Orientador: Helena Maria Andre Bolini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T11:37:53Z (GMT). No. of bitstreams: 1 Palazzo_AlessandraBugatte_M.pdf: 1251502 bytes, checksum: 52b2b3c641c083e12c1ea4e84eea424b (MD5) Previous issue date: 2008 / Resumo: Diante do cenário da alimentação humana atual, do ritmo agitado do cotidiano e aumento do consumo de alimentos industrializados, cada vez é maior a preocupação das pessoas em praticar dietas saudáveis, ricas nutricionalmente e que sejam de preparo fácil e rápido. A gelatina se torna um produto importante neste aspecto, consideradas suas propriedades como regeneração muscular e fortalecimento dos ossos. Além disso, é consumida por todas as faixas etárias. Este trabalho teve por objetivo avaliar o comportamento de gelatinas em pó sabor framboesa de diferentes marcas comercializadas atualmente, tanto em versão tradicional com adição de sacarose, quanto à versão adicionada de edulcorantes, sob ponto de vista físico-químico e sensorial. As análises físico-químicas foram determinação de cor, textura, pH e ºBrix. Os testes sensoriais realizados foram análise descritiva quantitativa (ADQè), análise tempo-intensidade (TI) em relação aos estímulos doce, ácido, sabor framboesa e derretimento na boca e teste de aceitação com 120 consumidores para os atributos aparência, aroma, sabor, textura e impressão global. A análise estatística incluiu Análise de Variância (ANOVA), teste de média de Tukey e análise multidimensional de preferência (MDPREF), realizadas com auxílio do programa estatístico SAS. As amostras adoçadas com edulcorantes apresentaram amargor residual mais acentuado e menor translucidez que as amostras que utilizam sacarose em sua composição, reforçando assim a baixa aceitação destas pelos consumidores. A amostra adoçada com aspartame/acessulfame de potássio apresentou-se como a mais escura entre as amostras e obteve altos valores para doçura residual, aroma de cereja e firmeza, além de ser pouco aceita pelos consumidores em vários parâmetros. Os resultados demonstraram que não houve diferença significativa entre todas as amostras em relação ao tempo em que ocorre a intensidade máxima para gosto doce, gosto ácido e derretimento na boca. Em relação à textura, as amostras analisadas instrumentalmente como sendo as mais duras, foram menos aceitas pelos consumidores e também as que obtiveram menor intenção de compra pelos mesmos. As amostras tradicionais foram preferidas pela maioria dos provadores (85% em relação à intenção de compra). O aspartame/acessulfame de potássio, utilizados como substitutos da sacarose para finalidade dietética e redução calórica foram os que apresentaram comportamento mais distante ao da sacarose, quando comparados com a amostra contendo sacarina sódica e ciclamato de sódio como adoçantes. Sendo assim, é importante que a unidade produtora de gelatinas reavalie sua produção, garantindo que a substituição da sacarose por outros edulcorantes não afete outras características como o sabor / Abstract: Nowadays, consumers are concerned about purchasing practical products, fast to prepare and that are considered healthy. Gelatin is an interesting product because of its proprieties related to muscular regeneration and bone strengthening. Besides, it is widely consumed at all age groups. The objective of this study was to sensorially and physico-chemically evaluate the performance of different gelatin raspberry flavored currently consumed, in both versions traditional (with sucrose addition) and diet (sweetened with edulcorants). The sensorial tests carried out were quantitative descriptive analysis (ADQ), time-intensity analysis for sweetness, acidity, raspberry fruitiness and melt in the mouth and the consumer test with 120 consumers through the following attributes: appearance, aroma, flavor, texture and global feeling. The statistical analysis included Analysis of Variance (ANOVA), Tukey's Test for means and a multidimensional preference analysis (MDPREF), using the statistical program SAS. The sweetened samples with edulcorants had a strong bitter aftertaste and low translucency than other samples with sucrose, strengthening the smallest acceptance by consumers. The sample sweetened with aspartame/potassium acessulfame showed as the darkest between the samples, besides the smallest acceptance by consumers for different parameters and had high means for sweetness aftertaste, cherry¿s aroma and hardness. The results showed no significantly difference between all the samples for the attribute time of higher intensity of sweetness, acidity and melt in the mouth. For texture analysis, the instrumental evaluated samples as the most hardness were the less accept by consumers and had the smaller purchase intention too. The samples with great acceptance were the traditional, with 85% about the purchase intention. The mix aspartame/potassium acessulfame, using as sucrose substituent's to purpose dietetic and caloric reduction showed the most distant profile of sucrose, when compare with sample AT, using cyclamate/saccharin as sweeteners / Mestrado / Consumo e Qualidade de Alimentos / Mestre em Alimentos e Nutrição

