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Sangeeta N. Bhatia. Anahtar, Melis Nuray Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering 2009-04-29T17:45:44Z 2009-04-29T17:45:44Z 2008 2008 http://hdl.handle.net/1721.1/45457 318454172 Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008. Includes bibliographical references (p. 37-41). Magnetic Resonance Imaging (MRI) is one of the most powerful noninvasive tools for diagnosing human disease, but its utility is limited because current contrast agents are ineffective when imaging air-tissue interfaces, in regions with low signal-tonoise ratios, or in areas that undergo motion, like the heart and bowel. A technique called dynamic nuclear polarization can be used to hyperpolarize nuclei and achieve dramatic MRI signal enhancement with minimal background noise. It has been shown that ballmilled silicon nanoparticles have the advantageous properties of hyperpolarizability and biodegradability, but in vivo utilization requires the modification of the particle surface to prevent aggregation that leads to very fast removal from circulation through phagocytosis by the liver, spleen, and lymph nodes. This thesis describes a method to functionalize hyperpolarizable silicon nanoparticles using silane chemistry and coating by poly(ethylene glycol). The particles were characterized using dynamic light scattering, scanning electron microscopy, and laser Doppler electrophoresis. The extent of amination was quantified using a fluorescamine assay, and stability was assessed by visualizing flocculation and measuring aggregation in different solvents. The functionalized particles were stable in solutions that resemble physiological conditions. These silicon nanoparticles can potentially be used for in vivo cancer imaging to enable early diagnoses and assist with clinical decision-making through disease monitoring. by Melis Nuray Anahtar. S.B. 41 p. eng Massachusetts Institute of Technology 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. http://dspace.mit.edu/handle/1721.1/7582 Mechanical Engineering. Designing and characterizing hyperpolarizable silicon nanoparticles for magnetic resonance imaging Thesis application/pdf Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="eafcdc68-6555-4086-98d7-c1473f54e7f9"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Designing and characterizing hyperpolarizable silicon nanoparticles for magnetic resonance imaging</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2008</PublicationDate> <Authors> <Author> <DisplayName>Anahtar, Melis Nuray</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Mechanical Engineering.</Keyword> <Abstract>Magnetic Resonance Imaging (MRI) is one of the most powerful noninvasive tools for diagnosing human disease, but its utility is limited because current contrast agents are ineffective when imaging air-tissue interfaces, in regions with low signal-tonoise ratios, or in areas that undergo motion, like the heart and bowel. A technique called dynamic nuclear polarization can be used to hyperpolarize nuclei and achieve dramatic MRI signal enhancement with minimal background noise. It has been shown that ballmilled silicon nanoparticles have the advantageous properties of hyperpolarizability and biodegradability, but in vivo utilization requires the modification of the particle surface to prevent aggregation that leads to very fast removal from circulation through phagocytosis by the liver, spleen, and lymph nodes. This thesis describes a method to functionalize hyperpolarizable silicon nanoparticles using silane chemistry and coating by poly(ethylene glycol). The particles were characterized using dynamic light scattering, scanning electron microscopy, and laser Doppler electrophoresis. The extent of amination was quantified using a fluorescamine assay, and stability was assessed by visualizing flocculation and measuring aggregation in different solvents. The functionalized particles were stable in solutions that resemble physiological conditions. These silicon nanoparticles can potentially be used for in vivo cancer imaging to enable early diagnoses and assist with clinical decision-making through disease monitoring.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>