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1
Clegg, Stuart Mark. „Gelation and melting of gelatin“. Thesis, Cranfield University, 1990. http://dspace.lib.cranfield.ac.uk/handle/1826/4514.
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Chiroptical, rheological and thermodynamic studies have been undertaken to investigate temperature-induced changes in the ý molecular organisation of gelatin. From the results obtained, a unified model for gelation and melting has been developed, and tested using Monte Carlo computer simulation. The temperature at which gelatin gels are formed has a major influence on the properties of the resulting network, with higher curing temperatures conferring increased thermal stability. In particular, gels formed by sequential curing at two different temperatures show biphasic melting. This is explained in terms of a temperature-dependence of helix length within the junction zones of the gel, and quantified by considering end-effects in the thermodynamics of helix stability. Measurements of 'initial slope' kinetics, performed over a broad concentration range, showed first-order kinetics at low gelatin concentrations, while at higher concentrations a second-order process was also evident. The results are interpreted as triple-helix nucleation at metastable 'hairpin turns' in one chain (bringing two chain segments into close proximity) together with a third strand from either the same chain (first order) or a different chain (second order). From simple geometric considerations, the maximum length of intermolecular helices ( which contribute to the gel network) is greater than that of twasted 9 intramolecular structures, giving a qualitative explanation of the increased strength of gels formed by precuring at higher temperatures (where only long helices are stable) over those quenched directly to low temperature. Monte Carlo simulation incorporating an initial assumption that helix propagation is rapid and proceeds to geometric limits gave unrealistic helix lengths and simulated melting profiles, and was replaced by the assumption that cis-trans isomerisation of peptide bonds is the controlling factor in helix propagation. Using the latter assumption, most aspects of the observed behaviour were successfully reproduced using program variables set within realistic ranges or, where possible, fixed at experimentally-determined values. In particularg the co-operativity of the simulated melting process was critically dependent on the value of a parameter x (the number of triplet units within each helix incapable of participating in bonding, due to end-effects), with a value of x=1 giving the best fits with experiment (consistent with accepted bonding patterns for the collagen triple helix). Other key parameters were the midpoint temperature for melting of the parent collagen, which gave best agreement when set at 37-38"C, and t6e proportion of cis peptide residues present in disordered gelatin chains, with an optimum lower limit of 0.15. Using these values, the simulation reproduced, with excellent precision, the helix fraction and melting profile of gels formed over a wide range of quench temperatures, and gave an acceptable approximation to the form of reaction progress curves obtained for helix formation. The biphasic melting of samples held at intermediate temperature before final quenching was also modelled realistically.
2
Pepino, Rebeka de Oliveira. „Desenvolvimento de géis e esponjas de quitosana e blendas quitosana/gelatina em ácido adípico“. Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-19042016-162109/.
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A quitosana é um biopolímero estudado em diversas áreas, tais como, ambiental, alimentícia, farmacêutica, biomédica e biotecnológica. Ela pode ser obtida de diferentes formas polimórficas de quitina, dentre as quais a forma β tem se mostrado vantajosa, pois favorece modificações químicas mais homogêneas e leva a um produto final menos alergênico. A quitosana pode ser combinada com outros compostos a fim de interagir e/ou reagir com eles e modificar suas propriedades. O objetivo deste trabalho foi estudar como uso de ácido adípico, em substituição ao acético, afeta as propriedades de géis e esponjas de quitosana e de quitosana/gelatina, que foram posteriormente reticuladas com os agentes reticulantes EDC/NHS. As técnicas utilizadas para os estudos foram: reologia, FTIR, MEV, absorção em PBS e ensaios de citotoxicidade. Por reologia, observou-se que o aumento na concentração dos géis de quitosana tornou os géis mais elásticos e viscosos. O mesmo ocorreu na presença de gelatina ou EDC/NHS. O efeito do uso de ácido adípico em substituição ao acético também foi mostrado nos ensaios reológicos, pois os géis com 2% de quitosana e com quitosana/gelatina sem EDC/NHS se mostraram mais elásticos e mais viscosos quando o ácido adípico foi usado. Os espectros FTIR mostraram a presença de interações entre a quitosana e a gelatina e a formação de ligações amidas II após reticulação com EDC/NHS. Na preparação das esponjas observou-se que os géis de quitosana em ácido adípico geravam esponjas instáveis que se desfizeram durante a neutralização, mas essa instabilidade não ocorreu com a blenda. As esponjas preparadas com a blenda foram estudadas após neutralização e o MEV mostrou que o uso de EDC/NHS alterou a morfologia levando a formação de poros interconectados. Nos ensaios de absorção em tampão de PBS foi observado que o uso de ácido acético aumenta a absorção para as esponjas sem EDC/NHS, enquanto para as esponjas com EDC/NHS a absorção é maior quando se usa ácido adípico. Todas as esponjas foram não citotóxicas o que torna esses materiais promissores para serem estudados em aplicações na área médica, tais como material de curativo, implantes, liberação controlada de fármacos.Chitosan is a natural polymer studied in various fields such as environmental, food, pharmaceutical, biomedical and biotechnology. It can be obtained from different polymorphic forms of chitin, of which the form β has proven advantageous because it promotes more homogeneous and chemical modifications leads to a final product less allergenic. Chitosan can be combined with other compounds and thus further improve its properties. The aim of this study was to analyze how the use of adipic acid, replacing acetic acid affects the properties of gels and sponges of chitosan and chitosan/gelatin, which were subsequently crosslinked with EDC/NHS. The techniques used for these studies were: rheology, FTIR, SEM, absorption in PBS and cytotoxicity assays. In rheology, it was observed that increasing the concentration of chitosan was possible to prepare more elastic and viscous gels. The same occurs in the presence of gelatin or EDC/NHSO. The effect of the use of adipic acid to replace the acetic acid was also shown on rheological measurements, because the gels with 2% chitosan or chitosan/gelatin without EDC/NHS were more elastic and more viscous when the adipic acid has been used. The FTIR spectra showed the presence of interactions between chitosan and gelatin and the formation of amide II Bonds after crosslinking with EDC/NHS. In the preparation of the sponges it was observed that the gels of chitosan with adipic acid generated unstable sponges crumbled during neutralization, but this instability does not occur with the blend. Sponges prepared with the blend were studied after neutralization and SEM showed that the use of EDC/NHS altered the morphology leading to the formation of interconnected pores. The use of acetic acid increases the absorption in PBS for sponges without EDC/NHS, while for sponges with EDC/NHS the absorption is greater when adipic acid was used. All sponges were non-cytotoxic making them promising materials to be studied for applications in the medical field, such as dressing materials, implants, controlled drug release.
3
Elliott, Delyth Elin. „Electrospinning of gelatin“. Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590136.
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Nanofibres have potential in biomedical and pharmaceutical applications including tissue engineering and drug release, which demand specific material properties to perform the required function without toxic side-effects, and preferably with minimal adverse ecological impact. Electrospinning is a promising technique for generating fibres with specific requirements and properties from organic, replaceable, non-toxic materials. Aqueous gelatin solution was chosen for its ability to react to changes in temperature. This work, including development of enhanced temperature control, demonstrated nanofibres of gelatin electrospun from aqueous solution with appropriate production conditions, which was previously unreported. To characterise the effects of the gelation mechanism caused by the partial reformation of the triple helix with aqueous gelatin solutions, electrospinning was attempted over a wide range of concentrations and temperatures. The study included measurements of the surface tension, viscosity and conductivity for the solutions, Scanning Electron Microscopy for size and form of product, and Wide Angle X•ray Scattering to ascertain the development of the structures from the solution to the fibre, determining the presence of the triple helix structure, and ThermoGravimetric Analysis to determine fibre water content. To provide comparison and continuity with previous studies, solutions of gelatin dissolved in glacial acetic acid, and polystyrene dissolved in MEK and DMF was electrospun and the products characterised in a similar manner to aqueous gelatin. Polystyrene solutions were chosen as examples of non-gelling solutions, thereby providing a contrast to the aqueous gelatin solutions. A potential area for nanofibres is in drug delivery. Aspirin (acetylsalicylic acid) was considered as an example, but its solubility in water is insufficient to incorporate into electrospun nanofibres for this purpose. Hence, the soluble salt, sodium acetylsalicylate, which shares some of the same medicinal properties as aspirin, was chosen. Nanofibres were electrospun from a solution of gelatin and sodium acetylsalicylate dissolved in water, but then 'disappeared', presumed to have dissolved in air moisture. This demonstrated that gelatin nanofibres could be considered for drug delivery, but further studies would be required to determine methods to stabilise the fibres. Gelatin was dissolved in a suspension of cellulose nanofibres derived from carrots and the resulting liquid was successfully electrospun to produce nanofibres. The nanofibres did not exhibit the expected properties of the gelatin triple helix structure. Attempts to silver coat gelatin nanofibres for medical applications, using Tollens' reagent showed the fibres must be made less soluble by polymer cross-linking or otherwise. A limited study of incorporating gold nanoparticles within the nanofibres to increase their electrical conductivity was inconclusive as the elemental analysis equipment was unable to detect the gold.
4
Jiang, Junyuan. „Gelation Time and Rheological Property of Gelatin Gels Prepared with a Phosphate-buffered Saline-ethanol Solution“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1430821495.
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Marfil, Paulo Henrique Mariano. „Estudo reológico de sistemas gelatina/colágeno/amido para obtenção de géis e aplicação dietéticas de gelatina /“. São José do Rio Preto : [s.n.], 2010. http://hdl.handle.net/11449/90752.
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Resumo: O comportamento reológico de soluções aquosas de gelatina e colágeno hidrolisado (4 e 10 % de sólidos totais) e de gelatina e amido de milho modificado de forma ácida (AMMA) (10 % de sólidos totais) foi estudado através de testes dinâmicos oscilatórios em um reômetro de tensão controlada com geometria cone e placa (60 mm de diâmetro e distância de trabalho de 52 mm). Para todas as concentrações, o módulo de armazenamento, G', aumentou com aumento da freqüência angular. Como esperado, os valores dos módulos correspondentes aos platôs aumentou com o aumento da concentração de gelatina e os valores de G' foram maiores nas soluções contendo amido. Os valores de G' e G' aumentaram com a diminuição da temperatura. O colágeno hidrolisado não apresentou comportamento de gel. A substituição de 25 % de gelatina por amido de milho modificado resultou em valores similares de G' nas amostras contendo somente gelatina. Foi realizado um estudo de separação de fases nas suspensões aquosas de gelatina e AMMA através de microscopia laser confocal, sendo observado que os biopolímeros co-existem, sem separação de fases na amostra em que gelatina e AMMA representam, respectivamente, 37,5 % e 62,5 % dos sólidos totais. Em geral, os demais sistemas apresentaram separação de fases, sendo esta mais pronunciada à medida que as amostras foram ficando enriquecidas com gelatina ou amido. Também foi estudado o comportamento reológico por compressão e as propriedades colorimétricas de gomas de gelatina dietéticas enriquecidas com colágeno hidrolisado e preparadas à base de xarope de maltitol e xilitol. A análise dos parâmetros de textura e o estudo colorimétrico permitiram observar que não há efeitos significativos (p<0,05) na interação entre concentração de gelatina e colágeno hidrolisado quanto à dureza das amostras. Além disso, a maior concentração... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: The rheological behavior of aqueous solutions of gelatin and hydrolyzed collagen (4 and 10 % total solids) or gelatin and acid modified corn starch (AMCS) (10 % total solids) was studied. A controlled stress rheometer fitted with a cone and plate geometry (60 mm, gap 52 mm) was used for the dynamic oscillatory shear tests. For all concentrations, the storage modulus increased with the increasing angular frequency. As expected, the modulus plateau values increased with gelatin concentration increasing and G' was higher in the solutions with modified corn starch. G' and G' values attained the highest observed values at lower temperatures. Hydrolyzed collagen did not show gel formation ability. When 25 % of the gelatin content was substituted by AMCS, the observed values of G' were similar to those corresponding to pure gelatin suspensions. A phase separation study was carried out with gelatin and AMCS aqueous suspensions using confocal laser scanning microscopy. The results showed that the two biopolymers co-exist, without phase separation in a system containing 37,5 % of gelatin and 62,5 % of AMCS (based in a 10 wt% total solids). In general, the others systems showed phase separation, which was more intense with increasing gelatin/AMCS concentration. The rheological behavior in compression and the optical proprieties of diet gelatin gummy enriched with hydrolyzed collagen were also studied. The gummies were prepared with maltitol syrup and xilitol. The analysis of texture and opacity parameters showed that significant effects (p<0.05) were not observed in the interaction between the two factors with regard to samples hardness. High concentrations of gelatin and hydrolyzed collagen resulted in a high opacity. The rheological behavior in compression and the optical proprieties of gelatin/AMMA gels were also studied. When AMCS was introduced into gelatin gels, the system structure... (Complete abstract click electronic access below)
Orientador: Vânia Regina Nicoletti Telis
Coorientador: Geórgia Álvares Castro Fernandes
Banca: Rosiane Lopes da Cunha
Banca: Célia Maria Landi Franco
Mestre
6
Kirby, Shaun. „The behaviour of gelatin and gelatin surfactant complexes at the oil/water interface : a study of dye transport and gelatin adsorption“. Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260572.
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7
Gardiner, Michael. „The behaviour of gelatin and gelatin surfactant complexes at the electrolyte/oil interface“. Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280623.
