This thesis describes the development of a high-throughput approach towards the encapsulation of cancer cells in biopolymer microgels with tunable mechanical properties. In particular, this thesis is focused on: i) the high-throughput generation of biopolymer microgels with tunable mechanical properties ii) the measurement of the mechanical properties of the microgels, and iii) the high-throughput encapsulation of a cancer cell line within biopolymer gels. The microgels will be generated by (i) introducing in a microfluidic device two distinct streams of biopolymer solutions; (ii) mixing the streams; (iii) emulsifying the biopolymer and (iv) using thermosetting to transform the droplets in situ into microgels. By applying a compression force to the hydrogel microbead and measuring its deformation, the Young’s modulus and relaxation time of the microgel can be examined. The properties of cells were examined within the gels using various spectroscopic techniques such as absorption (UV-Vis) and fluorescence microscopy (fluorescent microscopy, confocal microscopy).

This thesis describes the development of a high-throughput approach towards the encapsulation of cancer cells in biopolymer microgels with tunable mechanical properties. In particular, this thesis is focused on: i) the high-throughput generation of biopolymer microgels with tunable mechanical properties ii) the measurement of the mechanical properties of the microgels, and iii) the high-throughput encapsulation of a cancer cell line within biopolymer gels. The microgels will be generated by (i) introducing in a microfluidic device two distinct streams of biopolymer solutions; (ii) mixing the streams; (iii) emulsifying the biopolymer and (iv) using thermosetting to transform the droplets in situ into microgels. By applying a compression force to the hydrogel microbead and measuring its deformation, the Young’s modulus and relaxation time of the microgel can be examined. The properties of cells were examined within the gels using various spectroscopic techniques such as absorption (UV-Vis) and fluorescence microscopy (fluorescent microscopy, confocal microscopy).

Poly-γ-glutamic acid (γ-PGA) is a naturally occurring biopolymer made up of repeating units of glutamic acid and can be potentially used for multiple applications. This study compared the production of γ-PGA by eight bacteria (B. subtilis 23856, B. subtilis 23857, B. subtilis 23858 B. subtilis 23859, B. subtilis natto, B. licheniformis 1525, B. licheniformis 6816 and B. licheniformis 9945a) in GS and E media. B. subtilis natto and B. licheniformis 9945a have been investigated extensively for γ-PGA production, however, the remaining six have not previously been used. Using the eight bacteria, yields of up to 22.3 g/l were achieved in shake flasks. On characterization, it was observed that γ-PGA with different properties (crystallinity, acid/salt form and molecular weights ranging from 3,000 Da to 871,000 Da) was produced. Production of γ-PGA by B. subtilis natto in GS medium was scaled up using a fermenter and was tested for novel probiotic applications. The survival of probiotics during freeze drying, storage and ingestion was improved by combining them with a γ-PGA matrix. For L. paracasei, 10% γ-PGA protected the cells significantly better (P < 0.05) than 10% sucrose during freeze drying, whereas for B. longum and B. breve, it showed comparable cryoprotectant activity (P > 0.05) to 10% sucrose. This study also demonstrated the potential use of a non-dairy foodstuff (orange juice) for delivery of probiotics. Two Bifidobacteria strains protected with γ-PGA survived significantly better (P < 0.05) in orange juice for 39 days, with a log reduction in viability of less than 2.99 CFU/ml, when compared to unprotected cells, which showed complete loss in viability by day 20. In addition, γ-PGA protection improved survival of Bifidobacteria in a solution mimicking the environment of the stomach. γ-PGA-protected Bifidobacteria showed little (< 0.47 log CFU/ml) or no loss in viability when stored in simulated gastric juice (pH 2.0) for four hours, whereas unprotected cells died within two hours.