Orientador: Carlos Raimundo Ferreira Grosso / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T16:31:42Z (GMT). No. of bitstreams: 1 Davanco_Taciana_M.pdf: 2629355 bytes, checksum: cdbb1966776fdc55926071d8c776dbb4 (MD5) Previous issue date: 2006 / Resumo: Desenvolvimento de biofilmes tem crescido devido a possibilidade de substituição parcial de materiais plásticos não degradáveis. Proteínas e polissacarídeos têm sido utilizados para a produção de filmes com boas propriedades mecânicas. Porém filmes a partir desses materiais apresentam alta permeabilidade ao vapor de água. Uma alternativa usada para diminuir a permeabilidade ao vapor de água dos filmes é a incorporação de substancias hidrofóbicas na composição da solução filmogênica, porém a incorporação dessas substâncias na matriz filmogênica não ocorre de maneira homogênea. Com o objetivo de melhorar a incorporação das substâncias hidrofóbicas na matriz protéica do filme foram adicionados os surfactantes (SDS e Tween 80), que são compostos orgânicos constituídos por moléculas anfifílicas, contendo uma parte polar e outra apolar, com o intuito desta substância interagir na proteína e no ácido graxo, tornando a matriz filmogênica menos heterogênea. O efeito do pH também foi estudado, com a finalidade de observar se este exerce influência na homogeneidade da matriz filmogênica. Os ácidos graxos utilizados no trabalho foram o ácido capróico (6C), e o ácido esteárico (18C), com o objetivo de avaliar e comparar se o número de carbonos da cadeia do ácido graxo exerce influencia na incorporação da matriz protéica. Os filmes foram caracterizados quanto as propriedades de barreira ao vapor de água e propriedades mecânicas, solubilidade em água, opacidade, isotermas de sorção e calorimetria diferencial de varredura, podendo ser observado que a adição dos surfactantes melhorou a barreira ao vapor de água e diminuiu a resistência à tração dos filmes, não sendo observado diferenças na cor e opacidade dos filmes . Posteriormente foram analisadas as características morfológicas, através da microscopia ótica, microscopia eletrônica de varredura e microscopia confocal de varredura a laser, observando que o ajuste do pH e a adição do surfactante modificam a estrutura morfológica do filme / Abstract: Development of biofilms has grown considering the possibility of partial substitution of plastic materials not degradable. Proteins and polysaccharides have been used for the production of films with good mechanical properties. However films produced with these materials present high water vapor permeability to the water vapor. An used alternative to improve the water vapor barrier of the films is the incorporation of hydrophobic substances in the composition of the filmogenic solution, however the incorporation of these substances in the filmogenic matrix does not occur in homogeneous way. Thus with, the objective to improve the incorporation of hydrofhobic substances in the protein matrix of the film surfactants had been added (SDS and Tween 80). They are organic compounds constituted by anphiphilics molecules, incluing a polar part and other apolar, with the intention that is substances improve the interaction between the protein and the fats acids, producing a less heterogeneous filmogenic matrix. The effect of pH also was studied, with the purpose to observe if this produce influence in the homogeneity of the filmogenic matrix. The fats acids used in this work were the caproic acid (6C), and the stearic acid (18C), with the objective to evaluate and to compare if the carbon number of the fats acids exerts influences in the incorporation on the protein matrix. The films were characterized with respect to the properties of barrier to the water vapor, solubility in water, opacity, isotherms of sorption and thermal properties, being able to be observed that the addition of the surfactants improved the water vapor permeability and decreased the tensile strenght of the films, not being observed differences in the color and opacity of the films. Later the morphologic characteristics had been analyzed, through optics microscopy, scanning electron microscopy and confocal laser scanning microscopy, observing that the adjustment of pH and the addition of the surfactant modify the morphological structure of the films / Mestrado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Mestre em Alimentos e Nutrição

