of such natural compounds. Other groups have been concerned with the search of potential applications for porphyrin macrocycles. Currently applications in medicine, in catalysis, solar energy conversion, as new materials and as sensors are already known. Certainly the most significant applications are those related with cancer detection and treatment (photodynamic therapy, PDT) and also those related with the photoinactivation of microorganisms and treatment of water samples. A porphyrin derivative being accumulated in neoplastic cells, by interaction with ground state oxygen and under adequate radiation, generates cytotoxic species (singlet oxygen and/or radicals) which can kill the cancer cells. A similar procedure might take place in the photoinactivation of microorganisms (e.g, antibiotic resistant bacteria). The success of such significant action of porphyrin derivatives greatly depends on certain structural requirements, in close connection with the amphiphilicity of the compound. All this requires scientific investigations leading to new synthetic methodologies making available new porphyrin derivatives for biological testings.

For more than two decades we have been carrying out studies on the synthesis and reactivity of tetrapyrrolic macrocycles, mainly those containing the porphyrin skeleton, having in mind their potential biological activities. We have established that porphyrins can react as dienophiles and as dipolarophiles under cycloaddition conditions. As a result, several new derivatives with important structural features like chlorins (dihydroporphyrins) or bacteriochlorins (tetrahydroporphyrins) can be obtained.

Synthetic methodologies leading to new porphyrin derivatives containing other biological active groups (e.g., carbohydrate, triazole, quinolone) have also been considered. Methodologies involving metathesis, click chemistry, Suzuky, Heck and Buchwald-Hartwig conditions have been set up with porphyrins. Such reactivity features of porphyrins will be considered in this lecture. The biological evaluation already carried out with some new derivatives will also be taken into consideration.