Nanopores (1 – 10 nm diameter) constructed in solid-state membranes, have shown promise as next-generation biopolymer analysis devices offering both high resolution and high throughput. One promising application of nanopores is in the analysis of nucleic acids, such as DNA. This involves translocation experiments in which DNA is placed in an ionic solution and is forced through a nanopore with the aid of an applied electric field. The modulation of ionic current through the pore during DNA translocation can then be correlated to various properties of the biopolymer such as the length. To optimally design and operate nanopore devices, it would be advantageous to develop an accurate computer simulation methodology to predict the physics of the translocation process. Hence, I have developed a physically accurate, computationally efficient simulation methodology to predict and analyze the physics of biopolymer translocation through solid-state (silicon nitride) nanopores. The overall theme of this thesis is to use this simulation methodology to thoroughly investigate important issues in the physics underlying translocation experiments and thereby determine the effects of key structural and operation parameters, such as nanopore dimensions, applied voltage, hydrodynamic interactions, solvent viscosity, and the polymer chain length. The results from these simulation studies can assist in not only proper nanopore design, but also help determine the proper experimental environments and parameters for nanopore operation.

Conducting polymer is a rapidly developing area of research due to its potential in combining the physical properties of polymers with electrical properties previously found only in inorganic systems. These conducting polymers owe their unique properties to a conjugated polymer backbone and become conducting upon oxidation or reduction. Melanin, a biopolymer, possess a conjugated backbone required of a conducting polymer, and has shown properties of an amorphous semiconductor. However, there has not been much study done in this area despite its potential, and this is partially due to the lack of processing methods as melanin is generally synthesised as an intractable powder. Thus, a better synthetic method was required, and a possible solution is the use of electrochemical synthesis. In our previous study we have shown that melanin can be synthesised electrochemically as a free-standing film, which was the first step towards the use of melanin as a bulk material. This project aims to continue from this preliminary work, investigating the various synthetic parameters and possible modifications as well as investigating possible applications for the electrochemically synthesised melanin film.

abstract: It is estimated that wind induced soil transports more than 500 x 106 metric tons of fugitive dust annually. Soil erosion has negative effects on human health, the productivity of farms, and the quality of surface waters. A variety of different polymer stabilizers are available on the market for fugitive dust control. Most of these polymer stabilizers are expensive synthetic polymer products. Their adverse effects and expense usually limits their use. Biopolymers provide a potential alternative to synthetic polymers. They can provide dust abatement by encapsulating soil particles and creating a binding network throughout the treated area. This research into the effectiveness of biopolymers for fugitive dust control involved three phases. Phase I included proof of concept tests. Phase II included carrying out the tests in a wind tunnel. Phase III consisted of conducting the experiments in the field. Proof of concept tests showed that biopolymers have the potential to reduce soil erosion and fugitive dust transport. Wind tunnel tests on two candidate biopolymers, xanthan and chitosan, showed that there is a proportional relationship between biopolymer application rates and threshold wind velocities. The wind tunnel tests also showed that xanthan gum is more successful in the field than chitosan. The field tests showed that xanthan gum was effective at controlling soil erosion. However, the chitosan field data was inconsistent with the xanthan data and field data on bare soil. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2011

The recycling industry which is efficiently functioning now has technical expertise, contented consumers, and resource availability and capital contributors. The potential inflow of new material into this existing system should be able to fulfill all the needs of the stakeholders involved in it. With most of the polymer wastes received from the polyethylene (PE) and polyethylene terephthalate (PET), they are available in abundant crossing the threshold quantity (Cornell, 2007) needed for the recycling process to be carried for every single polymer starting from the individual source separation till the granulation of pellets with active investment for the potential expectancy of returns in the recycling market targeting suitable consumers. Unlike other polymers like polyvinyl chloride and polypropylene (PP), biopolymers fail to fulfill the necessary criteria of being in threshold quantity to carry out the recycling process. With the very small inflow of biopolymers in the recycling industry, standalone recycling units for the same is not highly performed and appreciated. In addition to this, there are possible means and ways of the biopolymers getting infused into the conventional petrochemical polymers either through the mis-throws in manual sorting or in automated sorting. Though the studies so far don't have any substantial threatening effect over the biopolymer infusion, still it has its adversity affecting the industry by other means. The volumes of biopolymers are presently small and contamination of biopolymer in the plastic waste stream is presently not a problem. However, with increasing volumes of biopolymers, this can be a problem. Contamination could then be a future problem. This study investigates that problem and checks the truth to the claims of biopolymer infusion in the conventional post-consumer recycling systems affecting the quality of the recyclates. In order to investigate this, a biodegradable biopolymer (TPS &amp; PHA) will be mixed into a conventional polymer (PE, PP, PET) at various percentages. The mechanical and thermal properties are then measured as a function of the percentage biopolymer. In a second part of the project, the blend of conventional plastics and bioplastic is conditioned in humidity in order to simulate what will happen to a conventional polymer that has been contaminated with a biopolymer in a humid climate.

