Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-07-04T22:33:07Z No. of bitstreams: 1 Monica_Scariotto_2018.pdf: 1771323 bytes, checksum: 1281a118a9ea7e2155e71f785f0e816f (MD5) / Made available in DSpace on 2018-07-04T22:33:07Z (GMT). No. of bitstreams: 1 Monica_Scariotto_2018.pdf: 1771323 bytes, checksum: 1281a118a9ea7e2155e71f785f0e816f (MD5) Previous issue date: 2018-03-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / New techniques have emerged in the field of environmental science with the aim of developing water treatments using biodegradable materials, such as some polymers, and secondary materials such as household, industrial and agricultural waste. Films with good adsorption capacity of pollutants can be produced by the electrospinning technique using biodegradable polymers. The adsorption of contaminants can also be efficient by means of modified carbon from natural sources. The objective of the present work was to produce Ecovio® and PCL electrospun films, with and without incorporation of functionalized carbon from tilapia bone residue (CAF), for the adsorption of tetracycline (TC) in aqueous solution. Initially, adsorptive tests were performed to select the physicochemical modification of the CAF that obtained the highest adsorption. Then, polymer films were produced with and without the incorporation of CAF, and subjected to adsorption tests at different pHs along with the isolated CAF. The materials were analyzed by means of Optical Microscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). CAF treated with HCl in 150 mesh granulometry obtained the highest adsorptive efficiency and was used in the subsequent tests. The parameters of electrospinning and preparation of solutions presented discrete differences for the obtained fiber diameters. A small reduction in diameters was observed with incorporation of CAF. The electrospinning parameters selected were 14 kV, 1 mL h-1 and 12 cm. The SEM showed that CAF had heterogeneous sites on its surface and, for electrospun films, there was beads formation and differences in the surface of the fibers, according to the solvent used. The FTIR indicated that CAF consists mainly of HAp and collagen. The influence of the pH was verified through adsorptive tests, in which alkaline pH was more efficient, with adsorption of TC (100 mg L-1) of 20.45 mg g-1 (pH 10) and 19.23 mg g-1 (pH 9) for CAF and 19.93 mg g-1 (pH 9) for the Ecovio®85/PCL15/CAF blend of 15% (w/v) with chloroform/DMF solvents. The mechanisms suggested in the adsorption of TC in the present work are diffusion of charges on the surface of carbon and formation of complexes. / Novas técnicas têm surgido no ramo da ciência ambiental com o objetivo de desenvolver tratamentos de água utilizando materiais biodegradáveis, como alguns polímeros, e materiais de uso secundário, como resíduos de fontes domésticas, industriais e agrícolas. Filmes com boa capacidade de adsorção de poluentes podem ser produzidos pela técnica de eletrofiação utilizando polímeros biodegradáveis. A adsorção de contaminantes também pode ser eficiente por meio de carvão modificado proveniente de fontes naturais. O objetivo do presente trabalho visou produzir filmes eletrofiados de Ecovio® e PCL, com e sem a incorporação de carvão funcionalizado a partir de resíduo de osso de tilápia (CAF), para a adsorção de tetraciclina (TC) em solução aquosa. Inicialmente, ensaios adsortivos foram realizados para selecionar a modificação físico-química do CAF que obteve maior adsorção. Em seguida, filmes poliméricos foram produzidos com e sem a incorporação de CAF, e submetidos a ensaios adsortivos em diferentes pH juntamente com o CAF isolado. Os materiais foram analisados por meio de Microscopia Óptica, Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Análise Termogravimétrica (TGA), Calorimetria Exploratória Diferencial (DSC) e Difratometria de Raios-X (DRX). O CAF tratado com HCl na granulometria de 150 mesh obteve a maior eficiência adsortiva, sendo utilizado nos ensaios subsequentes. Os parâmetros de eletrofiação e preparo de soluções poliméricas apresentaram diferenças discretas para os diâmetros de fibras obtidos. Notou-se uma redução discreta nos diâmetros com a incorporação de CAF. Os parâmetros de eletrofiação selecionados foram 14 kV, 1 mL h-1 e 12 cm. A MEV mostrou que o CAF apresenta sítios heterogêneos em sua superfície e que para os filmes eletrofiados houve a formação de beads e diferenças na superfície das fibras, de acordo com cada solvente utilizado. O FTIR indicou que o CAF é formado por principalmente por HAp e colágeno. A influência do pH foi constatada por meio de ensaios adsortivos, em que pH alcalino se mostrou mais eficiente, com adsorção de TC (100 mg L-1) de 20,45 mg g-1 (pH 10) e 19,23 mg g-1 (pH 9) para o CAF e 19,93 mg g-1 (pH 9) para a blenda de 15% (m/v) de Ecovio®85/15PCL/CAF com solventes clorofórmio/DMF. Os mecanismos sugeridos na adsorção de TC no presente estudo são a difusão de cargas na superfície do carvão e a formação de complexos.

