Gold nanoshells, a material generally composed of a core of silica surrounded by a thin shell of gold, are of great interest due to their unique and tunable optical properties. By varying the shell thickness and core size, the absorption and scattering properties are greatly enhanced. The nanoshells can be made to absorb or scatter light at various regions across the electromagnetic spectrum, from visible to the near infrared. The ability to tune the optical properties of nanoshells allows for their potential use in many different areas of research such as optical imaging, tumor ablation, drug delivery, and solar energy conversion. The research in this thesis focused on the synthesis and characterization of two novel gold nanoshell materials containing thermally-responsive, organic-inorganic hybrid layers. One type of material was based on a two-layer particle with a thermally responsive hybrid core of N-isopropylacrylamide (NIPAM) copolymerized with 3-(trimethoxysilyl)propyl methacrylate (MPS) that was then coated with a thin layer of gold. The second material was a three-layer particle with a silica core, a thermally responsive copolymer of NIPAM and MPS middle layer and an outer shell of gold. Various techniques were used to characterize both materials. Transmission electron microscopy (TEM) was used to image the particles and dynamic light scattering (DLS) was used to determine particle size and the temperature response. Additionally, UV-Vis spectroscopy was used to characterize the optical properties as a function of temperature.

Poly (Ethylene Oxide) (PEO, with a general formula (CH₂-CH₂-O)[subscript pi] ) is completely soluble in water at room temperature over an extremely wide molecular weight range and has been widely studied by experiment and theory. The objective of our work is to study the solubility behavior by the method of Monte Carlo simulation. The insertion factor lnB, which is equivalent to the infinite dilute Henry's Law Constant, is used to represent the solubility of various molecules in water. Our research started with simple fluid and aqueous solutions of small molecules including hard spheres, inert gases, hydrocarbons and dimethyl ether (DME, as a precursor for PEO). Solubility consists of a favorable energy term and an unfavorable entropy term. Against the common belief of entropy-dominating-hydrophobicity effect, it is actually the ability of the solute to interact with solvent (or the energetic factor) that dominates solubility. The solubility minimum appearing for both hydrophobic and hydrophilic solutes along the water coexistence curve is the result of competition between the favorable energy contribution and the unfavorable entropy contribution. Normal alkanes with carbon number from 1 to 20 have been modeled by LJ chains to study the solubility of non-polar polymer chains in water. Various constraints have been put on the LJ model to evaluate their effect on solubility. No significant difference was observed for LJ chain with or without fixed bond angles, but torsional interaction changed the chain solubility dramatically. The temperature and chain-length effect on chain solubility has been examined and it can be explained by the balancing between the intra-chain interaction and entropy penalty. By choosing the right torsional interaction parameters we may be able to reproduce by simulations the solubility minimum of normal alkanes at C₁₁. PEO was modeled by united atom chains with length up to 30. The most probable distance between two nearest ether oxygens in both vacuum and aqueous solutions matches the hydrogen bond length in bulk water. Hydrogen bonding plays an important role in the unique water solubility behavior of PEO since the water-PEO interaction effectively increases the total number of hydrogen bonds and results in a favorable change in energy. A trans-gauche-trans conformation along the O-C-C-O bonds does enable hydrogen bond formation between one water molecule and two nearest or next nearest ether oxygens. A helix structure is not required for the PEO to have favorable interactions with water. Two polymers with similar structure as PEO but are insoluble in water: Poly (methylene oxide) (PMO) and Poly (propylene oxide) (PPO) have been studied to compare with PEO. Their difference in structure from PEO, though slight, reduces the chance of hydrogen bond forming between water and chains so as to decrease the solubility. / text

Polymer electrolyte films based on poly(trimethylene carbonate) (PTMC) mixed with LiTFSI salt in different compositions were synthesized and investigated as electrolytes for lithium ion batteries, where the ionic conductivity is the most interesting material property. Electrochemical impedance spectroscopy (EIS) and DSC were used to measure the ionic conductivity and thermal properties, respectively. Additionally, FTIR and Raman spectroscopy were used to examine ion coordination in the material. Additives of nanosized TiO2 and powders of superionically conducting Li1.3Al0.3Ti1.7(PO4)3 were investigated as enhancers of ionic conductivity, but no positive effect could be shown. The most conductive composition was found at a [Li+]:[carbonate] ratio of 1, corresponding to a salt concentration of 74 percent by weight, which showed an ionic conductivity of 2.0 × 10–6 S cm–1 at 25 °C and 2.2 × 10–5 S cm–1 at 60 °C, whereas for even larger salt concentrations, the mechanical durability of the polymeric material was dramatically reduced, preventing use as a solid electrolyte material. Macroscopic salt crystallization was also observed for these concentrations. Ion coordination to carbonyls on the polymer chain was examined for high salt content compositions with FTIR spectroscopy, where it was found to be relatively similar between the samples, possibly indicating saturation. Moveover, with FTIR, the ion-pairing was found to increase with salt concentration. The ionic conductivity was found to be markedly lower after 7 weeks of aging of the materials with highest salt concentrations.