Orientador: Yoon Kil Chang / Tese (doutorado)- Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T16:41:50Z (GMT). No. of bitstreams: 1 Sebio_Leonard_D.pdf: 5261418 bytes, checksum: c5f42d63b358e2b0af36c89bdbdd0259 (MD5) Previous issue date: 2003 / Resumo: Devido ao crescente acúmulo de lixo proveniente de plásticos sintéticos, agredindo o ecossistema, diferentes estratégias estão sendo seguidas com o intuito de procurar diminuir essa agressão através da prevenção, redução, reciclagem, valorização química dos materiais sintéticos e especialmente oo uso de polímeros biodegradáveis. O uso de amido como materiais termoplásticos é promissor devido principalmente à disponibilidade natural desse produto, que é extraído de uma fonte inesgotável de matérias-primas (cereais, raízes, tubérculos, etc.). No entanto, as blendas não são totalmente biodegradáveis. Nessa ótica a presente pesquisa envolveu o uso de processo de extrusão termoplástica de dupla rosca e uma matriz retangular apropriada para produzir materiais laminados termoplastificados biodegradáveis a base de amido e gelatina plastificados por glicerol e água susceptíveis de serem moldados na forma de descartáveis, etc. Foi empregada a metodologia de superfície de resposta (MSR) para estabelecer modelos matemáticos preditivos baseados em Modelo Central Composto Rotacional (CCDR), num planejamento fatorial completo 23 de 5 níveis e de 3 variáveis independentes, a saber as concentrações de gelatina (50,0; 100,0, 150,0 g/g base úmida), de glicerina (50,0, 100,0, 150,0 g/g) em 1000g da blenda e umidade (30, 35, 40 %). As respostas obtidas das combinações 2 a 2 dos 3 fatores foram avaliadas considerando as propriedades mecânicas de tração e de barreira dos laminados termoplásticos obtidos após extrusão, tais como: a Resistência Máxima à Tração, Percentagem de Alongamento, Elasticidade (Modulo de Young), Permeabilidade ao vapor de água e Índice de desintegração em meio aquoso. Foi em seguida, desenvolvida uma metodologia matemática de otimização de ensaios que permitiu a partir de uma fórmula de combinação de melhores respostas, escolher 6 ensaios principais entre os 18 do delineamento. Após escolher as amostras de melhores propriedades foram avaliadas as ropriedades fisico-químicas e morfológicas, a saber: Microscopia Eletrônica de varredura (MEV), Estimativa de Condições de Armazenamento, Absorção de Água, Difratometria de Raios-X e Índice de Cristalinidade Relativa. Para observar o comportamento térmico dos laminados, avaliou-se as seguintes propriedades térmicas: Condutividade Térmica, Análise Termogravimétrica (TGA), Análise Térmica Dinâmica Mecânica (TDMA) e Calorimetria Diferencial de Varredura (DSC). As propriedades mecânicas foram principalmente influenciadas pelas concentrações de gelatina e de glicerol na avaliação dos laminados termoplásticos que apresentaram valor médio de resistência máxima à tração de 4,87 MPa; com valor máximo de 12,62 MPa; valor médio de porcentagem de alongamento de 46,46 % com máximo em 81,58% e valor médio de Módulo de Elasticidade de 160,70 MPa com máximo em 568,49 MPa. Quanto à permeabilidade ao vapor de água, apesar de ser influenciada exclusivamente pela concentração de glicerol, apresentou uma pequena variabilidade, pois o menor valor foi próximo do maior valor. Enquanto que o índice de desintegração em água foi dependente das concentrações de gelatina e do plastificante, onde foi observado que quanto menores ambas as concentrações, menor a desintegração. Avaliando o comportamento dos laminados em condições ambientais simuladas, verificou-se que alguns não sofreram alterações nas suas propriedades durante 25 dias de armazenamento a 65 e 75 % de UR. Os resultados de microscopia Eletrônica de Varredura indicaram que as diversas formulações empregadas em diferentes ensaios provocaram alterações na morfologia da matriz polimérica. As concentrações de gelatina e de glicerol influenciaram a cristalinidade dos laminados onde o laminado controle mostrou ser