Biocatalytic membranes (BMs) have promising applications in a diversity of fields including food, pharmaceutical and water treatment industries. Of particular relevance, Alcalase is a commercially important protease that has been applied for the production of peptides from the hydrolysis of proteins. In this study, two different approaches were applied for the modification of electrospun polyacrylonitrile nanofibrous membranes (EPNMs) for Alcalase immobilization. The first approach is alkali modification of EPNMs followed by EDC/NHS coupling for covalent bonding with Alcalase, whereas the other is based on polydopamine coating with or without glutaraldehyde grafting as a covalent linker. Immobilized Alcalase on these prepared BMs were studied and compared with free enzymes. It was found that the stabilities of Alcalase on BMs created using both approaches were improved, which enabled their reuse of 10 cycles with significant retention of enzymatic activity. A continuous reactor housing BMs were tested for hydrolysis of both model substrate, azo-casein and soybean meal protein (SMP). It was found that decreasing flux could improve the extent of hydrolysis and that a single-layer reactor can hydrolyze about 50% of the substrate to peptides with the molecular weight of 10 kDa or less. Hydrolysis of SMPs was demonstrated in a continuous five-layer BM reactor and both BMs showed excellent hydrolysis capacity. This study provides the groundwork for the development of high-efficiency BM for continuous and cost-effective protein hydrolysis for the production of value-added peptides.

Electrospinning has been the focus of countless studies for the past decades for applications, including but not limited to, filtration, tissue engineering, and catalysis. Electrospinning is a one-step process for producing nano- and/or micro-fibrous materials with diameters ranging typically from 50 to 5000 nm. The simulation algorithm presented here is based on a novel mass-spring-damper (MSD) approach devised to incorporate the mechanical properties of the fibers in predicting the formation and morphology of the electrospun fibers as they travel from the needle toward the collector, and as they deposit on the substrate. This work is the first to develop a physics-based (in contrast to the previously-developed geometry-based) computational model to generate 3-D virtual geometries that realistically resemble the microstructure of an electrospun fibrous material with embedded particles, and to report on the filtration performance of the resulting composite media. In addition, this work presents a detailed analysis on the effects of electrospinning conditions on the microstructural properties (i.e. fiber diameter, thickness, and porosity) of polystyrene and polycaprolactone fibrous materials. For instance, it was observed that porosity of a PS electrospun material increases with increasing the needle-to-collector distance, or reducing the concentration of PS solution. The computational tool developed in this work allows one to study the effects of electrospinning parameters such as voltage, needle-to-collector distance (NCD), or polymer concentration, on thickness and porosity of the resulting fibrous materials. Using our MSD formulations, a new approach is also developed to model formation and growth of dust-cakes comprised of non-overlapping non-spherical particles, for the first time. This new simulation approach can be used to study the morphology of a dust-cake and how it impacts, for instance, the filtration efficiency of a dust-loaded filter, among many other applications.

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PREPARATION AND CHARACTERIZATION OF ELECTROSPUN POLY(D,L-LACTIDE-CO-GLYCOLIDE) SCAFFFOLDS FOR VASCULAR TISSUE ENGINEERING AND THE ADVANCEMENT OF AN IN VITRO BLOOD VESSEL MIMIC Tiffany Richelle Peña Currently, an estimated 1 in every 3 adult Americans are affected by one or more cardiovascular complications. The most common complication is coronary artery disease, specifically atherosclerosis. Outcomes of balloon angioplasty treatments have been significantly improved with the addition of drug eluting stents to the process. Although both bare metal and drug eluting stents have greatly increased the effectiveness of angioplasty and decreased the occurrence of restenosis, several complications still exist. For this reason, the stent industry is continually advancing toward better stent and drug-eluting designs, deployment methods, and adjuvant drug therapies, necessitating fast, reliable pre-clinical test methods. Recently, advancements in tissue engineering have led to the development of an in vitro blood vessel mimic (BVM) and the feasibility of evaluating cellular response to intravascular device implantation has been demonstrated. There are several physiological and scalability limitations of the current BVM model that must be addressed before effective use of the model can be initiated. The limiting aspect addressed in this thesis is the use of expanded poly(tetrafluorethylene) [ePTFE] scaffolding for the development of the BVM. There are several disadvantages and limitations to ePTFE including high cost and non-native mechanical properties. The ability to produce and tailor scaffolds in-house would greatly impact the scalability, cost effectiveness, and control over scaffold properties for BVM optimization. Also, in-house fabrication will open up further avenues of research into optimum scaffold design for better cellular responses when cultured in vitro. Electrospinning is a relatively simple and economical method of creating tissue engineering constructs with micro-architecture similar to the native extracellular matrix. Based on the clinical problem and the potential for the BVM, the aim of this thesis is to employ electrospinning for the development of poly(D,L-lactide-co-glycolide) [PLGA] vascular scaffolds as a replacement to ePTFE for the BVM. After primary literature review, PLGA was determined an advantageous polymer for tissue engineering vascular scaffolds and electrospinning based on evidence of adequate endothelial cell attachment, mechanical properties similar to the native vessels, controlled degradation, and good biocompatibility. The first phase of this thesis was to develop an acceptable protocol for the fabrication of electrospun PLGA scaffolds by varying solution concentration, flow rate and applied voltage. Electrospun solutions of 15 wt% PLGA in CHCl3 resulted in continuous un-beaded fibers of 5-6 microns and tensile properties (3-5 MPa) similar to the native vessel. The optimum protocol for electrospinning 15 wt% PLGA incorporated a flow rate of 5.5 ml/hr and an applied voltage of 12,000 V. In the second phase of this thesis, final protocol PLGA scaffolds were cultured in vitro with human umbilical vein endothelial cells (HUVECs) up to 6 days. Fluorescent microscopy and SEM analysis suggest the porous nature of the scaffolds was conducive to sub-luminal cellular penetration. Although results were not optimal for developing an endothelium for the ideal BVM design, the potential of using electrospinning for in-house production of scaffolds for tissue engineering was established. Further optimization of the electrospinning protocol to develop nano-sized structural features could enhance the ability to form an intimal lining of endothelial cells for the next generation BVM design.

