Mar. 2022, 応用物理学会フォトニクス奨励賞　　　　　　　　　　　　　　　

Sep. 2021, 第3 回 物質・デバイス共同研究賞　　　　　　　　　　　　　　　

Oct. 2020, 新化学技術研究奨励賞　　　　　　　　　　　　　　　

Jun. 2013, Reaxys Ph.D. Prize 2013 Finalist　　　　　　　　　　　　　　　

Mar. 2012, The 4th HOPE Meeting Unique Presentation Award　　　　　　　　　　　　　　　

Mar. 2012, The 4th HOPE Meeting Best Poster Award　　　　　　　　　　　　　　　

Aug. 2010, 錯体化学若手の会夏の学校2010 学生講演賞　　　　　　　　　　　　　　　

Sep. 2009, 第59回錯体化学討論会 ポスター賞　　　　　　　　　　　　　　　

Sep. 2009, 第62回コロイドおよび界面化学討論会 ポスター賞　　　　　　　　　　　　　　　

Jun. 2009, 第2 回京都大学融合ナノ基盤工学研究者交流会 奨励賞　　　　　　　　　　　　　　　

Accessing a Hidden Pathway to Supramolecular Toroid through Vibrational Strong Coupling
Shunsuke Imai, Takumi Hamada, Misa Nozaki, Takatoshi Fujita, Mariko Takahashi, Yasuhiko Fujita, Koji Harano, Hiroshi Uji-i, Atsuro Takai, Kenji Hirai
Journal of the American Chemical Society, American Chemical Society (ACS), 29 May 2025, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

A Sub‐Diffraction‐Limit Dimension All‐Plasmonic Optical Memory Using Non‐Linear Photochromism
Shuichi Toyouchi, Mathias Wolf, Kenji Hirai, Yasuhiko Fujita, Tomoko Inose, Beatrice Fortuni, Eduard Fron, Johan Hofkens, Steven De Feyter, James Hutchison, Tsuyoshi Fukaminato, Hiroshi Uji‐i
Advanced Science, Wiley, 08 May 2025, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Abstract

The development of compact, high‐speed, and energy‐efficient optical memories remains a significant challenge in photonic and plasmonic technologies. Conventional optical memories are inherently limited by light diffraction, restricting miniaturization and causing inefficient energy transfer. A promising strategy to overcome these limitations is using propagating surface plasmon polaritons (SPPs), enabling the confinement and propagation of optical fields along metal interfaces, and allowing photonic devices to scale down to sub‐diffraction‐limit dimensions. This work presents an all‐plasmonic optical memory system based on silver nanowires (AgNWs) coated with photochromic diarylethene (DAE). By utilizing SPPs, reversible Write/Erase functions are achieved through multiphoton excitation, modulating the photostationary state of DAE. The refractive index changes regulate SPP propagation efficiency along the AgNW, with the memory state being read via plasmonic second‐harmonic generation. The synergy between nonlinear plasmonics in AgNWs and the photochromic properties of DAE enables complete memory operations, including writing, erasing, and reading ON/OFF states. This sub‐diffraction‐limit system paves the way for ultra‐compact, molecular‐scale optical memory devices.

Cellular Responses to Photothermal Therapy: Heat-Induced ERK Signaling and Intercellular Communication in Solid Tumors
Farsai Taemaitree, Yuta Takano, Daisuke Yamaguchi, Kazushi Yamaguchi, Yudai Yamashita, Motosuke Tsutsumi, Chentao Wen, Kohei Otomo, Kenji Hirai, James Hutchison, Indra Van Zundert, Sandra Krzyzowska, Maria Bravo, Sayuki Hirano, Koutarou D Kimura, Kazuhiro Aoki, Susana Rocha, Tomomi Nemoto, Beatrice Fortuni, Hiroshi Uji-i
bioRxiv, Cold Spring Harbor Laboratory, 03 Mar. 2025
Abstract

Nanoparticle-mediated photothermal therapy (PTT) shows promise as a standalone cancer treatment but faces clinical challenges due to inconsistent efficacy. Its translation is further hindered by a limited understanding of plasmon-induced heat effects, such as stress responses and intercellular signaling. Here, we investigate how plasmon-induced local heating affects cellular behavior and fate within tumor spheroids by focusing on the activity of the extracellular signal-regulated kinase (ERK). Spheroids were prepared from HeLa cells that express a FRET-based ERK sensor, and ERK activity changes under photothermal stimuli were tracked using a deep-learning program, 3DeeCellTracker. Gold nanostars were used as highly efficient photothermal transducers. Our results revealed significant alterations in ERK signaling patterns upon photothermal stimulation compared to spontaneous ERK activity in untreated spheroids, including changes in the activation frequency, timing, and duration. Notably, photothermal-induced ERK activity propagated across neighboring cells within the spheroid, suggesting intercellular communication. Furthermore, analysis of cell death and division further demonstrated that laser power modulates cellular fate during photothermal therapy. This study provides insights for predicting the therapeutic effects of PPT and guides the rational design of next-generation photothermal strategies. Additionally, our approach demonstrates the potential of FRET-based biosensors and deep-learning tools as powerful methods to study the effects of various therapeutic stimuli on solid tumors at the single-cell level.

