Fibroin is a biopolymer obtained from the cocoons of the Bombyx mori silkworm that offers many unique advantages. In this thesis work, fibroin was processed into a regenerated film and examined for potential biomaterial applications. The adsorption of bovine serum albumin onto the fibroin film was investigated to examine the biocompatibility of the film, and it was found that BSA adsorption capacity increased with an increase in BSA concentration. At 10 mg/mL of BSA, the BSA sorption reached 0.045 mg/cm2. This level of BSA is indicative of good blood compatibility and biocompatibility of the fibroin. The gas permeabilities of oxygen, nitrogen, and carbon dioxide were tested for potential applications in contact lenses and wound dressings. Over a pressure range of 70 – 350 psig, the permeability of oxygen and nitrogen was 5 Barrer, while that of carbon dioxide ranged from 26 to 37 Barrer. The oxygen transmissibility of the fibroin films prepared in this study was on the low end required for use in daily wear contact lenses, but sufficient to aid the healing process for use in wound dressings. The permeability and diffusivity of four model drugs in the fibroin film was investigated for potential applications in controlled drug release. The permeability at higher source concentrations leveled out to 0.8 – 4.3 x 10-7 cm2/s depending on the drug tested. The diffusion coefficient determined from sorption experiments was approximately 1.8 x 10-9 cm2/s, while the diffusion coefficients from desorption experiments were determined to be 0.8 – 2.7 x 10-9 cm2/s. The magnitude of the drug permeability and diffusivity are consistent with many other controlled release materials, and the fibroin film showed good potential for use in controlled release.

This research is set in the context of a collaborative agreement between the Industrial Design Department, University of Canberra and the Faculty of Applied Art and Design at Ubon Rajathanee University in the northeast or Isan region of Thailand. In this thesis the textile production of the region was studied with an objective of evaluating the potential for product design process to positively influence production outcomes. Traditional textile production techniques could be lost because these processes are complex and slow, and the current environment, both physical and operational, is changing rapidly. Product design and the design process are relevant to the industrial development of Thailand and village textile production could benefit from structured design and manufacturing strategies that have a consumer focus and improved production outcomes. From a critical review of the relevant literature, it was found that village weavers valued the traditions of their craft and traditional patterns and colours were important in terms of cultural identity and village social organization. Product design process or more specifically, the Generic Design Process (GDP) was reviewed and a model developed that adapted the GDP to the prevailing research environment. The findings led to a program of field research including village interviews where the major issue of the devaluation of traditional natural material dyeing techniques was identified. Field experiments tested alternative dyeing techniques which were evaluated in a survey by village weavers. During the field research care was taken to adapt to the way in which village weavers lived and worked as the two activities were closely interrelated. The degree of skill and knowledge residing in the aging women, who constitute the majority of village weavers, in extensive and profound, and is often described as an example of local wisdom. The theoretical and experimental work has been related, with appropriate results and conclusions, to the potential for maintaining traditional natural dyeing processes albeit with different preservation techniques. The findings from this research suggests that product design processes are appropriate for village production and that the tradition of natural material colour dyes will survive, new colours were created and the potential for new trade in preserved colour dye products. Substantial databases of useful relevant information have been compiled and recommendations are made for future research.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

With the introduction of fragment protective fabrics into combat clothing, there was a need to understand the effect of laundering on the performance of these fabrics. This thesis investigated the effect of typical laundering regimes on selected ballistic protective fabrics representative of those suitable for clothing applications. This study presents evidence that knitted silk and felted ultra-high molecular weight polyethylene retained their ballistic protective performance after laundering. The para-aramid fabrics showed significant improvement from laundering. The dimensional stability of the selected fabrics was affected by laundering and the effect was cumulative. The damage imparted to the fibres was determined to be due to mechanical wear. This mechanical wear was significantly increased when the fabrics were wet. This was due to the water increasing the friction between fibres during the laundering process. The fabrics investigated were shown to be suitable for use in fragment protective clothing, and were more robust than was generally considered.