yes / A major challenge in the production of 3D tissue engineered skin is the recreation of the basement membrane region to promote secure attachment and yet segregation of keratinocytes from the dermal substitute impregnated with fibroblasts. We have previously shown that simple electrospun scaffolds provide fibres on which the cells attach, proliferate, and self-sort into epithelium and dermis. In a development of this in this study tri-layered scaffolds were then electrospun from poly L-lactic acid and poly hydroxybutyrate-co-hydroxyvalerate. In these a central layer of the scaffolds comprising nano-porous/nano-fibrous poly hydroxybutyrate-co-hydroxyvalerate fibres was interwoven into the bulk micro-porous poly L-lactic acid microfibers to mimic the basement membrane. Keratinocytes and fibroblasts seeded onto these scaffolds and cultured for 2 weeks showed that neither cell type was able to cross the central nano-porous barrier (shown by SEM, and fluorescence monitoring with CellTracker™) while the micro-fibrous poly L-lactic acid provided a scaffold on which keratinocytes could create an epithelium and fibroblasts could create a dermal substitute depositing collagen. Although cells did not penetrate this barrier the interaction of cells was still evident-essential for epithelial development.

No description available.

Yes / In this study, we prepared chitosan (Cs_P) nanofibers (NFs) membrane by electrospinning. The Cs_P NFs membrane was then chemically functionalized (CsF) by a novel stepwise chemical process. The CsF NFs membrane was electrospray with TiO2 nanoparticles (NPs) to prepare the CsF_Coa NFs membrane. A second NFs membrane with embedded TiO2 NPs (Cs_Co) was also prepared by electrospinning. The TiO2 NPs, Cs_P, CsF s, CsF_Coa NFs, and Cs_Co NFs membranes were analyzed by standard spectroscopic, microscopic, X-ray, and thermal methods. Fourier transform infrared (FTIR) analysis confirmed the incorporation of the new functional group into the Cs structure. X-ray photoelectron spectroscopy (XPS) data confirmed the FTIR results and the fabrication of the CsF NFs membrane. Scanning electron microscope (SEM) micrographs showed a smooth morphology for the Cs_P NFs membrane and a denser morphology for the CsF NFs membrane (NFs swelled with functionalization). The SEM micrographs also showed a dense cloud of TiO2 NPs on the surface of the Cs_Coa NFs membrane. Transmission electron microscope (TEM) showed that the particle size of TiO2 NPs varied between 20 and 35 nm and tended to be spherical. The X-ray diffraction (XRD) pattern confirmed the existence of the anatase phase of the TiO2 NPs. The presence of TiO2 in the Cs_Coa and Cs_Co NFs membranes was also confirmed by energy-dispersive x-ray spectroscopy (EDX). Surface profilometry confirmed an increase in the surface roughness of the CsF and Cs_Coa NFs membranes. Brunauer–Emmett–Teller (BET) analysis revealed that the isotherms and hystereses for all NFs membranes were of the IV and H3 types, respectively, corresponding to mesopores and slit pores. The higher photocatalytic activity of the Cs_Coa NFs membrane (89%) compared to the Cs_Co NFs membrane (40%) was attributed to a balance between the short band gap, high surface roughness, and lower surface area.

