Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: Dennis W. Prather, Dept. of Electrical & Computer Engineering. Includes bibliographical references.

Thesis (M.S.E.C.E.)--University of Delaware, 2008. / Principal faculty advisor: . Includes bibliographical references.

This thesis is dedicated to developing novel photofunctional molecular materials for the applications in chemical sensing, bioimaging and electrochromic. To begin with, a brief introduction of photofunctional molecular materials and an overview of their applications in chemical sensing, bioimaging and electrochromic were presented in Chapter 1. In chapter 2, we have synthesized a series of water-soluble phosphorescent cationic iridium(III) solvato complexes (1-7) as multicolor cellular probes for imaging in living cells. All of these complexes can be dissolved in PBS. The emission of complexes can be tuned from green to red by changing the chemical structure of cyclomedtalating ligands. All complexes exhibit low cytotoxicity to living cells and exhibit cell membrane permeability and specific staining of cytoplasm. They enter the cells by the mechanism of energy-independent passive diffusion mechanisms. More importantly, complex 7 can act as a two-photon phosphorescent cellular probe, and fluorescence lifetime imaging microscopy is successfully applied for bioimaging in the presence of short-lived background fluorescence. We developed two excellent optical probes for CO2 detection in Chapter 3. The first one for the CO2 detection is a phosphorescent probe based on an iridium(III) complex with 2-phenylimidazo-[4,5-f][1,10]phenanthroline. After bubbling CO2 into the detection solution, the quenched phosphorescence by the addition of CH3COO can be recovered. Photobleaching experiment demonstrates that this phosphorescent CO2 probe shows higher photostability than some of the reported organic probes. More importantly, the time-resolved PL experiment demonstrates that this probe can be used to detect CO2 in the presence of strong background fluorescence, which improves the sensitivity and signal-to-noise ratio of the sensor in complicated media. The second one is a water-soluble fluorescent probe based on tetraphenylethene derivative. After bubbling CO2 into the detection solution, remarkable color change and fluorescence enhancement could be observed. The response of this probe to CO2 in aqueous solution is fast and the detection limit is about 2.4 × 106 M. To emphasize the practical application of this probe, a porous film was successfully fabricated by mixing the dye with sodium carboxymethyl cellulose in water, which can serve as an efficient CO2 gas sensor. More importantly, this probe exhibits low cytotoxicity towards live cells and has the ability to monitor the external CO2 concentration changes of living cells. Chapter 4 focused on the development of novel soft salt based phosphorescent probe. This type of probe consists of two oppositely charged ionic complexes with two distinguishable emission colors, which makes it a perfect candidate as a ratiometric probe. The emission color of 10 changes from blue to red with increasing pH value. 10 is cell-permeable and exhibits low cytotoxicity, and it has been successfully applied for ratiometric pH imaging with the use of confocal microscopy, demonstrating its great potential for intracellular environment monitoring. Furthermore, phosphorescence lifetime imaging experiments can detect intracellular pH variations by photoluminescence lifetime measurements, which allowed for eliminating background fluorescence and selecting long-lived phosphorescence images. Quantitative measurement of intracellular pH fluctuations caused by oxidative stress has been successfully carried out for 10 based on the pH-dependent calibration curve. A series of cationic Zn(II) complexes has been designed and synthesized in chapter 5. The photophysical properties of these Zn(II) complexes are affected by the counterions. By altering the counterions, the emission peak can be changed from 549 nm to 622 nm. Interestingly, the CIE coordinate and the emission colors can be simply tuned by adjusting the concentration of 11d in the polyether. Under an electric field of about 15 V applied onto the electrodes, the emission color of the solution of 11b-11d near the cathode changed its original emission color to sky blue. Based on this interesting electrochromic fluorescence of 11d, a quasi-solid information recording device has been successfully designed. Furthermore, data encryption has been realized by combining 1d with BODIPY, and information decoding processed has been accomplished, for the first time, by employing TPA excitation techniques, in which the large TPA cross section of 11d is differentiated from small TPA cross section of common organic dyes. Finally, Chapters 6 and 7 present the concluding remarksand the experimental details of the work described in Chapters 25

[pt] Nas últimas décadas, vem ocorrendo uma importante revolução na área da tecnologia médica, em particular nos equipamentos de diagnóstico por imagem. O propósito central da presente tese concentra-se na análise e compreensão das estratégias e sistemas produtivos empregados na produção desses equipamentos, com enfoque específico na produção de equipamentos de Ressonância Magnética, pela importância de se dispor de dados e informações principalmente em países como o Brasil que, apesar de ainda não apresentarem produção nacional, fazem uso de toda essa tecnologia e necessitam preparar recursos humanos não só para a sua própria utilização, mas também para o desenvolvimento e produção de componentes e periféricos específicos. Um grande motivador para esta pesquisa foi o Projeto ToRM, desenvolvido pela Universidade de São Paulo. O projeto constava do desenvolvimento local de um equipamento de ressonância para que fosse possível a formação de mão-de-obra especializada e a realização de estudos para acessórios e componentes. A metodologia empregada neste estudo, o qual é de caráter exploratório, envolve uma pesquisa bibliográfica e dois estudos de casos realizados em empresas produtoras de equipamentos de diagnóstico por imagem - Philips Medical Systems e Siemens Medical. Assim, com a compreensão dos sistemas produtivos aplicados, objetiva-se subsidiar as empresas e universidades com informações atualizadas referentes a essa indústria, principalmente pela falta de material acadêmico sobre o assunto. / [en] In the last decades, an important revolution has taken place in the medical technology field, particularly in image diagnosis equipment. The central purpose of the present thesis is to analyze and understand the strategies and productive systems used in the production of such equipment, with specific focus on the production of Magnetic Resonance equipment. It is important to make data and information available especially in countries like Brazil, which, despite still not having a national production, make use of this technology and need to prepare human resources not only for its own use but also for the development and production of specific components. A great motivation to this research was the ToRM Project, developed by the University of São Paulo. This project consisted in the local development of a resonance machine, which would allow for the preparation of specialized professionals and the development of studies about accessories and components. The methodology used in the present study, which is exploratory in character, involves a literature review and case studies performed in two major manufacturers of image diagnosis equipment - Philips Medical Systems and Siemens Medical. Thus, by understanding the productive systems applied, our goal is to provide companies and universities with updated information about this industry, especially considering the lack of academic material on this subject.