Optical Cavity Enhancement of Visible Light-Driven Photochemical Reaction in the Crystalline State
Ikuto Sasaki, Kiyonori Takahashi, Farsai Taemaitree, Takayoshi Nakamura, James Andell Hutchison, Hiroshi Uji-i, Kenji Hirai
Chemical Communications, Royal Society of Chemistry (RSC), Jan. 2025, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
Scientific journal, Photochemical reactions enable the synthesis of energetically unfavorable compounds but often require irradiation with ultraviolet light, which potentially induces side reactions. Here, cavity strong coupling enhances the efficiency of an...

Molecular Assembly in Optical Cavities
Kenji Hirai, Hiroshi Uji‐i
Chemistry – An Asian Journal, 19 Nov. 2024, [Peer-reviewed], [Invited], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, AbstractChemistry has traditionally focused on the synthesis of desired compounds, with organic synthesis being a key method for obtaining target molecules. In contrast, self‐assembly —where molecules spontaneously organize into well‐defined structures— has emerged as a powerful tool for fabricating intricate structures. Self‐assembly was initially studied in biological systems but has been developed for synthetic methods, leading to the field of supramolecular chemistry, where non‐covalent interactions/bonds guide molecular assembly. This has led to the development of complex molecular structures, such as metal‐organic frameworks and hydrogen‐bonded organic frameworks. Parallel to this field, cavity quantum electrodynamics (QED), developed in the mid‐20th century, has recently intersected with molecular assembly. Early research in cavity strong coupling focused on inorganic solids and simple molecules, but has since extended to molecular assemblies. The strong coupling synergized with molecular assembly will generate new polaritonic phenomena and applications.

Spatially heterogeneous dynamics of droplets formed by arginine-rich dipeptides and poly-A RNA during liquid-liquid phase separation
Ya Tian, Qiang Zhang, Kenji Hirai, Han Wen, Guilin Feng, Jiangtao Li, Farsai Taemaitree, Tomoko Inose, Kohsuke Kanekura, Hiroshi Uji-i
Molecular Crystals and Liquid Crystals, 29 May 2024, [Peer-reviewed], [Invited], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Mechanical Properties of Modulative Undulating Layers in Two-Dimensional Metal–Organic Frameworks
Yuudai Iwai, Sotaro Kusumoto, Ryo Suzuki, Masaru Tachibana, Kazuki Komatsu, Takashi Kikuchi, Saori I. Kawaguchi, Hirokazu Kadobayashi, Yuji Masubuchi, Yuzuki Yamamoto, Yoshiki Ozawa, Masaaki Abe, Kenji Hirai, Benjamin Le Ouay, Masaaki Ohba, Ryo Ohtani
Chemistry of Materials, 36, 11, 5446, 5455, American Chemical Society (ACS), 21 May 2024, [Peer-reviewed], [International Magazine]
English, Scientific journal

Optical Cavity Design and Functionality for Molecular Strong Coupling
Kenji Hirai, James Andell Hutchison, Hiroshi Uji-i
Chemistry – A European Journal, Wiley, 08 Nov. 2023, [Peer-reviewed], [Invited], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Optical cavity/molecule strong coupling offers attractive opportunities to modulate photochemical or photophysical processes. When atoms or molecules are placed in an optical cavity, they can coherently exchange photonic energy with optical cavity vacuum fields, entering the strong coupling interaction regime. Recent work suggests that the thermodynamic and kinetic properties of molecules can be significantly changed by strong coupling, resulting in the emergence of intriguing photochemical and photophysical phenomena. As more and more physico‐chemical systems are studied under strong coupling conditions, optical cavities have also advanced in their sophistication, responsiveness, and (multi)functionality. In this review, we highlight some of these recent developments, particularly focusing on Fabry‐Perot microcavities.