Studies of biomolecular interactions are of interest for several reasons. Beside basic research, the knowledge gained from such studies is also very valuable in for example drug target identification. Medical care is another area where biomolecules may be used as biomarkers to aid physicians in making correct diagnosis. In addition, the highly specific interactions between antibodies and almost any substance opens up the possibilities to design systems for detection of trace amounts of both biological and non-biological substances within environmental restoration, law enforcement, correctional care, customs service and national security. A biochip, which contains a biologically active material, offers a means of monitoring the molecular interactions in the above applications in a sensitive and specific manner. The biochip is a key component of a biosensor, which also includes components for transforming the interaction events into a human-readable signal. This thesis describes the use of poly(ethylene glycol) (PEG) in biochip design. Two different approaches are presented, the first based on ethylene glycol (EG)-containing alkyl thiol self-assembled monolayers (SAMs) on flat gold and the second on photo-induced graft copolymerisation of PEG-containing methacrylate monomers onto various substrates. The former is a two dimensional system where EG-terminated thiols are mixed with similar thiols presenting tail groups that mimic the explosive substance 2,4,6-trinitrotoluene (TNT). In an immunoassay, the detection limit for TNT was determined to fall in the range 1-10 µg/L. In the second approach, a branched three dimensional biosensor matrix (hydrogel) is proposed. The carboxymethylated (CM) dextran matrix, which is commonly used within the biosensing community, is not always ideal for studies of biointeractions, due to the non-specific binding frequently encountered in work with complex biological solutions and various proteins. To employ PEG, which displays a low non-specific binding of such species, is therefore an interesting option worth investigating. The use of a branched graft polymerised PEG matrix in biosensor applications is novel as compared to previous reports which have focused on linear PEG chains. The latter approach provides, at maximum, one functional group, per surface anchoring point, for immobilisation of sensor elements. Thus, it has the inherited disadvantage that it limits the number of available immobilisation sites. The present PEG matrix contains a large number of functional groups, for immobilisation of sensor elements, per grafting site and offers the potential of improved response upon binding to the analyte as demonstrated in a series of successful sensor experiments. Furthermore, the nature of the process enables easy preparation of matrix patterns and gradients. In a PEG matrix gradient, protein permeability is studied and the capabilities of immobilising proteins are demonstrated. By combining the patterning technique with different monomers in a two-step process, an inert platform, lacking chemical attachment sites, is provided with arrays of spots (with immobilisation capabilities), which are conveniently addressed via microdispensing and used for biosensor purposes. The EG-terminated thiols present another means of generating such inert platforms, a route which is also investigated. To further explore the sensor quality of these spots, the concepts of patterning and gradient formation are combined and studied. / Det är intressant att studera biomolekylära interaktioner av många anledningar. För att kunna bedriva framgångsrik läkemedelsutveckling är det oerhört viktigt att känna till hur olika molekyler samverkar i människokroppen. Inom sjukvården kan biomolekyler användas som biomarkörer, då närvaro av dem eller förändringar av deras koncentrationer är kopplade till sjukdomstillstånd, och därmed hjälper läkaren att ställa rätt diagnos. Dessutom kan de mycket specifika interaktionerna mellan antikroppar och (i princip) valfri substans användas för detektion av spårämnen vid miljösaneringsarbete, gränskontroller, polisarbete, fängelser och arbete med nationell säkerhet. Den här avhandlingen beskriver hur polymeren polyetylenglykol (PEG) kan användas vid design av biochip. Ett biochip är en liten anordning, som kan användas för att detektera specifika molekyler med hjälp av en biologisk interaktion. Traditionellt har PEG använts inom biomaterialsektorn, men återfinns även i hygienartiklar som tvål och tandkräm. Ett annat användningsområde är konservering av bärgade träskepp och i en del litiumjonbatterier ingår PEG som en komponent. Dessutom pågår utveckling av PEG-innehållande skyddsvästar. I det här arbetet används PEG framför allt på grund av sin förmåga att minimera ospecifik inbindning av proteiner, som utgör en stor del av gruppen biomolekyler, till ytor på biochip. Två olika typer av ytbeläggningar, som innehåller den här polymeren, har använts. Den första typen ger mycket tunna (~0.000003 mm), tvådimensionella filmer medan den andra ger en något tjockare (~0.00005 mm), tredimensionell struktur (matris). De tvådimensionella filmerna har använts för att utveckla en sprängämnesdetektor med mycket hög känslighet (detektionsgräns mellan 1-10 ppb). En viktig beståndsdel i detta system är antikroppar riktade mot sprängämnet trinitrotoluen (TNT). Den tredimensionella matrisen är mer generell och kan användas för att studera många olika molekylära interaktioner. Tillverkningsmetoden av matrisen är baserad på belysning med ultraviolett ljus och är därmed lämpad för att skapa mönstrade ytor. Genom att blockera delar av ljusflödet begränsas tillväxten av matrisen till de belysta delarna. På så sätt har bland annat så kallade mikro-arrayer, bestående av mikrometerstora (tusendels millimeter) strukturer i ett regelbundet mönster, tillverkats. Tekniken tillåter även tillverkning av gradienter, där matrisens tjocklek varierar längs med provet, genom att belysa olika delar av provytan olika länge. Genom att undersöka dessa gradienter har information om matrisens genomsläpplighet för proteiner kunnat extraheras. Gradientkonceptet har även kombinerats med mikro-arraytillverkningen och gett möjlighet att studera interaktioner mellan flera olika modellproteiner och deras motsvarande antikroppar i olika tjocka matriser på en och samma yta. Det finns ett stort antal sätt att utnyttja interaktionerna mellan olika molekyler på ett biochip. Ett tilltalande tillvägagångssätt är exempelvis att i en mikro-array binda in olika molekyler som kan fånga kliniskt intressanta biomolekyler, i syfte att skapa en hälsoprofil. Ett sådant biochip skulle ge möjlighet att parallellt detektera eller bestämma koncentrationen av ett stort antal biomolekyler i till exempel en droppe blod. På så sätt kan en diagnos snabbt ställas, kanske till och med utan att patienten behöver uppsöka sjukvården. Den utvecklade PEG-matrisen har god potential att fungera i en sådan applikation.