Biomolecule structural fluctuations determine function, regulating numerous biological processes My research has shed light on several interesting cases in which structural fluctuations have been identified to assess functional differences. Chapter 2 discusses the effects of structural rearrangement of the β2-β3 loop on the DNA binding affinity of the type 6 human papillomavirus E2 protein. Chapter 3 investigates the effects of phosphorylation on the C-terminal domain of Cdc37, a protein important in the Hsp90 chaperone cycle. Chapter 4 studies the effects on cyclycization on the conformational fluctuations of a γ-AApeptide used for high-throughput libraries. Chapter 5 is a structural study on a mini-fibril of spider dragline silk, in which a native-like ensemble was generated using temperature replica exchange. Chapter 6 investigates the structural features of repetitive motifs found in spider dragline silk when subject to both dope-like and fiber-like conditions. Chapter 7 elucidates conformational differences between the RXRα and the RXRβ ligand-binding domains and seeks to understand the atomic basis for different ligand binding affinities. This body of work has contributed to the understanding of conformational fluctuations and changes that occur in protein-DNA binding systems, drug-binding, regulation of chaperones via post-translations modifications and spider dragline silk.

A fibroína da seda (SF) é uma proteína estrutural encontrada nos casulos do Bombyx mori e que possui propriedades potencialmente aplicáveis em fotônica. Esta matriz biocompatível é um substrato interessante para diferentes íons ou moléculas; além disso, o seu índice de refração variável permite que fótons sejam guiados neste material, possibilitando seu uso como guias de ondas biocompatíveis e reabsorvíveis, que pode ser utilizado para fornecer energia ótica para diversas aplicações, por exemplo, terapia ou imagem dentro de tecidos vivos. A sua boa adequação em sistemas ópticos deve-se principalmente a propriedades como: ser mecanicamente robusta, apresentar superfícies muito lisas, altamente transparentes (> 95%) em toda a região visível do espectro e ser modelável. Além disto, há uma característica adicional: a viabilidade de funcionalização bioquímica, o que pode conferir uma maior versatilidade a estes dispositivos. Já os íons terras raras (TR) possuem um papel amplamente conhecido no ramo da fotônica; porém, não há nenhum estudo envolvendo a produção de luz em SF dopada com íons TR, e a combinação das propriedades mecânicas e óticas desta matriz com a multifuncionalidade destes íons pode ser uma forma de se produzir dispositivos fotônicos novos e distintos. Desta forma, o presente trabalho teve como objetivo estudar a estrutura da matriz de SF na presença de diferentes íons TR (Eu3+ e Tb3+), bem como a interação existente entre os aminoácidos que constitui a matriz e estes íons. Os resultados apresentados nesta dissertação mostraram as interações TR-SF e suportam os mecanismos de transferência de energia para excitação de diferentes íons TR nesta matriz, sendo importante para futuras aplicações em fotônica / Silk fibroin (SF) is a structural protein found in Bombyx mori cocoons and has properties that are potentially applicable in photonics. This biocompatible matrix is an interesting substrate for different ions or molecules. Furthermore, its variable refractive index allows for photons to be guided in this material enabling their use as biocompatible and resorbable waveguides, which can be used to provide optical energy for various applications, e. g., therapy or imaging into living tissue. Its suitability in optical systems is mainly due to its properties such as: being mechanically robust, presenting very smooth surfaces, highly transparent (> 95%) throughout the visible region of the spectrum and being moldable. In addition, there is an extra feature: the possibility of biochemical functionalization, which may confer greater versatility to these devices. On the other hand, rare earth ions (RE) play a widely known role in the field of photonics. However, there is no studies involving the production of light in doped SF with RE ions and the combination of the mechanical and optical properties of this matrix with the multifunctionality of these ions can be a way to produce new photonic devices. Thus, the aim of the present work was to study the SF matrix structure in the presence of different RE ions (Eu3+ and Tb3+) as well as the interaction between the amino acids from the matrix and these RE ions. The results presented in this manuscript have characterized the RE-SF interactions and supported the mechanisms of energy transfer for excitation of different RE ions in this matrix being important for future applications in photonics