Submitted by Marcos Wanderley (marcos.wanderley@ufcg.edu.br) on 2018-07-31T20:22:18Z No. of bitstreams: 1 FILIPE SAMPAIO BATISTA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 4329942 bytes, checksum: 55ad9fec74dbaf8ba526dbb0b3c5b8ff (MD5) / Made available in DSpace on 2018-07-31T20:22:18Z (GMT). No. of bitstreams: 1 FILIPE SAMPAIO BATISTA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 4329942 bytes, checksum: 55ad9fec74dbaf8ba526dbb0b3c5b8ff (MD5) Previous issue date: 2017-03-08 / CNPq / Neste trabalho são avaliados dois polímeros à base de óleo de soja como redutores de filtrado em fluidos de perfuração sintéticos à base N-parafina, visando sua utilização na perfuração de poço de petróleo e gás. Realizou-se o estudo em duas etapas: primeiramente, a caracterização dos polímeros ( POS1A e POS2A) por meio das análises de espectroscopia no infravermelho por transformada de Fourier (FTIR), microscopia óptica (MO), termogravimétrica (TGA), térmica diferencial (DTA) e ensaio de toxicidade; na segunda etapa, a avaliação dos polímeros como redutores de filtrado por meio das propriedades reológicas (viscosidade aparente (VA), viscosidade plástica (VP), limite de escoamento (LE)), da estabilidade elétrica (EE) e do volume de filtrado HPHT (VF) de acordo com as normas da API. Ainda nesta etapa, como critério de balizamento, foram avaliados fluidos sem redutores e com redutor de filtrado padrão, utilizado pela indústria. Os resultados indicam que o polímero POS2A possui maior diâmetro médio de partículas e melhor distribuição dos grãos que POS1A. Os espectros de FTIR dos polímeros indicam a existência de funções carboniladas, ácido carboxílico e éster. A termogravimetria indicou que os polímeros possuem boa estabilidade térmica. O polímero POS2A apresentou baixíssima toxicidade e o POS1A nenhuma toxicidade. Os fluidos apresentaram curvas de fluxos de plásticos de Bingham. Os polímeros não apresentaram influências significativas sobre as propriedades de VA, VP, LE e EE. A presença de polímeros no sistema reduziu os volumes de filtrado HPHT dos fluidos e foram competitivos com o redutor utilizado pela indústria, entretanto, superaram os resultados apenas para os fluidos com concentração de 2g de POS2A, na razão óleo/água 60/40. / In this work we evaluated two soybean oil-based polymers as filtrate reducers in synthetic N-paraffin-based drilling fluids, aiming their use in oil and gas well drilling. This study was conducted in two stages: First, the characterization of the polymers (POS1A and POS2A) by analysing through the Fourier spectroscopy analysis in transformed infrared (FTIR), optical microscopy (OM), thermogravimetric (TGA), differential thermal ((DTA) and toxicity test; In the second stage, the evaluation of the polymers as filtration reducers by means of the rheological properties (apparent viscosity (AV), plastic viscosity (PV), flow limit (FL)), electrical stability (ES) and HPHT filtrate volume (FV) in accordance with API standards. Still in this stage, as a beacon criterion, we evaluate fluids with no reducers and with standard filter reducer, used by the industry. The results indicate that the POS2A polymer has a higher mean particle diameter and better grain distribution than POS1A. The FTIR spectra of the polymers indicate the existence of carbonylated functions, carboxylic acid and ester. Thermogravimetry indicated that the polymers have good thermal stability. The POS2A polymer presented a very low toxicity and POS1A had no toxicity at all. The fluids showed Bingham plastic flow curves. The polymers had no significant influence on the properties of AV, PV, FL and ES. The presence of polymers in the system reduced the volumes of HPHT filtrates from the fluids and were competitive with the reducer used by the industry, however, they exceeded the results only for fluids with a concentration of 2g of POS2A in the 60/40 oil / water ratio.

