研究者詳細 - 仁科　勇太

Efficient and stable visible-light-driven Z-scheme overall water splitting using an oxysulfide H₂ evolution photocatalyst 国際誌

Lin, L., Ma, Y., Vequizo, J.J.M., Nakabayashi, M., Gu, C., Tao, X., Yoshida, H., Pihosh, Y., Nishina, Y., Yamakata, A., Shibata, N., Hisatomi, T., Takata, T., Domen, K.

Nature Communications 15 ( 1 ) 1146 - 1146 2024年

Enhanced OH⁻ conductivity from 3D alkaline graphene oxide electrolytes for anion exchange membrane fuel cells

Nonoka Goto, Mohammad Atiqur Rahman, Md. Saidul Islam, Ryuta Tagawa, Chiyu Nakano, Muhammad Sohail Ahmed, Yoshihiro Sekine, Yuta Nishina, Shintaro Ida, Shinya Hayami

Energy Advances 2024年

Phosphorus Release from Agricultural Drainage Sediments with Iron-Added Sediment Microbial Fuel Cells

Gamamada Liyanage Erandi Priyangika Perera, Morihiro Maeda, Satoshi Akao, Hiroaki Somura, Chiyu Nakano, Yuta Nishina

Journal of Water and Environment Technology 22 ( 2 ) 75 - 91 2024年

Effects of Sediment Microbial Fuel Cells on CH<sub>4</sub> and CO<sub>2</sub> Emissions from Straw Amended Paddy Soil

Adhena Tesfau Bekele, Morihiro Maeda, Satoshi Akao, Hiroaki Somura, Chiyu Nakano, Yuta Nishina

Journal of Water and Environment Technology 22 ( 6 ) 271 - 285 2024年

The use of covalent reactions to improve the biomedical applications of carbon nanomaterials

Yajuan Zou, Yuta Nishina, Alberto Bianco

Carbon Reports 2 ( 4 ) 185 - 198 2023年12月

酸化グラフェンを応用した既存抗菌物質の効果持続性向上への挑戦

加納玄, 大久保圭祐, 伊東孝, 大森一弘, 仁科勇太, 高柴正悟

岡山歯学会雑誌 42 ( 2 ) 76 - 77 2023年12月

Improved performance of strain sensors constructed by highly crystalline graphene with nanospacer

Zizhao Xu, Yuna Himura, Chikako Ishiguro, Taiki Inoue, Nishina Yuta, Yoshihiro Kobayashi

Japanese Journal of Applied Physics 2023年11月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

Graphene shows promise as an alternative material for strain sensors, due to its excellent properties, which can overcome the limitations of conventional metal ones. However, current graphene-based strain sensors were fabricated from chemically reduced graphene oxide (rGO) and suffered from low linearity and large hysteresis in sensor response as well as high initial resistance. These issues should be caused by functional groups and defects remaining on the rGO. Herein, highly crystalline rGO is employed for the fabrication of the strain sensor. The porous rGO sponge with low defect density is prepared in bulk scale via the ethanol-associated thermal process at ultra-high temperature. The obtained rGO sensor exhibits improved linearity, low initial resistance, and very small hysteresis owing to the high crystallinity of the rGO. Composite of rGO with nano-diamond, which has a role as nanospacer to separate the rGO layers, is found to be very effective to enhance the sensitivity.

DOI： 10.35848/1347-4065/ad0cdb

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ad0cdb/pdf

Enzyme-immobilized Screen-printed Sensor for One Drop of Sample Using Porous Silica Spheres

Shunsuke Fujii, Akiko Yoshida, Tracy T Chuong, Yuka Minegishi, Yuta Nishina, Hirotomo Nishihara, Kouji Masumoto, Tetsuji Itoh

Sensors and Materials 35 ( 10 ) 4769 - 4769 2023年10月

Highly Stretchable Stress-Strain Sensor from Elastomer Nanocomposites with Movable Cross-links and Ketjenblack. 国際誌

Ryohei Ikura, Kota Kajimoto, Junsu Park, Shunsuke Murayama, Yusei Fujiwara, Motofumi Osaki, Tomohiro Suzuki, Hidenori Shirakawa, Yujiro Kitamura, Hiroaki Takahashi, Yasumasa Ohashi, Seiji Obata, Akira Harada, Yuka Ikemoto, Yuta Nishina, Yasutomo Uetsuji, Go Matsuba, Yoshinori Takashima