Visualizing Ribbon‐to‐Ribbon Heterogeneity of Chemically Unzipped Wide Graphene Nanoribbons by Silver Nanowire‐Based Tip‐Enhanced Raman Scattering Microscopy
Tomoko Inose, Shuichi Toyouchi, Shinnosuke Hara, Shoji Sugioka, Peter Walke, Rikuto Oyabu, Beatrice Fortuni, Wannes Peeters, Yuki Usami, Kenji Hirai, Steven De Feyter, Hiroshi Uji‐i, Yasuhiko Fujita, Hirofumi Tanaka
Small, Wiley, 30 Aug. 2023, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Abstract

Graphene nanoribbons (GNRs), a quasi‐one‐dimensional form of graphene, have gained tremendous attention due to their potential for next‐generation nanoelectronic devices. The chemical unzipping of carbon nanotubes is one of the attractive fabrication methods to obtain single‐layered GNRs (sGNRs) with simple and large‐scale production.  The authors recently found that unzipping from double‐walled carbon nanotubes (DWNTs), rather than single‐ or multi‐walled, results in high‐yield production of crystalline sGNRs. However, details of the resultant GNR structure, as well as the reaction mechanism, are not fully understood due to the necessity of nanoscale spectroscopy. In this regard, silver nanowire‐based tip‐enhanced Raman spectroscopy (TERS) is applied for single GNR analysis and investigated ribbon‐to‐ribbon heterogeneity in terms of defect density and edge structure generated through the unzipping process.  The authors found that sGNRs originated from the inner walls of DWNTs showed lower defect densities than those from the outer walls. Furthermore, TERS spectra of sGNRs exhibit a large variety in graphitic Raman parameters, indicating a large variation in edge structures. This work at the single GNR level reveals, for the first time, ribbon‐to‐ribbon heterogeneity that can never be observed by diffraction‐limited techniques and provides deeper insights into unzipped GNR structure as well as the DWNT unzipping reaction mechanism.

Light-mediated Covalently Patterned Graphene Substrate for Graphene-Enhanced Raman Scattering (GERS)
Guilin Feng, Nozomu Suzuki, Qiang Zhang, Jiangrao Li, Tomoko Inose, Farsai Taemaitree, Muhammed Shameem K M, Shuichi Toyouchi, Yasuhiko Fujita, Kenji Hirai, Hiroshi Uji-i
Chemical Communications, Royal Society of Chemistry (RSC), Aug. 2023, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, We report covalently patterned graphene with acetic acid as a new potential candidate for graphene-enhanced Raman scattering (GERS). Rhodamine 6G molecule in direct contact with the covalently modified region shows...

Site-Specific Synthesis of Conductive Graphitic Nanomaterials on a NiFe Thin Film by Localized Laser Irradiation
Hideki Fujiwara, Seigo Daikokuya, Tatsuki Mirokuin, Kyohei Hayashi, Mizuki Matsuzaka, Yuri Ohashi, Christophe Pin, Hideo Kaiju, Kenji Hirai, Hiroshi Uji-i
ACS Applied Nano Materials, 6, 15, 13885, 13893, American Chemical Society (ACS), 22 Jul. 2023, [Peer-reviewed], [International Magazine]
English, Scientific journal

Molecular Chemistry in Cavity Strong Coupling
Kenji Hirai, James A. Hutchison, Hiroshi Uji-i
Chemical Reviews, 123, 13, 8099, 8126, American Chemical Society (ACS), 30 Jun. 2023, [Peer-reviewed], [Invited], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
Scientific journal

SERS Endoscopy for Monitoring Intracellular Drug Dynamics
Beatrice Fortuni, Monica Ricci, Raffaele Vitale, Tomoko Inose, Qiang Zhang, James Andell Hutchison, Kenji Hirai, Yasuhiko Fujita, Shuichi Toyouchi, Sandra Krzyzowska, Indra Van Zundert, Susana Rocha, Hiroshi Uji-i
ACS Sensors, 8, 6, 2340, 2347, American Chemical Society (ACS), 23 May 2023, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
Scientific journal

Selective Detection of Intracellular Drug Metabolism by Metal‐Organic Framework‐Coated Plasmonic Nanowire
Qiang Zhang, Taku Murasugi, Kotomi Watanabe, Han Wen, Ya Tian, Monica Ricci, Susana Rocha, Tomoko Inose, Hitoshi Kasai, Farsai Taemaitree, Hiroshi Uji‐i, Kenji Hirai, Beatrice Fortuni
Advanced Optical Materials, Wiley, 21 May 2023, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Liquid-Phase Photo-induced Covalent Modification (PICM) of Single-Layer Graphene by Short-Chain Fatty Acids
Guilin Feng, Tomoko Inose, Nozomu Suzuki, Han Wen, Farsai Taemaitree, Mathias Wolf, Shuichi Toyouchi, Yasuhiko Fujita, Kenji Hirai, Hiroshi Uji-i
Nanoscale, 15, 10, 4932, 4939, Royal Society of Chemistry (RSC), 2023, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, We report an efficient photo-induced covalent modification (PICM) of graphene by short-chain fatty acids (SCFAs) with an alkyl chain at the liquid-solid interface for spatially resolved chemical functionalization of graphene....