Submitted by Programa de Pós-graduação em Biotecnologia (mebiotec.ufba@gmail.com) on 2017-04-04T13:41:41Z No. of bitstreams: 1 DISSERTAÇÃO Final - Sueli.pdf: 2426193 bytes, checksum: 5cd08338c3132f14d2db37b31d5b43f8 (MD5) / Approved for entry into archive by Delba Rosa (delba@ufba.br) on 2017-07-06T13:03:30Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO Final - Sueli.pdf: 2426193 bytes, checksum: 5cd08338c3132f14d2db37b31d5b43f8 (MD5) / Made available in DSpace on 2017-07-06T13:03:30Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO Final - Sueli.pdf: 2426193 bytes, checksum: 5cd08338c3132f14d2db37b31d5b43f8 (MD5) / FAPESB / Recentemente tem aumentado muito o interesse em exopolissacarideos (EPS) de origem microbiana. Esse composto é um constituinte comum de muitos produtos comerciais em diferentes setores industriais como alimento, petróleo e farmacêutico. O objetivo desse trabalho foi o de quantificar e otimizar a produção de EPS a partir de duas bactérias previamente identificadas como sendo Enterobacter sp., pertencente a coleção de culturas do Laboratório de Biotecnologia e Ecologia de Micro-organismos LABEM. Os isolados foram primeiramente identificados com a nomenclatura CCMICS 544 e CCMICS 549 para ambas as cepas. Testes de cultivo em glicerol identificaram a Enterobacter CCMICS 549 como sendo a mais produtiva entre as cepas testadas alcançando a produção de EPS de aproximadamente 4 g.L-1 em 36 horas. Essa cepa foi submetida a testes genéticos (16S rRNA) e bioquímicos que a identificaram como sendo Enterobacter amnigenus grupo 2. Para otimizar a produção de EPS foi realizado planejamento experimental utilizando a Metodologia “Superficie de Resposta”. Os resultados mostraram que as condições ótimas de cultivo acontecem a 35°C, pH 7.0, agitação de 240 rpm e com 3% glicerol. Nessas condições a produção de EPS foi de 0.05 g.L-1h-1 alcançando um total de (5,012) g.L-1 em 60 horas, e com produção em meio a base de água produzida com produção de 7,27g.L-1. A viscosidade do EPS em solução foi de aproximadamente 160 cP mesmo nas condições de alta salinidade (5% NaCl), temperatura (80 oC) e baixa concentração (1%). O modelo de Ostwald-de-Waele (parâmetros k e n) indicaram um comportamento pseudoplástico em todas as concentrações testadas (0.1-2.0%, w/v), temperaturas (15-80 °C) e, principalmente, salinidade (1 a 5%). A consistência de index indica que o polímero possui propriedades reológicas promissoras para aplicação como fluido de perfuração. O tratamento térmico mostrou que o EPS perde grande parte de sua massa em temperaturas acima de 300°C, mas ainda retém 50% do seu peso total a 1000°C indicando a presença de constituintes minerais em concentrações significantes. A caracterização do EPS no infravermelho identificou semelhanças químicas significativas com a goma Xantana. / The interest in microbial produced exopolysaccharides (EPS) has increased considerably in recent years. This compound is a common constituent of many commercial products in different industrial sectors; such as food, petroleum, and pharmaceuticals. The aim of this study was to quantify and optimize EPS production from two bacterial previously identified as Enterobacter sp., Belonging to a culture collection of the Laboratory of Biotechnology and Ecology of Microorganisms LABEM. The isolates were primarily identified with CCMICS 544 and 549 CCMICS nomenclature for both strains. Culturing tests on glycerol identified Enterobacter CCMICS 549 as more productive among the strains reaching an EPS production value of about 