ACS polymers Au 3 ( 5 ) 394 - 405 2023年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Practical applications like very thin stress-strain sensors require high strength, stretchability, and conductivity, simultaneously. One of the approaches is improving the toughness of the stress-strain sensing materials. Polymeric materials with movable cross-links in which the polymer chain penetrates the cavity of cyclodextrin (CD) demonstrate enhanced strength and stretchability, simultaneously. We designed two approaches that utilize elastomer nanocomposites with movable cross-links and carbon filler (ketjenblack, KB). One approach is mixing SC (a single movable cross-network material), a linear polymer (poly(ethyl acrylate), PEA), and KB to obtain their composite. The electrical resistance increases proportionally with tensile strain, leading to the application of this composite as a stress-strain sensor. The responses of this material are stable for over 100 loading and unloading cycles. The other approach is a composite made with KB and a movable cross-network elastomer for knitting dissimilar polymers (KP), where movable cross-links connect the CD-modified polystyrene (PSCD) and PEA. The obtained composite acts as a highly sensitive stress-strain sensor that exhibits an exponential increase in resistance with increasing tensile strain due to the polymer dethreading from the CD rings. The designed preparations of highly repeatable or highly responsive stress-strain sensors with good mechanical properties can help broaden their application in electrical devices.

DOI： 10.1021/acspolymersau.3c00010

Unveiling the Reduction Process of Graphene Oxide by Ascorbic Acid: Grafting and Reduction Sequences for High Surface Area Graphene Materials. 国際誌

Israel Ortiz-Anaya, Yuta Nishina

ChemPlusChem 88 ( 8 ) e202300328 2023年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

This work reports the synthesis of high surface area reduced graphene oxides using L-ascorbic acid as a reducing agent by precisely controlling the interaction between graphene oxide and L-ascorbic acid. Based on the structural characterization, such as textural properties (specific surface area, pore structure), crystallinity, and carbon chemical state, we identified that the temperature and reaction time are critical parameters to control the stacking degree of the final reduced product. Besides, by performing a time course analysis of the reaction, we identified the side products of the reducing agent by LC-MS and verified the reduction mechanism. Following our results, we proposed an optimum condition for producing a graphene derivative adsorbent with a high surface area. This graphene derivative was tested in an aqueous solution with organic and inorganic pollutants such as methylene blue, methyl orange, and cadmium.

DOI： 10.1002/cplu.202300328

Countercation Engineering of Graphene-Oxide Nanosheets for Imparting a Thermoresponsive Ability 国際誌

原材料と焼成温度の異なるバイオ炭の酸化処理が土壌からの一酸化二窒素放出に及ぼす影響査読

増倉勇樹, 前田守弘, 中野知佑, 宗村広昭, 山根信三, 仁科勇太

日本土壌肥料学雑誌 94 ( 4 ) 245 - 253 2023年8月

Shoma Kondo, Tomoki Nishimura, Yuta Nishina, Koki Sano

ACS Applied Materials & Interfaces 15 ( 31 ) 37837 - 37844 2023年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：American Chemical Society (ACS)

Graphene-oxide (GO) nanosheets, which are oxidized derivatives of graphene, are regarded as promising building blocks for functional soft materials. Especially, thermoresponsive GO nanosheets have been widely employed to develop smart membranes/surfaces, hydrogel actuators, recyclable systems, and biomedical applications. However, current synthetic strategies to generate such thermoresponsive GO nanosheets have exclusively relied on the covalent or non-covalent modification of their surfaces with thermoresponsive polymers, such as poly(N-isopropylacrylamide). To impart a thermoresponsive ability to GO nanosheets themselves, we focused on the countercations of the carboxy and acidic hydroxy groups on the GO nanosheets. In this study, we established a general and reliable method to synthesize GO nanosheets with target countercations and systematically investigated their effects on thermoresponsive behaviors of GO nanosheets. As a result, we discovered that GO nanosheets with Bu4N+ countercations became thermoresponsive in water without the use of any thermoresponsive polymers, inducing a reversible sol-gel transition via their self-assembly and disassembly processes. Owing to the sol-gel transition capability, the resultant dispersion can be used as a direct writing ink for constructing a three-dimensionally designable gel architecture of the GO nanosheets. Our concept of "countercation engineering" can become a new strategy for imparting a stimuli-responsive ability to various charged nanomaterials for the development of next-generation smart materials.