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8
Lancelotti, Cindia. „Preparação e caracterização de hidrogéis neutros de colágeno aniônico:gelatina:extrato de semente de uva“. Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-11122014-171635/.
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O desenvolvimento de uma matriz de colágeno associado à gelatina tem potencial como biomaterial devido sua alta biocompatibilidade, capacidade de alterar suas propriedades físico-químicas e estruturais por modificações químicas e a habilidade de formar géis estáveis. Porém, um ponto negativo de sua aplicação está na biodegradabilidade. Desta forma, para reduzir esta degradação, agentes de reticulação, como a proantocianidina (PA), que age formando ligações de hidrogênio as quais estabilizam o complexo proteína-PA, podem ser empregados. Este trabalho teve como objetivo a obtenção de hidrogéis neutros de colágeno aniônico:gelatina:extrato de semente de uva. Para tanto, foram utilizadas duas proporções de extrato, 0,25 e 0,50% e três diferentes tempos de hidrólise alcalina do colágeno, 24, 72 e 120 horas, gerando nove diferentes biomateriais, incluindo os hidrogéis sem tratamento com o extrato. O colágeno foi extraído de tendão bovino e o agente reticulante foi o extrato de semente de uva cujo componente majoritário é a proantocianidina. A caracterização foi feita por termogravimetria (TG), calorimetria exploratória diferencial (DSC), espectroscopia de absorção no infravermelho (FTIR), microscopia eletrônica de varredura (MEV), cinética de absorção de água e ensaios de citotoxicidade in vitro, pelos métodos de difusão em ágar e difusão de extrato em solução (MTT). Estudos de TG mostraram a perda de água em um processo único, representando em média 95% do hidrogel. As curvas DSC mostraram que quanto maior a concentração de extrato, maior é a temperatura de desnaturação, aumentando em média 6,8°C com a adição de 0,50% de extrato, o que indica a eficácia da proantocianidina na reticulação do colágeno. Além disso, notaram-se temperaturas menores para maiores tempos de hidrólise alcalina do colágeno, sendo de 58,4°C, 49,7°C e 46,5°C para hidrogéis preparados com colágeno 24, 72 e 120 horas, respectivamente. A presença do extrato não causou alterações significativas nos espectros FTIR, apenas surgimento das bandas em 1118 e 1288 cm-1 referentes ao anel aromático da proantocianidina, mas gerou mudanças nas estruturas internas dos hidrogéis, visualizadas por MEV, como aumento do número de poros e interconectividade entre eles. A cinética de absorção de água mostrou que o equilíbrio é atingido em aproximadamente 10 minutos, indicando vantagem para a aplicação do hidrogel, já que é obtido rapidamente a partir de sua forma liofilizada, adequada para o armazenamento. Também foi observado que quanto menor é o tempo de hidrólise, maiores são as absorções, variando de 540 até 1360%. Com os ensaios de citotoxicidade foi possível concluir que o hidrogel C24GE50 mostrou-se mais adequado para uma aplicação como biomaterial, com um índice de 92,7% de sobrevivência celular.The development of a collagen matrix associated with gelatin has potential as biomaterial due to its high compatibility, ability to change its physical-chemical and structural properties by chemical modifications and also the ability to form stable gels. However, a negative point of its application is the biodegradability. Thus, to reduce this degradation, crosslinking agents, such as proanthocyanidin (PA), which acts forming hydrogen bonds which stabilize the PA protein complex may be employed. This project aimed to obtain neutral hydrogels prepared by mixture of anionic collagen: gelatin: grape seed extract. It was used two extract proportions (0.25 and 0.50%) and three different periods of time for collagen alkaline hydrolysis (24, 72, 120 hours), giving nine different biomaterials, including hydrogels without treatment with the extract. The collagen was extracted from bovine tendon and the crosslinking agent was grape seed extract whose major component is the proanthocyanidin. The characterization was done by thermogravimetry (TG), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), water absorption kinetics and in vitro cytotoxicity assays, by agar diffusion method and diffusion of extract in solution (MTT). TG results showed loss of water in a single process, representing about 95% of the hydrogel.DSC curves showed that the higher the concentration of the extract, the higher the melting temperature, increasing on average 6.8 °C with the addition of 0.50% extract, which indicates the effectiveness of the proanthocyanidin crosslinking of the collagen. Moreover, lower temperatures were observed for longer periods of alkaline hydrolysis of collagen, being 58.4°C, 49.7°C and 46.5°C for preparations with 24, 72 and 120 hours, respectively. The presence of the extract did not cause significant changes in the FTIR spectra, only appearance of bands at 1118 and 1288 cm-1 related to the aromatic ring of proanthocyanidin but led to changes in internal structures of the hydrogels viewed by SEM, showing increased number of pores and interconnectivity between them. The water absorption kinetics showed that the equilibrium is achieved in approximately 10 minutes, indicating advantages in using this hydrogel, which is quickly obtained from its lyophilized form, a suitable form for storage. It was also observed that the shorter the time of hydrolysis, the greater the absorptions, ranging from 540 to 1360%. It was possible to conclude from the cytotoxicity analysis that the C24GE50 is more suitable for application as a biomaterial, with an index of 92.7% cell survival.
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Silva, Roberto de Souza Gomes da. „Obtenção de gelatina utilizando cabeças de carpa comum (Cyprinus carpio): avaliação das etapas de pré-tratamento e extração“. reponame:Repositório Institucional da FURG, 2010. http://repositorio.furg.br/handle/1/2574.
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A carpa comum (Cyprinus carpio) é conhecida por ser geradora de quantidade considerável de rejeitos mal aproveitados por indústrias pesqueiras. Estes rejeitos são constituídos por vísceras, peles, ossos e cabeças. Diversos fatores têm contribuído para a utilização de cabeças de carpa provenientes da industrialização, dentre estes a quantidade de cabeças desperdiçadas, que pode atingir 22% do volume da matériaprima, e é uma fonte de nutrientes de baixo custo e rica em colágeno. A maioria das gelatinas comerciais é derivada de mamíferos, sendo peles e ossos de bovinos e suínos as principais matérias-primas do produto. A gelatina é de uma proteína pura, digestível, que se obtém a partir da hidrólise à quente do colágeno, e por este motivo, o pescado torna-se uma potencial fonte de matéria-prima. A aplicação da gelatina é diversificada, podendo ser utilizada na indústria cosmética, farmacêutica,fotográfica e alimentícia. O presente estudo foi dividido em dois objetivos. Primeiramente foram avaliados os efeitos da concentração alcalina, tempo de pré-tratamento e prétratamentos com ou sem troca de solução alcalina do material para a obtenção de gelatina das peles das cabeças de carpa. Foi utilizado um planejamento fatorial 23 completo, e os fatores de estudo foram concentração de NaOH (3-4 M), tempo de prétratamento(45-105 min), e troca de solução de NaOH no pré-tratamento, tendo como respostas rendimento em gelatina, força do gel e ponto de fusão. Na segunda etapa, os ossos remanescentes deste processo foram utilizados para o estudo da influência da granulometria (1-2 mm) nas respostas consideradas das gelatinas extraídas da fração óssea, através da comparação das médias pela aplicação do teste de Tukey, com intervalo de 95% de confiança. Foram realizadas quatro extrações com pH e temperaturas de cada extração de 5,3-60°C, 4,4-70°C, 3,8-80°C e 3,6-85°C. Para as gelatinas extraídas das peles, o maior rendimento (2,27%) foi obtido com solução de NaOH 3 M, 45 min e sem troca de solução no pré-tratamento. Os maiores valores de força do gel (298,7 g) e ponto de fusão (29°C) foram obtidos a concentração de solução NaOH 3 M, 45 min e sem troca de solução alcalina. Para as gelatinas extraídas dos ossos, o maior rendimento (4,86%) foi obtido na granulometria de 1 mm. Os maiores valores de força do gel (128,2 e 131,5 g) não apresentaram diferença significativa (p≤0,05) e foram encontrados na primeira extração das granulometrias de 1 e 2 mm, respectivamente. Na fração óssea a 2 mm, se obteve o maior ponto de fusão, sendo 28,5°C na a primeira extração. O rendimento total da gelatina obtida a partir das cabeças de carpa foi de 7,13%.
Common carp (Cyprinus carpio) is known to produce large amount of byproduct does not made use for fisheries industries. These byproduct can be viscera, skin, bone and head, all riches in collagen. Several factors have been contributing to the use of the carp head coming from industrialization, among which the amount of carp head wasted, with which it can reach around 22% of the volume of the raw material, and it is a source of low costs nutrients. Most of commercial gelatin is derived from mammalian, being skins and bones of bovine and porcine the main raw material of this foodstuff. Gelatin is a pure and digestible protein, which is obtained from hydrolysis of the collagen, and for this reason, the fish become a potential source from raw material. Its application is branched out, being able to used in the cosmetic, pharmaceutical, photographic and food industries. The present study was divided into two parts. At first, it was valued the effect of alkaline concentration, pre-treatment time of the raw material, and treatment with and without change of alkaline solution, in the process of extraction of skin/muscles fraction gelatin of carp head coming from manufacturing processing of this fish. It was used 23 complete experimental design. Pre-treatment time (45-105 min), concentration of alkaline solution (3-4 M) and pre-treatment with change of alkaline solution were chosen as independent variable. Gelatin yield, gel strength and melting point were the response variable. At the second part, was valued of the influence of the bones granulometry (1-2 mm), remaining of the skin extraction of common carp head, in the gelatin yield, gel strength and melting point through the average results comparison by the Tukey test, where differences were considered significant at p≤0.05. It was used four extraction with pH and temperature of each extraction 5.3-60°C, 4.4-70°C, 3.8-80°C and 3.6-85°C. To the skin gelatin the higher gelatin yield (2.27%) was obtained with NaOH solution 3 M, 45 min and pre-treatment without change of alkaline solution. The higher gel strength (298.7 g) was achieved using NaOH solution 3 M, 105 min and pre-treatment without change of the alkaline solution. As for the melting point, the higher value (29.1°C) was obtained with NaOH solution 4 M, 45 min, and pre-treatment with change of NaOH solution. To the bones extraction, the higher gelatin yield was reached with size 1 mm (4.86%). The higher gel strength (128.2 and 131.5 g) were not significantly difference, and they were found in the first extraction with bones size 1 and 2 mm, respectively. Using 2 mm of granulometry, it was possible to obtain the higher melting point values, being 28.5°C to the first extraction.
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裕子, 鳥井, und Hiroko Torii. „Anti-adhesive effects of the newly developed two-layered gelatin sheet in dogs“. Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13045015/?lang=0, 2017. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13045015/?lang=0.
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外科手術後の癒着防止を目的としてゼラチンを使用した新規癒着防止材を開発した。ゼラチンを数種類の形状に加工し、その有用性を従来製材との比較のもとに検討した。実験により①熱架橋を行うことで性質を制御でき、様々な形状にも容易に加工できる。②創傷治癒を阻害することなく十分な癒着防止効果を持ち、従来製材では禁忌とされていた環境でも使用が可能である。③腹腔鏡手術でも使用可能な材型にも加工できるとの結果を得た。To prevent adhesion after surgical operation, we developed a new anti-adhesive material that is made of gelatin. We processed gelatin into several kinds of shapes and examined its usefulness compared with conventional materials. We got the result that ① it can be controlled properties by thermal crosslinking, and easily processed into various shapes ② It has sufficient anti-adhesive effects without inhibiting wound healing, and can be used the sites which are typically contraindicated for conventional materials. ③ it can be processed into a shapes that can be used also in laparoscopic surgery.
博士(理学)
Doctor of Philosophy in Science
同志社大学
Doshisha University
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Newell, John Christopher William. „Optical holography in dichromated gelatin“. Thesis, University of Oxford, 1987. http://ora.ox.ac.uk/objects/uuid:df0f4182-1743-47bf-a7f9-d90c312cd2e1.
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Chapter 1 contains an introduction to holography, holographic optical elements and coupled wave theory. Chapter 2 contains a detailed review of dichromated gelatin based on published literature and on experimental observations made during work for this thesis. In Chapter 3 the non-linearity of the recording characteristic and changes in the bulk properties of the material during processing are determined. In Chapter 4 the non-uniformity of planar gratings is investigated by making a detailed comparison with a coupled wave theory in which the grating parameters are functions of depth. The effect of different processing procedures on these non-uniformities is demonstrated. In Chapter 5 the mechanism behind the formation of real-time gratings in dichromated gelatin is determined by applying a dynamic form of coupled wave theory. The source of diffraction is found to be a pure absorption grating. In Chapter 6 the use of dichromated gelatin as a medium for copying holograms and for recording efficient noise gratings is demonstrated. In Chapter 7 a theoretical model of holographic optical elements based on vectorial coupled wave theory is presented and is used to investigate the effects of polarisation. In Chapter 8 an optical method for the measurement of distance is developed using the dispersive properties of an on-axis holographic lens. Conclusions are then presented in Chapter 9.
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Wittich, William John. „New Automated Industrial Technologies for Improving Chemical Penetration of Bovine Pieces in the Raw Material Processing and Conditioning Areas of Gelatine Manufacture“. Thesis, University of Canterbury. Chemical and Process Engineering, 2005. http://hdl.handle.net/10092/1115.