A fibroína de seda é uma proteína sintetizada pela espécie Bombyx mori, popularmente conhecida como bicho-da-seda. O casulo de Bombyx mori é composto por fibras de fibroína e pela sericina, responsável por unir os fios de fibroína. A fibroína é um polímero natural bastante versátil e pode ser processada de maneira a formar materiais como filmes, microesferas e hidrogéis. Os hidrogéis são redes tridimensionais formadas por macromoléculas e capazes de absorver grande quantidade de água sem perder sua integridade estrutural. Devido à características como biocompatibilidade, elevado teor de água e boas propriedades de difusão de oxigênio e nutrientes, os hidrogéis são amplamente utilizados em pesquisa biomédica. A fibroína é biodegradável, termicamente estável, altamente cristalina, flexível, resistente à tração, além de insolúvel em água e na maioria dos solventes orgânicos. A fibroína derivada das sedas Frison Extra e Meada 21 Denier foi separada da sericina pelo processo de degomagem, onde as fibras de seda foram imersas em soluções alcalinas e submetidas à aquecimento com posterior remoção de sericina. Os fios de fibroína foram dispersos nas soluções de CaCl2:H2O, LiCl:H2O e LiCl:EtOH:H2O. Diferenças nos tempos de dispersão para amostras distintas degomadas ou não foram observadas, bem como para cada um dos sistemas salino/solvente empregados. Após o processo de dispersão da fibroína as dispersões obtidas foram caracterizadas quanto à textura e reologia. As amostras não degomadas apresentaram maior firmeza e aumento do módulo elástico G\'. Algumas amostras contendo sericina ou etanol apresentaram comportamento newtoniano. Em uma segunda etapa, as amostras foram dialisadas para a produção do hidrogel e em seguida liofilizadas. Não houveram diferenças entre os tempos de gelificação para amostras distintas. Finalmente objetivou-se a caracterização dos hidrogéis obtidos por meio de ensaios termogravimétricos, difratométricos, espectrofotométricos e microscópicos. Todos os hidrogéis de fibroína de seda apresentaram alta resistência térmica, com presença predominante da conformação em folha-β da fibroína. Morfologicamente, os hidrogéis obtidos a partir de dispersões em LiCl:EtOH:H2O e CaCl2:EtOH:H2O apresentaram aspecto de rede enovelada, enquanto que os hidrogéis oriundos de dispersões em LiCl:H2O apresentaram estrutura lamelar. / The silk fibroin is a protein synthesized by Bombyx mori species, popularly known as silkworm silk. The Bombyx mori cocoon is composed of fibroin fibers and the sericin protein, which is responsible for joining the fibroin yarns. The fibroin is a quite versatile natural polymer and can be processed to form materials such as films, microspheres and hydrogels. Hydrogels are three-dimensional networks formed by macromolecules and capable of absorbing large quantities of water without losing their structural integrity. Due to biocompatibility, ability to mimic biological tissues, high water content and good diffusion properties of oxygen and nutrients, hydrogels are widely used in biomedical research. The fibroin is biodegradable, thermally stable, highly crystalline, flexible and tensile resistant. Besides, it is insoluble in water and in most organic solvents. The fibroin from Frison Extra and Meada 21 Denier silks was separated from the sericin by the degumming process, whereby the silk fibers were immersed in alkaline solutions and subjected to heating with subsequent dissolution and removal of sericin. Fibroin yarns were dispersed in various solutions: CaCl2:H2O; LiCl:H2O; and LiCl:EtOH:H2O. It was observed that according to the fibroin type and solvent solution used the time to achieve dispersion varied. Texture and rheology were determined for every sample after dispersion. All non-degummed samples had shown increased firmness and elastic module G\'. It was observed that the samples presented a wide behavior range, some that contained sericin or ethanol presented Newtonian behavior. Subsequently the samples were dialyzed to obtain the hydrogels and lyophilized. All samples (with exception of two) have formed hydrogels in a 24 hours period. The lyophilized hydrogels were analyzed by thermogravimetry, diffractometry, spectrophotometry and microscopy. All silk fibroin hydrogels presented high thermic resistance with β-sheet predominance. Morphologically, all hydrogels obtained from LiCl:EtOH:H2O and CaCl2:EtOH:H2O solutions had shown entangled aspect wile hydrogels from LiCl:H2O solutions had shown lamellar structures.

