Clays are ubiquitous near the Earth’s surface. Medicinal properties of these nontoxic minerals have been intuitively recognized since ancient times. Up till now, clays have been used in pharmaceutical formulations as active agents and excipients. Currently, there is an urgent need to seek advanced, functional materials with low environmental impact. Answering to that trend, clay-biopolymer nanocomposites were synthesized in this thesis and applied in a drug delivery system. In the first part of the thesis, Portuguese clay from a bentonite deposit in Benavila (Portugal) was collected from six sampling sites and characterized. The highest content of clay fraction, approximately 30%, was found in two of the sampling sites. After purification, the smectite-rich samples were analyzed with respect to clay content, mineralogical and chemical composition, physicochemical and mechanical properties. SEM-EDS revealed that the smectite present in the ore is montmorillonite with varying Fe content. This was also indicated by the means of XRD, XRF and FTIR. The Benavila sample, which was richest in smectite, as well as the sodium Wyoming montmorillonite from the Source Clay Repository (SWy-2) were successfully used to synthesize clay-biopolymer nanocomposites. The chosen biopolymers were the plant-extracted polysaccharides – neutral guar gum and its cationic form. The obtained materials were thoroughly characterized by XRD, TGA and NMR, and the intercalated structure was reported. The prepared nanocomposites were loaded with an anti-inflammatory drug ibuprofen and tested in an in-vitro release system. The drug-loaded materials were characterized with XRD, TGA and NMR. A membrane diffusion method was chosen as a dissolution testing strategy and the drug was quantified by UV-Vis spectroscopy. The materials exhibited improved properties as a noticeable reduction of release rate was achieved.

Orientador: Luiz Francisco Malmonge / Resumo: Os fertilizantes de liberação modificada têm conquistado âmbitos cada vez maiores nas pesquisas e em utilizações agrícolas devido a suas principais características de menores perdas de nutrientes e por seu menor custo, que envolve menos aplicações no campo e menores quantidades de fertilizantes utilizados, comparado aos fertilizantes convencionais. Este trabalho teve como objetivo elaborar fertilizantes com possível comportamento de liberação modificada, através da incorporação do fosfato de potássio monobásico (KH2PO4) no polímero quitosana, contribuindo, dessa forma, com as três fontes de nutrientes primários essenciais requeridos pelas plantas: nitrogênio, fósforo e potássio, por apenas dois recursos. Foram elaboradas duas amostras diferentes para posterior comparação, análise e aplicação. Os métodos utilizados no preparo das amostras foram: gotejamento em solução básica coagulante e casting. Foram feitas soluções de 8% de quitosana (m/v) dissolvidas em soluções de 5% de ácido acético, e subsequentemente foi adicionado o KH2PO4 (em diferentes concentrações para análise e para aplicação agrícola, foi usada a concentração de 60% (m/m) em relação à massa de quitosana). Foram feitas Microscopia eletrônica de varredura (MEV) para análise morfológica das amostras, Energia dispersiva de raios-X (EDX) para constatação dos elementos contidos nas amostras, o estudo da liberação dos nutrientes em solução aquosa (em pHs 5,4 e 6,7) e por fim, as amostras foram aplicadas em mudas de alf... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Modified-release fertilizers have been increasingly used in research and in agricultural uses due to their main characteristics of lower nutrient losses and their lower cost, which involves fewer applications in the field and less quantities of utilized fertilizers, compared to the conventional ones. This work aimed to elaborate fertilizers with possible modified release behavior, through the incorporation of monobasic potassium phosphate (KH2PO4) in the chitosan polymer, thus contributing with the three sources of essential primary nutrients required by plants: nitrogen, phosphorus and potassium, from only two resources. Two different samples were prepared for later comparison, analysis and application. The methods used in preparing the samples were: dripping in a basic coagulant solution and casting. Solutions of 8% chitosan (w/v) were prepared dissolved in solutions of 5% acetic acid, and subsequently KH2PO4 was added (in different concentrations for analysis and for agricultural application, the concentration of 60% (w/w) in relation to the chitosan mass). Scanning electron microscopy (SEM) was performed for the morphological analysis of the samples, energy dispersive X ray (EDX) to verify the elements contained in the samples, the study of the release of nutrients in aqueous solution (at pH 5.4 and 6, 7) and finally, the samples were applied to lettuce seedlings for comparative effect and material efficiency. The results of the EDX spectra showed that in the samples made... (Complete abstract click electronic access below) / Mestre