mais cristalino que os laminados dos ensaios formulados. O valor da condutividade térmica dos laminados revelou-se maior que o dos materiais sintéticos. Na degradação térmica, observou-se uma estabilidade até cerca de 230 oC quando iniciou-se a perda de massa observada através da termogravimetria, enquanto que as transições vítreas determinadas através de DMTA e DSC foram dependentes dos componentes das formulações dos ensaios e do tempo de armazenamento / Abstract: Due to the increasing accumulation of synthetic plastic rubbish, damaging the ecosystem, various strategies are being followed aimed at decreasing this aggression by way of prevention, reduction, recycling and chemical valorization of the synthetic materials, and especially by the use of biodegradable polymers. The use of starch to make thermoplastic materials is promising, due principally to the natural availability of the product, which is extracted from an endless stock of raw materials (cereals, roots, tubers etc.). However, the blends are not completely biodegradable. Thus this research involved the use of twin screw thermoplastic extrusion with an appropriate rectangular matrix, to produce biodegradable thermoplastic laminated materials based on starch and gelatin and plastified by glycerol and water, capable of being molded into the form of discardable products etc.. Response Surface Methodology (RSM) was used to establish predictive mathematical models based on the Central Compound rotational Design (CCRD) in a 23 complete factorial plan with 5 levels and 3 independent variables, these being the gelatin (50.0; 100.0; 150.0 g/g, wet basis) and glycerin (50.0; 100.0; 150.0 g/g, wet basis) concentrations in 1000g of mix, and the moisture content (30, 35, 40%). The responses obtained to the 2 x 2 combinations of the three factors were evaluated, considering the barrier and strain mechanical properties of the thermoplastic laminates obtained after extrusion, such as: Maximum resistance to strain, Percentage of stretching, Elasticity (Young's modulus), Water vapor permeability and the disintegration index in an aqueous medium. Mathematical methodology to optimize the trials was then developed which allowed one to choose the 6 main trials from the total of 18 from the design using a combination formula of best responses. After choosing those samples showing the best properties, the physical, chemical e morphological properties were evaluated using the following techniques: scanning electron microscopy (SEM), an estimate of the storage conditions, water absorption, X-ray diffraction and relative crystallinity index. The following thermal properties were evaluated in order to observe the thermal behavior of the laminates: Thermal Conductivity, Thermogravimetric analysis (TGA), Thermal Dynamic Mechanical analysis (TDMA) and Differential Scanning Calorimetry (DSC). The mechanical properties of the thermoplastic laminates were mostly influenced by the gelatin and glycerol concentrations, presenting a mean value for maximum resistance to strain of 4.87 MPa and a maximum value of 12.62 MPa; a mean value for % stretching of 46.46% with a maximum of 81.58% and a mean value for the Young's Modulus of 160.70 Mpa with a maximum of 568.49 MPa. With respect to water vapor permeability, despite being influenced exclusively by the glycerol concentration, this presented only slight variation, with the smallest value being similar to the largest value, whilst the disintegration index in water was dependant on both the gelatin and plastifier concentrations and the smaller the concentrations of these two concentrations, the smaller the disintegration. An evaluation of the behavior of the laminates under simulated environmental conditions, showed that some of them presented no alterations in their properties during 25 days of storage at 65 and 75% RH. The SEM results indicated that several of the various formulations used in the different trials caused alterations in the morphology of the polymeric matrix. The concentrations of gelatin and glycerol influenced the crystallinity of the laminates, the control laminate being more crystalline than those formulated in the trials. The Thermal Conductivity of the laminates was shown to be greater than that of the synthetic materials. For thermal degradation, stability was observed at about 230°C, point at which the materials started to loose mass as observed by the Thermogravimetric analysis, whilst the vitreous transitions determined by TDMA and DSC were dependant on the components of the trial formulations and storage time / Doutorado / Doutor em Tecnologia de Alimentos