Evidence shows there is no ideal membrane, i.e., biocompatible, biodegradable, with adequate mechanical and physical properties that enable reorganization of periodontal tissues. Eletrospinning technique has demonstrated good processing results on scaffolds made from polymers. Nanofibrous formed by this technique have characteristics that resemble the extracellular matrix. The aim of this study was to evaluate the biocompatibility of nanofibrous polydioxanone scaffolds (PDS II®) containing metronidazole or ciprofloxacin in subcutaneous implantation model in rats Wistar. PDS II® is biocompatible polyester having various applications in the medical field. Our conceptual hypothesis considers that scaffolds with antimicrobials have similar inflammatory behavior when compared to PDS positive control. Sixty adult male rats were randomized into 6 groups: negative control (SHAM) animals with incision and surgical pocket, without scaffold; positive control (PDS) animals with PDS scaffolds; 1MET animals with one PDS scaffold containing 25%wt metronidazole; 2MET animals with two PDS scaffolds containing 25%wt metronidazole, 1CIP animals with PDS scaffolds containing 25%wt ciprofloxacin; 2CIP animals with two PDS scaffolds containing 25%wt ciprofloxacin. Animals were euthanized at 3 days (n=30) and 30 days (n=30), corresponding to initial and late inflammatory responses, respectively. Outcomes measures were the degradation of collagen fibers (Picrosirius Red and Masson´s trichrome), activity of cellular enzyme (Myeloperoxidase activity and N-acetyl-β-D-glucosaminidase activity) and local oxidative profile (reactive oxygen species, lipid peroxidation, protein carbonyl, vitamin C, catalase and reduced glutathione). Dara were analyzed statistically (p<0.05) by two-way ANOVA (treatment and time). Collectively, results show that antibiotics scaffolds have a lower inflammatory response compared to PDS group. Among the nanofibers with antibiotics, the group showed better early and late inflammatory response was 2CIP. The findings of this research suggest the potential study of these scaffolds with metronidazole and ciprofloxacin in regenerative models, able to confirm the effectiveness of these artificial matrices for periodontal regeneration. / Evidências mostram que não há membranas ideais, ou seja, biocompatíveis, biodegradáveis, com propriedades mecânicas e físicas adequadas que permitam a reestruturação dos tecidos periodontais. A técnica do eletrospinning tem demonstrado bons resultados no processamento de scaffolds confeccionados a partir de polímeros. As nanofibras formadas por esta técnica possuem características que se assemelham a matriz extracelular. O objetivo do presente estudo foi avaliar a biocompatibilidade de scaffolds nanofibrosos de polidioxonona (PDS II®) contendo metronidazol ou ciprofloxacina em modelo de implantação subcutânea em ratos Wistar. A PDS II® é um poliéster biocompatível com diversas aplicações na área médica. Nossa hipótese conceitual considerou que scaffolds com antimicrobianos teriam semelhante comportamento inflamatório quando comparados ao controle positivo PDS. Sessenta ratos machos adultos foram randomizados em seis grupos: controle negativo (SHAM) - animais com incisão e loja cirúrgica, ausentes de scaffolds; controle positivo (PDS) - animais com scaffolds de PDS, 1 scaffold PDS com 25%wt de metronidazol (1MET), 2 scaffolds PDS com 25%wt de metronidazol (2MET), 1 scaffold PDS com 25%wt de ciprofloxacina (1CIP), 2 scaffolds com 25%wt de ciprofloxacina (2CIP). Os animais foram eutanasiados em 3 (n=30) e 30 dias (n=30), correspondendo a resposta inflamatória inicial e tardia, respectivamente. Os desfechos avaliados foram degradação de fibras colágenas (Picrosírius Red e Tricrômico de Masson), atividade de enzimáticas celulares (mieloperoxidase e N-Acetil β-D-Glicosaminidase) e perfil oxidativo local [espécies reativas de oxigênio (ROS), peroxidação lipídica (LP), proteína carbolinada (PC), catalase (CAT), vitamina C (VIT.C) e glutationa reduzida (GSH)]. Os dados foram analisados estatisticamente (p<0,05) através do teste Two-way ANOVA (tratamento e tempo). Coletivamente, os resultados mostram que scaffolds com antibióticos possuem menor resposta inflamatória se comparado ao grupo PDS. Entre as nanofibras com antibióticos, o grupo que apresentou melhor resposta inflamatória inicial e tardia foi 2 CIP. Os achados desta pesquisa sugerem o potencial estudo destes scaffolds com metronidazol e ciprofloxacina em modelos regenerativos, capazes de confirmar a efetividade dessas matrizes artificiais para a regeneração periodontal.