Världens fokus på hållbarhet ökar och utveckling inom biobaserade material är nödvändig för att nå det globala klimatmål som satts upp. Biologiska material kommer frånförnyelsebara resurser, dvs att det både kommer från naturen och är tänkt att brytas ner av naturen. Inom kategorin naturliga polymerer finns proteiner, polysackarider och lipider där framförallt polysackarider fått fokus för användning både som biobränsle och som regenererade fibrer inom textilindustrin. Vete är ett spannmål som består av alla dessa tremakromolekyler. Vete används framförallt inom matindustrin men har på senare tid odlats för dess höga mängd av stärkelse som utvunnits och använts till bland annat biobränsle. Vid denna utvinning av stärkelsen blir resterande proteiner och lipider en biprodukt. Mängden protein är mellan 20-30% i vetet och stor del av detta är gluten. Denna rapport går igenom vad gluten är, hur gluten kan modifieras, vilken potential gluten har att regenereras till en textil fiber och hur en sådan process kan se ut. Gluten är ett vegetabiliskt växtprotein som består av ämnena gliadin och glutenin. Gluten är stabil i högre temperaturer och vattenolöslig, men det har visat sig att gluten vid kontakt med vatten får försämrade mekaniska egenskaper och att gluten har en glasomvandlingstemperatur på ca 38℃, vilket leder till att materialet är sprött vid rumstemperatur. Proteinerna inom gluten innehåller även olika mängder disulfidbindningar, även kallade tvärbindningar. Dessa tvärbindningar påverkar även glutens mekaniska egenskaper, och dess möjlighet att processas vidare. En rapport från 2009 diskuterar glutens potential som en regenererad fiber och tar även upp vilka modifieringar som krävs för att gluten ska kunna regenereras genom våtspinning. Olika modifieringar har olika betydelse för glutens fortsatta processande och med hjälp av en litteratursökning där artiklar och rapporter från tidigare forskning sammanfattats har denna studie gett ett resultat om en potentiell metod för att genomföra vidare tester inriktade mot att producera gluten till en regenererad fiber. Resultatet ger en metod där flera modifieringar sammanflätas i olika steg, där förhoppningen är att hitta den optimala metoden för att processa gluten till en textil fiber. Vidare presenteras en marknadsanalys där resultatet pekar på att odling av vete är stor och stabil. En jämförelse mellan olika marknader och råvaror visar även på ett teoretiskt pris för gluten, där det hamnar i ett intervall mellansyntetiska fibrer och bomull. / Big focus all around the world is on sustainability, where the progress of using biobased material is necessary to reach the global goals of sustainable development. Biological materials is produced from renewable resources, they are extracted from nature and eventually broken down by nature. Within the category of natural polymers is proteins, polysaccharides and lipids, where polysaccharides have got large attention for their use as biofuel and regenerated textile fibers. Wheat is a grain that contains all of this three macromolecules. Wheat is mainly used in the food industry but have lately been produced for it´s high volume of starch which can be useful as biofuel. When starch are extracted, the by-product of this production is proteins and lipids. Proteins are responsible for 20-30% of the content in wheat and the majority of this protein is gluten. This study introduce gluten, it’s properties, how it can be modified, the potential to regenerate gluten as a textile fiber and how that process might look like. Gluten is a vegetable protein containing the substances gliadin and glutenin. Gluten is stable in high temperature and water-insoluble, but in contact with water, the mechanical properties of gluten is decreased. It has also been showed that the glass transition temperature of gluten is 38℃, witch make gluten brittle in room temperature. The proteins within gluten contains disulfide bonds, also called crosslinking bonding. This crosslinking affects the mechanical properties of gluten and also the ability to be processed. An article from 2009 discuss about the potential of gluten as regenerated textile fiber and what modifications that can be made to regenerate gluten in the process of wet-spinning. Different modifications have different implications for the gluten's continued processing, and with the help of a literature search that summarizes articles and reports from previous research, this study has yielded a potential method for conducting further tests aimed at producing gluten into a regenerated fiber. The result provides a method where several modifications are intertwined in different stages, where the hope is to find the optimal method for processing gluten into a textile fiber. Furthermore, a market analysis is presented where the result indicates that wheat cultivation is large and stable. Comparing different markets gives gluten a theoretical price range between synthetic fibers and cotton.

