Orientador: Oswaldo Luiz Alves / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T15:35:46Z (GMT). No. of bitstreams: 1 Moraes_AnaCarolinaMazarinde_D.pdf: 5504556 bytes, checksum: ff8566e313e82701925549e2ecd544ab (MD5) Previous issue date: 2015 / Resumo: O óxido de grafeno (GO) é uma forma quimicamente modificada de grafeno que possui grupos funcionais contendo oxigênio (epóxi, carboxila, carbonila, e hidroxila) distribuídos sobre a base e as bordas de suas folhas. Devido à abundância dos grupamentos oxigenados, o GO tem sido usado como uma plataforma para suportar e estabilizar nanoestruturas metálicas, tais como nanopartículas de prata (NPAgs), visando aplicações biológicas. Além disso, devido à sua excelente capacidade de dispersão e elevada área superficial, o GO tem sido considerado uma carga promissora para a construção de compósitos poliméricos. Neste trabalho, relatamos a síntese do GO e dos nanocompósitos de óxido de grafeno funcionalizado com NPAgs (GO-Ag) os quais podem ser utilizados como agentes antibacterianos de amplo espectro. O GO foi sintetizado por meio do método de Hummers modificado, e o GO-Ag foi preparado através da redução in situ dos íons de prata por citrato de sódio. As folhas de GO foram funcionalizadas com NPAgs esféricas de diâmetro médio de 9,4 nm. Estes nanocompósitos exibiram excelente atividade antimicrobiana contra as principais bactérias em ambiente hospitalar, tais como Escherichia coli, Enterococcus faecalis, Acinetobacter baumannii, e Staphylococcus aureus resistente à meticilina. Os nanocompósitos GO-Ag também foram aplicados como eficazes agentes antimicrobianos a fim de evitar a proliferação bacteriana em membranas de micro e ultrafiltração. Neste sentido, membranas antimicrobianas de acetato de celulose (CA) foram fabricadas a partir da incorporação de GO e GO-Ag na matriz polimérica (CA-GOAg). Após a funcionalização, as membranas permeáveis modificadas com GO-Ag foram capazes de inativar cerca de 90% das células de E. coli em comparação com as membranas de CA não modificadas. Os resultados sugerem que a incorporação de nanocompósitos GO-Ag é uma abordagem promissora para controlar o desenvolvimento da adesão bacteriana em membranas de purificação de água. Com relação à demanda de novos materiais com elevada estabilidade e com capacidade de proteção contra radiação ultravioleta (UV), foram fabricados filmes compósitos transparentes a partir de acetato de celulose e óxido de grafeno. A caracterização físico-química revelou que as folhas de GO estão bem dispersas por toda a matriz polimérica, proporcionando filmes compósitos lisos e homogêneos. Em comparação com os filmes pristinos de CA, os filmes compósitos exibiram melhor capacidade de proteção contra radiação UV combinado com transparência óptica à luz visível, o que reforça a sua aplicação como revestimentos transparentes com proteção UV para alimentos, produtos farmacêuticos, biomédicos, e produtos eletrônicos / Abstract: Graphene oxide (GO) is a chemically modified form of graphene that possesses oxygen-containing groups (epoxy, carboxyl, carbonyl, and hydroxyl) distributed on the plane and edges of the sheets. Owing to the abundance of oxygenated groups, GO has been used as a platform to support and stabilize metallic nanostructures such as silver nanoparticles (AgNPs), aiming biological applications. In addition, GO has been considered a promising material for building polymeric composites because of its excellent dispersibility and high surface area. In this work, we report the synthesis of GO and GO functionalized with AgNPs (GO-Ag) for use as a broad-spectrum antibacterial agent. GO was synthesized through the modified Hummers method, and the GO-Ag was prepared through the in situ reduction of silver ions by sodium citrate. Spherical AgNPs with average size of 9.4 nm were found well-dispersed throughout the GO sheets. This nanocomposite exhibited excellent antimicrobial activity against common nosocomial bacteria such as Escherichia coli, Enterococcus faecalis, Acinetobacter baumannii, and methicillin-resistant Staphylococcus aureus. GO-Ag nanocomposites were also applied as an effective antimicrobial agent in order to prevent the bacterial proliferation on micro and ultrafiltration membranes. Cellulose acetate (CA) membranes were then fabricated from the incorporation of GO and GO-Ag into the polymeric matrix (CA-GOAg). After functionalization, the permeable CA membranes modified with GO-Ag were able to inactivate mostly 90% of E. coli cells compared to the non-modified CA membranes. The results suggest that the incorporation of GO-Ag nanocomposites is a promising approach to control biofouling development in water purification membranes. Concerning the demand for novel ultraviolet shielding materials with high stability, transparent and UV-shielding composite films were fabricated by casting a mixture of GO with cellulose acetate (CA). The physicochemical characterization revealed that GO sheets were well-dispersed throughout the polymeric matrix, providing smooth and homogeneous composite films. By comparison with pristine CA films, the composite films displayed an improved UV-shielding capacity combined with optical transparency under visible light, which underscores their application as transparent UV-protective coatings for food, pharmaceutical, biomedical, and electronic products / Doutorado / Quimica Inorganica / Doutora em Ciências