Length-Controllable Gold-Coated Silver Nanowire Probes for High AFM-TERS Scattering Activity
Han Wen, Jiangtao Li, Qiang Zhang, Tomoko Inose, Wannes Peeters, Beatrice Fortuni, Hitoshi Asakawa, Akito Masuhara, Kenji Hirai, Shuichi Toyouchi, Yasuhiko Fujita, Hiroshi Uji-i
Nano Letters, 23, 1615, 1621, 09 Dec. 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Autotuning of Vibrational Strong Coupling for Site-Selective Reactions
Kenji Hirai, Hiroto Ishikawa, Yasufumi Takahashi, James Andell Hutchison, Hiroshi Uji-i
Chemistry - A European Journal, 28, 47, e202201260, Jun. 2022, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Site-selective chemistry opens new paths for the synthesis of technologically important molecules. When a reactant is placed inside a Fabry-Perot (FP) cavity, energy exchange between molecular vibrations and resonant cavity photons results in vibrational strong coupling (VSC). VSC has recently been implicated in modified chemical reactivity at specific reactive sites. However, as a reaction proceeds inside an FP cavity, the refractive index of the reaction solution changes, detuning the cavity mode away from the vibrational mode and weakening the VSC effect. Here we overcome this issue, developing actuatable FP cavities to allow automated tuning of cavity mode energy to maintain maximized VSC during a reaction. As an example, the site-selective reaction of the aldehyde over the ketone in 4-acetylbenzaldehyde is achieved by automated cavity tuning to maintain optimal VSC of the ketone carbonyl stretch during the reaction. A nearly 50% improvement in site-selective reactivity is observed compared to an FP cavity with static mirrors, demonstrating the utility of actuatable FP cavities as microreactors for organic chemistry.

All-Optical and One-Color Rewritable Chemical Patterning on Pristine Graphene under Water
Shuichi Toyouchi, Mathias Wolf, Guilin Feng, Yasuhiko Fujita, Beatrice Fortuni, Tomoko Inose, Kenji Hirai, Steven De Feyter, Hiroshi Uji-i
The Journal of Physical Chemistry Letters, 13, 17, 3796, 3803, American Chemical Society (ACS), 05 May 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
Scientific journal

Host and guest joining forces: a holistic approach for metal-organic frameworks in nonlinear optics
Mathias Wolf, Kenji Hirai, Shuichi Toyouchi, Brent Daelemans, Eduard Fron, Hiroshi Uji-i
Journal of Materials Chemistry C, 10, 25, 9471, 9477, Royal Society of Chemistry ({RSC}), 2022, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Metal–organic frameworks (MOFs) are interesting candidates for nonlinear optics (NLO). Here, it will be demonstrated how combining host and guest emission can greatly improve NLO performance of MOFs by accommodating Li@C₆₀ into MOF-177.

Gold-coated silver nanowires for long lifetime AFM-TERS probes
Han Wen, Tomoko Inose, Kenji Hirai, Taiki Akashi, Shoji Sugioka, Jiangtao Li, Wannes Peeters, Eduard Fron, Beatrice Fortuni, Yoshihiko Nakata, Susana Rocha, Shuichi Toyouchi, Yasuhiko Fujita, Hiroshi Uji-i
Nanoscale, 14, 14, 5439, 5446, 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Li@C60 thin films: characterization and nonlinear optical properties
Mathias Wolf, Shuichi Toyouchi, Peter Walke, Kazuki Umemoto, Akito Masuhara, Hiroshi Fukumura, Yuta Takano, Michio Yamada, Kenji Hirai, Eduard Fron, Hiroshi Uji-i
RSC Advances, 12, 1, 389, 394, 2022, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Data science assisted investigation of catalytically active copper hydrate in zeolites for direct oxidation of methane to methanol using H2O2
Junya Ohyama, Airi Hirayama, Nahoko Kondou, Hiroshi Yoshida, Masato Machida, Shun Nishimura, Kenji Hirai, Itsuki Miyazato, Keisuke Takahashi
Scientific Reports, 11, 1, Springer Science and Business Media LLC, Dec. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal

Gold-Photodeposited Silver Nanowire Endoscopy for Cytosolic and Nuclear pH Sensing
Qiang Zhang, Tomoko Inose, Monica Ricci, Jiangtao Li, Ya Tian, Han Wen, Shuichi Toyouchi, Eduard Fron, Anh Thi Ngoc Dao, Hitoshi Kasai, Susana Rocha, Kenji Hirai, Beatrice Fortuni, Hiroshi Uji-i
ACS Applied Nano Materials, 4, 9, 9886, 9894, 07 Sep. 2021, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Selective Crystallization via Vibrational Strong Coupling
Kenji Hirai, Hiroto Ishikawa, Thibault Chervy, James Andell Hutchison, Hiroshi Uji-i
Chemical Science, 12, 36, 11986, 11994, 10 Aug. 2021, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Controlling polymorphism of metal-organic frameworks
Kenji Hirai, Atsushi Nagahashi, Taisei Kitagawa, Hiroshi Uji-i
Metamaterials, Metadevices, and Metasystems 2021, SPIE, 01 Aug. 2021, [Peer-reviewed], [Invited], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
International conference proceedings