Microspheres are spherically shaped particles within the size range of 1-1000 μm in diameter. Due to the their small size and round shape, microspheres show many advantages in various applications such as pharmaceuticals, composites and coatings. The microspheres can be customized to fit a specific application and are manufactured in various forms such as solid, hollow and encapsulating. Encapsulating cellulose microspheres have been produced in this project by the emulsionsolvent evaporation technique. The purpose of this study was to further investigate the possibility of producing encapsulating microspheres with a size range of 10-50 μm that will have a high encapsulation. A second purpose of this study was optimizing the emulsifier system for the preparation of these spheres. This has been accomplished by varying several process parameters such as type of emulsifiers and solvents to study the effect on morphology and encapsulation efficiency. The analyses of the spheres were performed with optical microscopy, thermal gravimetric analyzer (TGA) and scanning electron microscopy (SEM). The emulsifier type and concentration affected the encapsulation and size distribution but had no direct effect on the internal and external structure, which was multi-cellular and porous, respectively. The highest encapsulation in relation to average size was obtained with 0.1 v/v- % of the emulsifier mixture Emulsifier 1 (E1)/Emulsifier 2 (E2) (70/30 %). The solvent used to dissolve the polymer had a direct effect on encapsulation, a combination of Solvent 2 (S2) and Solvent 1 (S1) proved best for the three tested cellulose derivatives with low, medium and high number average molecular weight. The solvent also had an effect on the internal structure of the microspheres, becoming more core-shell when using the S1/S2 combination.

Plasten Polyvinylklorid har under lång tid kritiserats ur miljösynpunkt på grund av plastens hälsofarliga beståndsdelar. PVC har medfört enorma miljöskador på ozonskiktet som orsakats av klorfluorkolväten men det som framförallt varit bekymrande på senare tid är mjukningsmedel som har skapat oro över deras möjliga hormonstörande effekter. Detta har medfört en politisk osäkerhet och otrygghet för företag som arbetar med PVC. Företaget HRD Carpets AB önskar utveckla ett alternativt ersättningsmaterial för PVC plastmattor och ser helst fram emot en biobaserad lösning. Syftet med denna studie är att finna ett lämpligt ersättningsmaterial för PVC plastmattor. Målet har varit att genomföra en studie som ger underlag för ett alternativt ersättningsmaterial som går att vidareutveckla i form av fortsatta studier. Kravspecifikationen har varit utgångspunkten i denna studie för att finna ett lämpligt ersättningsmaterial. De mekaniska egenskaperna för PVC plasten som används i fabriken har identifierats och tolkats genom ett dragprovningstest som genomförts. Dessa egenskaper har varit de elementära kraven tillsammans med övriga krav som framgår i kravspecifikationen. I denna studie undersöks alternativa biomaterial samt syntetiska material. Med hjälp utav programvaran Cambridge Engineering Selector har ett urval av material tagits fram och undersökts genom en urvalsprocess. Genom intervjuer, publikationer, journaler och litteraturer har biobaserade alternativ undersökts. Resultatet visade att den syntetiska plasten Polybutylentereftalat (PBT) tillsammans med färgämnen uppfyller de basala krav för det tillämpningsområdet som undersöks. Resultatet visade att biomaterialet Polymjölksyra (PLA) och Polybutensuccinat (PBS) uppfyller samtliga krav och kan lämpa sig som alternativa lösningar. Dessa material har dock en kort livslängd och att öka materialets hållbarhet är en utmaning med dessa biomaterial. / The Polyvinyl chloride (PVC) has been criticized from an environmental point of view due to the plastic's hazardous components for a long time. PVC has caused enormous environmental damage to the ozone layer caused by chlorofluorocarbons. The plasticizers used for PVC are concerning because of their possible endocrine disrupting effects. This has led to political uncertainty and insecurity for companies working with PVC. The company HRD Carpets AB wishes to develop an alternative replacement material for PVC plastic carpets and looks preferably towards a bio-based solution. The purpose of this study is to find a suitable replacement material for PVC plastic carpets. The goal of this study is to provide a basis for an alternative replacement material and can be further developed in the form of further studies. The requirements specifications have been the starting point in this study to find a suitable replacement material. The mechanical properties of PVC, which is used in the company, have been identified and interpreted through a tensile test. These properties have been the elementary requirements combined with other requirements that appear in the requirements specification. This study examines alternative biomaterials and synthetic materials. With the help of the Cambridge Engineering Selector software, a selection of materials was found through a selection process. Then through interviews, publications, journals and literature, bio-based alternatives have been explored. The results showed that the synthetic plastic Polybutylene Terephthalate (PBT) together with color additives meet the basic requirements specification being investigated. The results also showed that the biomaterial Polylactic Acid (PLA) and Polybutene Succinate (PBS) meet the requirements and can function as alternative solutions. However, these materials have a short lifespan, increasing the durability of the material is a challenge with these biomaterials.