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The production of gelatine at Gelita N.Z. Ltd. is a time consuming process. The time limiting step in the process is the pre-treatment of the collagen tissue of the raw material in a lime/sodium sulfide solution. The liming solution breaks down the collagen in the tissue to gelatine. This is a necessary step prior to the extraction of gelatine from the hide pieces. The current liming process takes nearly 50 days to complete. Methods were investigated to increase the rate of penetration of the chemicals into the bovine hide raw material. An increase in the penetration of the liming solutions would lead to shorter processing times for this step in the process. The methods that were investigated were temperature controlled mixing, fluidization of the hide pieces and the use of ultrasound. Of all the methods tested, the fluidization of the hide pieces gave the best results. The pretreatment time of the hide pieces was reduced 9 days with this technique. Methods were also investigated to monitor the levels of conditioning in the raw material An accurate technique to measure hide conditioning was important to pilot plant trials. This helped determine how well any of the trail methods increased the penetration of chemicals into the hide pieces. The use of an ultraviolet dye proved an effective method of measuring conditioning for all the pilot plant trials. The level of chemical penetration was monitored by assessing the penetration of the UV dye. The penetration of the UV dye could be quantified by using imaging software. A possible method of monitoring conditioning in full-scale production was tested. It was determined that the glycosaminoglycans and soluble collagen released into the liming solution could be accurately measured, and related to the overall conditioning of the raw material.
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Sá, Anderson Moreira. „Desenvolvimento de materiais catódicos para células a combustível de óxido sólido (SOFC)“. Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/8497.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Fuel cells (FC) are electrochemical devices that convert chemical energy from certain fuels into electrical energy, through oxidation-reduction reactions. They have a basic structure consisting of an electrolyte layer intercalating two electrodes: the cathode (positive electrode) and anode (negative electrode). In this work, cathode materials for solid oxide fuel cells (SOFC) were developed, such as lanthanum cobaltite doped with strontium and iron (La0,6Sr0,4Co0,2Fe0,8O3-8-LSCF6428) was synthesized by the modified polymeric precursors method, also known as modified Pechini method and compared the performance with the composite electrodes La0,6Sr0,4Co0,2Fe0,8O3-8/Ce0,9 Gd0,1O2-8 (LSCF6428/ CGO) and La0,6Sr0,4Co0,2Fe0,8O3-8/Ce0,9Gd0,1O2-8/Prox (LSCF6428/CGO/PROX). The method of synthesis consists in the use of commercial gelatin as polymerizing agent for metal ions. The powder obtained at 350 ° C / 2h was calcined at 800 and 1000 ° C / 4h and characterized by thermal gravimetric analysis (TG), particle size distribution, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The films of (LSCF6428), (LSCF6428 / CGO) and (LSCF6428 / CGO / PROX) were obtained by serigraph of calcined powders at 1000 ° C. The films were deposited on ceria substrates doped with gadolinia Ce0,9Gd0,1O2-8(CGO), sintered at 1150°C and characterized by impedance spectroscopy (in pure oxygen) between 600 and 800°C. The obtained results indicated that the method used was efficient in the formation of porous powders and with the perovskite crystalline structure. The crystallite size for the composite of LSCF6428 / CGO was of 336 (nm) for the LSCF6428 and 98 (nm) for the CGO, being also the expected for a powder calcined at 1000 ° C. The value of the area specific resistance (ASR) for the electrode of pure LSCF6428 at 750 ° C was of 0.25 ohms.cm2 quite plausible, especially because it was not made use of platinum, for the LSCF/CGO/ Prox was obtained an ASR of 0.02 ohms.cm2 at 750 ° C.
As células a combustível (CaC) são dispositivos eletroquímicos que transformam a energia química de determinados combustíveis em energia elétrica, por meio de reações de oxirredução. Possuem uma estrutura básica que consiste em uma camada de eletrólito intercalando dois eletrodos: cátodo (eletrodo positivo) e anodo (eletrodo negativo). Neste trabalho, foram desenvolvidos materiais catódicos para células a combustíveis de óxidos sólidos (SOFC), tais como, a cobaltita de lantânio dopada com estrôncio e ferro (La0,6Sr0,4Co0,2Fe0,8O3-δ – LSCF6428) foi sintetizado pelo método dos precursores poliméricos modificado, também conhecido como Pechini modificado e comparado o desempenho com o de eletrodos compósitos La0,6Sr0,4Co0,2Fe0,8O3-δ/Ce0,9Gd0,1O2-δ (LSCF6428/CGO) e La0,6Sr0,4Co0,2Fe0,8O3-δ/ Ce0,9Gd0,1O2-δ/PrOx (LSCF6428/CGO/PrOx). O método de síntese consiste na utilização da gelatina comercial como agente polimerizante para íons metálicos. O pó obtido a 350 °C/ 2h foi calcinado a 800 e 1000 °C/ 4h e caracterizados por analise termogravimétrica (TG), distribuição de tamanho de partícula, difração de raio X (DRX) e microscopia eletrônica de varredura (MEV). Os filmes de (LSCF6428), (LSCF6428/CGO) e (LSCF6428/CGO/PrOx), foram obtidos por serigrafia de pós calcinados a 1000 °C. Os filmes foram depositados sobre substratos de céria dopada com gadolínia Ce0,9Gd0,1O2-δ (CGO), sinterizados a 1150 °C e caracterizados por espectroscopia de impedância (em oxigênio puro) entre 600 e 800 °C. Os resultados obtidos indicaram que o método utilizado foi eficiente na formação de pós porosos e com a estrutura cristalina perovskita. O tamanho de cristalito para o compósito de LSCF6428/CGO foi de 336 (nm) para o LSCF6428 e 98 (nm) para o CGO, sendo, também o esperado para um pó calcinado a 1000 °C. O valor da resistência específica de área (REA) para o eletrodo de LSCF6428 puro a 750 °C foi de 0,25 ohms.cm2 bastante plausível, principalmente por não ter sido feito uso de platina, para o LSCF/CGO/PrOx foi obtido uma REA de 0,02 ohms.cm2 a 750 °C.
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Redmond, Ian Russell. „Holographic optical elements in dichromated gelatin“. Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/946.
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Restall, Edward John. „Holographic optical interconnects in dichromated gelatin“. Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/694.
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Gebre-Mariam, T. „Drug migration in soft gelatin capsules“. Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381225.
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Gornall, Joanne Louise. „The helix-coil transition in gelatin“. Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612077.
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Steiger, Martyn R. „Gelatin-based bioadhesives for meniscal repair“. Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/131882/1/Martyn_Steiger_Thesis.pdf.
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This research was motivated by the paucity of bioadhesives possessing suitable mechanical and biological properties for meniscal repair. Gelatin-based biomaterials cured with light were investigated for this application with a focus on their tensile properties when adhered to meniscal tissue. A novel methodology for tensile testing meniscal bioadhesive tensile properties was developed and employed successfully. Candidate gelatin-based bioadhesives were identified that demonstrated suitable tensile properties and cytocompatibility for meniscal tear applications.
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Batista, Juliana Alves. „Desenvolvimento, caracterização e aplicações de biofilmes a base de pectina, gelatina e acidos graxos em bananas e sementes de brocolos“. [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255985.
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Orientador: Carlos Raimundo Ferreira GrossoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O desenvolvimento e a aplicação de filmes ou coberturas biodegradáveis são técnicas praticadas há vários anos que visam promover melhoria na qualidade do produto embalado ou revestido. O objetivo do presente trabalho foi desenvolver e caracterizar filmes a base de pectina e ácidos graxos e da mistura pectina/gelatina, adicionados ou não de ácidos graxos, e verificar sua eficiência como cobertura para bananas e sementes de brócolos. Os filmes foram caracterizados quanto às propriedades de barreira à água e ao oxigênio, solubilidade em água, propriedades mecânicas, opacidade e microscopia eletrônica de varredura (MEV). A adição crescente dos ácidos láurico, palmítico e esteárico e da mistura (blenda) desses ácidos (1:1:1) em todos os filmes elaborados promoveu um aumento da permeabilidade ao vapor de água, verificando-se através da MEV que não houve incorporação desse material lipídico na matriz filmogênica. Filmes compostos de pectina/gelatina apresentaram aumento da permeabilidade ao vapor de água e da opacidade, diminuição da resistência à tração e aumento da elongação, quando a blenda de ácidos graxos foi adicionada. Os filmes compostos com maior proporção de gelatina apresentaram a menor solubilidade em água. Todos os filmes caracterizados quanto à permeabilidade ao oxigênio apresentaram resultados semelhantes. A partir dos filmes obtidos com menor permeabilidade ao vapor de água e alta resistência à tração, as soluções filmogênicas foram elaboradas e aplicadas como cobertura para banana 'Nanica¿ e para sementes de brócolos 'Ramoso¿. Durante o armazenamento das bananas foram realizadas análises de cor, perda de massa e textura a cada dois dias. A contagem e observação de sementes germinadas foi realizada em média a cada três dias e ao final do experimento as plantas foram submetidas a quantificação do teor de matérias fresca e seca. As bananas com aplicação de cobertura apresentaram menor perda de massa e menor índice de dureza em relação ao controle. A aplicação tornou-se inviável devido a perda acentuada da dureza da fruta. No caso das sementes de brócolos, as coberturas filmogênicas não afetaram a emergência das plantas
Abstract: The development and application of edible films and coatings have been studied for a long time in order to improve the quality of a packed or coated product. The objective of this work was the development and characterization of pectin-based edible films with fatty acids and pectin/gelatin blend films with the addition of fatty acids or not and the application as coatings for bananas and broccoli seeds. Water vapor and oxygen permeability, solubility in water, mechanical properties, opacity and surface morfology were measured for the films. The addition of increasing concentrations of lauric, palmitic and stearic acid and their blend (1:1:1 v/v/v) increased water vapor permeability that was verified by the scanning electron microscopy that showed no incorporation of these lipids into the film matrix. Films with gelatin/pectin blend showed higher water vapor permeability, opacity and elongation and lower tensile strength when the fatty acids blend was additioned. Films with higher concentration of gelatin had lower solubility in water. There was no significant difference in oxygen permeability between all the films. Films with lower water vapor permeability and higher tensile strength were used as coatings for the application on 'Nanica¿ bananas and 'Ramoso¿ broccoli seeds. Weight loss, firmness retention and color were analyzed in each 2 days during the storage of bananas. For the seeds, counting and visual observation of the germinated seeds were effected in each 3 days, and the fresh and dried weight of the plants were determined in the end of the experiment. The coated bananas showed lower weight loss and also firmness retention than the control. The coating application is unfeasible due to the high loss of texture. The coated seeds showed no negative effect of the coating to the growing of the plants
Mestrado
Mestre em Alimentos e Nutrição
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Roman, Janesca Alban. „Isolado proteico de soro de leite e gelatina bovina : caracterização fisico-quimica, nutricional e tecnologica para o desenvolvimento de um produto geleificado“. [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/322565.
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Orientador: Valdemiro Carlos SgarbieriTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O isolado protéico de soro de leite bovino (WPI) utilizado nesse trabalho foi obtido em planta piloto através do processo de separação em membrana, ultrafiltração, diafiltração e liofilização. O processo de obtenção do WPI foi realizado na planta piloto do Instituto Nacional de Pesquisa Agronômica (INRA), Rennes¿França. Obteve-se WPI com 96,8% de proteína (base seca) e 2,2% de resíduos minerais em condições microbiológicas adequadas para o consumo, com perfil de aminoácidos apresentando quantidades suficientes de todos os aminoácidos essenciais. O perfil eletroforético e a cromatografia em coluna comprovaram que o WPI é composto principalmente pelas frações b-lactoglobulina (b-Lg) e a-lactalbumina (a-La) além de outras proteínas presentes, como albumina de soro bovino (BSA), imunoglobulinas (Ig) e outras em menores quantidades. A gelatina apresentou-se deficiente em relação a todos os aminoácidos essenciais e ausência de triptofano, apresentando elevadas concentrações dos aminoácidos não essenciais arginina, prolina, glicina e alanina, superiores às do WPI. A desnaturação térmica do WPI, determinada pela análise DSC ocorreu em 75,4ºC e da mistura 60:40% WPI/GB em 75,7ºC, ambas apresentando apenas um pico definido. Para a gelatina a desnaturação ocorreu em 36,1ºC. A solubilidade do WPI, pH entre 2,5 a 7,5, em solução aquosa e 0,1M NaCl foi elevada (87,4 a 97,5%), a gelatina apresentou solubilidade inferior (63%) sendo o valor mais baixo (24%), em pH 6,5. A solubilidade da mistura foi intermediária, na faixa de 58 a 81%. Estudou-se a influência da concentração de proteína (3,2 a 8,8%), da temperatura (51 a 79°C) e do tempo de aquecimento entre 10 e 40 min, na de textura de géis mistos. O gel com as melhores características foi o obtido com 60% WPI:40%GB, pH 6,5, aquecido 30 min a 65ºC, com 6% de proteína. A melhor textura encontrada foi na faixa de 270-310g-força, mastigabilidade e gomosidade próximas a 265 g-força, elasticidade e coesividade elevadas, 0,87-0,96. O gel misto (60WPI:40GB) apresentou capacidade de retenção de água de 48,6% enquanto que a do gel de GB foi 23,2%. O planejamento experimental elaborado permitiu uma boa descrição e previsão do comportamento de geleificação dos géis mistos em função da concentração de proteínas e da temperatura. Amostras de produtos geleificados à base de misturas de proteínas (soro de leite/gelatina) foram degustadas por 65 julgadores não treinados, utilizando-se a Escala Hedônica estruturada de nove pontos. As médias obtidas para os atributos de cor, sabor, aroma e textura, apresentaram-se nas categorias gostei ligeiramente e gostei regularmente. As maiores notas foram atribuídas à consistência, independentemente de formulação. O produto contendo isolado protéico de soro de leite apresentou aceitabilidade acima de 70%, semelhante à gelatina comercial, o que sugere um índice satisfatório de aceitação no mercado consumidor
Abstract: The bovine whey protein (WPI) utilized in the present work was obtained in pilot plant employing membrane ultrafiltration/diafiltration and liofilization. The WPI was obtained at the National Institute of Agronomic Research (INRA) at Rennes, France. WPI with 96.8% protein (dry basis), 2.2% ash, and adequate essential amino acids and microbiological profiles, was obtained. Electrophoretic and chromatographic profiles showed ß-lactoglobulin (ß-Lg), a-lactalbumin (a-La), bovine serum albumin (BSA) and imunoglobulins (Igs) as the major protein components of WPI. Gelatin revealed deficiency in all essential amino acids and absence of tryptofan, presenting elevated concentration of the non essential amino acids arginine, proline, glycine and alanine, which were at higher concentrations than in WPI. Difference Scanning Calorimetry (DSC) showed that WPI denatures at 75.4ºC and the WPI:BG mixture (60:40%) at 75.7ºC, both samples presenting only one defined pike. Gelatin (BG) denaturation occurred at 36.1ºC. The solubility of WPI, pH 2.5 to 7.5, in water or 0.1M NaCl solution was high (87.4 to 97.5%). For gelatin the highest solubility was 63% and the lowest (pH 6.5) 24%. The solubility of the mixture 60:40% was in the 58 to 81% range. The influence of protein concentration (3.2 to 8.8%), temperature (51 to 79ºC) and heating time (10-40min), in the texture of mixed gels, was studied. Best texture was defined in the range 270-310g-force, chewiness and gomosity around 265g-force, high elasticity and coesiviness (0.87-0.96). The 60% WPI:40%BG gel presented 48.6% water holding capacity (WHC) while for BG gel WHC was 23.2% The experimental design used permitted good prevision and description of the behavior of the mixed 60:40% WPI/BG gels, as a function of protein concentration and temperature. Samples of products were tasted by 65 non-trained judges, a non-structured mine point Hedonic Scale. Average scores were obtained for the color, taste, aroma, and texture. The highest scores were attributed to viscosity, independently of the formulation. The product containing 60% WPI and 40% BG presented acceptability above 70%, similar to the commercial gelatin, an index that suggests adequacy for market consumption
Doutorado
Nutrição Experimental e Aplicada à Tecnologia de Alimentos
Doutor em Alimentos e Nutrição
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Salles, Taís Helena Costa 1986. „Eletrofiação de nanofibras de blendas de gelatina/PVP (poli (vinil pirrolidona)) a partir de soluções de água e ácido acético“. [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263536.
