Orientador: Nelson Ramos Stradiotto / Banca: Sonia Maria Alves Jorge / Banca: Leonardo Lataro Paim / Banca: André Luiz dos Santos / Banca: Rodrigo Alejandro Abarza Munoz / Resumo: A vinhaça é um expressivo coproduto da destilação do etanol que apesar de ser considerada poluidora, vem sendo utilizada como fertilizante nas plantações de cana-de-açúcar, colocando em risco a contaminação de aquíferos subterrâneos e salinização do solo. Cerca de 10 a 18 litros de vinhaça são produzidos por litro de etanol destilado e sua constituição é de principalmente sais de potássio, cálcio, magnésio e compostos orgânicos. Dentre estes, os polióis tornam-se importantes compostos por estarem presentes em concentrações altamente significativas e também por apresentar expressiva importância na indústria farmacêutica e alimentícia. Com isso, o conceito de biorrefinarias surge como a possibilidade das usinas terem um pleno aproveitamento deste resíduo, garantindo fins mais lucrativos e ecológicos. Assim, é de grande importância o desenvolvimento de novos métodos para determinação desses compostos, com destaque aos eletroanalíticos, que vem nos últimos anos se destacando por apresentar métodos de análises confiáveis mesmo em baixas concentrações do analito, pequenos volumes de amostra e em matrizes complexas que requerem alta especificidade. Sendo assim, nesse trabalho foi desenvolvido sensores eletroquímicos baseados na técnica de impressão molecular, capaz de produzir polímeros que incorporam as moléculas de interesse em sua estrutura e que são capazes de formar locais específicos de reconhecimento molecular, tornando-se atrativos devido a sua elevada seletividade e estabil... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Vinasse is an expressive co - product of ethanol distillation, which despite being conside red polluting, has been used as fertilizer in sugarcane plantations, which may put at risk the contamination of groundwater and soil salinization. About 10 to 18 liters of vinasse are produced per liter of distilled ethanol and its composition is mainly of salts of potassium, calcium, magnesium and organic compounds. Among these, polyols become important compounds because they are present in highly concentrations and also due to its importance in the pharmaceutical and food industry . With this, the concept of biorefineries becomes a possibility for the sugar cane plants to take full advantage of this residue, guaranteeing more profitable and ecological ends. Thus, the development of new methods for the determination of these compounds is very important, wit h emphasis on electroanalytical methods, which recently has been presenting reliable methods of analysis even at low analyte concentrations, small sample volumes and in complex matrices that require high specificity . So, in this work, we developed electroc hemical sensors based on the molecular imprinted technique, capable of producing polymers that incorporate the molecules of interest in their structure and that are able to form specific sites of molecular recognition . Therefore, this work reports the deve lopment of an electrochemical method for the determination of polyols based on molecularly imprinted polymers (MIP) using go... (Complete abstract click electronic access below) / Doutor