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No description available.

The design and discovery of new surface-active polymers that self-assemble on solid substrates to form brush layers will have a major impact on numerous applications. Through recombinant DNA technology, there exists the potential to harness a cell's protein synthesis machinery to produce a brush-forming poly(amino acid) (or PAA) with an exactly specified amino acid sequence, thus controlling the polymer's composition at a level unequaled by conventional organic polymer synthesis. The presented work demonstrates the cloning, expression, purification and characterization of de novo-designed PAA's designed to form brush layers on alumina surfaces. Using conventional recombinant DNA methods, the feasibility of producing a PAA consisting of a poly-glutamate block and a poly-proline block was demonstrated. However, the PAA design was limited by the inherent limitations of conventional cloning techniques. We introduce here the development of a simple and versatile strategy for producing de novo-designed, high molecular weight PAA's using recombinant DNA technology. The basis of this strategy is that small DNA modules encoding for short PAA blocks can be easily inserted directly into a commercially available and unmodified expression vector. The insertions can be made repeatedly until the gene encodes for a polymer of desired molecular weight and composition. Thus, sequential modifications can be made to the PAA without having to re-start the gene assembly process from the beginning, thereby allowing for quick determination of how these changes affect polymer structure and function. The feasibility and simplicity of this method was shown during the production of a PAA, consisting of a long zwitterionic tail block and a short acidic anchor block, designed to form optimal brush layers on alumina surfaces. The success and flexibility of this method indicates that it can be applied for production of de novo-designed polypeptides in general. It is hoped that this method will contribute towards the rapid development of bio-inspired protein-based polymers for a variety of applications. This dissertation also contains research that aimed to use phage display technology to develop a new liposome-based immunoassay against biological toxins. This work was part of a collaboration effort with the U.S. Department of Defense and Luna Innovations. / Ph. D.

Microtubules are cytoskeletal protein polymers relevant to a wide range of cell functions. In order to polymerize, the constituent tubulin subunits need to bind the nucleotide GTP, but its subsequent hydrolysis to GDP in the microtubule lattice induces depolymerization. The resulting behaviour of stochastic switching between growth and shrinkage is called dynamic instability. Both dynamic instability and microtubule mechanical properties are integral to many cell functions, yet are poorly understood. The present study uses thermal fluctuation measurements of grafted microtubules with different nucleotide contents to extract stiffnesses, relaxation times, and drag coefficients with an unprecedented precision. Both the stiffness and the relaxation time data indicate that stiffness is a function of length for GDP microtubules stabilized with the chemotherapy drug taxol. By contrast, measurements on microtubules polymerized with the non-hydrolizable GTP-analogue GMPCPP show a significantly higher, but constant, stiffness. The addition of taxol is shown to not significantly affect the properties of these microtubules, but a lowering of the GMPCPP content restores the length-dependent stiffness seen for taxol microtubules. The data are interpreted on the basis of a recent biopolymer model that takes into account the anisotropic architecture of microtubules which consist of loosely coupled protofilaments arranged in a tube. Using taxol microtubules and GMPCPP microtubules as the respective analogues of the GDP and GTP state of microtubules, evidence is presented that shear coupling between neighbouring protofilaments is at least two orders of magnitude stiffer in the GTP state than in the GDP state. Previous studies of nucleotide effects on tubulin have focussed on protofilament bending, and the present study is the first to be able to show a dramatic effect on interprotofilament bonds. The finding’s profound implications for dynamic instability are discussed. In addition, internal friction is found to dominate over hydrodynamic drag for microtubules shorter than ∼ 4 μm and, like stiffness, to be affected by the bound nucleotide, but not by taxol. Furthermore, the thermal shape fluctuations of free microtubules are imaged, and the intrinsic curvatures of microtubules are shown for the first time to follow a spectrum reminiscent of thermal bending. Regarding the extraction of mechanical data, this assay, though previously described in the literature, is shown to suffer from systematic flaws.