The widespread adoption of hybrid organic-inorganic solar cells has been delayed by low performance. Improving performance requires a firm understanding of how to optimize both material composition and processing parameters. In this thesis, we examine processing parameters that include solution composition, annealing temperature, and the rates of spin casting and evaporative coating. We also find that the optimal weight ratio for the active layer of a ZnO:P3HT solar cell is 40 wt. % ZnO. / text

The specific interactions of macromolecules along with the activity of enzymes are central to all aspects of biology. It is well recognized that when the relative concentration or activity of macromolecules is perturbed, it can lead to human diseases. Thus, the development of simple methods for the detection of macromolecules and the activity of enzymes in complex environments is important for understanding biology. Moreover, the development of methods for measuring interactions allows for the testing of inhibitors that can be used as tools or drugs for improving human health. Towards this goal, a promising new method has been developed, which is the focus of this thesis, called split-protein reassembly or protein fragment complementation. In this method, a protein reporter, such as the green fluorescent protein or firefly luciferase, is dissected into two fragments, which are attached to designed adaptor proteins. The designed split-protein systems only produce a measurable signal, either fluorescence or luminescence, when a specific macromolecular interaction or activity is present. In this thesis, I have extended previous research on the direct detection of DNA using split-protein sensors utilizing a red fluorescent protein, dsRED from Discosoma that allows for multiplexed DNA detection. I have designed a new split-luciferase based sensor for detection of poly (ADP-ribose) or PAR, which plays a key role in the response to DNA damage and have applied it for monitoring the activity of poly (ADP-ribose) glycohydrolase that controls PAR levels in the cell. Furthermore, I have significantly expanded upon a three-hybrid split-luciferase system for identifying protein kinase inhibitors. I have designed and tested two orthogonal peptide based chemical inducers of dimerization based on BAD and p53mt conjugates. I have studied these chemically induced dimerization systems in detail in order to begin to provide a theoretical basis for the observed experimental results. Finally, in a less related area, I have developed methods for producing water soluble semiconductor nanoparticles called Quantum Dots (QDs), with potential application in biological imaging. I have developed methods for functionalizing the QDs with orthogonal peptides, which can be potentially used for the assembly of high affinity non-covalent QD targeted proteins.

