Publications by authors named "Yushi Nishimura"

5 Publications

  • Page 1 of 1

Wide-field fluorescent nanodiamond spin measurements toward real-time large-area intracellular thermometry.

Sci Rep 2021 Feb 19;11(1):4248. Epub 2021 Feb 19.

Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan.

Measuring optically detected magnetic resonance (ODMR) of diamond nitrogen vacancy centers significantly depends on the photon detectors used. We study camera-based wide-field ODMR measurements to examine the performance in thermometry by comparing the results to those of the confocal-based ODMR detection. We show that the temperature sensitivity of the camera-based measurements can be as high as that of the confocal detection and that possible artifacts of the ODMR shift are produced owing to the complexity of the camera-based measurements. Although measurements from wide-field ODMR of nanodiamonds in living cells can provide temperature precisions consistent with those of confocal detection, the technique requires the integration of rapid ODMR measurement protocols for better precisions. Our results can aid the development of camera-based real-time large-area spin-based thermometry of living cells.
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http://dx.doi.org/10.1038/s41598-021-83285-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7895939PMC
February 2021

Real-time nanodiamond thermometry probing in vivo thermogenic responses.

Sci Adv 2020 Sep 11;6(37). Epub 2020 Sep 11.

Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan.

Real-time temperature monitoring inside living organisms provides a direct measure of their biological activities. However, it is challenging to reduce the size of biocompatible thermometers down to submicrometers, despite their potential applications for the thermal imaging of subtissue structures with single-cell resolution. Here, using quantum nanothermometers based on optically accessible electron spins in nanodiamonds, we demonstrate in vivo real-time temperature monitoring inside worms. We developed a microscope system that integrates a quick-docking sample chamber, particle tracking, and an error correction filter for temperature monitoring of mobile nanodiamonds inside live adult worms with a precision of ±0.22°C. With this system, we determined temperature increases based on the worms' thermogenic responses during the chemical stimuli of mitochondrial uncouplers. Our technique demonstrates the submicrometer localization of temperature information in living animals and direct identification of their pharmacological thermogenesis, which may allow for quantification of their biological activities based on temperature.
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http://dx.doi.org/10.1126/sciadv.aba9636DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486095PMC
September 2020

Macroscopically Anisotropic Structures Produced by Light-induced Solvothermal Assembly of Porphyrin Dimers.

Sci Rep 2018 07 23;8(1):11108. Epub 2018 Jul 23.

Department of Physics, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuencho, Naka-ku, Sakai, Osaka, 599-8531, Japan.

Porphyrin-based molecules play an important role in natural biological systems such as photosynthetic antennae and haemoglobin. Recent organic chemistry provides artificial porphyrin-based molecules having unique electronic and optical properties, which leads to wide applications in material science. Here, we successfully produced many macroscopically anisotropic structures consisting of porphyrin dimers by light-induced solvothermal assembly with smooth evaporation in a confined volatile organic solvent. Light-induced fluid flow around a bubble on a gold nanofilm generated a sub-millimetre radial assembly of the tens-micrometre-sized petal-like structures. The optical properties of the petal-like structures depend on the relative angle between their growth direction and light polarisation, as confirmed by UV-visible extinction and the Raman scattering spectroscopy analyses, being dramatically different from those of structures obtained by natural drying. Thus, our findings pave the way to the production of structures and polycrystals with unique characteristics from various organic molecules.
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http://dx.doi.org/10.1038/s41598-018-28311-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6056561PMC
July 2018

Submillimetre Network Formation by Light-induced Hybridization of Zeptomole-level DNA.

Sci Rep 2016 12 5;6:37768. Epub 2016 Dec 5.

Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, 1-2, Gakuencho, Nakaku, Sakai, Osaka 599-8570, Japan.

Macroscopic unique self-assembled structures are produced via double-stranded DNA formation (hybridization) as a specific binding essential in biological systems. However, a large amount of complementary DNA molecules are usually required to form an optically observable structure via natural hybridization, and the detection of small amounts of DNA less than femtomole requires complex and time-consuming procedures. Here, we demonstrate the laser-induced acceleration of hybridization between zeptomole-level DNA and DNA-modified nanoparticles (NPs), resulting in the assembly of a submillimetre network-like structure at the desired position with a dramatic spectral modulation within several minutes. The gradual enhancement of light-induced force and convection facilitated the two-dimensional network growth near the air-liquid interface with optical and fluidic symmetry breakdown. The simultaneous microscope observation and local spectroscopy revealed that the assembling process and spectral change are sensitive to the DNA sequence. Our findings establish innovative guiding principles for facile bottom-up production via various biomolecular recognition events.
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http://dx.doi.org/10.1038/srep37768DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5137144PMC
December 2016

A high performance photothermal film with spherical shell-type metallic nanocomposites for solar thermoelectric conversion.

Nanoscale 2015 May;7(17):7580-4

Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, Sakai 599-8570, Japan.

A photothermal film (PTF) with densely assembled gold nanoparticle-fixed beads on a polymer substrate is fabricated. Remarkably, a temperature rise higher than 40 °C is achieved in the PTF with only 100 seconds of artificial solar irradiation, and the output power of the thermoelectric device was enhanced to be one order higher than that without PTF. These results will pioneer a rapid solar thermoelectric device.
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http://dx.doi.org/10.1039/c5nr00943jDOI Listing
May 2015
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