Electrode-embedded solid-state nanopore is considered as a promising device structure offering prospects for
$1000 genome. Despite the huge potential, fabrication of a molecular-scale nanoelectrode-in-nanopore system has
been a formidable task that requires atomic-level alignment of a nanopore and an electrode gap. Here, we developed
a self-alignment technique compatible with silicon integrated circuit technology that allows formation of a
nucleotide-sized electrode-embedded in-plane nanopore at a relatively high yield. We demonstrated single-molecule
counting of sub-nanometer size metal-encapsulated fullerenes in a liquid by tunneling current measurements using
the in-plane nanopore detector. We also applied this new nanopore sensor for identifying single-nucleotides in
a short DNA oligomer. This planar device architecture is amenable to integration of additional single-molecule
techniques such as fluorescence imaging, and can be used as a platform for the electrical DNA sequencing.
We succeeded in fabricating ZnO microspheres by laser ablation in superfluid helium. From transmission electron
microscopy observation, we found that fabricated ZnO microspheres with high sphericity are single crystals. Also
we achieved low threshold lasing in single ZnO microspheres at room temperature.
We report direct observations of lattice vibration of inner gold submicron crystals on the fused quartz substrate using picoseconds time-resolved X-ray diffraction. The gold island film is produced by annealing from vaporevaporated gold film. The change and vibration period of lattice constants of 111, 200, 220, 311 and 222 after femtosecond laser irradiation at 400 nm and 800 nm are almost similar. These results indicate that the strain generated from suddenly expansion propagates into the finite size gold crystals. The feature of these lattice vibrations is discussed.
We have performed first principles band structure calculations for some types of one-dimensional (1D) peanutshaped fullerene polymers (PSFPs). Our results show that electronic states of the 1D PSFPs strongly depend on the geometrical structure of six-membered rings. We found that there are two necessary conditions for the PSFPs to be a metal: six-membered rings must be connected from left to right in each unit cell, and they must not be distorted significantly.
X-ray computed tomography (CT) is commonly used to make a diagnosis in hospital. Contrast agents are often used to enhance contrast and thus improve diagnostic accuracy. Currently-used clinical contrast agents are low molecule. The agents circulate in the bloodstream and before being excreted from the kidney, move to extravascular tissue through the capillary vessel depending on their concentration gradient. Thus there is a situation that the agents nonspecifically enhance the tissue. To image tumor specifically with CT, we here developed a new contrast agent. Recently an enhanced permeability and retention effect (EPR effect) draws attention in the fields of imaging and DDS of cancer. EPR effect is a characteristic phenomenon of tumor tissue. The neovascular vessel differs from normal vessel in terms of the anatomical structure. The endothelial cells of the vessel in tumor are irregular in shape and lacunal. As the result, properly-sized (20-200 nm) nanoparticle can pass through the vessel wall in tumor while not through the most of vessel in normal tissue. To perform CT imaging of tumor using EPR effect, we made gold (Au) nanoparticle. Au has higher X-ray absorption coefficient than iodine which is a normally-used clinical contrast agent. As high blood retention is desirable for effective EPR effect, polyethylene glycol (PEG)-supported Au nanoparticles (Au-PEG) were prepared. The surface modification with PEG is often used to increase the blood retention. We injected the Au-PEG nanoparticles into the tumor-bearing mice and the distribution of Au-PEG was examined with CT and TEM images, showing that the Au-PEG were well-localized to tumor by EPR effect.
Nanostructured carbons have been widely used for fabricating enzyme-modified electrodes due to their large specific surface area. However, because they are random aggregates of particular or tubular nanocarbons, the postmodification of enzymes to their intra-nanospace is generally hard to control. Here, we describe a free-standing film of carbon nanotube forest (CNTF) that can form a hybrid ensemble with enzymes through liquid-induced shrinkage. This provides in-situ regulation of its intra-nanospace (inter CNT pitch) to the size of enzymes, and eventually serves as a highly active electrode. Application of the free-standing, flexible character of the enzyme-CNTF ensemble electrodes is demonstrated via their use in the patch or wound form.
The ability to control chemical wave propagation dynamics could stimulate the science and technology of artificial and biological spatiotemporal oscillating phenomena. In contrast to the conventional chemical approaches to controlling the wave front dynamics, here we demonstrated a physical approach to tune the initial propagation dynamics under the same chemical conditions. By using well-designed microchannels with different channel widths and depths, the propagation velocity was successfully controlled based on two independent effects. Furthermore, possibility toward light-controlled mass-transport function has been found by coupling between chemical wave propagation and photochemical properties of dye molecule doped in the medium.
Ni1-xZnxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8) nanoparticles with average diameter ranging 13 nm were produced by using wet chemical method. Magnetic properties and temperature rise were measured by SQUID magnetometer and applying an alternative magnetic field. AC magnetic susceptibility suggested heating mechanism of magnetic relaxation system. This sample showed adequate heating ability to destroy tumor cells under the similar condition of magnetic hyperthermia treatment.