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Orientador: Marcos Akira d'ÁvilaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: A eletrofiação é reconhecida como uma técnica eficiente para a fabricação de microfibras e nanofibras de polímero, devido à sua versatilidade e potencial para aplicações em diversos campos. As aplicações notáveis incluem engenharia tecidual, biossensores, filtração, curativos, liberação controlada de fármacos e imobilização de enzimas. As nanofibras são geradas através da aplicação de um campo elétrico em uma solução polimérica. As fibras fiadas por este processo oferecem várias vantagens, como elevada área de superfície em relação ao volume, alta porosidade e a capacidade de manipular a composição de nanofibras, a fim de obter as propriedades e funções desejadas. Neste trabalho, a eletrofiação de blendas de gelatina com polivinilpirrolidona (PVP) para a fabricação de nanofibras foi investigada. Os polímeros foram fiados a partir de soluções contendo diversas concentrações de água e ácido acético. As soluções foram fiadas a uma tensão positiva de 29,0-29,2 kV, uma distância da ponta da agulha ao coletor de 10 cm, e uma vazão de 1 mL / h. Todas as soluções foram avaliadas quanto ao pH, condutividade elétrica, tensão superficial e viscosidade. Foram investigados os efeitos da concentração de ácido acético nas propriedades das soluções que por sua vez, influenciaram no processo de obtenção de fibras por eletrofiação. Foi observado que há uma correlação entre a concentração de ácido acético e a formação de fibras desse sistema, assim como a influência no diâmetro final das fibras. No presente estudo, uma matriz de nanofibras uniformes com diâmetro aproximado de 519, 355 e 154 nm foram produzidas via eletrofiação. A morfologia das membranas foi avaliada por Microscopia Eletrônica de Varredura (MEV). Foi realizada a análise térmica termogravimétrica (TGA) e avaliação de citotoxicidade, visando futuras aplicações em engenharia tecidual
Abstract: The electrospinning is recognized as an efficient technique for the fabrication of polymeric microfibers and nanofibers due to its versatility and potential for applications in many fields. Notable applications include tissue engineering, biosensors, filtration, wound dressings, controlled drug release and enzyme immobilization. The nanofibers are generated by applying an electric field in a polymer solution. The fibers spun by this process offers several advantages such as high surface area relative to volume, high porosity and the ability to manipulate the composition of nanofibers in order to obtain the desired properties and functions desired. In this work, the electrospinning blends of gelatin with polyvinylpyrrolidone (PVP) to fabrication nanofibers were investigated. The polymers were electrospun from solutions containing various concentrations of water and acetic acid. The solutions were electrospun at a positive voltage of 29.0 to 29.2 kV, a distance from the needle tip to the collector of 10 cm and a flow rate of 1 mL / h. All solutions were analyzed as your pH, electrical conductivity, surface tension and viscosity. We investigated the effects of acetic acid concentration on the properties of the solutions, on the other hand, influenced the process of obtaining fibers by electrospinning. It was observed that there was a correlation between the concentration of acetic acid and formation of fibers of that system, as well the influence on the final diameter of the fibers. In the present study, a matrix of nanofibers uniform with diameters of approximately 519, 355 and 154 nm had been produced by electrospinning. The morphology of the membranes was evaluated by Scanning Electron Microscopy (SEM). We made thermal analysis (TGA) and assessment of cytotoxicity, aiming future applications in tissue engineering
Mestrado
Materiais e Processos de Fabricação
Mestra em Engenharia Mecânica
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Sousa, Lorena Oliveira de. „Obtenção e caracterização de membrana de gelatina e membrana de gelatina com prata para uso em regeneração tecidual guiada“. Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-07102013-152945/.
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O estudo de biomateriais aplicados à cicatrização levou à modalidade do tratamento chamada de regeneração tecidual guiada (RTG). A RTG reconstitui novos tecidos usando membranas como barreira de proteção da área defeituosa, impedindo a invasão de outros tecidos, especialmente dos tecidos conjuntivos fibrosos. Em outras palavras, a RTG é uma forma de isolar o tecido ósseo do tecido mole, resultando dessa forma em uma ótima condição para a formação óssea. Atualmente, mais de 20 tipos diferentes de polímeros são usados em aplicações biomédicas, e entre eles está o colágeno, polímero ao qual, pela sua hidrólise parcial pode-se obter a gelatina. A gelatina é um polipeptídeo biodegradável, biocompatível, que apresenta anti-genicidade, plasticidade e elasticidade. A prata tem seu efeito antimicrobiano bem conhecido, com utilidade em diferentes campos da medicina, odontologia e biomateriais. Nesse contexto, este trabalho desenvolve e estuda o comportamento das membranas de gelatina e membranas de gelatina com prata para aplicações em RTG. As Membranas de gelatina foram obtidas com concentração de 4% em massa e as membranas de gelatina com prata foram obtidas nas concentrações de 0,01%, 0,05% e 0,1% da solução. Na etapa de reticulação, as membranas secas foram imersas em solução tampão de fosfato de sódio com concentrações de glutaraldeído (GTA) a 0,5%, 1% e 2%, 24 horas. O ensaio de intumescimento foi realizado em membranas reticuladas e não reticuladas, pesadas e imersas em solução tampão de fosfato pH 7,4 por períodos de 5 minutos, 15 minutos, 30 minutos, 1 hora, 3 horas, 22 horas e 24 horas e durante 8 semanas. Obteve-se membranas de gelatina com prata mediante a metodologia de adição da solução de Ag compravada pelas técnicas de DRX, FTIR, MEV e pelo teste de halo de inibição. As membranas reticuladas apresentaram menor valor de porcentagem de intumescimento quanto maior foi a concentração do agente reticulante, com exceção das amostras com concentração de 0,1M de prata. Além da atuação do GTA a prata também interfere no processo de intumescimento, aspecto e comportamento das membranas de gelatina. O efeito bactericida foi avaliado utilizando ensaio de cultura de bactérias - Teste de halo de inibição, onde as membranas de gelatina com Ag apresentaram efeito bacteriostático contra bactéria Gram positiva e Gram negativa.The study of biomaterials applied to healing led to the treatment modality called guided tissue regeneration (GTR). The RTG reconstruct new tissue using the membranes as a barrier to protect the defective area, preventing the invasion of other tissues, especially connective tissue fibers. In other words, the RTG is a way of isolating the bone tissue of the soft tissue, thereby resulting in an excellent condition for bone formation. Currently, more than 20 different types of polymers are used in biomedical applications, and among them is the collagen polymer to which, by its partial hydrolysis can get the gelatin. Gelatin is a polypeptide biodegradable, which has antigenicity, plasticity and elasticity. Silver has antimicrobial effect well known, are useful in different fields of medicine, dentistry and biomaterials. In this context, this paper develops and studies the behavior of membranes of gelatin and gelatin silver membranes for applications in RTG. Membranes were obtained with gelatin concentration of 4% by weight and gelatin silver membranes were obtained at concentrations of 0.01%, 0.05% and 0.1% of the solution. In the crosslinking step, the dried membranes were immersed in sodium phosphate buffer to concentrations of glutaraldehyde (GTA) at 0.5%, 1% and 2% 24 hours. The swelling test was performed on crosslinked and uncrosslinked membranes, weighed and immersed in phosphate buffer pH 7.4 for a period of 5 minutes, 15 minutes, 30 minutes, 1 hour, 3 hours 22 hours and 24 hours, and for 8 weeks. Obtained gelatin membranes with silver by the method of adding the solution of Ag proven by XRD techniques, FTIR, SEM and the zone of inhibition test. The crosslinked membranes had lower percentage of swelling the higher the concentration of crosslinking agent, except for the samples with a concentration of 0.1 M silver. In addition to operating the GTA silver also interferes with the process of swelling, appearance and behavior of gelatin membranes. The bactericidal effect was evaluated by bacterial culture test - Test of inhibition zone, where the gelatin membrane with Ag Ag exhibited bacteriostatic effect exhibited against Gram positive and Gram negative.
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Vial, Ximena. „Gelatin Based Scaffolds for Bone Tissue Engineering“. Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/163.
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Bone is a dynamic tissue that in some cases, due to fractures, infection or interruption of blood supply, does not repair completely, leading to bone loss; therefore it is necessary to recur to bone grafts. However, bone grafts (i.e.autografts) may require additional surgery and present risks associated with potential disease transmission from donor to recipient (i.e.allografts). The limitations of these grafts have encouraged the pursuit of engineered alternatives that are based on the synchronous interplay between biomaterials, biological macromolecules and cells. 3-D gelatin-based scaffolds were prepared and evaluated for their ability to promote osteogenesis. Three types of gelatin based scaffolds were prepared via the crosslinking of gelatin B with glutaraldehyde or EDC/NHS in the presence or absence of PLG . The porosity and pore size of the scaffolds were controlled by varying the freeze-drying temperature (-20°C and -80°C). To promote osteogenesis, human stromal MIAMI cells were incorporated in the scaffolds. Results demonstrated MIAMI cells grew and spread actively throughout gelatin and gelatin/PLG scaffolds after 14 days of incubation. The rate of osteogenic activity was confirmed through histochemical staining for alkaline phosphatase and calcium. Mineral deposition was increased in the gelatin scaffold as opposed to the gelatin/PLG scaffold after at day 35.
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Rogers, Michael D. H. „Rheological properties of gelatin/starch composite gels“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58374.pdf.
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Parker, William 1969. „Brachytherapy dosimetry with fricke-gelatin and MRI“. Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22786.
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Magnetic Resonance Imaging (MRI) and Fricke-gelatin dosimetry are used to measure absorbed dose distributions from high dose rate (HDR) brachytherapy treatments. The high activity of the HDR brachytherapy source is suitable for the prompt delivery of the high doses required to give changes in the Fricke-gelatin Nuclear Magnetic Resonance (NMR) characteristics which are readily detected by MRI. The MR images can map 3D dose distributions deposited in the Fricke-gelatin matrix. Spin-lattice relaxation times (T1) and rates (R1) are computed from MR images of irradiated Fricke gelatin phantoms in order to study the dose response relationship for the Fricke gelatin system. It was confirmed that the Fricke gelatin system's R1 varies linearly with absorbed dose to a saturation limit. A fast approach for determining radiation dose from MR image intensity using a calibration curve is described. Dose distributions generated from MR images via the calibration curve show good agreement with expected distributions generated from a computerized treatment plan. As well, dose data generated using R1 maps agreed well with those generated by calibration curve. The use of MRI with Fricke-gel dosimetry is shown to be a viable means of verifying the dose distributions from high activity brachytherapy sources.
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Chatham, Sarah Marianna. „Characterisation of molten filled hard gelatin capsules“. Thesis, King's College London (University of London), 1985. https://kclpure.kcl.ac.uk/portal/en/theses/characterisation-of-molten-filled-hard-gelatin-capsules(5b2e73bf-b02c-4ecc-b00a-146fd90ec814).html.