Orientador: Carlos Raimundo Ferreira Grosso / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-24T10:13:53Z (GMT). No. of bitstreams: 1 Costa_BiancaSouzada_M.pdf: 3645103 bytes, checksum: ee9884c2d54163da7814b0ea032a53c5 (MD5) Previous issue date: 2014 / Resumo: O objetivo deste trabalho foi produzir partículas de pectina e alginato por gelificação iônica, com posterior recobrimento com isolado proteico de soja (IPS), gelatina de pele de tilápia (GPT) e com a mistura dessas duas proteínas (IPS:GPT), avaliando suas características físico-químicas e seu comportamento frente a diferentes tratamentos. No estudo preliminar foram analisadas as condições que promovessem a carga elétrica livre que otimizassem a interação entre os polissacarídeos e proteínas, formando complexos insolúveis. A partir desses ensaios foram estabelecidas as seguintes proporções de polissacarídeo: proteína e valores de pH: 1:2 em pH4 para recobrimento com gelatina de pele de tilápia, e 1:0,75 em pH3 para interação com o isolado proteico de soja e para a mistura das duas proteínas. Foram testados 4 níveis de proteína em solução ( 1, 2, 4 e 8 %) para recobrimento das partículas de pectina e alginato. As partículas obtidas foram caracterizadas pelo teor de umidade, conteúdo proteico adsorvido e pela sua morfologia. A partir deste estudo preliminar foi selecionada a concentração de 8% de proteína em solução, devido à produção de partículas com alto teor proteico. Estas partículas foram avaliadas com relação à sua estabilidade frente a variações de pH, diferentes concentrações de NaCl e sob simulação das condições gastrointestinais in vitro. Utilizando a concentração de 8% de proteína em solução foram obtidos altos valores de adsorção proteica, resultando no percentual de proteína de 61,87%, 47,61% e 52,06% para as partículas recobertas com GPT, IPS e IPS:GPT, respectivamente. A variação de pH e das concentrações de sal influenciaram na solubilidade da camada proteica, apresentando uma maior solubilidade em condições de extrema acidez (pH 1) e a medida em que aumentava a concentração de sal. Nas faixas de pH (1 a 7) e nas concentrações de NaCl (0 a 584 mM) estudadas, independente do valor da solubilidade proteica obtida, todas as partículas permaneceram íntegras. No ensaio gastroentérico in vitro, as partículas de pectina e alginato (PEC:ALGPart) sem recobrimento e as recobertas com gelatina de pele de tilápia (GPTPart) foram resistentes as condições gástricas e entéricas, permanecendo íntegras. As partículas recobertas com isolado proteico de soja (IPSPart) e com a mistura de proteínas (IPS:GPTPart), foram resistentes às condições gástricas, porém desintegraram-se em meio intestinal, liberando o material encapsulado / Abstract: The aim of this work was to produce particles of pectin and alginate by ionic gelation with subsequent coating with isolated soy protein (IPS), tilapia skin gelatin (GPT), and a mixture of these two proteins (IPS:GPT), evaluating their physico-chemical characteristics and behavior to different treatments. In the preliminary study, the conditions that promote the balance of free electrical charge due the interaction between polysaccharides and proteins were analyzed. From these tests the following proportions of polysaccharide:protein and pH values were established: 1:2 at pH 4 for covering with tilapia skin gelatin, and 1:0.75 at pH3 for interaction with the isolated soybean protein and mixing of the two proteins. Four protein levels were tested (1, 2, 4 and 8%) in solutions for coating the particles of pectin and alginate. The particles obtained were characterized by moisture content, adsorbed protein content and their morphology. From this preliminary study it was selected the concentration of 8% protein solution, due to the production of particles with high protein content. These particles were evaluated for their stability against pH changes, different concentrations of NaCl and simulation under the simulated gastrointestinal conditions. Using a concentration of 8% protein solution high levels of protein adsorption were obtained, resulting in percentage of protein adsorbed of 61.87%, 47.61% and 52.06% for the coated particles GPT, IPS and IPS: GPT, respectively. The variation of pH and salt concentrations influence the solubility of the protein layer having a higher solubility in conditions of extreme acidity (pH 1) and the extent to which increased