Synthesis and postmodification of functionally relevant organically modified silica particles

This thesis describes the synthesis and properties of organically modified silica (ORMOSIL) particles with possible applications in the field of drug delivery. Nanoparticle drug delivery methods take advantage of the unique physical properties of nanoscale architecture to deliver a large payload of drug to a targeted site. They are highly porous, contain many organic functionalities for covalent attachment, and their surfaces can be functionalized. A particle-based approach allows for the delivery of a large and localized payload in a single package.;Initial study focused on the generation of submicron organically modified silica particles containing boron. This involved the synthesis of vinyl-enriched silica particles and the postmodification of the vinyl functionalities throughout the particle body. Hydroboration and bromination of the vinyl functionalities showed for the first time that the organic functionalities of ORMOSIL particles could be significantly modified.;Next, new organically modified silica particle types were developed. These new particle types incorporated unique organic functionalities that may undergo additional functionalization. Organic functionalities included alkenyl-, cyano-, mercapto-, and isocyanto- throughout the particle body. The different organic functionalities were then modified to demonstrate their reactivity.;Finally, a particle containing nuclei suitable for neutron capture therapy, a fluorescent tag, and targeting ligand was synthesized. Boron was the active nuclei, fluorescein was the fluorescent label, useful for in vitro studies, and folic acid is a broad field targeting ligand, useful in targeting a variety of cancer types. The particle containing the three unique motifs underwent early stages of in vitro studies against the OVCAR-3 cell line.;This thesis has considerably advanced the field of ORMOSIL chemistry through the development and modification of new ORMOSIL products. While initial efforts were geared toward the development of an ORMOSIL suitable for drug delivery, the variety of products formed that possess unique characteristics make these materials useful far beyond drug scaffolding. Additional work that is currently being pursued in the Zharov research lab includes the development of highly porous OMROSIL particles for MRI imaging, ORMOSIL hybrids that are degradable under acidic conditions, and the use of ORMOSIL particles as a stationary phase for solid phase extraction.