| Summary: | 博士 === 國立臺灣大學 === 化學研究所 === 104 === Nanomaterials (NMs) reveal unique chemical and physical properties based on small-sized effects, allowing their application as drug carriers, biosensors, and in bio-imaging. However, the safety of these NMs has also attracted attention because the complex interaction between NMs and organism can cause damage or cytotoxicity. This thesis focuses on developing a new type of highly efficient nanomedicine and investigating the cytotoxicity and safety of NMs. A multifunctional NM that consists of upconversion nanoparticles (UCPs) and Au NMs was fabricated for therapy and imaging. UCPs can convert light from high energy to low energy and serve as light source in multi-emission. Moreover, Au NMs generate heat when absorbing the light from UCPs through strong surface plasmon resonance (SPR). The difference in heat quality and distribution between sphere- or rod-shaped Au NMs was studied by photothermal effect and stimulation model. The efficiency of photothermal therapy (PTT) was tested through cell viability assay by irradiating with a 980 nm laser. Photodynamic therapy (PDT) was carried out by doping photosensitizer-methylene blue (MB) in the similar upconverting nanocomposites. MB was used to produce reactive oxygen species (ROS) in PDT to optimize the loading amount by changing the thickness of silica shell. In particular, the amount of ROS was further enhanced by conjugating with Au nanorods, which expectedly increased the absorption cross section of MB. The efficacy and mechanism among different SPR peaks were investigated and compared between sphere- and rod-shaped Au NMs. The low cytotoxicity of novel CuInS2 quantum dots (CIS QDs) was investigated because of the absence of contention. Caenorhabditis elegans was used as organism model with CIS QDs for toxicity study, and X-ray absorption near edge structure was employed to study the relationship between toxicity and chemical stability of CIS QDs under various treatment times. Moreover, TiO2 NMs with various sizes and structures were used to treat different human oral and lung cells to investigate the toxic effects. To determine the cellular response of cells to TiO2 NM treatment, we performed apoptosis assay and cell cycle analysis to identify the mechanism of cytotoxicity. Consequently, we successfully developed multifunctional NMs based on UCPs and Au NMs for PTT or PDT and bio-imaging. We also determined the factors that affected the low cytotoxicity for CIS QDs and the causes of damage from TiO2 NMs.
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