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

  • water soluble SiNCs

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-1xzd-3g75

• License

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