Polariton Chemistry in Cavity Vacuum Fields
Kenji Hirai, Hiroshi Uji-i
Chemistry Letters, 50, 4, 727, 732, 05 Apr. 2021, [Peer-reviewed], [Invited], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Adaptive Optical Two-Photon Microscopy for Surface-Profiled Living Biological Specimens
Kazushi Yamaguchi, Kohei Otomo, Yuichi Kozawa, Motosuke Tsutsumi, Tomoko Inose, Kenji Hirai, Shunichi Sato, Tomomi Nemoto, Hiroshi Uji-i
ACS Omega, 6, 1, 438, 447, American Chemical Society (ACS), 30 Nov. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
Scientific journal

Pseudo‐Membrane Jackets: Two‐Dimensional Coordination Polymers Achieving Visible Phase Separation in Cell Membrane
Ryo Ohtani, Kenichi Kawano, Masanao Kinoshita, Saeko Yanaka, Hikaru Watanabe, Kenji Hirai, Shiroh Futaki, Nobuaki Matsumori, Hiroshi Uji‐i, Masaaki Ohba, Koichi Kato, Shinya Hayami
Angewandte Chemie International Edition, 59, 41, 17931, 17937, Wiley, 05 Oct. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Cell membranes contain lateral systems that consist of various lipid compositions and actin cytoskeleton, providing two-dimensional (2D) platforms for chemical reactions. However, such complex 2D environments have not yet been used as a synthetic platform for artificial 2D nanomaterials. Herein, we demonstrate the direct synthesis of 2D coordination polymers (CPs) at the liquid-cell interface of the plasma membrane of living cells. The coordination-driven self-assembly of networking metal complex lipids produces cyanide-bridged CP layers with metal ions, enabling "pseudo-membrane jackets" that produce long-lived micro-domains with a size of 1-5 μm. The resultant artificial and visible phase separation systems remain stable even in the absence of actin skeletons in cells. Moreover, we show the cell application of the jackets by demonstrating the enhancement of cellular calcium response to ATP.

Low-Cytotoxic Gold-Coated Silver Nanoflowers for Intracellular pH Sensing
Qiang Zhang, Han Wen, Kiri Watanabe, Ibuki Kotani, Monica Ricci, Beatrice Fortuni, Anh Thi Ngoc Dao, Akito Masuhara, Kenji Hirai, Hitoshi Kasai, Tomoko Inose, Hiroshi Uji-i
ACS Applied Nano Materials, 3, 8, 7643, 7650, 28 Aug. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Recent Progress in Vibropolaritonic Chemistry
Kenji Hirai, James A. Hutchison, Hiroshi Uji‐i
ChemPlusChem, 85, 9, 1981, 1988, Aug. 2020, [Peer-reviewed], [Invited], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Controlled Fabrication of Optical Signal Input/Output Sites on Plasmonic Nanowires
Shuichi Toyouchi, Mathias Wolf, Yusuke Nakao, Yasuhiko Fujita, Tomoko Inose, Beatrice Fortuni, Kenji Hirai, Johan Hofkens, Steven De Feyter, James Hutchison, Hiroshi uji-i
Nano Letters, 20, 2460, 2467, 10 Mar. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Modulation of Prins Cyclization by Vibrational Strong Coupling.
Kenji Hirai, Rie Takeda, James A Hutchison, Hiroshi Uji-I
Angewandte Chemie (International ed. in English), 59, 5332, 5335, 22 Jan. 2020, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Light-molecule strong coupling has emerged within the last decade as an entirely new method to control chemical reactions. A few years ago it was discovered that the chemical reactivity could be altered by vibrational strong coupling (VSC). While the potential of VSC in organic chemistry appears enormous, only a limited number of reactions have been investigated under VSC to date, including solvolysis and deprotection reactions. Here we investigate the effect of VSC on a series of aldehydes and ketones undergoing Prins cyclization, an important synthetic step in pharmaceutical chemistry. We observe a decrease of the second-order rate constant with VSC of the reactant carbonyl stretching groups. We measure an increased activation energy due to VSC, but proportional changes in activation enthalpy and entropy suggest no substantive change in reaction pathway. The addition of common cycloaddition reactions to the stable of VSC-modified chemical reactions is another step towards establishing VSC as a genuine tool for synthetic chemistry.