During the global pandemic of coronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak, the world was desperately searching for simpler yet more effective solutions to stop the spread of coronavirus (COVID-19). Since no one was prepared for the fast spread of such a contagious virus, there was a shortage of proper protective solutions to stop the spread. Large quantities of alcohol-based disinfectant and hand sanitizers were used, but it led to global shortages. It is desired to have a water-based, easily applied, low-cost and long-lasting disinfectant that can prevent the spread of coronavirus on any surface, without the issue of skin allergies or skin-drying as often found while using alcohol. Inspired by nature, chitosan (CS), a natural biopolymer with well-known antimicrobial and film-forming properties, was tested in this study for the preparation of coatings spread onto various surfaces and the antiviral effect was evaluated. Zinc oxide (ZnO), a material generally recognized as safe (GRAS) by the US Food and Drug Administration (FDA), is a photocatalyst that was embedded in chitosan to enhance the antimicrobial and antiviral performance of the coatings. In order to apply water-based chitosan formulation on hydrophobic polypropylene (PP) surgical mask and polyethylene terephthalate (PET) surface, the plastics were treated with either oxygen plasma or corona plasma to improve the surface hydrophilicity. The corona plasma treatment decreased the water contact angle (WCA) of the surgical mask from approximately 125° to 101° and drastically reduced WCA of the PET film from approximately 100° to 29°. The PET film was coated with CS – ZnO nanocomposite, which contains 1% chitosan and 5 wt.% (w.r.t weight of chitosan) ZnO nanoparticles. The capability of photocatalytic degradation of CS – ZnO coating was demonstrated during the degradation of methylene blue dye molecules. Additionally, we evaluated the antiviral effect of the CS – ZnO nanocomposite coating on PET plastic films under typical room lighting conditions by measuring the inactivation of lentivirus. This approach utilizes the pseudotype system, which is a reliable tool to study under conventional biosafety conditions, particularly for certain pathogenic strains of coronaviruses (CoVs) which have a strong pathogenicity. / Under den globala coronapandemin, utbrottet av allvarligt akut respiratoriskt syndrom coronavirus 2 (SARS-CoV-2), sökte världen desperat efter enklare men ändå mer effektiva lösningar för att stoppa spridningen av coronaviruset (COVID-19). Eftersom ingen var förberedd på en så smittsam sjukdom uppstod en brist på lämpliga skyddsmetoder för att stoppa spridningen. Stora mängder alkoholbaserade desinfektionsmedel och handdesinfektionsmedel användes, vilket skapade en global brist. Det önskades en vattenbaserad, lättapplicerad, kostnadseffektiv och långvarig desinfektionsmedel som kunde förhindra spridningen av coronaviruset på vilken yta som helst, utan problem med allergiska reaktioner eller uttorkning av huden som ofta uppstår vid användning av alkohol. Med inspiration från naturen testades kitosan, en naturlig biopolymer med välkända antimikrobiella och film-formande egenskaper, för att göra beläggningar på olika ytor och testa deras antivirala effekt. Zinkoxid (ZnO), ett material som allmänt erkänns som säkert (GRAS) av US Food and Drug Administration (FDA), är en fotokatalysator och användes i kitosanbeläggningen för att förbättra den antimikrobiella och antivirala effekten. För att applicera den vattenbaserade kitosanformuleringen på hydrofoba ytor på en kirurgisk mask av polypropen (PP) och en plastfilm av polyetylentereftalat (PET), behandlades plasterna med antingen O2 eller corona plasma för att förbättra ytornas hydrofilicitet. Behandlingen av corona plasma minskade vattenkontaktvinkeln på den kirurgiska masken från cirka 125° till 101° och för PET-filmen från cirka 100° till 29°. PET-filmen belades med CS – ZnO nanokomposit, som innehåller 1% kitosan och 5 wt.% (med avseende på vikten av kitosan) ZnO nanopartiklar. Förmågan till fotokatalytisk nedbrytning av CS – ZnO-beläggningen demonstrerades genom att bryta ned metylenblå färgmolekyler. Dessutom utvärderades vi den antivirala effekten av CS – ZnO nanokompositbeläggningen på PET-filmer i normal rumsbelysning genom att mäta dess förmåga att inaktivera lentivirus. Denna metod använder pseudotypsystemet, vilket är ett tillförlitligt verktyg för att studera under konventionella biosäkerhetsförhållanden, särskilt för vissa patogena stammar av coronavirusen (CoVs) som har en hög patogenicitet.