Orientadores: Fernando Antônio Santos Coelho, Marcelo Lancellotti / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T15:24:47Z (GMT). No. of bitstreams: 1 Martins_LucimaraJulio_D.pdf: 12763777 bytes, checksum: 670ed8192951c8aad06412cfaae2c843 (MD5) Previous issue date: 2014 / Resumo: Substâncias que possuem em sua estrutura um padrão espiro-hexadienona, normalmente apresentam importantes atividades biológicas. Na maioria dos casos, essa atividade biológica está intimamente associada à presença desse padrão estrutural. Neste trabalho de doutorado descrevemos a síntese de espiro-hexadienonas com diferentes padrões estruturais e a avaliação do perfil biológico dessas substâncias como agentes anti-bacterianos e anti-tumorais. Tomando por base uma metodologia previamente descrita pelo nosso grupo de pesquisa e otimizada nesse trabalho, sintetizamos uma série de espiros com diferentes substituintes, com rendimentos globais que variaram de 12-43%. A metodologia utilizada se baseia em uma reação de oxidação fenólica, mediada por reagentes de iodo hipervalente, de 'beta'-cetoésteres adequadamente funcionalizados em posição'alfa', com um substituinte 4-hidroxibenzil. Esses últimos foram preparados, de forma eficiente e direta, através de uma reação de Mizoroki-Heck, utilizando adutos de Morita-Baylis-Hillman na presença de um catalisador de paládio, desenvolvido por Nájera. A síntese de uma série de espiro-hexadienonas mono- e dibromadas também foi descrita nesse trabalho. Para atingirmos esse objetivo, os mesmos ?-cetoésteres funcionalizados foram seletivamente bromados no anel fenólico. Esses produtos bromados foram também utilizados como substrato para etapa de oxidação fenólica, fornecendo espiro-hexadienonas mono- e dibromadas com rendimentos que variaram de 5 a 44%. A estrutura das espiro-hexadienonas dibromadas foi confirmada por análise de difração de raios-X. Descrevemos, ainda, a síntese de compostos aza-espiros utilizando oximas com configuração Z. Essas oximas foram utilizadas como substrato na oxidação fenólica, fornecendo espiro-hexadienonas contendo em sua estrutura uma nitrona. A estrutura destes aza-compostos também foi confirmada por análises de difração de raios-X. A avaliação do perfil biológico da biblioteca de compostos sintetizados demonstrou que estas moléculas são altamente citotóxicas, e que exibem atividade antibacteriana contra bactérias Gram positivas, incluindo linhagens de S. aureus resistentes à Meticilina. Interessados em avaliar a relação estrutura-atividade, realizamos a redução do intermediário 'alfa'-(4-hidroxibenzil)-'beta'-cetoéster visando obter um espiro com o anel de cinco membros saturado. O espiro obtido desta redução perdeu completamente a atividade antibacteriana, sugerindo que a olefina na posição 2-3 faça parte de um grupo farmacofórico. A atividade antitumoral das espiro-hexadienonas sintetizadas também foi testada, demonstrando um excelente perfil anti-proliferativo. Algumas dessas moléculas inibem a tubulina, aparentemente no sítio de ligação da colchicina. Por fim, é possível afirmar que este trabalho permitiu a síntese e avaliação biológica de novas moléculas espiro, que futuramente poderão servir como protótipos para o desenho de novos fármacos antibacterianos e/ou antitumorais / Abstract: Based on a methodology of synthesis for spirohexadienones preparation, recently developed in our lab, this work was done aiming to increase spirohexadienones' structural diversity and to make an antimicrobial and antitumor biological analysis of these molecules. This way, a series of spiros was synthesized with different substituents, optimizing the previous strategy developed, aiming to improve global yields. Two sequences of analogs were prepared through bromination of phenolic rings of the intermediary 'alpha'-(4-hydroxybenzyl)-'beta'-ketoesters, which were later cyclized to afford the corresponding spirohexadienones. The spiro di- and mono-brominated were obtained through this method. The structures of the di-brominated spiros were confirmed by X-ray diffraction analysis. Also oximes were prepared from the 'alpha'-(4-hydroxybenzyl)-'beta'-ketoesters that enabled access to aza-spiros, containing nitrones. These aza-compounds structures were also confirmed by X-ray diffraction analysis. The evaluation of the biological profile of the synthesized compounds library demonstrated that these molecules are highly cytotoxic and that they exhibit antibacterial activity against Gram positive bacteria, including strains of S. aureus resistant to Methycillin. In order to evaluate the relation structure-activity, the reduction of the intermediary 'alpha'-(4-hydroxybenzyl)-'beta'-ketoesters was made to obtain a spiro with the saturated ring of five members. The spiro obtained employing this reduction completely lost the antibacterial activity. The antitumor activity of the synthesized spirohexadienones was also tested, demonstrating an excellent antiproliferative profile. Some of these molecules inhibited tubulin, apparently in the binding site of colchicine. Lastly, it is possible to affirm that this work provided the synthesis and biological evaluation of new spiro molecules, which hereafter may serve as prototype for the design of new antibacterial and/or antitumor drugs / Doutorado / Quimica Organica / Doutora em Ciências