salt concentration. In the pH ranges and concentrations of NaCl studied, regardless of the amount of protein solubility obtained, all the particles remained intact. In the gastrointestinal assay, pectin and alginate particles (PEC: ALGPart) uncoated and coated particles with tilapia skin gelatin (GPTPart) were resistant to the gastric and enteric conditions, remaining intact. The coated particles with isolated soy protein (IPSPart) and the protein mixture (IPS:GPTPart) were resistant to gastric conditions, but disintegrated in the intestinal environment, releasing the encapsulated material / Mestrado / Nutrição Experimental e de Alimentos / Mestra em Alimentos e Nutrição

Wound infection is a major clinical burden that can significantly impede the healing process and cause severe pain. Prolonged wound infection can lead to long-term hospitalization or death. Pre-clinical research to evaluate new drugs or treatment strategies relies on animal studies. However, animal studies have several challenges including interspecies variations, cost, and, ethics question the success of these models. Recent advances in tissue engineering have enabled the development of in vitro human skin models for wound infection modeling and drug testing. The existing skin models are mostly representative of the healthy human skin and its normal functions. However, to study the wound healing process and the response of skin to the infection, there is still a need to develop a skin model mimicking the wound infection. This work presents a simplified functional infected epidermis model, fabricated with enzymatically crosslinked gelatin hydrogel. The immortalized human keratinocytes, HaCaT cells, was successfully cultured and differentiated to a multilayer epidermis structure at the air-liquid interface, and expressed terminal differentiation marker, filaggrin, in the outer layer. The barrier function of the epidermis model was studied by measuring the electrical resistance and tissue permeability across the layer. The results showed that the developed epidermis model offered a higher electrical resistance and a lower drug permeability compared to the cell monolayer on gelatin and cell-free gelatin. To show the capability of the developed epidermis model in wound modeling and drug, the model was infected with Escherichia coli and the inflammatory response of keratinocytes was studied by measuring the level of proinflammatory cytokines, including IL-1β and TNF-α. The results demonstrated the proinflammatory response of the epidermis model to infection by producing a higher level of TNF-α and IL-1β compared to the control group. While treating with antibiotic ciprofloxacin terminated the proinflammatory response and reduced the level of TNF-α and IL-1β. The robust fabrication procedure and functionality of this model suggest that this model has great potential for wound modeling and high throughput drug testing. / Graduate

oundry production, which forms an integral part of the engineering industry, is a source of waste with a negative impact on the working and living environment. The pressure on greening the production in all production branches of industry does not dodge the foundry industry and technical engineers seek out possibilities of decreasing the negative impact of the production of casting on the environment. An important source of environmentally dangerous waste in foundry operation is the use of organic compounds during the preparation of shaping and core mixtures. Their substitution with materials that would ensure similar technological features of the shaping and core mixtures as the organic materials used hitherto and at the same time decrease the amount of solid, liquid and gaseous ecologically undesirable compounds used in or arising during the preparation and use of shaping and core mixtures, would be significant for decreasing the ecological burden connected to casting production. A promising group of materials usable as components of shaping and core mixtures are the biopolymer materials which can substitute the organic connective systems used in the production of foundry cores by the means of the so-called hot processes – Hot-Box and Warm-Box. This work focuses on the exploration of the technological and ecological features of several biopolymer materials available on the domestic market which have the potential to become a full alternative of the binders used so far on the basis of urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde and furan resins.