4 g.L-1 within 36 hours. This strain was then submitted to biochemical and genetic characterization (16S rRNA), which identified such strain as Enterobacter amnigenus group 2. To optimize the production of EPS was performed using experimental design methodology "Response Surface". The results showed that the optimum condition was achieved at 35°C, pH 7.0, agitation of 240 rpm and 3% crude glycerol. In such conditions, EPS production was of 0.05 gL-1h-1 reaching a total of 5,012 g.L-1 within 60 hours, with production of water-based medium produced using production 7,27g.L-1. EPS viscosity was of about 160 cP even at high salinity (5% NaCl), temperature (80 oC) and low concentration (1%). The Ostwald-de-Waele model parameters (K and n) indicated a pseudoplastic behavior at all concentrations (0.1 to 2.0%, w/v) temperatures (15-80 °C) and especially saline (1 to 5%). The consistency index indicates that the polymer has rheological properties promising for use as a drilling fluid. Thermal treatment showed that most of mass loss occurs at 300°C, but the polymer retains about 50% of its total weight at 1000°C indicating the significant presence of mineral constituents. The characterization of EPS synthesized by Enterobacter amnigenus infrared identified significant chemical similarities with the xanthan gum.

MIRANDA, Kelvi Wilson Evaristo. Filme antimicrobiano composto de base lipídica com aplicabilidade em alimentos. 2015. 139 f . : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2015 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-05T12:44:41Z No. of bitstreams: 1 2015_dis_kwemiranda.pdf: 3327106 bytes, checksum: f3e79fd6592caaf506a5ef33d484f2e0 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-05T12:44:56Z (GMT) No. of bitstreams: 1 2015_dis_kwemiranda.pdf: 3327106 bytes, checksum: f3e79fd6592caaf506a5ef33d484f2e0 (MD5) / Made available in DSpace on 2016-07-05T12:44:56Z (GMT). No. of bitstreams: 1 2015_dis_kwemiranda.pdf: 3327106 bytes, checksum: f3e79fd6592caaf506a5ef33d484f2e0 (MD5) Previous issue date: 2015 / Hydrocolloid and lipid-based films although they are considered technological innovations, have been studied since the mid-90s as potential replacements for synthetic polymers. This study aimed to develop composite films monolayer (Ms) and bilayers (Bs), with incorporation of acetic acid ester of monoglyceride (MGA) in different concentrations and rosemary essential oil peppermint, Lippia sidoides, for applicability in foods with high moisture content. In a previous experiment, it was determined the percentage of 40% (w/w) of plasticizer (D (-) sorbitol) for composite film formation (starch + lipid). Based on this film, it was prepared an experimental design, using plasticizer and various concentrations of AMS (0 to 20% w/w). The films were developed through casting with a thickness of 0.8 mm and dried at room temperature (25 °C ± 1 °C) 12-15 hours. Diffusion tests were performed on agar; physical properties (color, opacity, thickness, moisture and solubility); morphological (medium size, polydispersity – PdI – zeta potential, scanning electron microscopy - SEM, infrared spectroscopy and Fourier transform - IS-FT); barrier (permeability to water vapor - PWV); mechanical tests (tensile strength - TS, rupture elongation - RE - and elastic modulus - EM); termoanalítica (differential scanning calorimetry - DSC). It’s believed that the films have shown a bacteriostatic studied in microorganisms (S. aureus, L. monocytogenes, E. coli, P. aeruginosa and S. Typhimurium). Color analysis