Yasuko Osakada

DNA nanostructures based on programmable DNA molecular recognition have been developed, but the nanoelectronics of using DNA is still challenging. A more rapid charge-transfer (CT) process through the DNA nanoassembly is required for further development of programmable DNA nanoelectronics. In this article, we present direct absorption measurements of the long-range CT over a 140-A DNA assembly based on a GC repetitive sequence constructed by simply mixing DNA building blocks. We show that a CT t

The photochromic molecule diarylethene works as a "toggle switch" for biocompatible fluorescence polymer dots and enables fluorescence switching in biological samples.

Here, we demonstrate that biomolecule-directed metal clusters are applicable in the study of hard X-ray excited optical luminescence, promising a new direction in the development of novel X-ray-activated imaging probes.

Charge transfer (CT) in DNA offers a unique approach for the detection of a single-base mismatch in a DNA molecule. While the single-base mismatch would significantly affect the CT in DNA, the kinetic basis for the drastic decrease in the CT efficiency through DNA containing mismatches still remains unclear. Recently, we determined the rate constants of the CT through the fully matched DNA, and we can now estimate the CT rate constant for a certain fully matched sequence. We assumed that further

In this study, cyclometalated iridium(III) complex-doped polymer dots were synthesized and shown to emit luminescence upon X-ray irradiation, potentially serving as a new probe for molecular imaging during X-ray computed tomography.

Organic polymers derived from covalent organic frameworks (COFs) have various applications, including photocatalysis. The synthesis of organic polymer materials from COFs to obtain higher activity for photocatalysis by changing the unit molecule has been investigated. The choice of the unit molecule is important to characterize the photochemical properties. Among various such unit molecules, porphyrins have attracted much attention as organic chromophores commonly used in photocatalytic reaction

Transient absorption measurements of charge transfer (CT) demonstrated that the CT in the DNA assembly constructed by simply mixing DNAs with sticky ends occurs over 200 angstroms selectively to the complementary sticky end sequences.

Fluorescence photoswitching using nanomaterials has recently emerged as a promising approach for the imaging of biological targets. However, despite intensive research efforts during the last decade, practical microscopy of biological targets using photoswitchable nanoparticles in real time remains challenging. To address this problem, we have developed live macrophage cell imaging and single particle imaging methods, using photoswitchable fluorescent diarylethene-doped polymer nanoparticles (P-

Crosstalk?! It is demonstrated that singlet oxygen molecules (1O2) are produced during the reaction between superoxide and the guanine radical cation; this suggests that the parallel type I and type II mechanisms intersect with each other during photosensitized DNA oxidation (see figure). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the author

The normal function of neurons depends on the integrity of microtubule-dependent transport of cellular materials and organelles to/from their cell bodies or axon terminus. In this chapter, we describe the design and implementation of a fluorescence imaging method to visualize axonal transport in neurons directly. We combine a pseudo total internal reflection microscopy, quantum dot fluorescence labeling, microfluidic neuronal culture chamber, and single molecule detection methods to achieve a hi

The development of efficient antibacterial agents is important for public health. To completely damage bacteria in situ, light has been used as an external stimulus, but the wavelength range of light is limited up to visible light at which the antimicrobial activity is incomplete. Here, we report on our investigation of the bactericidal effect of heat and nitric oxide (NO) generated simultaneously by near-infrared (NIR) light using vanadyl naphthalocyanine-doped polymer dots (P-dots). P-dots co-

We demonstrate that polymer dots doped with thermally activated delayed fluorescence (TADF) molecules clearly exhibit blue radio-luminescence upon hard X-ray and electron beam irradiation, which is a new design for nano-sized scintillators.

The development of antibacterial photocatalytic nanomaterials is important. Here, we prepared Zn-porphyrin nanodisks by exfoliation of covalent organic frameworks (COFs). We exfoliated COFs with free-base porphyrins by simple simultaneous coordination of Zn2+ and 4-ethylphyridine. The synthesized Zn-porphyrin nanodisks exhibited higher photocatalytic singlet oxygen production by visible light irradiation, and showed substantial light-irradiated antimicrobial activity against Escherichia coli.