Biomedical subjects

Shin-ichiro M Nomura

Publications and source records attributed to Shin-ichiro M Nomura.

6 recordsLinked to original sources

PubMed2005

Chemosensitive running droplet.

Chemical control of the spontaneous motion of a reactive oil droplet moving on a glass substrate under an aqueous phase is reported. Experimental results show that the self-motion of an oil droplet is confined on an acid-treated glass surface. The transient behavior of oil-droplet motion is also observed with a high-speed video camera. A mathematical model that incorporates the effect of the glass surface charge is built based on the experimental observation of oil-droplet motion. A numerical simulation of this mathematical model reproduced the essential features concerning confinement of oil droplet motion within a certain chemical territory and also its transient behavior. Our results may shed light on physical aspects of reactive spreading and a chemotaxis in living things.

Journal Article↗

PubMed2005

Nanogel-quantum dot hybrid nanoparticles for live cell imaging.

We report here a novel carrier of quantum dots (QDs) for intracellular labeling. Monodisperse hybrid nanoparticles (38 nm in diameter) of QDs were prepared by simple mixing with nanogels of cholesterol-bearing pullulan (CHP) modified with amino groups (CHPNH2). The CHPNH2-QD nanoparticles were effectively internalized into the various human cells examined. The efficiency of cellular uptake was much higher than that of a conventional carrier, cationic liposome. These hybrid nanoparticles could be a promising fluorescent probe for bioimaging.

Carbohydrate Sequence↗

PubMed2005

Changes in the morphology of cell-size liposomes in the presence of cholesterol: formation of neuron-like tubes and liposome networks.

Spontaneous changes in the morphology of cell-size liposomes (dioleoylphosphatidylcholine, DOPC and egg PC) as model cells were investigated in the presence of cholesterol. Tube structures and liposome networks connected by the tubes were observed in the presence of 5-30% cholesterol by dark-field and laser-scanning microscopy. Furthermore, in the presence of more than 40 mol% of cholesterol, the tubes disappeared and changed to small liposomes. Thus, cholesterol induced a morphological change in giant liposomes from tubes to small liposomes. These phenomena may be related to the role of cholesterol in the morphological changes in living cells such as neurons.

Cell Membrane↗

PubMed2003

Gene expression within cell-sized lipid vesicles.

Functional protein synthesis was observed in cell-sized lipid vesicles following encapsulation of a gene-expression system. Expression of rsGFP (red-shifted green fluorescent protein) within individual vesicles was observed by fluorescence microscopy. Interestingly, at the early stage of the reaction, the expression efficiency inside the vesicle was remarkably higher than that in the solution outside. The synthesized rsGFP in individual vesicles is safe from attack by proteinase K added to the external aqueous solution. Studies on cell-sized vesicles expressing protein should contribute to a fundamental understanding of certain aspects of living systems and will be useful for practical applications, such as the construction of microreactors.

Endopeptidase K↗

PubMed2002

Rhythmic bursting in a cluster of microbeads driven by a continuous-wave laser beam.

Rhythmic bursting on the order of seconds in a cluster of plastic beads under continuous irradiation of a focused neodymium-doped yttrium aluminum garnet (Nd:YAG) laser beam (1064 nm) is reported. The oscillatory instability is induced as a result of competition between trapping and scattering forces, where both forces are induced by the focused laser beam. Above a critical power of the laser beam, mode bifurcation from the stationary state into periodic bursting is observed. Our model employing ordinary differential equations reproduces the essential aspects of the experimental results.

Journal Article↗

PubMed2002

Autonomous swinging of a lipid tubule under stationary irradiation by a Nd3+:YAG laser.

A micrometer-sized lipid tubule exhibits oscillatory swinging motion under stationary irradiation by a Nd(3+):YAG laser ( lambda = 1064 nm). By choosing an appropriate optical path through an objective lens, the laser can be split into dual beams focused on the same position. Using this splitting, a lipid tubule can be shown to exhibit bistability with regard to the orientation of trapping. Driven by a temperature gradient induced by local photon heating, the trapped lipid tubule shows oscillatory motion between two possible orientations. This oscillatory phenomenon of the lipid tubule is thought to represent the breaking of time-translational symmetry under thermodynamically open conditions.

Journal Article↗