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Phosphorescent semiconductor nanocrystals and proteins for biological oxygen sensing

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dc.contributor.advisor Daniel G. Nocera. en_US
dc.contributor.author McLaurin, Emily J. (Emily Jane) en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Chemistry. en_US
dc.date.accessioned 2011-05-09T15:26:12Z
dc.date.available 2011-05-09T15:26:12Z
dc.date.copyright 2011 en_US
dc.date.issued 2011 en_US
dc.identifier.uri http://hdl.handle.net/1721.1/62726
dc.description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011. en_US
dc.description Vita. Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references. en_US
dc.description.abstract Oxygen is required for cellular respiration by all complex life making it a key metabolic profiling factor in biological systems. Tumors are defined by hypoxia (low pO2), which has been shown to influence response to radiation therapy and chemotheraphy. However, very little is known about spatio-temporal changes in P0 2 during tumor progression and therapy. To fully characterize and probe the tumor microenvironment, new tools are needed to quantitatively assess the microanatonical and physiological changes occurring during tumor growth and treatment. This thesis explores the design and construction of new oxygen sensors as tools for monitoring the tumor microenvironment in real-time. Semiconductor nanocrystals or quantum dots (QDs) are the basis of these tools. Previously, most imaging applications of QDs have used them as indicators of position; they have lacked a response to their local environment. Tethering a phosphorescent complex to a QD enables fluorescence resonance energy transfer to be exploited as a signal transduction mechanism, sensitizing the QD to oxygen. The mechanism for oxygen sensing involves kinetic quenching of the emission of the energy accepting phosphor in the presence of oxygen, while the emission of the energy donating QD remains stable. This mechanism was chosen owing to the unique ability of oxygen to quench emission from a phosphorescent compound, but not fluorescence from a QD. Phosphors such as osmium polypyridines (Chapter 2), Pd or Pt porphyrins (Chapters 3 and 4), or phosphorescent proteins (Chapters 5 and 6) may all be employed. An additional benefit of FRET excitation includes very large one- and two-photon excitation cross-sections of QDs. Together, these properties make the probes ideal candidates for 02 sensing applications in biological microenvironments, where probe concentrations may vary, and where the use of multiphoton excitation in microscopy presents significant advantages in imaging thick samples and in limiting extraneous tissue damage. en_US
dc.description.statementofresponsibility by Emily J. McLaurin. en_US
dc.format.extent 193 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri http://dspace.mit.edu/handle/1721.1/7582 en_US
dc.subject Chemistry. en_US
dc.title Phosphorescent semiconductor nanocrystals and proteins for biological oxygen sensing en_US
dc.type Thesis en_US
dc.description.degree Ph.D. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Chemistry. en_US
dc.identifier.oclc 716478788 en_US


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