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Thomas, M. „Gelatin film formation related to capsule production“. Thesis, Cardiff University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372355.
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Hager, Elizabeth A. (Elizabeth Ann). „Composite gelatin delivery system for bone regeneration“. Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32844.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, June 2005.Includes bibliographical references (p. 38-39).
In this thesis, the chemical/mechanical properties and biocompatibility of gelatin were investigated to produce a gelatin scaffold for the release of bone morphogenetic proteins (BMPs) from composite particles. This delivery system, designed to regenerate bone, holds much promise as an alternative to bone grafts. The chemical properties of gelatin were examined through zeta potential measurements, swelling studies, optical microscopy, environmental scanning electron microscopy (ESEM), and collagenase degradation. Compressive tests and mercury porosimetry were performed to study the mechanical and structural properties of the scaffold. The biocompatibility of the scaffold was determined through cell optical imaging and DNA quantification studies. Based on findings of this research, the material choices were made and the synthesis method for the gelatin scaffold was developed. Gelatin A, 300B, derived from bovine collagen, with an isoelectric point of [approx.] 9, was selected. Crosslinking was accomplished by reacting 10 w/v% glutaraldehyde with 10 w/v% gelatin solution. The most effective crosslinking condition was found to be 5 hours at room temperature. Glycine rinses were conducted to cap any non- reacted (toxic) aldehyde groups, and the necessary length of time was found to be at least 48 hours at 37⁰C. Finally, based on pore size distribution and mechanical stability, an optimal lyophilization method was developed with initial freezing at -20⁰C for 1 day, followed by lyophilization of the scaffold for 1-2 days. In terms of mechanical properties of the gelatin and amount of protein delivered, the most effective loading of poly(lactic-co-glycolic acid)/apatite/protein composite particles was found to be 10% of the mass of the gelatin.
by Elizabeth A. Hager.
S.B.
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Persson, Daniel, und Alexander Schmidt. „Utbyte av gelatin mot pektin i Namelaka“. Thesis, Örebro universitet, Restaurang- och hotellhögskolan, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-85929.
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Felix, Pascal Georges. „Characterization and correlation analysis of pharmaceutical gelatin“. [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000494.
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Di, Pietro Giovanna. „Silver mirroring on silver gelatin glass negatives /“. [S.l.] : [s.n.], 2002. http://edoc.unibas.ch/diss/DissB_6232.
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Nunes, Juliana Carla. „Preparação e caracterização de filmes comestíveis baseados em gelatina, chá-verde e nanoemulsão de óleo essencial de limão /“. Ilha Solteira, 2018. http://hdl.handle.net/11449/156001.
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Orientador: Marcia Regina de Moura AouadaResumo: Diante da crescente preocupação com os impactos ambientais relacionados ao uso de polímeros sintéticos, estudos visando à obtenção e aplicação de materiais poliméricos de fontes renováveis vêm aumentando, como por exemplo, o desenvolvimento de filmes comestíveis à base de polímeros naturais. Para a obtenção de filmes comestíveis necessita-se de um material polimérico que forme uma matriz homogênea e contínua. A gelatina é um polímero natural, de fonte abundante, biodegradável e biocompatível e tais características motivam sua utilização como matriz em filmes comestíveis. O uso de extrato de chá-verde e óleo essencial de limão em filmes de gelatina é uma alternativa para melhoria de suas características físicas e organolépticas para uma aplicação inovadora do produto como sachê de chá. Neste contexto, o objetivo do presente estudo foi preparar, caracterizar e avaliar a influência do extrato de chá-verde e da nanoemulsão de limão nas propriedades de solubilidade, mecânicas, térmicas e de permeabilidade ao vapor de água da matriz de gelatina. A nanoemulsão apresentou tamanho médio de 171 ± 3 nm e potencial zeta de -10,9 ± 0,1 mV. Os filmes foram obtidos por casting a partir de soluções filmogênica de gelatina com extrato de chá verde e nanoemulsão de limão. A adição de chá verde ocasionou um aumento da tensão máxima de ruptura do filme de gelatina de 86 ± 7 MPa para 101 ± 5 MPa e quando a nanoemulsão foi adicionada o valor diminuiu para 78 ± 8 MPa. A incorporação de chá-verde e ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In view of the growing concern about the environmental impacts related to the use of synthetic polymers, studies aimed to obtain and apply polymeric materials from renewable sources have been increased, as the development of edible films based on natural polymers. To obtain edible films, a polymeric material is needed to form a homogeneous and continuous matrix. Gelatin is a natural polymer, from an abundant source, biodegradable and biocompatible and such characteristics motivate its use as a matrix in edible films. The use of green tea extract and lemon essential oil in gelatin films is an alternative to improve its physical and organoleptic characteristics for an innovative application of the product as a tea bag. In this context, the objective of the present study was to prepare, characterize and evaluate the influence of the green tea extract and the lemon nanoemulsion on the solubility, mechanical, thermal and water vapor permeability properties of the gelatin matrix. The nanoemulsion had an average size of 170.6 ± 3 nm and a zeta potential of -10.9 ± 0.1 mV. The films were obtained by casting from filmogenic solutions of gelatin with green tea extract and lemon nanoemulsion. The addition of green tea caused an increase in the maximum tensile stress of the gelatin film from 86 ± 7 MPa to 101 ± 5 MPa and when the nanoemulsion was added the value decreased to 78 ± 8 MPa. The incorporation of green tea and nanoemulsion increased the permeability of water vapor and the solu... (Complete abstract click electronic access below)
Mestre
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Reis, Cathia dos. „Avaliação da capacidade emulsificante de gelatina acilada“. [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255643.
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Orientador: Rosiane Lopes da CunhaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A gelatina é uma proteína de alto interesse e valor comercial, no entanto seu uso como agente emulsificante ainda é bastante restrito devido à limitações tecnológicas. O objetivo geral deste trabalho foi investigar as alterações nas propriedades físicas, químicas e funcionais da gelatina de origem bovina quando submetida à modificação química através da reação de acilação com um cloreto de ácido graxo, bem como avaliar seu desempenho em aplicações com finalidade tecnológica de emulsificação. Para a definição das condições ótimas de reação de acilação (pH de reação e concentração do reagente), foram avaliados o grau de acilação (GA), a atividade (AE) e estabilidade emulsificante (ES), a força de gel (Bloom) e a viscosidade. As gelatinas aciladas obtidas foram também caracterizadas quanto aos teores de proteína, cinzas, umidade, cloretos, distribuição de peso molecular, ponto isoelétrico e espectroscopia de infravermelho. As emulsões (20% óleo) produzidas utilizando as gelatinas aciladas foram avaliadas através de medidas de separação visual de fases e determinação de tamanho de gota por microscopia ótica. Os resultados mostraram que a reação de acilação apenas tornou-se efetiva quando realizada em pH extremamente alcalino (pH 11,0), porém a força de gel e a viscosidade diminuíram nestas condições. As gelatinas aciladas com maior força de gel e viscosidade mostraram maior efeito na estabilização das emulsões do que o grau de acilação. Como conseqüência, as gelatinas ¿controle¿ apresentaram melhor atuação na estabilização das emulsões. Não foram observadas diferenças significativas na distribuição de ponto isoelétrico das gelatinas e nos espectros de infravermelho obtidos. No entanto, as gelatinas aciladas em pHs mais altos (pH 10,6 e 11,0) apresentaram aumento da massa molecular média quando comparadas as gelatinas ¿controle¿ devido a introdução do grupo acila na cadeia de gelatina
Abstract: Gelatin is a protein widely used in food industry. However, its use as an emulsifier agent is still restricted due to technological limitations. The objective of this work was to investigate the alterations at physical, chemical and functional properties of bovine gelatin after it has been subjected to a chemical modification through the acylation with a fatty acid chloride. In addition, the behavior of this acylated gelatin as emulsifier was evaluated. The acylation degree (AD), the emulsifying activity (EA) and stability (ES), the gel strength (or Bloom) and the viscosity of the modified gelatins were evaluated to define the more adequate conditions of the acylation reaction (pH and reactive concentration). The acylated gelatins were characterized regarding to protein, ash, moisture, chloride content, molecular weight distribution, isoelectric point distribution and infrared spectroscopy. O/W emulsions (20% oil) stabilized with acylated gelatins were evaluated through visual phase separation measurements and determination of drop size using optical microscopy. The results showed that the acylation reaction was effective only at very high pH (around 11.0). However, the gel strength and viscosity decreased at higher pH of reaction. Acylated gelatins with higher gel strength and viscosity showed more pronounced effect on emulsions stability than the acylation degree. As a consequence, the ¿control¿ gelatins presented better emulsion stability than acylated ones. It was not observed significant differences at isoelectric point distribution and infrared spectrum obtained for the acylated gelatins. However, acylated gelatins at higher pH (pH 10.6 and 11.0) showed an increase of the mean molecular mass when compared to the ¿control¿ gelatins due to the introduction of acyl groups to the gelatin chain
Mestrado
Engenharia de Alimentos
Mestre em Engenharia de Alimentos
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Lucena, Camilla Aquino Azevedo de. „Desenvolvimento e caracterização de filmes de xilana e gelatina para obtenção de formulações farmacêuticas transdérmicas“. Universidade Estadual da Paraíba, 2014. http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2245.
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Biodegradable films prepared from biopolymers such as polysaccharides, proteins, lipids or combinations of those components have received great interest in recent years. Xylan is the major hemicellulose in the plant kingdom and it accounts for onethird of renewable biomass available on earth. The aim of this work was to develop and characterize biodegradable films of xylan from corn cobs with potential use as transdermal formulations. Films were produced by casting the film-forming dispersions with different concentrations of xylan and glycerol. In addition, the gelatin was incorporated to xylan films. According to macroscopic characterization, three films were selected to evaluate the thickness, solubility, biodegradability, opacity, water content and microscopic morphology of the films. The best formulation was selected to study the incorporation of the drug (drug content and release profile). The results show that the macroscopic aspect of xylan/gelatin films was better than films containing only xylan, probably due the high solubility of the gelatin in the films. The increase in the polysaccharide concentration affected the films solubility, opacity, water content and thickness of films. The drug content was 87.88% and the drug release occurred mainly in the first 4h, followed by a slow release until the end of the study.
Filmes biodegradáveis desenvolvidos a partir de biopolímeros como polissacarídeos, proteínas, lipídeos ou através da combinação destes polímeros tem recebido grande interesse nos últimos anos. A xilana é a principal hemicelulose presente no reino vegetal e é responsável por um terço da biomassa renovável disponível na terra. O objetivo deste trabalho foi desenvolver e caracterizar filmes biodegradáveis à base xilana de sabugo de milho com potencial uso em formulações transdérmicas. Os filmes foram produzidos através da secagem das dispersões filmogênicas com diferentes concentrações de xilana e glicerol. Adicionalmente, a gelatina foi incorporada aos filmes. De acordo com a caracterização macroscópica foram escolhidas três formulações para caracterização de espessura, solubilidade, biodegradabilidade, opacidade, conteúdo de água e análise microscópica. Com base nestes resultados foi escolhido o filme para os estudos de incorporação do fármaco (teor e perfil de liberação). Os resultados mostraram que o aspecto macroscópico dos filmes de xilana/gelatina foi melhor que o dos filmes de xilana, isso ocorreu provavelmente devido à alta solubilidade da gelatina. O aumento da concentração de xilana afetou a solubilidade, conteúdo de água, espessura e opacidade dos filmes. O teor de diclofenaco sódico presente no filme foi de 87,88% e a liberação do fármaco se deu principalmente nas primeiras 4 horas, seguida de uma liberação lenta até o final do estudo.
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Oliveira, Camila Areias de. „Desenvolvimento, avaliação da segurança e eficácia clínica de sistemas nanoparticulados de gelatina contendo rutina“. Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-22122015-091834/.
