American Chemical Society (ACS) Acta Medica Okayama 1936-0851 18 52 2024 Bright Quantum-Grade Fluorescent Nanodiamonds 35202 35213 EN Keisuke Oshimi Department of Chemistry, Graduate School of Life, Environmental, Natural Science and Technology, Okayama University Hitoshi Ishiwata The National Institutes for Quantum Science and Technology (QST), Institute for Quantum Life Science (iQLS) Hiromu Nakashima Department of Chemistry, Graduate School of Life, Environmental, Natural Science and Technology, Okayama University Sara Mandić Department of Chemistry, Graduate School of Life, Environmental, Natural Science and Technology, Okayama University Hina Kobayashi Department of Chemistry, Graduate School of Life, Environmental, Natural Science and Technology, Okayama University Minori Teramoto Advanced Materials Laboratory, Sumitomo Electric Industries, Ltd. Hirokazu Tsuji Advanced Materials Laboratory, Sumitomo Electric Industries, Ltd. Yoshiki Nishibayashi Advanced Materials Laboratory, Sumitomo Electric Industries, Ltd. Yutaka Shikano Institute of Systems and Information Engineering, University of Tsukuba Toshu An School of Materials Science, Japan Advanced Institute of Science and Technology Masazumi Fujiwara Department of Chemistry, Graduate School of Life, Environmental, Natural Science and Technology, Okayama University Optically accessible spin-active nanomaterials are promising as quantum nanosensors for probing biological samples. However, achieving bioimaging-level brightness and high-quality spin properties for these materials is challenging and hinders their application in quantum biosensing. Here, we demonstrate bright fluorescent nanodiamonds (NDs) containing 0.6–1.3-ppm negatively charged nitrogen-vacancy (NV) centers by spin-environment engineering via enriching spin-less 12C-carbon isotopes and reducing substitutional nitrogen spin impurities. The NDs, readily introduced into cultured cells, exhibited improved optically detected magnetic resonance (ODMR) spectra; peak splitting (E) was reduced by 2–3 MHz, and microwave excitation power required was 20 times lower to achieve a 3% ODMR contrast, comparable to that of conventional type-Ib NDs. They show average spin-relaxation times of T1 = 0.68 ms and T2 = 3.2 μs (1.6 ms and 5.4 μs maximum) that were 5- and 11-fold longer than those of type-Ib, respectively. Additionally, the extended T2 relaxation times of these NDs enable shot-noise-limited temperature measurements with a sensitivity of approximately 0.28K/√Hz. The combination of bulk-like NV spin properties and enhanced fluorescence significantly improves the sensitivity of ND-based quantum sensors for biological applications. No potential conflict of interest relevant to this article was reported.

Elsevier BV Acta Medica Okayama 0045-6535 358 2024 Size, polyglycerol grafting, and net surface charge of iron oxide nanoparticles determine their interaction and toxicity in Caenorhabditis elegans 142060 EN Yajuan Zou Graduate School of Natural Science and Technology, Okayama University Yutaka Shikano Institute of Systems and Information Engineering, University of Tsukuba Yuta Nishina Graduate School of Natural Science and Technology, Okayama University Naoki Komatsu Graduate School of Human and Environmental Studies, Kyoto University Eriko Kage-Nakadai Department of Nutrition, Graduate School of Human Life and Ecology, Osaka Metropolitan University Masazumi Fujiwara Graduate School of Natural Science and Technology, Okayama University The widespread application of engineered nanoparticles (NPs) in environmental remediation has raised public concerns about their toxicity to aquatic organisms. Although appropriate surface modification can mitigate the ecotoxicity of NPs, the lack of polymer coating to inhibit toxicity completely and the insufficient knowledge about charge effect hinder the development of safe nanomaterials. Herein, we explored the potential of polyglycerol (PG) functionalization in alleviating the environmental risks of NPs. Iron oxide NPs (ION) of 20, 100, and 200 nm sizes (IONS, IONM and IONL, respectively) were grafted with PG to afford ION-PG. We examined the interaction of ION and ION-PG with Caenorhabditis elegans (C. elegans) and found that PG suppressed non-specific interaction of ION with C. elegans to reduce their accumulation and to inhibit their translocation. Particularly, IONS-PG was completely excluded from worms of all developmental stages. By covalently introducing sulfate, carboxyl and amino groups onto IONS-PG, we further demonstrated that positively charged IONS-PG-NH3+ induced high intestinal accumulation, cuticle adhesion and distal translocation, whereas the negatively charged IONS-PG-OSO3– and IONS-PG-COO– were excreted out. Consequently, no apparent deleterious effects on brood size and life span were observed in worms treated by IONS-PG and IONS-PG bearing negatively charged groups. This study presents new surface functionalization approaches for developing ecofriendly nanomaterials. No potential conflict of interest relevant to this article was reported.