DOI： 10.1021/acsami.3c07820

Graphene Oxide-BODIPY Conjugates as Highly Fluorescent Materials 国際誌

Giacomo Reina, Giovanni Mariano Beneventi, Ramandeep Kaur, Giacomo Biagiotti, Alejandro Cadranel, Cécilia Ménard-Moyon, Yuta Nishina, Barbara Richichi, Dirk M. Guldi, Alberto Bianco

Chemistry - A European Journal 29 ( 31 ) e202300266 2023年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

Covalent functionalization of graphene oxide (GO) with boron dipyrromethenes (BODIPYs) was achieved through a facile synthesis, affording two different GO-BODIPY conjugates where the main difference lies in the nature of the spacer and the type of bonds between the two components. The use of a long but flexible spacer afforded strong electronic GO-BODIPY interactions in the ground state. This drastically altered the light absorption of the BODIPY structure and impeded its selective excitation. In contrast, the utilisation of a short, but rigid spacer based on boronic esters resulted in a perpendicular geometry of the phenyl boronic acid BODIPY (PBA-BODIPY) with respect to the GO plane, which enables only minor electronic GO-BODIPY interactions in the ground state. In this case, selective excitation of PBA-BODIPY was easily achieved, allowing to investigate the excited state interactions. A quantitative ultrafast energy transfer from PBA-BODIPY to GO was observed. Furthermore, due to the reversible dynamic nature of the covalent GO-PBA-BODIPY linkage, some PBA-BODIPY is free in solution and, hence, not quenched from GO. This resulted in a weak, but detectable fluorescence from the PBA-BODIPY that will allow to exploit GO-PBA-BODIPY for slow release and imaging purposes.

DOI： 10.1002/chem.202300266

Development of Microdrip Enzyme Device Using Carbon-Coated Porous Silica Spheres

Shunsuke Fujii, Akiko Yoshida, Tracy T. Chuong, Yuka Minegishi, Kritin Pirabul, Zheng-Ze Pan, Yuta Nishina, Takashi Kyotani, Hirotomo Nishihara, Kouji Masumoto, Galen D. Stucky, Tetsuji Itoh

ACS Applied Engineering Materials 1 ( 5 ) 1426 - 1435 2023年5月

Functional Graphene for Peritumoral Brain Microenvironment Modulation Therapy in Glioblastoma 国際誌

Shan Min Chin, Giacomo Reina, Ngoc Do Quyen Chau, Tanguy Chabrol, Didier Wion, Ali Bouamrani, Emmanuel Gay, Yuta Nishina, Alberto Bianco, François Berger

Small 19 ( 18 ) e2208227 2023年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

Peritumoral brain invasion is the main target to cure glioblastoma. Chemoradiotherapy and targeted therapies fail to combat peritumoral relapse. Brain inaccessibility and tumor heterogeneity explain this failure, combined with overlooking the peritumor microenvironment. Reduce graphene oxide (rGO) provides a unique opportunity to modulate the local brain microenvironment. Multimodal graphene impacts are reported on glioblastoma cells in vitro but fail when translated in vivo because of low diffusion. This issue is solved by developing a new rGO formulation involving ultramixing during the functionalization with polyethyleneimine (PEI) leading to the formation of highly water-stable rGO-PEI. Wide mice brain diffusion and biocompatibility are demonstrated. Using an invasive GL261 model, an anti-invasive effect is observed. A major unexpected modification of the peritumoral area is also observed with the neutralization of gliosis. In vitro, mechanistic investigations are performed using primary astrocytes and cytokine array. The result suggests that direct contact of rGO-PEIUT neutralizes astrogliosis, decreasing several proinflammatory cytokines that would explain a bystander tumor anti-invasive effect. rGO also significantly downregulates several proinvasive/protumoral cytokines at the tumor cell level. The results open the way to a new microenvironment anti-invasive nanotherapy using a new graphene nanomaterial that is optimized for in vivo brain delivery.