A series of eight novel bidentate ligands, designed for use in the construction of nickel-selective molecularly imprinted polymers (MIP's), have been prepared. The synthetic pathway was established by retrosynthetic analysis of the target molecules to the readily available precursors, pyridine-2-carbaldehyde (or 6-methylpyridine-2-carbaldehyde) and ethyl bromoacetate. The ligands were designed to contain an allyl group for co-polymerisation and amine and pyridyl nitrogen donors, located to permit the formation of 5-membered nickel chelates. The eight novel ligands and their respective precursors were characterized by elemental (high-resolution MS) and spectroscopic (IR and ¹H and ¹³C NMR) analysis. High resolution electron-impact mass spectrometry has also been used, together with B/E linked scan data, to explore the fragmentation patterns of selected ligands. The various nickel(ll) complexes were analyzed using spectroscopic techniques and, in some cases, elemental analysis; computer modelling has also been used to explore conformational effects and complex stability. Numerous MIP's, containing nickel(II) complexes of the bidentate ligands, have been prepared, using ethylene glycol dimethylacrylate (EGDMA) as the cross-linker, azobis(isobutyronitrile) (AlBN) as the polymerization initiator and MeOH as the porogenic solvent. The template nickel(II) ions were leached out with conc. HCI, and the nickel(II) selectivity [in the presence of Fe(Ill)] of the nickel-imprinted polymers was examined by ICP-MS analysis. The ICP-MS data indicate that the MIP's examined exhibit extremely high selectivity for nickel over iron. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Orientador: Nelson Ramos Stradiotto / Banca: Hideko Yamanaka / Banca: Luiz Henrique Mazo / Resumo: O óleo fúsel é o co - produto da destilação do etanol e é formado pela mistura de álcoois superiores (álcoois com mais de 3 carbonos), ésteres, aldeídos, entre outros . O volume de óleo fúsel produzido em média é 2,5 L de óleo fúsel por 1000 L de etanol, sendo utilizado como combustível nas caldeiras das usinas, bem como precursores de ésteres utilizados em indústrias de cosméticos e em fabricação de plásticos. O presente trabalho teve como objetivo desenvolver um sensor eletroq uimico (GCE/ RGO /AuNP/MIP) baseado em polímeros molecularmente impressos (MIP), utilizando o pirrol (Py) como monômero, contendo nanopartículas de ouro (AuNP) e óxido de grafeno reduzido ( R GO ) para a de terminação do álcool isoamílico, um dos componentes do óleo fusel. Foram realizados estudos eletroquímicos, como estudo de velocidade de varredura, para determinar reversibilidade do sistema e diagnosticar o controle do processo eletródico. Após os estudos eletroquímicos, foram realizadas caract e rizaç ão morfol ógica por Microscopia Eletrônica de Varredura com Canhão de Emissão de Eletrons c om efeito de campo (MEV - FEG) e caracterização eletroquimica por Espectroscopia de Impedancia Eletroquímica (EIS). A pós a caracterização, foi avaliada a performance analítica do sensor GCE/ RGO /AuNP/MIP, utilizando um intervalo de concentração de 1,0 × 10 - 7 até 1,0 × 10 - 4 mol L - 1, encontra ndo um limite de detecção de 8,2 × 10 - 8 mol L - 1 . F oi determinada a concentração de álcool isoamí lico em amostra de óleo fúsel pelo método de adição de padrão e o valor encontrado foi de 1,6 ×10 - 4 mol L - 1 . O método foi validado através de ensaio de recuperação, mostrando que o sensor desenvolvido é promissor para a utilização em determinação de álcool isoamílico em óleo fúsel. / Abstract: The fusel oil is co - product of the distillation of ethanol and is formed by the mixture of higher alcohols (alcohols having more than 3 carbons) esters, aldehydes, etc. The volume of fusel oil produced on average is 2.5 L fusel oil by 1000 L of ethanol, used as fuel in the boilers of the plants, as well as esters of precursors used in the cosmetics and plastics manufacturing. This study aimed to develop an electrochemical sensor (GCE/ RGO /A u NP/MIP) based on molecularly imprinted polymers (MIP), using pyrrole (Py) as the monomer, containing gold nanoparticles (AUNP) and reduced graphene oxide (RGO) for determining the isoamyl alcohol, one of fusel oil compo nents. They were conducted electrochemical studies, such as study of scanning speed, to determine system reversibility and diagnose the control of the electrode process. After the electrochemical studies were conducted morphological caractrização by Scanni ng Electron Microscopy with Electrons Emission Cannon with field effect (SEM - FEG) and electrochemical characterization by spectroscopy Electrochemical Impedance (EIS). After the characterization, the analytical performance of the GCE/ RGO /AuNP/MIP sensor wa s evaluated using a concentration range of 1.0×10 - 7 to 1.0×10 - 4 mol L - 1, encountering a detection limit 8.2×10 - 8 mol L - 1 . Was determined the concentration of isoamyl alcohol in a sample of fusel oil by standard addition method and the value found was 1.6×1 0 - 4 mol L - 1 . The method was validated by recovery test, showing that the sensor is designed promising for use in determining isoamyl alcohol fusel oil. / Mestre