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A associação de filtros solares a compostos bioativos tem sido estudada com ênfase na última década. Contudo, a solubilidade limitada dos compostos naturais, tais como a rutina, restringe o desenvolvimento de preparações cosméticas seguras, funcionais e estáveis. A proposta deste estudo envolveu a obtenção de nanoestruturas de gelatina (contendo ou não rutina) para aplicação em protetores solares. Os objetivos específicos foram: (1) preparar partículas de gelatina; (2) realizar a caracterização física, físico-química, morfológica, térmica e funcional (in vitro); (3) avaliar a citotoxicidade e a penetração/permeação curtânea in vitro dos sistemas; (4) desenvolver fotoprotetores bioativos de eficácia estimada in vitro; e (5) determinar a segurança e eficácia clínica fotoprotetora das preparações contendo as estruturas proteicas. As nanopartículas apresentaram-se esféricas e com diâmetro médio e índice de polidispersividade variando entre 318,9 ± 6,9 (B-NC) a 442,8 ± 4,9 nm (R-NC) e 0,06 ± 0,03 (B-NC) a 0,12 ± 0,01 (R-NC), respectivamente. Os valores do potencial zeta apresentaram-se entre -28,5 ± 0,9 mV (B-NC) e -26,6 ± 0,5 mV (R-NC). R-NC apresentou eficiência de associação equivalente a 51,8 ± 1,4%. Os ensaios de segurança das nanopartículas evidenciaram perfil citotóxico adequado para aplicação cosmética, bem como, a ausente tendência de penetração/permeação cutânea. Tendo em vista os resultados obtidos in vitro, as nanopartículas contendo rutina apresentaram capacidade antioxidante 74% superior à rutina em seu estado livre e contribuíram para o aumento de 48% do fator de proteção solar (FPS) quando associada à avobenzona (butyl methoxydibenzoylmethane), ao p-metoxicinamato de octila (ethylhexyl methoxycinnamate) e ao octil dimetil PABA (ethylhexyl dimethyl PABA). A avaliação da eficácia clínica das formulações evidenciou a influência da nanopartícula, sem adição do flavonoide, na proteção da pele contra a formação do eritema UV induzido. Por meio da avaliação dos aspectos funcionais, foi possível constatar, in vitro e in vivo, que a adição das nanopartículas em sistemas fotoprotetores influenciou seu perfil de transmitância da radiação UV, bem como, seus efeitos sobre o eritema UV induzido. Os resultados obtidos apresentaram perspectivas de aplicação prática no desenvolvimento de produtos cosméticos fotoprotetores associados a substâncias bioativas, por meio de plataforma nanotecnológica.Especially, in the last decade, the association of chemical filters and bioactive compounds has been studied by several authors. However, the limited solubility of natural compounds, such as rutin restricts the development of safe and stable cosmetic preparations. The aim of this work was the development of gelatin nanoparticles (with or without rutin) as an ingredient in sunscreens. The specific goals were: (1) the development of rutin-loaded gelatin nanoparticles; (2) to perform the physical, physical-chemical, morphological, thermal and functional (in vitro) analysis; (3) to assess the cytotoxicity and skin penetration / permeation in vitro of the nanoparticles; (4) to develop bioactive sunscreens and to perform the in vitro photoprotection efficacy assay; and (5) to evaluate the in vivo sun protection factor (SPF) of the formulations. The nanoparticles were spherical with an average size and polydispersive index between 318.9 ± 6.9 nm (B-NC) at 442.8 nm ± 4.9 (R-NC), and 0.06 ± 0, 03 (B-NC) to 0.12 ± 0.01 (R-NC). The zeta potential values were high and negative, ranging from - 28.5 ± 0.9 mV (B-NC) and -26.6 ± 0.5 mV (R-NC). R-NC entrapment efficient was 51.8 ± 1.4%. The nanoparticle safety assessment showed a cytotoxic profile suitable for cosmetic application, as well as the absent trend of penetration/ permeation of the skin. The in vitro results indicated that the rutin-loaded gelatin nanoparticles increased 74% the antioxidant profile in comparison with free rutin and also increased 48% the SPF (in vitro) when combined with butyl methoxydibenzoylmethane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl PABA. The assessment of the clinical efficacy assays showed the influence of blank nanoparticle in the protection of the skin against UV-induced erythema response. It was established in vitro and in vivo that the addition of gelatin nanoparticles in sunscreens influenced its UV transmittance profile, as well as its anti-erythema effects on the skin. The results have practical application in the development of sunscreen with bioactive ingredients and at the design of an innovative ingredient with a chemopreventive profile.
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Iahnke, Aline Oliveira e. Silva. „Filmes biodegradáveis com propriedades funcionais produzidos a partir de resíduos industriais“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/129775.
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Filmes e coberturas comestíveis têm recebido cada vez mais atenção e interesse por parte de indústrias e pesquisadores pois eles representam uma alternativa para substituir plásticos comumente utilizados para embalagens em indústrias alimentícias. Nesse contexto, filmes biodegradáveis foram produzidos a partir de resíduos da fabricação de cápsulas nutracêuticas compostas por gelatina, glicerina e água e combinados com farinhas de resíduos da indústria de minimamente processados de cenoura e beterraba. Todos os filmes elaborados foram caracterizados quanto às propriedades físico-químicas, mecânicas, de barreira, ópticas e antioxidantes. Dentre os filmes desenvolvidos, os que apresentaram essas características aprimoradas e com maior funcionalidade, foram selecionados para serem estudados quanto a sua estrutura, estabilidade térmica e proteção contra oxidação primária em óleo de girassol embalado pelos filmes. Em geral, a adição de farinhas aos filmes gelatinosos ocasionou: redução de umidade, solubilidade em água, swelling, permeabilidade ao vapor de água e elongação; aumento de opacidade, porcentagem de inibição do radical DPPH; maior proteção aos efeitos da luz e da oxidação primária de óleo de girassol; e estrutura menos lisa e homogênea quando comparado aos filmes sem adição de farinhas. Além disso, os filmes estudados apresentaram estabilidade térmica até aproximadamente 200 °C. Com isso, foi possível desenvolver filmes biodegradáveis com propriedades funcionais a partir de resíduos industriais e colaborar com o desenvolvimento de tecnologias sustentáveis.Edible films and coatings have gained increasing attention and interest from the industry and researchers, as they represent an alternative to replace commonly used plastics for packaging in the food industry. In this context, biodegradable films were produced from the residues from the manufacture of nutraceutical capsules, mainly composed of gelatin, glycerin and water, and combined with different residue flour derived from the minimal processing of carrot and beet root. All the prepared films were characterized regarding their physicochemical, mechanical, barrier, optical and antioxidant properties. The films which presented improved characteristics and greater functionality were selected to be studied regarding their structure, thermal stability and protection against primary oxidation of sunflower oil packed in the films. In general, the addition of the flour into the gelatin-based films caused: reduction in the moisture content, water solubility, swelling, water vapor permeability and elongation at break; increase in the opacity and percentage inhibition of DPPH radical; greater protection against the effects of light and primary oxidation of sunflower oil; and less smooth and homogeneous structure when compared to films without addition of flours. Furthermore, the studied films showed thermal stability up to approximately 200 ° C. Thus, it was possible to develop biodegradable films with functional properties from industrial residues and contribute to the development of sustainable technologies.
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Eastman, John. „The shear and extensional flow properties of polymer/surfactant solutions“. Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319075.
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Stevenson, Andre Terrance Jr. „Synthesis, Characterization and Performance of Gelatin Biopolymer based Nanoparticle Formulations for Molecule Encapsulations“. Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/94607.
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Gelatin's ability to dissolve in water while also forming a gel upon cooling, produces melt in your mouth candies and frozen desserts, along with hard and soft capsules and tablets. This protein, which is extracted from pork skin and cattle hide, is categorized by a rigidity or stiffness value and remains one of the most common materials in food and pharmaceutical formulations. Its established use and safe certification are appealing characteristics for manipulation into nanoparticles (NPs) to encapsulate therapeutic molecules as medicine.
NPs are generally spherical materials, yet their abilities hold great promise to improve medical outcomes. These abilities include: protecting molecules from harsh locations like the stomach, improved therapeutic delivery through biological barriers such as the brain and controlled release for minimal side effects. NPs typically less than 200 nanometers (nm) overcome biological barriers more effectively than larger particles. For reference, 200 nm is equivalent to dividing the length of an ant (~4 millimeters) by 20,000. The potential applications of gelatin NPs to treat disease is impressive; however, an inability to consistently obtain ideal NP sizes (<200 nm average diameter) exists. Furthermore, gelatin NPs are commonly stabilized (or cross-linked) using toxic chemicals. The motivation for this research was to (1) contribute new understanding why ideal gelatin NPs are difficult to obtain and (2) form NPs using a non-toxic chemical for prospective brain injury treatment.
This dissertation determined low rigid and high rigid gelatin can consistently form NPs less than 200 nm, indicating rigidity alone is not a main factor for obtaining ideal NPs. Instead, characterization approaches indicated gelatin sample composition prior to NP formation must be very uniform. As a result, filtering solutions prior to NP formation proved a new technique to prepare ideal NPs.
Glyceraldehyde is a sugar and has shown to be a non-toxic gelatin NP stabilizer. For the first time, glyceraldehyde's non-toxicity was shown using various brain cell types and NPs were formed to be ~130 nm. After incorporation of a new therapeutic molecule for brain injury treatment, average particles were ~149 nm with slow therapeutic release profiles determined in simulated body fluid.Ph. D.
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Tronci, Giuseppe. „Synthesis, characterization, and biological evaluation of gelatin-based scaffolds“. Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2011/4972/.
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This work presents the development of entropy-elastic gelatin based networks in the form of films or scaffolds. The materials have good prospects for biomedical applications, especially in the context of bone regeneration. Entropy-elastic gelatin based hydrogel films with varying crosslinking densities were prepared with tailored mechanical properties. Gelatin was covalently crosslinked above its sol gel transition, which suppressed the gelatin chain helicity. Hexamethylene diisocyanate (HDI) or ethyl ester lysine diisocyanate (LDI) were applied as chemical crosslinkers, and the reaction was conducted either in dimethyl sulfoxide (DMSO) or water. Amorphous films were prepared as measured by Wide Angle X-ray Scattering (WAXS), with tailorable degrees of swelling (Q: 300-800 vol. %) and wet state Young’s modulus (E: 70 740 kPa). Model reactions showed that the crosslinking reaction resulted in a combination of direct crosslinks (3-13 mol.-%), grafting (5-40 mol.-%), and blending of oligoureas (16-67 mol.-%).
The knowledge gained with this bulk material was transferred to the integrated process of foaming and crosslinking to obtain porous 3-D gelatin-based scaffolds. For this purpose, a gelatin solution was foamed in the presence of a surfactant, Saponin, and the resulting foam was fixed by chemical crosslinking with a diisocyanate. The amorphous crosslinked scaffolds were synthesized with varied gelatin and HDI concentrations, and analyzed in the dry state by micro computed tomography (µCT, porosity: 65±11–73±14 vol.-%), and scanning electron microscopy (SEM, pore size: 117±28–166±32 µm).
Subsequently, the work focused on the characterization of the gelatin scaffolds in conditions relevant to biomedical applications. Scaffolds showed high water uptake (H: 630-1680 wt.-%) with minimal changes in outer dimension. Since a decreased scaffold pore size (115±47–130±49 µm) was revealed using confocal laser scanning microscopy (CLSM) upon wetting, the form stability could be explained. Shape recoverability was observed after removal of stress when compressing wet scaffolds, while dry scaffolds maintained the compressed shape. This was explained by a reduction of the glass transition temperature upon equilibration with water (dynamic mechanical analysis at varied temperature (DMTA)). The composition dependent compression moduli (Ec: 10 50 kPa) were comparable to the bulk micromechanical Young’s moduli, which were measured by atomic force microscopy (AFM). The hydrolytic degradation profile could be adjusted, and a controlled decrease of mechanical properties was observed. Partially-degraded scaffolds displayed an increase of pore size. This was likely due to the pore wall disintegration during degradation, which caused the pores to merge.
The scaffold cytotoxicity and immunologic responses were analyzed. The porous scaffolds enabled proliferation of human dermal fibroblasts within the implants (up to 90 µm depth). Furthermore, indirect eluate tests were carried out with L929 cells to quantify the material cytotoxic response. Here, the effect of the sterilization method (Ethylene oxide sterilization), crosslinker, and surfactant were analyzed. Fully cytocompatible scaffolds were obtained by using LDI as crosslinker and PEO40 PPO20-PEO40 as surfactant. These investigations were accompanied by a study of the endotoxin material contamination. The formation of medical-grade materials was successfully obtained (<0.5 EU/mL) by using low-endotoxin gelatin and performing all synthetic steps in a laminar flow hood.Diese Arbeit beschreibt die Entwicklung Entropie-elastischer Gelatine-basierter Netzwerke als Filme und Scaffolds. Mögliche Anwendungen für die entwickelten Materialien liegen im biomedizinischen Bereich, insbesondere der Knochenregeneration. Im ersten Schritt der Arbeit wurden Entropie-elastische, Gelatine-basierte Hydrogel-Filme entwickelt, deren mechanische Eigenschaften durch die Veränderung der Quervernetzungsdichte eingestellt werden konnten. Dazu wurde Gelatine in Lösung oberhalb der Gel-Sol-Übergangstemperatur kovalent quervernetzt, wodurch die Ausbildung helikaler Konformationen unterdrückt wurde. Als Quervernetzer wurden Hexamethylendiisocyanat (HDI) oder Lysindiisocyanat ethylester (LDI) verwendet, und die Reaktionen wurden in Dimethylsulfoxid (DMSO) oder Wasser durchgeführt. Weitwinkel Röntgenstreuungs Spektroskopie (WAXS) zeigte, dass die Netzwerke amorph waren. Der Quellungsgrad (Q: 300-800 vol. %) und der Elastizitätsmodul (E: 70 740 kPa) konnten dabei durch die systematische Veränderung der Quervernetzungsdichte eingestellt werden. Die Analyse der Quervernetzungsreaktion durch Modellreaktionen zeigte, dass die Stabilisierung der Hydrogele sowohl auf kovalente Quervernetzungen (3-13 mol.-%) als auch auf Grafting von (5-40 mol.-%) und Verblendung mit Oligoharnstoffen (16-67 mol.-%) zurückgeführt werden kann. Die Erkenntnisse aus dem Umgang mit dem Bulk-Material wurden dann auf einen integrierten Prozess der Verschäumung und chemischen Quervernetzung transferiert, so dass poröse, dreidimensionale Scaffolds erhalten wurden. Dafür wurde eine wässrige Gelatinelösung in Gegenwart eines Tensids, Saponin, verschäumt, und durch chemische Quervernetzung mit einem Diisocyanat zu einem Scaffold fixiert. Die Scaffolds hergestellt mit unterschiedlichen Mengen HDI und Gelatine, wurden im trockenen Zustand mittels Mikro Computertomographie (µCT, Porosität: 65±11–73±14 vol.-%) und Rasterelektronenmikroskopie (SEM, Porengröße: 117±28–166±32) charakterisiert. Anschließend wurden die Scaffolds unter Bedingungen charakterisiert, die für biomedizinische Anwendungen relevant sind. Die Scaffolds nahmen große Mengen Wasser auf (H: 630 1680 wt.-%) bei nur minimalen Änderungen der äußeren Dimensionen. Konfokale Laser Scanning Mikroskopie zeigte, dass die Wasseraufnahme zu einer verminderten Porengröße führte (115±47–130±49 µm), wodurch die Formstabilität erklärbar ist. Eine Formrückstellung der Scaffolds wurde beobachtet, wenn Scaffolds im nassen Zustand komprimiert wurden und dann entlastet wurden, während trockene Proben in der komprimierten Formen blieben (kalte Deformation). Dieses Entropie-elastische Verhalten der nassen Scaffolds konnte durch die Verminderung der Glasübergangstemperatur des Netzwerks nach Wasseraufnahme erklärt werden (DMTA). Die zusammensetzungsabhängigen Kompressionsmoduli (Ec: 10 50 kPa) waren mit den mikromechanischen Young’s moduli vergleichbar, die mittels Rasterkraftmikroskopie (AFM) gemessen wurden. Das hydrolytische Degradationsprofil konnte variiert werden, und während des Abbaus kam es nur zu kontrolliert-graduellen Änderungen der mechanischen Eigenschaften. Während der Degradation konnte ein Anstieg der mittleren Porengröße beobachtet werden, was durch das Verschmelzen von Poren durch den Abbau der Wände erklärt werden kann. Die Endotoxinbelastung und die Zytotoxizität der Scaffolds wurden untersucht. Humane Haut-Fibroblasten wuchsen auf und innerhalb der Scaffolds (bis zu einer Tiefe von 90 µm). Indirekte Eluat-Tests mit L929 Mausfibroblasten wurden genutzt, um die Zytotoxizität der Materialien, insbesondere den Einfluss des Quervernetzertyps und des Tensids, zu bestimmen. Vollständig biokompatible Materialien wurden erzielt, wenn LDI als Quervernetzer und PEO40 PPO20-PEO40 als Tensid verwendet wurden. Durch den Einsatz von Gelatine mit geringem Endotoxin-Gehalt, und die Synthese in einer Sterilarbeitsblank konnten Materialien für medizinische Anwendungen (Endotoxin-Gehalt < 0.5 EU/mL) hergestellt werden.