Plasmon-Associated Control of Chemical Reaction at Nanometer Scale
Shuichi Toyouchi, Tomoko Inose, Kenji Hirai, Hiroshi Uji-i
Photosynergetic Responses in Molecules and Molecular Aggregates, 117, 133, Springer Singapore, 2020, [Peer-reviewed], [Invited], ［Internationally co-authored］, [International Magazine]
In book

Label-free visualization of heterogeneities and defects in metal–organic frameworks using nonlinear optics
Mathias Wolf, Kenji Hirai, Shuichi Toyouchi, Eduard Fron, Wannes Peeters, Steven De Feyter, Hiroshi Uji-i
Chemical Communications, 56, 87, 13331, 13334, 2020, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Multicolour photochromic fluorescence of a fluorophore encapsulated in a metal–organic framework
Kenji Hirai, Taisei Kitagawa, Hideki Fujiwara, Jenny Pirillo, Yuh Hijikata, Tomoko Inose, Hiroshi Uji-i
Chemical Communications, 56, 67, 9651, 9654, 2020, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Water-mediated polyol synthesis of pencil-like sharp silver nanowires suitable for nonlinear plasmonics.
Inose T, Toyouchi S, Lu G, Umemoto K, Tezuka Y, Lyu B, Masuhara A, Fron E, Fujita Y, Hirai K, Uji-I H
Chemical communications (Cambridge, England), 55, 77, 11630, 11633, Sep. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

The Rise of Catalyst Informatics: Towards Catalyst Genomics
Takahashi, K., Takahashi, L., Miyazato, I., Fujima, J., Tanaka, Y., Uno, T., Satoh, H., Ohno, K., Nishida, M., Hirai, K., Ohyama, J., Nguyen, T.N., Nishimura, S., Taniike, T.
ChemCatChem, 11, 4, 1146, 1152, 2019, [Peer-reviewed], [International Magazine]
Scientific journal

Pyrolysis of Helical Coordination Polymers for Metal-Sulfide-Based Helices with Broadband Chiroptical Activity
Kenji Hirai, Bongjun Yeom, Kazuki Sada
ACS NANO, 11, 6, 5309, 5317, Jun. 2017, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Solid-Solution Coordination Polymers as Precursors for ZnxCd1-xS/C Composite Nanowires
Shinya Tajima, Yoshiki Kuroshima, Tetsuro Katayama, Naoto Tamai, Kazuki Sada, Kenji Hirai
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 18, 2444, 2449, May 2017, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal

Infrared laser writing of MOFs
K. Hirai, K. Sada
CHEMICAL COMMUNICATIONS, 53, 38, 5275, 5278, May 2017, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal

Nanoparticle Assemblies into Luminescent Dendrites in Shrinking Microdroplets
Taisuke Kojima, Kenji Hirai, Yunlong Zhou, Priyan Weerappuli, Shuichi Takayama, Nicholas A. Kotov
LANGMUIR, 32, 47, 12468, 12475, Nov. 2016, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Gas-generated thermal oxidation of a coordination cluster for an anion-doped mesoporous metal oxide
Kenji Hirai, Shigehito Isobe, Kazuki Sada
SCIENTIFIC REPORTS, 5, 18468, Dec. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal

Coordination Assembly of Discoid Nanoparticles
Kenji Hirai, Bongjun Yeom, Shu-Hao Chang, Hang Chi, John F. Mansfield, Byeongdu Lee, Sungsik Lee, Ctirad Uher, Nicholas A. Kotov
Angewandte Chemie International Edition, 54, 31, 8966, 8970, Jul. 2015, [Peer-reviewed], [Lead author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Diffusion-Coupled Molecular Assembly: Structuring of Coordination Polymers Across Multiple Length Scales
Kenji Hirai, Julien Reboul, Nobuhiro Morone, John E. Heuser, Shuhei Furukawa, Susumu Kitagawa
Journal of the American Chemical Society, 136, 42, 14966, 14973, Oct. 2014, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal

Confined synthesis of CdSe quantum dots in the pores of metal-organic frameworks
Takuo Wakaoka, Kenji Hirai, Koji Murayama, Yoshihiko Takano, Hiroshi Takagi, Shuhei Furukawa, Susumu Kitagawa
JOURNAL OF MATERIALS CHEMISTRY C, 2, 35, 7173, 7175, Sep. 2014, [Peer-reviewed]
English, Scientific journal

Trapping of a Spatial Transient State During the Framework Transformation of a Porous Coordination Polymer
Mio Kondo, Shuhei Furukawa, Kenji Hirai, Takaaki Tsuruoka, Julien Reboul, Hiromitsu Uehara, Stephane Diring, Yoko Sakata, Osami Sakata, Susumu Kitagawa
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 136, 13, 4938, 4944, Apr. 2014, [Peer-reviewed]
English, Scientific journal

Host-Guest Metal-Organic Frameworks for Photonics
Kenji Hirai, Paolo Falcaro, Susumu Kitagawa, Shuhei Furukawa
METAL-ORGANIC FRAMEWORKS FOR PHOTONICS APPLICATIONS, 157, 167, 186, 2014, [Peer-reviewed], [Invited], [Lead author], ［Internationally co-authored］, [International Magazine]
English, In book