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

T. pallidum can survive a primary immune response and continue growing in the host for an extended period of time. T. pallidum is thought to bind serum fibronectin (FN) through Tp0483 on the surface to obscure antigens. A Tp0483 fragment (rTp0483) was adsorbed onto functionalized self-assembled monolayers (SAMs) with FN. FN capture by adsorbed rTp0483 depended greatly on surface chemistry with COO- groups being best for FN binding. Hemocompatibility was determined by analysis of plasma protein adsorption, intrinsic pathway activation, and platelet activation. rTp0483+FN bound an equal or lesser amount of fibrinogen (Fg), human serum albumin (HSA), and factor XII (FXII) compared to rTp0483 or FN alone and adsorption of rTp0483 prior to FN greatly decreased platelet activation. Inhibition of protein binding and platelet activation suggested an attenuated hematological response. Biocompatibility of rTp0483 and FN coated surfaces was characterized by macrophage uptake of protein coated polystyrene microspheres (PSMs), macrophage adsorption onto protein coated surfaces, cytotoxic effects of adsorbed rTp0483 and FN, and TNF-α and NO2- release in macrophages stimulated with rTp0483 and FN adsorbed and in solution. Addition of FN to rTp0483 on plain and COO- PSMs reduced phagocytosis compared to rTp0483 alone and on plain PSMs compared to FN alone. On plain PSMs addition of FN to adsorbed rTp0483 decreased TNF-α generation. Adsorption of rTp0483 before FN on large, flat COO- surfaces decreased macrophage adsorption and TNF-α and NO2- generation. High concentrations of rTp0483 were mildly cytotoxic to macrophages. FN binding by Tp0483 on T. pallidum likely plays a role in antigenic disguise and rTp0483+FN coatings may potentially inhibit FN and rTp0483 specific interactions with macrophages. Molecularly imprinted polymer coatings were also examined for biomaterial development. Fouling resistant 2-methacryloyloxyethyl phosphorylcholine (MPC) was imprinted with bovine serum albumin (BSA) protein templates to facilitate BSA specific binding. The BSA template was constructed and verified and BSA specific binding quantified using quartz crystal microbalance (QCM) and enzyme linked immunosorbent assay (ELISA). BSA imprinted coatings were determined to bind significantly more BSA than nonfouling MPC controls demonstrating the feasibility of targeted protein capture.

Les glycosaminoglycannes (GAGs) sont des molécules polysaccharidiques polysulfatées intervenant dans des processus aussi variés que la prolifération, différenciation ou migration cellulaire, la coagulation sanguine ou l‟infection virale. Il est généralement admis qu‟une séquence particulière de GAG doit être associée à une fonction biologique spécifique. Les structures chimiques globales des GAGs sont connues. Cependant, contrairement au séquençage des gènes ou des protéines, la détermination de la séquence saccharidique exacte impliquée dans une fonction biologique particulière n‟est encore pas possible. Le séquençage « glycomique » constitue donc un enjeu majeur. L‟une des technologies les plus novatrices pour aborder ce problème de séquençage des GAGs semble être l‟impression moléculaire. En effet, elle permet d‟obtenir des polymères (MIPs pour Molecular Imprinted Polymer) spécifiquement imprimés par la forme structurale d‟une molécule cible.En nous appuyant sur des travaux antérieurs réalisés avec des modèles saccharidiques sulfatés simples, nous avons appliqué cette technologie à la reconnaissance de glycannes sulfatés complexes d‟intérêt biologique tels qu‟une héparine de bas poids moléculaire ou un mimétique ayant une activité anticoagulante. Il a été démontré une reconnaissance spécifique et sélective selon la molécule étudiée à l‟aide de MIPs spécialement conçus pour chaque GAG. De plus, nous avons obtenu des MIPs qui, en immobilisant temporairement un sucre, permettraient leur substitution de façon stéréospécifique. La détermination des conditions optimales de synthèse des MIPs s‟est avéré une étape nécessaire à l‟obtention d‟une bonne reconnaissance. Ces travaux ouvrent des perspectives d‟application de la technique d‟impression moléculaire à l‟analyse des séquences de GAGs d‟intérêt biologique / Glycosaminoglycans (GAGs) are polysulfated polysaccharide molecules involved in many biological processes such as cellular proliferation, differentiation or migration, blood clotting or viral infection. It is generally admitted that a particular GAG sequence is connected to a specific biological function. Depending on their composition in disaccharides, GAGs are classified into subfamilies whose overall chemical structures are known. Unlike gene or protein sequencing, determination of the exact saccharidic sequence involved in a particular biological function is not yet possible with the available technological tools. "Glycomics" is a real challenge nowadays. One of the most innovative technologies to achieve this goal seems to be the molecular imprinting. Indeed, it provides polymers (MIPs for Molecular Imprinted Polymer) imprinted by the structural form of a target molecule.Based on previous studies performed with simple sulfated saccharides, this technology has been applied to the recognition of complex sulfated glycans. MIPs were achieved demonstrating specific and selective recognition for a Low Molecular Weight Heparin or a synthetic anticoagulant mimetic. Other MIPs were able to temporally immobilize sugars which make them available for stereo-specific modifications. Screening of optimal synthesis conditions of MIPs appeared a necessary step to obtain a specific and selective recognition. These studies open further possibilities to analyze GAG sequences carrying biological functions by the molecular imprinting technology

