Date of Degree


Document Type


Degree Name





Hiroshi Matsui

Subject Categories

Chemistry | Nanoscience and Nanotechnology


Constant effort has been made for the detection of cancer cells. Recently, ovarian and kidney cancer cell lines have been shown to have higher cellular elasticity as compared to normal cells assessed by monitoring the degree of deformation under hyposmotic pressure. This method has been modified and applied to various cases. In cancer cells, the oncogenic mutant p53 (mtp53) protein is present at high levels and contributes to tumor growth and metastasis. Herein the influence of mtp53 on the mechanical property of breast cancer cells was assessed by monitoring the swelling ratio of cells with time using the impedance measurements. The depletion of mtp53 led to decrease of impedance variation, which is corresponding to the lower elasticity. All results suggest that electric probing for the extent of the mtp53 expression of breast cancer cells may serve as a meaningful fingerprint for the cancer diagnostics, and this outcome will also have an important clinical implication for the development of mtp53-based targeting for tumor detection and treatment. Meanwhile, the samples containing a mixture of red blood cells and cancer cells were examined by impedemetric detection. The results suggest that the cancer cells need to be enriched before applying impedance measurements to the samples with high concentration of red blood cells. Thus, dielectrophoresis (DEP) provides as a solution by taking most red blood cells apart from the cancer cells, which is supported by taking most red blood cells apart from the cancer cells, which is supported by experimental data. The DEP system will be integrated with microfluidic channels for DEP analysis in future.

Biomolecule-assisted synthesis of shape-controlled nanoparticles is the other part of this dissertation. One project refers to the PbSe nanocrystal growth with the aid of peptide. Pb-binding TAR-1 peptides (ISLLHST) were covalently conjugated on a peptide nanotube substrate and the precursors of PbSe were incubated at room temperature. This resulted in the growth of highly crystalline PbSe nanocubes on this biomimetic cylindrical substrate. The growth mechanism to generate nanocubes occurs via the directed self-assembly of nanoparticles and then nanoparticle fusion. The peptide conformation and the cylindrical peptide nanotube substrate play important roles in the mesoscopic crystallization of PbSe nanocubes. The conformational change of the TAR-1 peptide on the nanotubes due to the change in the buffer seems to be responsible for aggregating intermediate nanoparticles in different directions for the directed fusion and mesoscopic crystallization of PbSe into the different shapes. The other project is the directional growth of LiFePO4 nanoribbons using glutathione and PVP as capping agents. The structure, size and morphology were investigated by XRD, TEM, AFM, SEM. The HRTEM result suggests that the nanoribbons are growing along [010], which is highly possible to enhance the rate capability, achieving the better battery performance.