showed statistical significance (p<0.05) between mono and bilayer films. The opacity, showed variations from 214.74 to 323.12 A.nm (Ms) and 161.69 to 411.54 A.nm (Bs), except for the treatments with 10% and 15% lipid that doesn’t varied statistically (p<0.05) between Ms and Bs. The thicknesses resulted in asignificant difference (p<0.05) between treatments, ranging from 12% (Ms) and 48% (Bs). The films showed low solubility in aqueous media, with no separation of the layers. The Bs films presented stability of filmogenic solutions, combined with electrokinetic interactions of interaction between the layers, low solubility (16%), heat resistance, PdIbetween0.35 to 0.53; PVA around 2.232 g.mm/kPa.h.m², whose mechanical tests demonstrated tha the Bs films are hard and low elasticity with respect to Ms films, development perspective of a non-flexible packaging with excellent application in food with high moisture content, animal and/or plant origin. / Os filmes à base de hidrocóloides e lipídios apesar de serem consideradas inovações tecnológicas, vêm sendo estudados desde meados dos anos 90 como substitutos em potencial dos polímeros sintéticos. Este trabalho objetivou desenvolver filmes compostos em monocamada (Ms) e bicamadas (Bs), com incorporação de éster de monoglicerídeo de ácido acético (MGA) em diferentes concentrações e, óleo essencial de alecrim-pimenta, Lippia sidoides, para aplicabilidade em alimentos com alto teor de umidade. Em experimento prévio, determinou-se o percentual de 40% (m/m) de plastificante (D (-) sorbitol) para formação de filme composto (amido+lipídio). Com base neste filme, elaborou-se um delineamento experimental, utilizando-se plastificante e, diferentes concentrações de MGA (0 a 20%, m/m). Os filmes foram desenvolvidos através de casting, com espessura de 0,8 mm e secos à temperatura ambiente (25 ºC ± 1 ºC) entre 12-15 horas. Foram realizados teste de difusão em ágar; propriedade física (cor, opacidade, espessura, umidade e solubilidade); morfológica (tamanho médio, polidispersividade – PDI, potencial zeta, microscopia eletrônica de varredura – MEV, e espectroscopia no infravermelho com transformada de Fourier – FT-IR); barreira (permeabilidade ao vapor de água – PVA); ensaios mecânicos (resistência à tração – RT, elongação de ruptura – ER – e módulo de elástico – ME); termoanalítica (calorimetria diferencial de varredura – DSC). Acredita-se que os filmes tenham apresentado ação bacteriostática nos micro-organismos estudados (S. aureus, L. monocytogenes, E. coli, P. aeruginosa e S. Typhimurium). A cor apresentou diferença estatística (p<0,05) entre os filmes mono e bicamadas. A opacidade, apresentou variações de 214,74 a323,12 A.nm (Ms) e, 161,69 a411,54 A.nm (Bs), exceto para os tratamentos com 10% e 15% de lipídio que não variaram estatisticamente (p<0,05) entre Ms e Bs. A espessura resultou em uma diferença significativa (p<0,05) entre os tratamentos, variando 12% (Ms) e 48% (Bs). Os filmes apresentaram baixa solubilidade em meio aquoso, sem que houvesse a separação das camadas. Os filmes Bs apresentaram estabilidade das soluções filmogênicas, associado a interações eletrocinéticas de interação entre as camadas, baixa solubilidade (16%), resistência térmica, PDI entre 0,35-0,53; PVA em torno de 2,232 g.mm/kPa.h.m², cujos ensaios mecânicos demonstraram que os filmes Bs são rígidos e com baixa elasticidade em relação aos filmes Ms, evidenciando perspectiva de desenvolvimento de uma embalagem não flexível, com potencial de aplicação em alimentos com alto teor de umidade.