Abstract not available

Stem cell based therapy has the potential to treat several severe diseases; Parkinson’s disease is one well- known example. Transplantation of stem cell derived cells into animal models is unfortunately often associated with tumour formation or- uncontrolled growth of the transplanted cells. One strategy to suppress this tumour formation might be to induce differentiation of these cells, which in turn would prevent them from dividing.   Neuroblastoma tumors are known to demonstrate the complete transition from an undifferentiated state to a completely harmful, differentiated appearance and derived cells can be used as a model for cell differentiation and tumor suppression.   In this Master Thesis’s the conducting polymers PEDOT and PPy, that upon formation can be doped with biologically active compounds which in- turn can be released in a controlled manner through electrical stimulation, were formed together with various drugs (e.g. Methotrexate and Mycophenolic Acid), here shown to have effect on Neuroblastoma cells. Neuroblastoma- derived cell line SH- SY5Y was used as a model system for neuronal differentiation and tumour inhibition. Release profiles of neuroblastoma active drugs following electrical stimulation were evaluated and the effects from electrochemical processes on simultaneously growing SH- SY5Y cells were investigated.   The methods to deposit and release the drugs were based on electropolymerization and electrochemically controlled release, respectively. Controlled release of various drugs and compounds was monitored using Vis- and UV- spectroscopy and on some occasions using HPLC.   The electrochemically controlled release of a biologically inactive compound that can be used as a negative control for electrochemical release in future experiments was shown and that resulting electrochemical processes have negative effects on neuroblastoma cell growth.

The organic electronic ion pump (OEIP) is an electrically controlled polymer-based device that has the capability to interact with biological systems down to a single cell level by mimicking neural signalling. This is accomplished by translation of an electrical signal into a chemical output, such as ions and neurotransmitters. Because of the combined spatial and temporal precision, this is a technology with a promising future as an advanced therapeutic device. Depending on the application, the OEIP requires different geometries. Implants that will be used to control on a single cell level require very small dimensions, while for example extracorporeal mounted OIEPs, with only the delivery channel penetrating the skin, require much longer channels. Despite the application, it is necessary to have a good knowledge about the transport and delivery properties and how they change due to the geometry. These properties have been observed as very varying and unstable in early unpublished results, and these findings motivate this project. This project includes photolithographic fabrication and investigation of transport and delivery properties such as effective resistance, efficiency and stability of OEIPs with varying delivery channel lengths and widths. Shorter delivery channels show a consistent but relatively low efficiency. Delamination between different layers of the device is suspected as the cause. Initially, the longer delivery channels show a low functionality, most probably due to poor encapsulation. It is suggested that a soft, water-permeable plastic best encapsulates OEIPs that will be used as a medical implant, while a material impermeable to water, for example a metal, could successfully encapsulate OEIPs operating in air.

No description available.

Conducting polypyrrole (PPy) nanoparticles were synthesized via microemulsion polymerization system. The characterization of PPy nanoparticles was done by Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM). Nanocomposites were prepared by melt-mixing of polypyrrole with polypropylene (PP) and processed with injection molding. The amount of PPy in nanocomposites varied in the range of 1-20% by weight. The effect of PPy nanoparticles on mechanical, electrical properties and thermal stability of nanocomposites were investigated. Tensile test has revealed that increasing amount of PPy increased the strength and the stiffness of the nanocomposite while limiting the elongation of PP. Thermal gravimetric analysis has showed that incorporation of PPy nanoparticles has improved the thermal stability of the nanocomposites. Four probe conductivity measurement has exhibited that increasing amount of PPy nanoparticles increases the conductivity of nonconductive PP up to 2,4.10-4 Scm-1. In order to improve the dispersion of PPy in PP, sodium dodecylsulphate was used as dispersant. The same techniques were used to characterize nanocomposites containing 2% by weight dispersant. Composites prepared with dispersant have exhibited improvement in some mechanical and thermal properties and involved smaller dimension PPy nanoparticles.

Thesis (Ph.D.)--University of Wollongong, 2009. / Typescript. Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2000. / Bibliography: leaves 95-101.

Conducting polymers have been widely explored for many different purposes including sensing. In thisthesis the conducive properties of pyrrole and the carbohydrate binding properties of boronic acid iscombined to make a reagent-free detector for carbohydrates. The polymer is manufactured in form ofparticles in the μm scale to create a porous film which has a high surface to volume ratio.The material was characterised and the binding properties were evaluated for galactose and glucose.Proof of binding was found via both electrochemical methods and QCM-D. A correlation between R2 value and concentration of substrate was found which enables measurement of concentration of carbohydratesin unknown samples.

D.Tech. Chemical Engineering / This research emphasizes the potential application of conducting polymer based nanocomposites for the remediation of contaminants from water. This study facilitates the preparation of conducting polymer based nanomaterials for the efficient removal of fluoride and toxic chromium(VI) from water. This work also identifies the importance of understanding the physico-chemical properties of the synthesized nanomaterials which greatly influence the materials performance in removing contaminants from water.

Electronic materials are of great interest for use in photovoltaics, sensors, light-emitting diodes, and molecular electronics. Hybrid Inorganic/Organic materials have been studied for device application due to their unique electronic properties. These properties result from the formation of bulk heterojunctions between inorganic (n-type) and organic (p-type) materials. However, due to incomplete pathways for charge transport and poor interfaces between materials, charge trapping and exciton recombination is often high. In an effort to alleviate these problems, we have developed an approach to fabricate bulk heterojunction materials via a seeded growth process. Electropolymerizable Schiff base complexes have been designed, synthesized, and utilized as precursors for conducting metallopolymers. The embedded metal centers are used as seed points for direct growth of size-controllable semiconductor nanoparticles within the polymer film leading to direct electronic communication between the two materials. The synthesis of CdS, CdSe, Ga₂S₃, CuInS₂, CuInSe₂, CuGaS₂, CuGaSe₂, CuGa[subscript x]In[subscript x]-₁S₂, and CuGa[subscript x]In[subscript x]-₁Se₂ has been seen through TEM and EDX. Devices have been fabricated and current studies have focused on the photovoltaic characterization of these materials which have a PCE of 0.11%. As a second but closely related area, polymers have also been studied as organic semiconductors for device applications. However they are hard to process from solution and their polymeric structure can vary. Both of these problems can be solved by using well-defined solution processable oligomers. Thiophene oligomers have been synthesized and characterized through Single Crystal X-Ray Crystallography, Four Point Probe Conductivity, and Powder Diffraction. These oligomers have a well-defined structure and are solution processable from a variety of solvents which can then be used as models to predict and study the properties of polythiophene. / text