Předkládaná disertační práce se zabývá přípravou a charakterizací nových biokompatibilních nanovláken s potenciální aplikací v medicíně. V této práci byl výběr jednotlivých složek pro přípravu nanovlákenného materiálu zvolen tak, aby vyhovoval nárokům tkáňového inženýrství. Literární rešerše shrnuje poznatky o elektrostatickém zvlákňování a o jeho parametrech. Dále se věnuje možnostem elektrostatického zvlákňování proteinů kolagenu a želatiny a jejich směsmi se syntetickými polymery a biopolymery a anorganickými plnivy. Teoretická část řeší také různé postupy síťování nanovláken vedoucí ke zlepšení jejich hydrolytické stability a mechanických vlastností. Poslední část je zaměřena na anorganické nanotrubky halloysitu (HNT), které získaly svou pozornost díky svým vynikajícím fyzikálním a biologickým vlastnostem. V experimentální části byly zpracovány dvě případové studie, z nichž každá se zabývá přípravou nanovlákenných biomateriálů s potenciální aplikací v medicíně. První studie je zaměřena na přípravu a charakterizaci nových hydrolyticky stabilních antibakteriálních želatinových nanovláken modifikovaných pomocí oxidované celulózy. Unikátní inhibiční účinky nanovláken byly testovány na kmenu bakterie Escherichia coli pomocí metody chemické bioluminiscence. Kultivované buňky lidského papilárního adenokacinomu plic prokázaly dobrou adhezi a proliferaci k povrchu nanovláken. Druhá část popisuje vliv zdroje a množství anorganických halloysitových nanotrubek na strukturu a vlastnosti amfifilních nanovláken ze směsi želatiny a syntetického polykaprolaktonu. Přídavek HNT zlepšil tepelnou stabilitu, mechanické vlastnosti (jak tuhost, tak prodloužení) a snížil krystalinitu nanovláken. HNT z různých zdrojů neměl vliv na chování buněk, ale mírně ovlivnil proliferaci a životaschopnost buněk na povrchu nanovláken.