DOI： 10.1002/smll.202208227

Ball mill enhances the functionalization of boron nitride: The application for polyimide fillers

Yi Kai Cheng, Seiji Obata, Yuta Nishina

FlatChem 39 2023年5月

掲載種別：研究論文（学術雑誌）

Polymer properties can be tuned by the addition of filler materials such as carbon-base materials and inorganic materials. In recent years, 2D filers as additives for polymers have extensively been studied. Among them, functionalized hexagonal boron nitride (FBN) improves polymers’ physical properties. In this study, we prepared 27 types of FBNs by using different ball milling parameters in the presence of amine molecules. Ball mill conditions, such as the ratios of h-BN and the amine, rotation speeds, and treatment times of ball milling, were investigated, and then, the FBNs were covalently bonded with polyimide (PI) in all specimens. An optimum FBN-PI composite showed tensile strength and tensile modulus of 151.1 MPa and 3.8 GPa, respectively. Finally, we found that the tensile strength and modulus were increased to 159.2 MPa and 3.9 GPa by addition of a small amount of graphene oxide (GO) that were combined with FBN and PI. The ball milling and covalent bonding approach efficiently developed high-performance BN-polymer composite films.

DOI： 10.1016/j.flatc.2023.100489

Edge-Site-Free and Topological-Defect-Rich Carbon Cathode for High-Performance Lithium-Oxygen Batteries. 国際誌

Wei Yu, Takeharu Yoshii, Alex Aziz, Rui Tang, Zheng-Ze Pan, Kazutoshi Inoue, Motoko Kotani, Hideki Tanaka, Eva Scholtzová, Daniel Tunega, Yuta Nishina, Kiho Nishioka, Shuji Nakanishi, Yi Zhou, Osamu Terasaki, Hirotomo Nishihara

Advanced science (Weinheim, Baden-Wurttemberg, Germany) 10 ( 16 ) e2300268 2023年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

The rational design of a stable and catalytic carbon cathode is crucial for the development of rechargeable lithium-oxygen (LiO2 ) batteries. An edge-site-free and topological-defect-rich graphene-based material is proposed as a pure carbon cathode that drastically improves LiO2 battery performance, even in the absence of extra catalysts and mediators. The proposed graphene-based material is synthesized using the advanced template technique coupled with high-temperature annealing at 1800 °C. The material possesses an edge-site-free framework and mesoporosity, which is crucial to achieve excellent electrochemical stability and an ultra-large capacity (>6700 mAh g-1 ). Moreover, both experimental and theoretical structural characterization demonstrates the presence of a significant number of topological defects, which are non-hexagonal carbon rings in the graphene framework. In situ isotopic electrochemical mass spectrometry and theoretical calculations reveal the unique catalysis of topological defects in the formation of amorphous Li2 O2 , which may be decomposed at low potential (∼ 3.6 V versus Li/Li+ ) and leads to improved cycle performance. Furthermore, a flexible electrode sheet that excludes organic binders exhibits an extremely long lifetime of up to 307 cycles (>1535 h), in the absence of solid or soluble catalysts. These findings may be used to design robust carbon cathodes for LiO2 batteries.

DOI： 10.1002/advs.202300268

Plasma-Derived Fibrin Hydrogels Containing Graphene Oxide for Infections Treatment 国際誌

Cristina Martín, Ariadna Bachiller, Juan P. Fernández-Blázquez, Yuta Nishina, José L. Jorcano

ACS Materials Letters 5 ( 4 ) 1245 - 1255 2023年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

Wound infection is inevitable in most patients suffering from extensive burns or chronic ulcers, and there is an urgent demand for the production of bactericidal dressings to be used as grafts to restore skin functionalities. In this context, the present study explores the fabrication of plasma-derived fibrin hydrogels containing bactericidal hybrids based on graphene oxide (GO). The hydrogels were fully characterized regarding gelation kinetics, mechanical properties, and internal hydrogel structures by disruptive cryo scanning electron microscopies (cryo-SEMs). The gelation kinetic experiments revealed an acceleration of the gel formation when GO was added to the hydrogels in a concentration of up to 0.2 mg/mL. The cryo-SEM studies showed up a decrease of the pore size when GO was added to the network, which agreed with a faster area contraction and a higher compression modulus of the hydrogels that contained GO, pointing out the critical structural role of the nanomaterial. Afterward, to study the bactericidal ability of the gels, GO was used as a carrier, loading streptomycin (STREP) on its surface. The loading content of the drug to form the hybrid (GO/STREP) resulted in 50.2% ± 4.7%, and the presence of the antibiotic was also demonstrated by Raman spectroscopy, Z-potential studies, and thermogravimetric analyses. The fibrin-derived hydrogels containing GO/STREP showed a dose-response behavior according to the bactericidal hybrid concentration and allowed a sustained release of the antibiotic at a programmed rate, leading to drug delivery over a prolonged period of time.

DOI： 10.1021/acsmaterialslett.2c01044