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Detection of trace elements such as organic contaminants, explosive residues, and metal ions is an intellectually challenging task in science and engineering. It is also a topic of increasing importance due to its impact on society and the environment. Designing molecularly imprinted materials is one of the most promising approaches to explore sensing and detection applications. “Stimuli-sensitive” polymer materials are ideal candidates for these imprinted sensors as they are able to respond to changes in their environment and can be tailored by cross-linking the polymer chains. The responses can be amplified and transduced into measurable signals due to macromolecular properties provided by the use of a polymer. The purpose of the research in this project is to combine organic polymers with inorganic constituents to tailor the binding properties and the responses of the composite material for detection of metals ions in aqueous solutions. The research, here, is based on a thermally responsive polymer such as poly(Nisopropylacrylamide) (PNIPAM), which exhibits a well-known reversible volume phase transition in aqueous media around approximately 32°C. Combining cross-linked microgels formed from PNIPAM and its copolymers with gold nanoparticles (GNP) imparts the composite material with optical properties such as intense visible absorption due to the unique surface plasmon absorption of these small nanoparticles. The use of copolymers allows incorporation of functional groups, such as carboxylic acid, that are potential sites for binding metal ions. Cross-linking of the metal ion binding polymer imprints the metal ion in the PNIPAM microgel network. In this research, design of the composite material was investigated using copolymers of NIPAM and acrylic acid (AA), copolymers of NIPAM and glycidyl methacrylate (GMA), and interpenetrating networks of PNIPAM and PAA. A broad spectrum of polymerization conditions were studied such as changes in cross-linking density as well as changes in the synthetic procedure. Techniques such as turbidometry, ultraviolet visible spectroscopy (UV-VIS), transmission electron microscopy (TEM), and dynamic light scattering (DLS) were employed to characterize the microgels as well as their composites with GNP. Preliminary investigation of imprinting the microgels with heavy metal ions such as copper was also performed. The novel polymer-metal nanocomposites explored here will serve as an important contribution for the current ongoing research efforts in designing materials in the nano-scale capable of sensing and detecting metal ions in solution with high selectivity.

Molecularly Imprinted Polymers (MIPs) are potential generic alternatives to antibodies in diagnostics and separations. To compete with biomolecules in these technological niches, MIPs need to share the characteristics of antibodies (solubility, size, specificity and affinity) whilst maintaining the advantages of MIPs (low cost, short development time and high stability). For this reason the interest in preparing MIPs as nanoparticles (MIP NPs) has increased exponentially in the last decade. Cont/d.

Electrospun, non-woven, fibers have high surface area compared to conventional cast films. The thesis reports on the modification of electrospun fibers to concentrate and/or detect biohazards. In one study, electrospun fibers with affinity for the lectins ricin/concanavalin A were fabricated using molecular imprinting or through binding to immobilized antibodies, aptamers or lectin specific sugars. Attempts to fabricate imprinted electrospun fibers through inclusion of the template during the spinning process proved unsuccessful. However, electrospun fibers with affinity towards biohazards were successfully produced by post-modification with antibodies, aptamers or lectin specific saccharides. With regards to the latter, dextran, mannose and chitosan were immobilized onto nylon electrospun fibers that were partially hydrolyzed or treated with cyanuric chloride. The sugar-modified fibers bound significantly higher amount of lectins. Electrospun fibers were also fabricated, post modified with antibodies to capture and detect Salmonella. The study has illustrated the utility of electrospun fibers for biohazard diagnostics. / The National Center for Food Protection and Defense. USA