| This research is interdisciplinary work in which at least three different but related areas have been involved: fabrication of microfluidic devices, derivatization of solid surfaces and charge transfer processes.; We developed a non-lithographic procedure with micrometer resolution. This procedure enables fast and inexpensive prototyping of microfluidic devices made of elastomeric materials. The novelty of this approach is in the "shortcuts" taken during the preparation of the masters for casting the polymer components of the devices. Addition of microposts to the surface of the master allows for the formation of microfluidic channels with circular cross section and smooth walls. We used this new procedure for the fabrication a device for quantitative detection of bacterial spores.; In our surface work, we mainly focused on coating glass and silicon surfaces using different silanes and polyethylene glycol (PEG) derivatives. We were able to prepare highly packed and biocompatible surfaces, in which the coatings were covalently attached to the solid substrates. We have developed procedures for controlled formation of permanently adhered high-density monodispersed organic monolayers carrying the desired functionality. The surface derivative reactions were carried out under relatively mild conditions that were not harmful either for the surfaces of the solid substrates or for biomolecules attached to coating. We employed UV/vis absorption and fluorescence emission spectroscopic techniques for kinetic studies of surfaces with enzymes attached to them.; Studies of photoinduced charge transfer processes, which occur either in solution or across a solid-liquid interface, have provided considerable insight into molecular design strategies for systems capable of long distance charge separation, chemical potential storage, and artificial photosynthesis. In our research, we developed a model quarterthiophene anthraquinone system capable of photoinduced electron transfer. Electron transfer rates measured by laser flash photolysis or extracted from fluorescence data were found to be sensitive to the solvent polarity. By adding an external electron acceptor, 2,5-dichloro-1,4-benzoquinone-3-(4-carboxyly) benzoic acid (DCBQ), multistep intra/intermolecular electron transfer was observed. We were also able to immobilize charge transfer arrays to conducting surfaces and induce electron transfer across the interface. |