Impact of crystal orientation on the adsorption kinetics of a porous coordination polymer-quartz crystal microbalance hybrid sensor
Kenji Hirai, Kenji Sumida, Mikhail Meilikhov, Nicolas Louvain, Masashi Nakahama, Hiromitsu Uehara, Susumu Kitagawa, Shuhei Furukawa
JOURNAL OF MATERIALS CHEMISTRY C, 2, 17, 3336, 3344, 2014, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal

Binary Janus Porous Coordination Polymer Coating for Sensor Devices with Tunable Analyte Affinity
Mikhail Meilikhov, Shuhei Furukawa, Kenji Hirai, Roland A. Fischer, Susumu Kitagawa
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 52, 1, 341, 345, 2013, [Peer-reviewed]
English, Scientific journal

Shape-Memory Nanopores Induced in Coordination Frameworks by Crystal Downsizing
Yoko Sakata, Shuhei Furukawa, Mio Kondo, Kenji Hirai, Nao Horike, Yohei Takashima, Hiromitsu Uehara, Nicolas Louvain, Mikhail Meilikhov, Takaaki Tsuruoka, Seiji Isoda, Wataru Kosaka, Osami Sakata, Susumu Kitagawa
SCIENCE, 339, 6116, 193, 196, Jan. 2013, [Peer-reviewed]
English, Scientific journal

Programmed crystallization via epitaxial growth and ligand replacement towards hybridizing porous coordination polymer crystals
Kenji Hirai, Kebi Chen, Tomohiro Fukushima, Satoshi Horike, Mio Kondo, Nicolas Louvain, Chiwon Kim, Yoko Sakata, Mikhail Meilikhov, Osami Sakata, Susumu Kitagawa, Shuhei Furukawa
DALTON TRANSACTIONS, 42, 45, 15868, 15872, 2013, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal

Mesoscopic architectures of porous coordination polymers fabricated by pseudomorphic replication
Julien Reboul, Shuhei Furukawa, Nao Horike, Manuel Tsotsalas, Kenji Hirai, Hiromitsu Uehara, Mio Kondo, Nicolas Louvain, Osami Sakata, Susumu Kitagawa
NATURE MATERIALS, 11, 8, 717, 723, Aug. 2012, [Peer-reviewed]
English, Scientific journal

Redox reaction in two-dimensional porous coordination polymers based on ferrocenedicarboxylates
Kenji Hirai, Hiromitsu Uehara, Susumu Kitagawa, Shuhei Furukawa
DALTON TRANSACTIONS, 41, 14, 3924, 3927, 2012, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal

Targeted functionalisation of a hierarchically-structured porous coordination polymer crystal enhances its entire function
Kenji Hirai, Shuhei Furukawa, Mio Kondo, Mikhail Meilikhov, Yoko Sakata, Osami Sakata, Susumu Kitagawa
CHEMICAL COMMUNICATIONS, 48, 52, 6472, 6474, 2012, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal

Liquid Phase Separation of Polyaromatics on [Cu-2(BDC)(2)(dabco)]
Michael Maes, Stijn Schouteden, Kenji Hirai, Shuhei Furukawa, Susumu Kitagawa, Dirk E. De Vos
LANGMUIR, 27, 15, 9083, 9087, Aug. 2011, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Porous Coordination Polymer Hybrid Device with Quartz Oscillator: Effect of Crystal Size on Sorption Kinetics
Hiromitsu Uehara, Stephane Diring, Shuhei Furukawa, Ziya Kalay, Manuel Tsotsalas, Masashi Nakahama, Kenji Hirai, Mio Kondo, Osami Sakata, Susumu Kitagawa
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 133, 31, 11932, 11935, Aug. 2011, [Peer-reviewed], [International Magazine]
English, Scientific journal

MOF-on-MOF heteroepitaxy: perfectly oriented [Zn-2(ndc)(2)(dabco)](n) grown on [Cu-2(ndc)(2)(dabco)](n) thin films
O. Shekhah, K. Hirai, H. Wang, H. Uehara, M. Kondo, S. Diring, D. Zacher, R. A. Fischer, O. Sakata, S. Kitagawa, S. Furukawa, C. Woell
DALTON TRANSACTIONS, 40, 18, 4954, 4958, 2011, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Sequential Functionalization of Porous Coordination Polymer Crystals
Kenji Hirai, Shuhei Furukawa, Mio Kondo, Hiromitsu Uehara, Osami Sakata, Susumu Kitagawa
Angewandte Chemie International Edition, 50, 35, 8057, 8061, 2011, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal

Coordinatively Immobilized Monolayers on Porous Coordination Polymer Crystals
Mio Kondo, Shuhei Furukawa, Kenji Hirai, Susumu Kitagawa
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 49, 31, 5327, 5330, 2010, [Peer-reviewed], [International Magazine]
English, Scientific journal