This diploma thesis summarizes knowledge from the fields of synthesis, characterization and application of titanium dioxide nanotubes and its combination with silver nanoparticles for biomedical purposes. Basic protocols of working with cell cultures and bacteria are also included. Experimental part of this diploma thesis focuses mainly on the synthesis of tubular structures made of titanium dioxide via anodic oxidation of 500nm titanium layer and their subsequent decoration with silver by electrodeposition. Last section of the experimental part is devoted to testing of antibacterial properties of the new material and examining the effect of different silver concentrations on the adhesion of MG-63 cells. All results are compared to reference samples consisting of titanium dioxide nanotubes without silver.

>Magister Scientiae - MSc / Nanotechnology has emerged as an elementary division of modern science and stemmed directly from green chemistry twelve basic concepts, it receives global attention due to its unique character and ample applications. It also has great potential to mitigate the challenges they face in various fields, especially medical sector. Nanodrugs are increasingly considered as a potential candidate to carry therapeutic agents safely into a targeted compartment in an organ, particular tissue or cell. In this study, twenty (20) Libyan plants were selected and evaluated for their potential to synthesis gold and silver nanoparticles. The screening of the different plant extracts was performed using 96 well plate method at 25 °C and 70 °C. The NPs formation was confirmed and characterized using UV- Vis, DLS, HR-TEM and EDX. A well-defined NPs were obtained at high temperature (70 °C). The Au NPs had an average diameter of 92 nm at 25 °C and 66 nm at 70 °C. The zeta potential values were observed to be negative (-14 to -24) and indicate the stability of the Au NPs. The HR-TEM showed polydispersity, which decreased at higher temperature (70 °C). The stability of Au NPs in nutrient broth prior was conducted as well. All the Au NPs under study showed stability, only minimal changes in the UV-Vis spectra can be observed. Two plant extract viz Pistacia atlantica, Junipers phoenicea showed consistent results and forming stable and smaller NPs compared to others, both of the plant extracts and the corresponding NPs were tested against Streptococcus mutans and showed MIC value ~ 49 g/mL. In case of silver NPs, two plant extracts viz J. phoenicea, Rosmarinus officinalis, showed superior results than the others; both plants produced stable and small Ag NPs. The antibacterial activity against S. mutans demonstrated MIC valus ~ 50 g/mL. The synthesised NPs showed a promising bioactivity for developments of new antibacterial agents against S. mutans strains. Dose-dependent activity was observed for the tested NPs.

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Study program: Pharmacy Author: Simona Novotná Supervisor: RNDr. Klára Konečná, Ph.D. Title of diploma thesis: Advanced antibacterial activity testing of candidate newly synthesized compounds Background: The aim of this thesis was to perform an extended study of the antibacterial activity of selected newly synthesized rhodanine derivatives. In this study, activity against clinical isolates of bacterial strains of the genus Staphylococcus and Enterococcus was evaluated. The main part of the work also includes the evaluation of the antibacterial activity of one selected substance in combination with commercially available antibiotics using the checkerboard method. Methods: Evaluation of the antibacterial activity of tested substances was performed using the broth microdilution method according to EUCAST guidelines (with minor modifications). The activity of these substances was evaluated against clinical isolates of bacteria of the genera Staphylococcus and Enterococcus and one Staphylococcus aureus MRSA reference strain (ATCC 43300, CCM 4750). For a selected compound with a demonstrably promising antistaphylococcal effect, the combined effect of this substance was tested with three...