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Bria, Rosemarie Dorothy. „How Jell-O molds society and how society molds Jell-O : a case study of an American food industry creation /“. Access Digital Full Text version, 1991. http://pocketknowledge.tc.columbia.edu/home.php/bybib/1029871x.
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Thesis (Ed.D.)--Teachers College, Columbia University, 1991.Typescript; issued also on microfilm. Sponsor: Joan Dye Gussow. Dissertation Committee: Isobel Contento. Includes bibliographical references (leaves 198-203).
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Keller, Brian Michael. „Characterization of the NMR-based Fricke-gelatin dosimeter“. Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68194.
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In this thesis, the use of the Fricke-gelatin dosimeter in NMR-based radiation dosimetry is investigated. The relationship between the proton spin-lattice relaxation rate and the absorbed dose for the Fricke-gelatin dosimeter is determined using pulsed NMR at 25 MHz. This relationship is used to calculate the NMR dose sensitivity. Practical considerations of Fricke-gelatin dosimetry, such as the spontaneous conversion of ferrous to ferric ions and the effects of oxygen and sodium chloride on the dose response, are determined. Sensitization of the dosimeter by bubbling with a nitrous oxide/oxygen gas mixture is investigated. The system is modelled assuming a multi-site fast exchange between water bound to gelatin, water bound to ions, and water in the bulk. Preliminary aspects of the model are investigated and compared with experimentally determined data. Finally, the utility of the dosimeter is demonstrated by magnetic resonance imaging a Fricke-gel irradiated with an $ sp{192}$Ir radioactive seed.
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Alvarez, Gabriel Aguirre. „Gelatin Structures and their Storage Stability and Performance“. Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503783.
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Robertson, Brian. „Free-space holographic optical interconnects in dichromated gelatin“. Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1449.
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Nelson, Maria. „3D silica-gelatin hybrid scaffolds for tissue regeneration“. Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/56365.
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Cartilage defects affect millions of people worldwide however current treatment options do not provide the zonal organisation required to regenerate healthy hyaline cartilage. In particular, the regeneration of high density ECM and cells is required to provide the articular surface of the tissue. Developments in tissue scaffolds have typically focused on synthetic polymers with low bioactivity due to their ease of processing. Here, the silica-gelatin sol-gel hybrid system was further developed for 3D printing and electrospinning to generate a zonal, bioactive scaffold. GPTMS, (3-glycidyloxypropyl)trimethoxysilane, was used to couple the silicate network and gelatin molecules. A modified hybrid method was required to avoid rapid gelation but retain high levels of crosslinking and sol-gel network condensation. To produce the material, the gelatin and GPTMS were mixed for 3 h and 3D printed scaffolds were aged for 1 week at room temperature. The hybrid composition most compatible with the 3D printing process had a 78:22, gelatin to TEOS mass ratio, and C-factor of 500 (molar ratio of GPTMS to gelatin). When 3D printing the gels, a minimum strut separation of 1 mm was achievable. To dry the 3D printed scaffolds, freeze drying and critical point drying resulted in very different structures. Freeze drying produced very thin, < 40 μm struts, and large ~700 μm channels. Critical point drying produced ~160 μm struts and ~200 μm channels which falls within the range hypothesised to be suitable for cartilage regeneration. Electrospinning required further adjustments to the hybrid method to improve the volatility of the solvent. Conformable cotton wool-like fibres with ~1.5 μm diameter were achieved using a 70:30 gelatin to TEOS mass ratio. The C-factors used: 250, 500, and 750, resulted in increasing silica network condensation: 64.3 %, 75.5 %, and 81.1 % respectively. To create the cotton wool-like fibre structure, hybrid solutions with 60-80 cP viscosity were electrospun in 55 % humidity and dried without contacting each other or the collector surface. Both 3D printed and electrospun fibres showed promising dissolution results. The structures were maintained as only ~3 % gelatin was released over a one month study (3D printed) and ~2 %gelatin over a one week study (fibres). The silicon release was ~25 % of the silica content for 3D printed scaffolds, and ~13 % for fibres (CF500 and CF750). The silica-gelatin hybrids were biocompatible and provided native attachment sites for both osteoblasts and chondrocytes. Over 28-days, chondrocytes appeared to regenerate uniform density hyaline cartilage throughout the 3D printed scaffolds in vitro.
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Surbey, Wyatt R. „Mask Projection Microstereolithography 3D Printing of Gelatin Methacrylate“. Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/101053.
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Gelatin methacrylate (GelMA) is a ubiquitous biocompatible photopolymer used in tissue engineering and regenerative medicine due to its cost-effective synthesis, tunable mechanical properties, and cellular response. Biotechnology applications utilizing GelMA have ranged from developing cell-laden hydrogel networks to cell encapsulation and additive manufacturing (3D printing). However, extrusion based 3D printing is the most common technique used with GelMA. Mask projection microstereolithography (MPµSL or µSL) is an advanced 3D printing technique that can produce geometries with high resolution, high complexity, and feature sizes unlike extrusion based printing. There are few biomaterials available for µSL applications, so 3D printing GelMA using µSL would not only add to the repertoire materials, but also demonstrate the advantages of µSL over other 3D printing techniques. A novel GelMA resin was tested with µSL to create a porous scaffold with a height and print time that has not been displayed in the literature before for a scaffold of this size. The resin consists of GelMA, deionized water, lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP, photoinitiator), and 2-Hydroxy-4-methoxybenzophenone-5-sulfonic acid (sulisobenzone, UV blocker) and can be processed at room temperature. Four resins were tested (w/w %) and characterized for µSL printing: 20% GelMA 0.5% UV blocker, 20% GelMA 1.0% UV blocker, 30% GelMA 0.5% UV Blocker, and 30% GelMA 1.0% UV blocker. Swell testing, working curve, photo-rheology, photo-DSC (dynamic scanning calorimetry), 3D printing, and cell culture tests were performed and results showed that 30% GelMA 1.0% UV blocker had the best 3D print fidelity among resin compositions.Master of Science
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Luo, E.-Ching. „Topical therapy with novel targeted releasing formulations“. Thesis, De Montfort University, 2015. http://hdl.handle.net/2086/11436.
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Aims Novel low toxicity formulations using biomaterial (i.e. gelatin) for triggered release and controlled manner of formulated therapeutic agent for treatment of immuno-inflammatory disease on the skin were studied in the PhD project. It is a challenging concept because of difficulties in targeting and controlling for the releases that is tailored to disease severity or lesional inflammation extent. Background Psoriasis is a complicated disease with multi-factorial pathogenesis. Potent anti-psoriatic drugs are available but for managing the symptoms of the disease. Due to the toxicity of the therapeutic agents, different strategies have been suggested to avoid severe side effects from long term or high dose usage. Psoriasis is an optimal representative for this investigation in terms of the toxicities of recognized drugs, unpredictable or relapsed nature of the disease or even life threatening developments if generalised symptoms develop as they can in some types. Method Using the rheometry in temperature sweep mode, a series of concentrations of pure gelatin and gelatin mixture were developed. In addition, using tryptic enzyme, their action was studied rheologically. A Petri dish observational method was used to investigate the permeability of formulations chosen on the basis of the rheometric performance. Then, combining the Copley diffusion cell kit and UV/VIS spectrophotometer, the release of the model drug was investigated in porous artificial membranes and porcine skin for one or more of the formulations. The preliminary part using porous artificial membranes was to investigate the amount of the release of tartrazine from a candidate gel into the circulation system. In this part, alternatives were considered for dealing with gelatin or gelatin/carbomer swelling by using mechanical stress approach or changing to octanol solvent. For the latter a dye, rhodamine, which would partition into octanol had to be substituted for tartrazine (which has iv negligible organic solubility). In the final part, using skin membrane, the amount of the release tartrazine to the skin was measured because in this, skin staining, rather than partition was needed. Results Promising results were observed in each stage. The rheological investigation on the developed gelatin/water system and gelatin/carbomer intimate system in absence and presence of tryptic enzyme showed that a responsive but convenient formulation was possible and was independent of the presence of tartrazine. Analysis of these resulting rheological profiles suggested a prediction for the best gelatin/carbomer formulations to select for the permeability tests. The latter used Petri dishes to compare differential diffusion of these candidates showed the carbomer was able to stop three-dimensional spreading of the dye through the pure gelatin or its residue (after enzyme action). The drug release studies using artificial porous membranes for preliminary work showed significant differential release between enzyme free and enzyme treated versions of the 20% gelatin/0.9% carbomer formulation. The final success was the in vitro skin experiment in which the result was obtained for the pure gelatin and shown to deliver very substantially more to areas with applied enzyme s a simulated lesion.
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Bertan, Larissa Canhadas. „Desenvolvimento e caracterização de filmes simples e compostos a base de gelatina, acidos graxos e breu branco“. [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255988.
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Orientador: Carlos Raimundo Ferreira GrossoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Pesquisas sobre filmes comestíveis à base de polímeros surgiram nos últimos tempos devido ao impacto ambiental aliado a necessidade de reduzir os resíduos sólidos. Estudo com proteínas animais, como gelatina, demonstraram a capacidade de formar filmes, além de possuir grande produção e baixo custo no Brasil. O objetivo deste trabalho foi desenvolver e caracterizar filmes simples e compostos feitos de gelatina, triacetina, ácidos graxos (esteárico, palmítico e láurico) e breu branco. Filmes de gelatina simples e compostos foram produzidos e caracterizados quanto às propriedades de barreira ao vapor de água, oxigênio, solubilidade, propriedades mecânicas (resistência à tração e elongação), opacidade e isotermas de sorção (25°C). Posteriormente foram realizadas análises microestruturais, através da microscopia eletrônica de varredura e microscopia confocal a laser de varredura, temperatura de transição vítrea (Tg) obtida por análise térmica mecânica dinâmica (DMTA) e temperatura de fusão por calorimetria diferencial de varredura (DSC). A adição de substâncias hidrofóbicas (ácidos graxos e breu branco) produziu filmes menos permeáveis ao vapor de água e menor resistência a tração comparando ao filme simples Os filmes compostos causaram aumento da elongação, da opacidade, e da permeabilidade ao oxigênio. Os resultados da microscopia eletrônica de varredura e microscopia confocal a laser, indicaram boa distribuição das substâncias hidrofóbicas e alterações na morfologia da matriz polimérica. O aparecimento de duas a três transições e temperaturas de fusão sugere heterogeneidade dos biofilmes compostos
Abstract: Recently, many researches have been developed on biodegrable and edible films based on biopolymers due to environmental considerations allied to the necessity of reduction residues. Studies involving animal proteins, such gelatin demonstrated the capacity to form films, besides large production with low cost in Brazil. So that, the objective of this work was the development and characterization of the sim pie and composite films produced from gelatin, triacetin, fatty acids (stearic, palmitic, blend of both and blend more lauric acid) and elemi resin. Simple and composite gelatin films were produced and characterized with respect to the water vapor (Wvp) and oxygen permeabilities, solubility, mechanical properties (tensile strenght and elongation), opacity and sorption isotherm determination (25°C). Morphological analysis were effected, by scanning electronic microscopy (SEM) and confocallaser scanning microscopy (CLSM), glass transition temperature (Tg) obtained by dynamic mechanical analysis (DMT A), and temperature of melting by differential scanning calorimeter (DSC) The addition of hidrofobic substances (fatty acid and elemi resin) decreased the WVP and mechanical resistance comparing to the simple film. The composite film increased on elongation, opacity and oxygen permeability. The results SEM and confocal laser scanning microscopy (CLSM) indicated good distribution of hidrofobic substances and alterations in the morphology of the polimeric matrix. The appearance of two Tg's and temperature of melting suggests the heterogeneity of composites biofilms
Mestrado
Mestre em Alimentos e Nutrição
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Santos, Carla Danielle Silva. „Mineralização biomimética de hidrogéis quitosana/gelatina“. Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-30012015-102330/.