AIP Publishing Acta Medica Okayama 1932-1058 17 5 2023 Diamond quantum sensors in microfluidics technology 054107 EN Masazumi Fujiwara Department of Chemistry, Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Diamond quantum sensing is an emerging technology for probing multiple physico-chemical parameters in the nano- to micro-scale dimensions within diverse chemical and biological contexts. Integrating these sensors into microfluidic devices enables the precise quantification and analysis of small sample volumes in microscale channels. In this Perspective, we present recent advancements in the integration of diamond quantum sensors with microfluidic devices and explore their prospects with a focus on forthcoming technological developments. No potential conflict of interest relevant to this article was reported.

Royal Society of Chemistry (RSC) Acta Medica Okayama 1473-0197 22 13 2022 Glass-patternable notch-shaped microwave architecture for on-chip spin detection in biological samples 2519 2530 EN Keisuke Oshimi Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University Yushi Nishimura Department of Chemistry, Graduate School of Science, Osaka City University Tsutomu Matsubara Department of Anatomy and Regenerative Biology, Graduate School of Medicine, Osaka City University Masuaki Tanaka Department of Electrical and Information Engineering, Graduate School of Engineering, Osaka City University Eiji Shikoh Department of Electrical and Information Engineering, Graduate School of Engineering, Osaka City University Li Zhao State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University Yajuan Zou Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University Naoki Komatsu Graduate School of Human and Environmental Studies, Kyoto University Yuta Ikado Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University Yuka Takezawa Department of Human Life Science, Graduate School of Food and Human Life Science, Osaka City University Eriko Kage-Nakadai Department of Human Life Science, Graduate School of Food and Human Life Science, Osaka City University, Yumi Izutsu Department of Biology, Faculty of Science, Niigata University Katsutoshi Yoshizato Synthetic biology laboratory, Graduate school of medicine, Osaka City University Saho Morita Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University Masato Tokunaga Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University Hiroshi Yukawa Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University Yoshinobu Baba Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University Yoshio Teki Department of Chemistry, Graduate School of Science, Osaka City University Masazumi Fujiwara Department of Chemistry, Graduate School of Natural Science and Technology, Okayama University We report a notch-shaped coplanar microwave waveguide antenna on a glass plate designed for on-chip detection of optically detected magnetic resonance (ODMR) of fluorescent nanodiamonds (NDs). A lithographically patterned thin wire at the center of the notch area in the coplanar waveguide realizes a millimeter-scale ODMR detection area (1.5 × 2.0 mm2) and gigahertz-broadband characteristics with low reflection (∼8%). The ODMR signal intensity in the detection area is quantitatively predictable by numerical simulation. Using this chip device, we demonstrate a uniform ODMR signal intensity over the detection area for cells, tissue, and worms. The present demonstration of a chip-based microwave architecture will enable scalable chip integration of ODMR-based quantum sensing technology into various bioassay platforms. No potential conflict of interest relevant to this article was reported.