Introduction: Orthodontic treatment may cause an increased accumulation of cariogenic bacteria. An orthodontic resin with antibacterial properties may inhibit bacterial growth around the brackets. The aims of this in-vitro study were to compare the antibacterial and mechanical properties of the newly introduced orthodontic resin containing selenium with a standard resin and a resin modified glass ionomer (RMGI). Methods: Three orthodontic materials were tested (SeLECTDefense; TransbondXT, Fuji Ortho-LC). The antibacterial properties of these materials were evaluated by studying the bacterial growth in liquid media (BG) and agar diffusion (AD) tests. In the BG testing, 100 adhesive discs (3mmx2mm) were created of each material. Five discs were then placed into each vial containing 0.5ml of brain-heart-infusion broth and 2.5µl of streptococcus mutans (MS)(n=20). Following incubation (37°C, 24hours), the vials were placed in a Spectrophotomoter (Genesys 20) at 600 nm to determine bacterial growth by measuring the optical density (OD). In the AG testing, agar plates were inoculated with 100µl of MS in brain heart infusion agar. Fifteen adhesive discs (6mmx2mm) of each material were prepared and placed into groups of five on 3 agar plates. Following incubation (37°C, 48 hours), the agar plates were visually inspected for zones of bacterial inhibition. The mechanical properties were evaluated using shear bond strength testing (SBS) and an adhesive remnant index scoring (ARI). Sixty human premolars were randomly assorted into groups of 20 for each material (n=20). The brackets were bonded following the manufacturers' instructions. Debonding was performed using a universal testing device (Instron)(crossheadspeed 5mm/min). The mode of failure was evaluated using a stereomicroscope (OlympusSZX7) and scored 0-to-3 for remaining adhesive on enamel. Results were statistically analyzed using Welsch's ANOVA, One way ANOVA, Tukey's Kramer and Tukey's HSD tests. Results: In BG, the resin containing selenium (SD) promoted more bacterial growth (OD=0.427) compared to the standard resin (XT) (OD= 0.222) and RMGI (OD=0.275). In AD, no zones of inhibition were observed which means that no antibacterial agent was released from any of the orthodontic adhesives. In SBS, SD (11.63±2.07MPa) showed statistically lower bond strength than XT (15.16±4.68MPa) but both resins were in the clinically acceptable range. RMGI (6.03±3.95MPa) showed a statistically lower bond strength at a clinically unacceptable degree. Debonding was mostly at the bracket-adhesive interface for SD (ARI=2&3) meaning that most of the adhesive remained on the enamel. In XT and RMGI groups, debonding occurred mostly at the adhesive-enamel interfaces (ARI=0&1). Conclusion: Within the limitations of this in vitro study, the resin containing selenium did not show any favorable antibacterial properties in comparison to the other materials. None of the materials, including fluoride-releasing RMGI, caused bacterial inhibition in their surroundings. The resin containing selenium showed clinically acceptable but statistically lower bond strength as compared to standard resin but its mode of failure was more favorable because most of the adhesive remained on enamel.

No / A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1H-benzo[d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal activity against the selected fungal strains. They displayed equivalent or greater potency in their MIC values than amphotericin B. The 5-halobenzimidazole derivatives could be considered promising broad-spectrum antimicrobial candidates that deserve further study for potential therapeutic applications.

The fungus growing termite species Macrotermes bellicosus (M. bellicosus) is used in nutrition and traditional medicine in the Republic of Benin for the treatment of infectious and inflammatory diseases. Previous findings demonstrated evidence of anti-inflammatory and spasmolytic properties of M. bellicosus. The aim of the present study was to evaluate the antimicrobial potential of different extracts of M. bellicosus samples and determine the chemical profile of an ethanolic M. bellicosus extract. Chemical profiling was conducted using centrifugal partition chromatography and 13C-NMR, followed by MALDI-TOF MS. Major identified compounds include hydroquinone (HQ), methylhydroquinone (MHQ), 3,4-dihydroxyphenethyl glycol (DHPG), N-acetyldopamine (NADA) and niacinamide. The fatty acid mixture of the extract was mainly composed of linoleic and oleic acid and highlights the nutritional purpose of M. bellicosus. Using the Kirby–Bauer disc diffusion and broth microdilution assay, an antibacterial activity of M. bellicosus samples was observed against various clinical strains with a highest growth inhibition of S. aureus. In addition, HQ and MHQ as well as fractions containing DHPG, niacinamide and NADA inhibited S. aureus growth. The reported antimicrobial activity of M. bellicosus and identified active substances provide a rationale for the traditional medicinal use of M. bellicosus.