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Heavy metal ions are one of the most toxic materials in the environment. Adsorption is the most used process for the removal of heavy metals from wastewater. Much research has been conducted into processes to remove heavy metals using different adsorbents. Various adsorbents have been used to remove heavy metal ions from wastewater especially those that are harmful to mankind. Zeolite, clay, activated carbon and biopolymers are the most common adsorbents used. In this research, gelatin, and cellulose nanocrystals (CNCs) were used to synthesize a hydrogel membrane to remove Cu(II) and Co(II) metal ions from mining processes wastewater. The synthetic wastewater was prepared in the laboratory to conduct the experiments. Batch experiments were conducted to obtain the optimum conditions for the Cu(II) and Co(II) metal ions. The effect of parameters such as pH, ratio, contact time, and temperature were also determined. The optimum conditions obtained were 120 min contact time for both metal ions at the temperature of 30oC, pH 5 for copper and pH 7 for cobalt. The high removal of both metals ions was obtained using the ratio 3:1 (75% Gelatin and 25% CNCs) at the temperature of 303K. The maximum adsorption capacity of Cu(II) and Co(II) was 7.6923 mg/g and 10.988 mg/g, respectively. The high percentage removal of Cu(II) and Co(II) metal ions obtained was found to be 70.5% for Cu(II) at pH 5 and 74.5% for Co(II) at pH 7. The experimental data fit well to Pseudo-first-order kinetic and Freundlich isotherm models (KF= 1.89x103 mg/g for copper and 3.7x102 mg/g for cobalt) for both metal ions. The values of energy (E) from D-R model have shown that the adsorption of both metal ions was of physical nature (E<8kJ/mol) then confirmed by the thermodynamic results (ΔH°). The kinetic diffusion models have shown that the experimental data fit well with the film diffusion (R2= 0.977 and 0.989) for both metal ions at pH 5. Negative values of ΔG°obtained for both metal ions indicate that the adsorption process was spontaneous. The positive values of ΔH° obtained showed a physical adsorption process and also indicate that the adsorption process of both metal ions was endothermic. The positive values of ΔS° indicate an increase in randomness at the solid/solution interface during adsorption.

Bone transplantation is regarded as the preferred therapy to treat a variety of bone defects. Autologous bone tissue is often lacking at the source, and the mesenchymal stem cells (MSCs) responsible for bone repair mechanisms are extracted by invasive procedures. This study explores the potential of autologous mesenchymal stem cells derived from the hair follicle outer root sheath (MSCORS). We demonstrated that MSCORS have a remarkable capacity to differentiate in vitro towards the osteogenic lineage. Indeed, when combined with a novel gelatin-based hydrogel called Osteogel, they provided additional osteoinductive cues in vitro that may pave the way for future application in bone regeneration. MSCORS were also compared to MSCs from adipose tissue (ADMSC) and bone marrow (BMMSC) in a 3D Osteogel model. We analyzed gel plasticity, cell phenotype, cell viability, and differentiation capacity towards the osteogenic lineage by measuring alkaline phosphatase (ALP) activity, calcium deposition, and specific gene expression. The novel injectable hydrogel filled an irregularly shaped lesion in a porcine wound model displaying high plasticity. MSCORS in Osteogel showed a higher osteo-commitment in terms of calcium deposition and expression dynamics of OCN, BMP2, and PPARG when compared to ADMSC and BMMSC, whilst displaying comparable cell viability and ALP activity. In conclusion, autologous MSCORS combined with our novel gelatin-based hydrogel displayed a high capacity for differentiation towards the osteogenic lineage and are acquired by non-invasive procedures, therefore qualifying as a suitable and expandable novel approach in the field of bone regeneration therapy

The local release of complexed siRNA from biomaterials opens precisely targeted therapeutic options. In this study, complexed siRNA was loaded to gelatin microparticles cross-linked (cGM) with an anhydride-containing oligomer (oPNMA). We aggregated these siRNA-loaded cGM with human mesenchymal stem cells (hMSC) to microtissues and stimulated them with osteogenic supplements. An efficient knockdown of chordin, a BMP-2 antagonist, caused a remarkably increased alkaline phosphatase (ALP) activity in the microtissues. cGM, as a component of microtissues, mineralized in a differentiation medium within 8–9 days, both in the presence and in the absence of cells. In order to investigate the effects of our pre-differentiated and chordin-silenced microtissues on bone homeostasis, we simulated in vivo conditions in an unstimulated co-culture system of hMSC and human peripheral blood mononuclear cells (hPBMC). We found enhanced ALP activity and osteoprotegerin (OPG) secretion in the model system compared to control microtissues. Our results suggest osteoanabolic effects of pre-differentiated and chordin-silenced microtissues.