Two major hurdles face the production of recombinant spider silk protein (rSSp) based materials. First, the production of sufficient quantities of rSSp has proven difficult due to their highly repetitive nature and protein size (>250kDa). Secondly, rSSp and native silks are practically insoluble in water based solutions, necessitating the use of harsh organic solvents that can remain in the material after production. While others are working on solving production problems, this dissertation demonstrates a novel aqueous solubilization method that is rapid (<1 minute) and results in near 100% solubilization of the rSSp. From this new solubilization method films, foams, gels (hydrogels and lyogels), adhesives, coatings and fibers have been produced as well as the previously unreported sponge. All of these novel materials were derived from entirely aqueous solutions with and without minor additives to influence the final physical state of the rSSp.

Spider silks are incredible natural materials that possess desirable combinations of strength, elasticity, weight, and robustness. Other properties such as biocompatibility and biodegradability further increase the worth of these materials. The possibility of farming spiders is impractical due to spiders’ natural behaviors. Modern biotechnologies have allowed for recombinant spider silk proteins (rSSps) to be produced without the use of spiders. However, the features responsible for spider silks impressive properties can cause difficulties with producing silk materials. A recently developed water-based and biomimetic solvation method has provided a solution to such difficulties and has also led to novel silk biomaterials. Most notable among these materials are; coatings, fibers, adhesives, films, foams, hydrogels, aerogels, capsules, and sponges. Many of these material possess specific properties that may be suitable for many commercial, industrial, and biomedical uses. This study has developed numerous spider silk biomaterials, identified their essential properties and features, provided preliminary evidence for various applications, and identified directions for future studies and uses.

Major ampullate spider silk represents a promising biomaterial with diverse commercial potential ranging from textiles to medical devices due to the excellent physical and thermal properties from the protein structure. Recent advancements in synthetic biology have facilitated the development of recombinant spider silk proteins from Escherichia coli (E. coli), alfalfa, and goats. This study specifically investigates the economic feasibility and environmental impact of synthetic spider silk manufacturing. Pilot scale data was used to validate an engineering process model that includes all of the required sub-processing steps for synthetic fiber manufacture: production, harvesting, purification, drying, and spinning. Modeling was constructed modularly to support assessment of alternative protein production methods (alfalfa and goats) as well as alternative down-stream processing technologies. The techno-economic analysis indicates a minimum sale price from pioneer and optimized E. coli plants at $761 kg-1 and $23 kg-1 with greenhouse gas emissions of 572 kg CO2-eq. kg-1 and 55 kg CO2-eq. kg-1, respectively. Spider silk sale price estimates from goat pioneer and optimized results are $730 kg-1 and $54 kg-1, respectively, with pioneer and optimized alfalfa plants are $207 kg-1 and $9.22 kg-1 respectively. Elevated costs and emissions from the pioneer plant can be directly tied to the high material consumption and low protein yield. Decreased production costs associated with the optimized plants include improved protein yield, process optimization, and an Nth plant assumption. Discussion focuses on the commercial potential of spider silk, the production performance requirements for commercialization, and impact of alternative technologies on the sustainability of the system.