Bio-applications and Bio-imaging of Nanomaterials
Date Issued
2010
Date
2010
Author(s)
Chen, Yu-Chun
Abstract
Nanochemistry, a new realm in scientific research, has attracted numerous attention as materials at this scale possess different properties compared to their bulk counterparts. In addition to designing and synthesizing nanomaterials of different kind, explorations of applications of these unique structures are conducted. Utilizing the high resolution of two-photon/confocal microscopy, unparallel penetration depth of magnetic resonance imaging (MRI), and other cellular assays, the feasibility and biocompatibility of superparamagnetic iron oxide (SPIOs), quantum dots, and Au nanomaterials are investigated and evaluated.
It was discovered that by coating the hydrophobic nanomaterials with silica or serum albumin, not only the solubility and chemical modification fesibility could be significantly enhanced, but the greatly surpressed cytotoxicity also enable these treated nanomaterials being biocompatible.
The first chapter of the thesis elucidates how a three-in-one nano system was achieved by employing silica as a shell and a template to encapsulate the superparamagnetic iron oxide core and Ir complexes. The iron oxide core served as a MRI contrast agent, whereas the Ir complex, which was prone to oxygen quenching, simultaneously provided sufficient phosphorescence for optical labeling and efficient singlet oxygen generation to induce apotosis of cancer cells (photo dynamic therapy) . Chapter 2 introduces a new series of quadrupolar type two-photon absorption (2PA) chromophores. Taking advantage of the high quantum yield and very large 2PA corss section value (~7,000 GM at 800 nm in toluene) in the region of near infared window, observation of the particles internalization by rat macrophages with light microscopy and quantitative determination of the efficacy of the photo dynamic therapy with cellular assay were successful. Chapter 3 discribes a FePt/Fe3O4 core shell system, which Pt inside the core would be released once entered the acidic organelle of a cell. Pt would eventually interact with the DNA and induce cell death. Chapter 4 illistrates the importance of delaying the photo-oxidation procedsure to recover the emission quenching often encountered when encapsulating quantum dot in silica shells. The cell line employed for toxicity evaluation and labeling has also been switched from common cancer cell lines or marcophages to a more delicate and important human mesenchymal stem cell line. Chapter 5 explores the two-photon induced luminescence of 11-mercaptoundecanoic acid funtionals quantum-sized Au nanodots. The high single and two photon induced emission with high biocompatibility after dextan coating, makes the nano size Au a promising imaging agent for human mesenchymal stem cells.
Subjects
nanomaterials
bio-imaging
SDGs
Type
thesis
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