The Preparation of Silicon Nanocrystal-Based Materials for Biomedical Applications

  • Author / Creator
    Zhang, Xiyu
  • Silicon nanocrystals (SiNCs) are a biocompatible and elemental abundant sub-class of quantum dots. Since SiNCs were prepared, many efforts have been made to get a tunable size and rich surface chemistry that greatly expanded their applications from electronic devices to target treatments. Among all the potential applications, SiNCs have distinct advantages over fluorescent organic dyes in biomedical applications (e.g. bioimaging), such as high stability against photobleaching, long photoluminescence (PL) lifetime, and the ability of conjugating with other molecules to achieve dual-imaging or theranostics. However, their limited compatibility with water restrained their applications. Therefore, this thesis mainly focuses on preparing SiNCs with high water solubility without compromising their PL properties to extend their abilities for future use in biomedical applications. The thesis starts with an introduction about two kinds of nanomaterials (SiNCs and dendrimers) used in the experimental parts, including properties, synthetic approaches, and applications. Chapter 2 focuses on building dendrimer structures (poly(amidoamine) and commercialized dendrons) on SiNCs to combine the complementary advantages of each material. In the divergent method, a series of stepwise reactions was performed on functionalized SiNCs, providing a promising path to build dendrimer structures on SiNCs. Some preliminary results of conjugating commercialized dendrons and SiNCs also are presented. Chapter 3 introduces a method to prepare amphiphilic SiNCs (AP-SiNCs) by thermal hydrosilylation of H-SiNCs with the mixed ligands. By studying the stabilities of SiNCs in buffer solutions, it is found that the stability of AP-SiNCs could be tuned by changing the duration of thermal hydrosilylation to adapt the needs of various applications. Chapter 4 presents the conclusions of each chapter and some future work related to water soluble SiNCs.

  • Subjects / Keywords
  • Graduation date
    Spring 2019
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.