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Um dos maiores desafios da ortopedia é recuperar o tecido ósseo que tenha sido perdido por motivo de doença ou acidente. Na busca de substitutos para os enxertos, tem-se utilizado comumente biomateriais, para recuperação desse tecido. A quitosana é um polímero biocompatível, biodegradável e juntamente com a gelatina, que é produto da desnaturação do colágeno, possuem uso potencial no área de regeneração de tecidos ósseos. O objetivo deste trabalho é a preparação, caracterização de hidrogéis de quitosana:gelatina mineralizados, em diferentes proporções (1:0,5; 1:1 e 1:2) e estudar a liberação controlada de gentamicina utilizando como suporte o hidrogel mineralizado. A quitosana foi obtida a partir da desacetilação parcial da quitina oriunda de gládios de lula e a gelatina utilizada é a comercial Sigma®. Os hidrogéis foram mineralizados pelo método de imersão alternada em soluções de CaCl2 0,2 mol L-1 pH=7,4 e de Na2HPO4 0,12 mol L-1 pH=9,0. A mineralização foi caracterizada por espectroscopia na região do infravermelho (FTIR), análise termogravimétrica (TG), microscopia eletrônica de varredura (MEV), dispersão de raios-X (EDS), difração de raios-X (DRX) e cinética de absorção em PBS. Nas análises de TG e MEV pode-se observar a ocorrência de mineralização homogênea no hidrogel, aproximadamente 60% (m/m) em todas as proporções. Nos espectros de FTIR, EDS e DRX, observou-se que o sal de fosfato de cálcio formado durante o processo de mineralização alternada corresponde à hidroxiapatita. Quanto ao estudo de absorção em PBS, os hidrogéis mineralizados apresentam menor intumescimento que os não-mineralizados. Estudou-se o comportamento da liberação in vitro (em PBS, pH 7,4) de gentamicina no hidrogel mineralizado de quitosana/gelatina (1:1) quando se altera a temperatura da liberação (25°C e 37°C). A gentamicina foi incorporada ao hidrogel mineralizado através da imersão em uma solução com concentração de 30 mg ml-1 de gentamicina. O estudo de liberação foi realizado em duas temperaturas 25°C e 37°C. A quantidade de fármaco liberado após 24 horas não é afetada pela alteração na temperatura, mas a velocidade da liberação nas duas primeiras horas é maior a 37°C do que a 25°C. O mecanismo de liberação da gentamicina foi ajustado para o modelo Korsmeyer-Peppas sugerindo que segue a difusão Fickiana.The replacement of bone tissue lost due to illness or accident is a great challenge in orthopedic area. Biomaterials have been commonly used to prepare new materials for substitution of lost tissue. Chitosan is a biocompatible and biodegradable polymer and its association with gelatin has potential application in bone tissue regeneration. The objective of this study is to describe the preparation and characterization of mineralized hydrogels of chitosan/gelatin prepared with different ratios (1:0.5, 1:1 and 1:2) and the controlled release of gentamicin using the mineralized hydrogel as a support. Chitosan was obtained from the partial deacetylation of squid pens and gelatin was commercial (Sigma ®). The mineralization process was carried out by the alternate soaking method. Hydrogels were soaked in 0.2 mol L-1 CaCl2 buffered with 0.05 mol L-1 Tris buffer (pH 7.4) at 25°C for 30 min, taken out of the Ca2+ solution, rinsed with deionized water and then soaked in 0.12 mol L-1 Na2HPO4 solution buffered with 0.05 mol L-1 Tris buffer (pH 9.0) for 30 min, taken out of the PO43- solution and rinsed with deionized water. The alternate soaking cycle was repeated 6 times to obtain the mineralized matrices which were then rinsed with water, frozen and lyophilized. Mineralized hydrogels were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TG), scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD) and kinetic absorption in PBS. SEM results showed an homogeneous mineralization, and for all hydrogels a quantity of approximately 60% (w/w) of mineralization was determined by TG. FTIR, EDS and XRD indicated that phosphate calcium deposited during mineralization process was hydroxyapatite. Mineralized hydrogels had lower swelling values in comparison with non-mineralized, as observed by absorption in PBS. Release of gentamicin in mineralized hydrogel was performed at 25°C and 37°C. Gentamicin was incorporated in the mineralized hydrogel by immersion in a gentamicin solution with a concentration of 30 mg ml-1. The change in release temperature showed that the quantity of drug delivery was not affected after 24 hours. However, the release rate in the first hour is higher at 37°C. The release mechanism of gentamicin was adjusted to the Korsmeyer-Peppas model suggesting that drug release is mostly controlled by a diffusion process.
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Mota, Lucas Ponez da. „Preparação e caracterização de eletrólitos sólidos poliméricos à base de gelatina comercial para aplicação em células solares“. Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-24032010-203744/.
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O presente trabalho visou estudar e caracterizar eletrólitos sólidos poliméricos (ESP) à base de gelatina plastificada com glicerol, entrecruzada com formaldeído e contendo LiI/I2 para a aplicação em células solares. O objetivo foi obter os eletrólitos à base de gelatina comercial (Dr. Oetker) de origem animal, uma vez que a mistura de aminoácidos presentes na mesma apresenta propriedades mecânicas interessantes e torna-se um gel transparente na região do visível. Glicerol foi usado para promover a plastificação e o formaldeído para promover as ligações cruzadas na mistura das proteínas aumentando a estabilidade e resistência dos filmes. As fontes iônicas foram o LiI.2H2O e I2 na proporção de 10:1 m/m. O estudo revelou que as amostras apresentaram os valores de condutividade iônica de 7,68 x 10-5 S.cm-1, 6,38 x 10-5 S.cm-1, 8,81 x 10-5 S.cm-1, 9,97 x 10-5 S.cm-1 e 7,87 x 10-5 S.cm-1 dependendo da concentração da mistura LiI.2H2O / I2 . As medidas de condutividade em função da temperatura mostraram que o mecanismo que governa a condutividade é do tipo VTF. As análises de estrutura das membranas por difração de Raios-X mostraram o caráter predominantemente amorfo e as análises térmicas (DSC) os valores da temperatura de transição vítrea (Tg) da ordem de -77ºC. A transparência das amostras de 80 a 90% foi confirmada por espectroscopia UV-Vis e as análises microscópicas (MEV) mostraram a presença de pequenos pontos brancos nas superfícies das amostras. Os eletrólitos aplicados em um pequeno protótipo de célula solar renderam um máximo de 0,15% de eficiência.This present work aimed study and characterization of solid polymer electrolytes (SPE) based on gelatin plasticized with glycerol, crosslinked with formaldehyde and containing LiI/I2 for application in solar cells. The plan was to get the electrolytes based on commercial gelatin (Dr. Oetker) of animal, since the mixture of amino acids present interesting mechanical properties and becomes a transparent gel in the visible region. Glycerol was used to promote plasticization and formaldehyde to promote cross-linking of the mixture of proteins leading to increase the stability and strength of the films. The ion sources were LiI.2H2O and I2 at a ratio of 10:1 m/m. The study revealed that the samples showed the values of ionic conductivity of 7.68 x 10-5 S.cm-1, 6.38 x 10-5 S.cm-1, 8.81 x 10-5 S.cm-1, 9.97 x 10-5 S.cm-1 and 7.87 x 10-5 S.cm-1, depending on the concentration of the mixture LiI.2H2O / I2. Ionic conductivity measurements as a function of temperature revealed VTF conducting model. X-ray diffractogramms showed the predominantly amorphous nature and thermal analysis (DSC) values of the glass transition temperature (Tg) of about -77 ° C. The transparency of the samples of 80 and 90% was confirmed by UV-Vis and the microscopic analysis (SEM) showed the presence of small white points in the surface of the samples. The electrolytes used in small solar cell prototypes yielded a maximum of 0.15% efficiency.
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Denari, Nizia Sophia Mayer. „Biomateriais binários de quitosana/amido e quitosana/gelatina em L-ácido lático“. Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-27082014-100801/.
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Derivada da quitina, a quitosana apresenta aplicações que variam desde a liberação controlada de fármacos, a filmes de revestimento comestível, biomaterial, lentes de contato. A utilização da beta-quitina para obter a quitosana é vantajosa, pois apresenta-se menos alergênica e mais reativa que a alfa-quitina. A combinação da quitosana com outros materiais pode proporcionar materiais com diferentes propriedades e neste trabalho foram estudadas as misturas de quitosana/gelatina e quitosana/amido, solubilizadas em L-ácido lático. Técnicas como FT-IR, termogravimetria, absorção de água, ensaios de DMA no modo tração e análises reológicas foram usadas em ambas as misturas nas proporções 2:1, 1:1 e 1:2. Os espectros FT-IR mostraram que nos géis e filmes ocorreu interação eletrostática entre os componentes. A termogravimetria mostrou que há diminuição da estabilidade térmica dos componentes quitosana e gelatina quando em presença do L-ácido lático, mas o amido pouco foi afetado pela presença do L-ácido lático. Para os filmes, tanto no caso de quitosana/gelatina quanto no caso quitosana/amido, as misturas mais estáveis termicamente são as que contêm maior quantidade de gelatina ou amido. Isso mostra que é favorável a adição de gelatina ou amido à quitosana quando se deseja maior resistência à temperatura. O aumento da concentração de gelatina ou amido nos filmes de quitosana em L-ácido lático aumentou a absorção de água, o que possibilita a aplicação como suporte na liberação controlada de fármacos. Os ensaios de DMA no modo tração mostraram que o aumento da quantidade de gelatina ou amido nos filmes torna estes mais frágeis. A mistura dos polímeros em diferentes proporções na formação dos géis mostrou que os géis de quitosana/amido adquiriram características de gel em menores frequências que os géis de quitosana/gelatina. O aumento da concentração de gelatina aumenta a temperatura de gelificação, mas para os géis de quitosana/amido nenhum efeito foi observado. Em relação à viscosidade, a gelatina mostrou comportamento newtoniano e as amostras de quitosana e as misturas apresentaram comportamento pseudoplástico, tanto em L-ácido lático como em ácido acético. Os valores de energia de ativação (Ea) de fluxo calculados para quitosana/gelatina e quitosana/amido aumentaram com o conteúdo de quitosana. Os géis de quitosana/amido apresentaram menor Ea que os géis de quitosana/gelatina, apresentando, portanto, maior facilidade para fluir. Os valores de Ea de fluxo para os géis em L-ácido lático são menores que os obtidos para géis em ácido acético. O ácido lático melhorou as propriedades dos géis em relação ao ácido acético, proporcinando filmes mais flexiveís para a liberação controlada de fármacos e géis mais fáceis de deslizar na pele.Derived from chitin, chitosan has applications ranging from drug delivery system, edible films, biomaterials, contact lenses. The use of beta-chitin for chitosan preparation is advantageous because it is less allergenic and more reactive than alpha-chitin. The association of chitosan with other materials can provide materials with different properties. In this work, mixtures of chitosan/gelatin and chitosan/starch solubilized L-lactic acid were studied. Techniques such as FT-IR, thermogravimetry, water absorption, DMA in traction mode and rheology were studied in both mixtures with proportions of 2:1, 1:1 and 1:2. FTIR spectra showed that both, gels and films, presents electrostatic interaction between the components. The thermogravimetric analysis has shown that there is a decrease in thermal stability of gelatin and chitosan in the presence of L-lactic acid. Thermal stability of starch was little affected by the presence of L-lactic acid. The most thermally stable films are those containing higher amounts of gelatin or starch. This shows that the addition of gelatin or starch to chitosan is favorable. Increasing the gelatin or starch concentration in the films provoked an increase in water absorption, which enables the application to drug delivery system. DMA tests in traction mode showed that increasing the gelatin or starch amount turns films more fragile. Chitosan/starch biomaterial presents gel characteristics at lower frequencies than chitosan/gelatin biomaterial. Increasing the gelatin concentration, an increasing in gelation temperature was observed, however for chitosan/starch gels, no effect was observed. Regarding the viscosity, gelatin showed Newtonian behavior while chitosan samples and the mixtures exhibited pseudoplastic behavior both in L-lactic and acetic acid. The values of flow activation energy calculated for chitosan/gelatin and chitosan/starch increased with chitosan amount. The chitosan/starch gels showed lower energy when compared to chitosan/gelatin gels, thus presenting facility to flow. The values of Ea to chitosan/gelatin and chitosan/starch solubilized in L-lactic acid are smaller than those obtained in acetic acid. L- lactic acid improved the properties of gels with respect to acetic acid, resulting in more flexible films for drug delivery system and gels easier to slide in the skin.