Nano-cellulose fibers/suspension has very high viscosity, its viscosity has to be lower before it can be applied in the paper coating recipe. For this purpose the adsorption behaviour of polyvinyl alcohol on nano-cellulose fibers were investigated using method developed by Zwick in 1960, based on the formation of PVA-iodide blue complex in the presence of boric acid. The experiments showed that the maximum adsorbed amount i.e. 0.13 g PVA/g NFC was obtained in a dispersion with 0.2 % PVA concentration. It should be possible to further increase the PVA adsorption as the adsorbed amount didn’t reach a saturation point where the PVA adsorption attained a constant value. It was also found that adsorption of PVA on NFC is time dependent. The absorbance measurement after four days of mixing PVA/NFC suspension showed only partially adsorption of PVA on nano-cellulose surface.  An equilibrium time of 10-13 days was needed for PVA to fully adsorb on nano-cellulose fibers surface. Another important observation was that PVA adsorption also depends on the concentration of nano-cellulose fibers. A lower concentration of NFC easily allows PVA to adsorb on its surface, as compared to higher NFC concentration. An important finding during the methodology development was the method to get rid of formation of flocs in the blue iodide complex solution; by slowly addition of reactants, especially the KI/I2 solution under continuous stirring around 60oC the tendency to flocs formation was suppressed.

This work was undertaken with the objective of isolating and characterising the bdh gene of P. aeruginosa PAOI. Isolation of the bdh gene was initially attempted by PCR amplification and then by heterologous complementation of E. coli (LS5218) and S. meliloti (Rm11107) strains unable to catabolise 3-hydroxybutyrate. Three classes of plasmids were isolated. Class I comprised two plasmids, p5218-02 and p5218-07, isolated via complementation of LS5218, which were capable of complementing both LS5218 and Rm11107 for growth on 3-hydroxybutyrate. 3-hydroxybutyrate dehydrogenase (BDH) activity was not detected in an extract of LS5218 (p5218-02). The sole 3.6-kb EcoRI fist was partially sequenced and found to have three putative open reading frames (ORF). ORF 1 is homologous to the fusE gene of E. coli. We hypothesised that p5218-02 encodes an enzyme capable of degrading 3 hydroxybutyrate, but does not encode the bdh gene. Plasmids of class II (p30065) and class III (p30066) were isolated via complementation of Rm11107. Significant BDH activity was detected in an extract of Rm11107 (p30066), but not in Rm11107, leading to the hypothesis that p30066 carries the bdh gene.

Micromechanical adhesion force measurements were performed on tetrahydrofuran (THF) hydrate particles in n-decane. The experiments were performed at atmospheric pressure over the temperature range 261–275 K. A scoping study characterized the effects of temperature, anti-agglomerants, and interfacial energy on the particle adhesion forces. The adhesion force between hydrate particles was found to increase with temperature and the interfacial energy of the surrounding liquid. The adhesion force of hydrates was directly proportional to the contact time and contact force. Both sorbitan monolaurate (Span20) and poly-N-vinyl caprolactam (PVCap) decreased the adhesion force between the hydrate particles. The measured forces and trends were explained by a capillary bridge between the particles.

The synthesis and characterization of a series of chiral indium complexes bearing a tridentate NNO ligand are reported. The ligand 2-[[[(dimethylamino)cyclohexyl]amino]methyl]- 4,6-bis(tert-butyl) phenol (H₂NNO) was synthesized via a previously published procedure and bound to indium by both a protonolysis and salt metathesis route. A dimethylated indium complex (NNO)InMe₂ (1) was isolated by reaction of InMe₃ with H₂NNO. A one-pot saltmetathesis route was used to produce a unique mixed-bridge dinuclear indium complex [(NNO)InCl] ₂(μ-OEt)(μ-Cl) (3) from a mixture of indium trichloride, potassium ethoxide and the monopotassiated salt of the ligand, KH(NNO). Direct reaction of KH(NNO) and indium trichloride resulted in the formation of (NNO)InCl₂ (4) which was carried forward to 3 by reaction with sodium ethoxide. The complex 3 is active for the ROP of β-butyrolactone ε-caprolactone and lactide and is the first reported indium-based catalyst for lactide or β-butyrolactone ROP. Kinetic studies of 3 for ROP of LA revealed that catalyst was well-behaved, and that the rate was first order with regard to lactide and catalyst. The enthalpy and entropy of activation for the ROP were experimentally determined. Polymer produced by ROP by 3 has narrow molecular weight distribution and a good correlation is seen between the observed moleular weight and monomer loading. A mechanism was proposed for 3 acting as a catalyst for the ROP of lactide; however further experiments are required to confirm this mechanism. Polymer samples isolated from the ROP of rac-lactide by rac-3 show isotactic enrichment. It is postulated that the chiral catalyst 3 is exerting stereocontrol via an enantiomorphic site control mechanism.