La sicurezza e la qualità degli alimenti sono tutt’ora un problema critico per i paesi in via di sviluppo. Le diete a basso contenuto di acido folico, per esempio, possono causare gravi problemi di salute, soprattutto nei bambini. Gravi disturbi legati al tubo neurale (DTN) nei neonati possono derivare infatti da madri che hanno insufficiente apporto di acido folico (400-600 g / giorno) durante il periodo di gravidanza. Inoltre, se non adeguatamente protetti o trattati, I prodotti alimentari possono essere vettori di funghi e batteri patogeni rappresentando una fonte potenziale di malattie per l’uomo e una perdita economica per le industrie agro-alimentari. Nella seguente tesi si è quindi quindi studiato il ruolo di batteri lattici selezionati (LAB) in grado di aumentare il valore nutrizionale del latte attraverso la produzione di acido folico durante il processo di fermentazione. Inoltre, ci si è concentrati sul loro uso come "bio-conservanti" contro funghi e batteri, attraverso la sintesi di composti antimicrobici (batteriocine) in grado di inibire la crescita di funghi filamentosi e/o batteri patogeni. / The safety and quality of food are still a critical issue in developing countries. Diets with a low content of folic acid, for example, may cause serious health problems, especially in children. Severe disorders related to neural tube (NTD) in infants may arise from mothers having inadequate intakes of folic acid (400-600 g/dia) during the mother pregnancy period. Moreover foods, when not properly protected or treated, can be vectors of pathogenic fungi and bacteria thereby representing a potential source of human diseases and an economical loss for the food industry. In the following thesis we have therefore investigated the role of selected lactic acid bacteria (LAB) in increasing the nutritional value of milk through the production of folic acid during the fermentation process. In addition, we focused on their use as “bio-preservatives” against fungal and bacterial spoilage, through the synthesis of antimicrobial compounds (bacteriocins) able to inhibit the growth of filamentous fungi and /or pathogenic bacteria.

<p>The aim of this study was to better understand the role of conditioned medium (CM) in Spodoptera frugiperda Sf9 insect cell proliferation and recombinant protein production using the baculovirus expression system.</p><p>CM was found to stimulate cell proliferation. Addition of CM and 10 kDa CM filtrate to an Sf9 culture decreased the lagphase and the maximum cell density was reached earlier than for cultures in fresh medium. The positive effect of 10 kDa CM filtrate showed that CM contains at least one small growth promoting factor. The effect was not eliminated by trypsin treatment. Addition of CM or 10 kDa CM filtrate to Sf9 cultures was found to have a negative effect on the recombinant protein production. The effect was thought to be indirect and most probably via the impact of CM on cell physiology. CM was also found to contain proteinase activity. The proteinase was identified as Sf9 cathepsin L. A proform with a molecular mass about 49 kDa and two active forms at about 39 and 22 kDa were found. The role of cathepsin L in Sf9 cultures is not yet clear. However, the knowledge of the presence of this proteinase in CM can be of great value for improving product quality and yield. Further, CM was found to have other properties as well: a concentrated fraction of CM exhibited strong antibacterial activity towards Bacillus megaterium and a weaker activity towards Escherichia coli. B. megaterium lysed rapidly after incubation in the CM fraction.</p><p>Repeated subculturing of Sf9 cells provoked a switch in growth kinetics. After 30-45 passages the cells started to proliferate earlier after inoculation and addition of CM had no longer a growth stimulating effect. However, CM still stimulated growth of a culture with low passage (LP) number (up to 45 passages). High passage cells (HP cells, over 100 passages) displayed a shorter lagphase than LP cells and the culture reached the maximum cell density 24-48 h earlier. Cell cycle analysis showed that the Sf9 cells were transiently synchronised in the G2/M phase 10 h after inoculation, before proliferation was initiated. This synchronisation was more pronounced for HP cells than for LP cells, which correlated to a higher recombinant protein production in baculovirus infected HP cells than in LP cells. Synchronisation of cells in G2/M by yeastolate-limitation before infection with baculoviruses suggested that the degree of synchronisation is connected to the cell density dependent decrease in recombinant protein production of Sf9 cultures.</p>