Heterogeneously Hybridized Porous Coordination Polymer Crystals: Fabrication of Heterometallic Core-Shell Single Crystals with an In-Plane Rotational Epitaxial Relationship
Shuhei Furukawa, Kenji Hirai, Keiji Nakagawa, Yohei Takashima, Ryotaro Matsuda, Takaaki Tsuruoka, Mio Kondo, Rie Haruki, Daisuke Tanaka, Hirotoshi Sakamoto, Satoru Shimomura, Osami Sakata, Susumu Kitagawa
Angewandte Chemie International Edition, 48, 10, 1766, 1770, 2009, [Peer-reviewed], [International Magazine]
English, Scientific journal

A block PCP crystal: anisotropic hybridization of porous coordination polymers by face-selective epitaxial growth
Shuhei Furukawa, Kenji Hirai, Yohei Takashima, Keiji Nakagawa, Mio Kondo, Takaaki Tsuruoka, Osami Sakata, Susumu Kitagawa
CHEMICAL COMMUNICATIONS, 34, 5097, 5099, 2009, [Peer-reviewed], [International Magazine]
English, Scientific journal

光共振器を使った機能物性化学　　　　　　　　　　　　　　　
平井健二, 応用物理学会有機分子・バイオエレクトロニクス分科会会誌, 34, 2, 58, 61, Jun. 2023, [Invited], [Lead author, Last author], [Domestic magazines]
Japanese, Introduction scientific journal

振動強結合による化学反応の制御と機能性材料の合成　　　　　　　　　　　　　　　
平井健二, 応用物理学会フォトニクスニュース, 8, 1, 52, May 2022, [Invited], [Lead author, Last author, Corresponding author], [Domestic magazines]

光共振器の中の化学反応　　　　　　　　　　　　　　　
平井健二, 光学, 51, 28, 33, Jan. 2022, [Peer-reviewed], [Invited], [Lead author, Last author, Corresponding author], [Domestic magazines]

振動強結合と分子化学の交差　　　　　　　　　　　　　　　
平井健二, 理論化学会誌フロンティア, 3, 4, 225, 230, Nov. 2021, [Peer-reviewed], [Invited], [Lead author, Last author, Corresponding author], [Domestic magazines]
Japanese

Modulation of Chemical Reactions in an Optical Cavity　　　　　　　　　　　　　　　
Kenji Hirai, 化学 2020年6月号, 12, 15, May 2020, [Lead author, Last author, Corresponding author]
Japanese

プラズモン導波路を用いた単一細胞解析と操作　　　　　　　　　　　　　　　
豊内秀一, 猪瀬朋子, 平井健二, 雲林院宏, 月刊「細胞」2020年 2月号, 51, 54, 2020

Creation and Application of Coordination Nano Space
平井 健二, 北川 進, 科学と工業, 86, 5, 151, 155, May 2012, [Lead author]
大阪工研協会, Japanese

多孔性金属錯体（PCP/MOF）の表面化学
平井健二, 古川修平, 表面科学会誌, 33, 9, 519, 523, 2012
日本表面科学会, Japanese

Multifunctional Porous Crystals by Hybridizing Coordination Polymers　　　　　　　　　　　　　　　
Kenji Hirai, Osami Sakata, Susumu Kitagawa, Shuhei Furukawa, SPring-8 Research Frontiers 2011, 84, 85, 2011

Evaluation of Structural Relationship in Hybridized Porous Coordination Polymer Crystals　　　　　　　　　　　　　　　
Kenji Hirai, Shuhei Furukawa, Osami Sakata, Susumu Kitagawa, SPring-8 Research Frontiers 2009, 98, 99, 2010

エピタキシャル成長によるハイブリッド型多孔性錯体結晶の創製　　　　　　　　　　　　　　　
平井健二, Bulletin of Japan Society of Coordination Chemistry, 55, 121, 122, 2010

PCP/MOFおよび各種多孔質材料の作り方、使い方、評価解析
技術情報協会, MOFの技術を用いたマイクロパターニングの開発とその応用
技術情報協会, Oct. 2019, 9784861047695, 639p, Japanese, Scholarly book

配位空間の化学 : 最新技術と応用
シーエムシー出版, Oct. 2009, 9784781301358, viii, 345p, Japanese

情報エレクトロニクス（電気回路）演習　　　　　　　　　　　　　　　
北海道大学工学部情報エレクトロニクス学科
2021 - Present

応用物性工学　　　　　　　　　　　　　　　
北海道大学工学部情報エレクトロニクス学科
2018 - Present

生体情報工学演習II　　　　　　　　　　　　　　　
北海道大学工学部情報エレクトロニクス学科
2018 - Present

ナノマテリアル特論　　　　　　　　　　　　　　　
北海道大学大学院情報科学院
2018 - Present

生体情報工学実験I　　　　　　　　　　　　　　　
北海道大学工学部情報エレクトロニクス学科
2021 - 2022

生体情報工学実験II　　　　　　　　　　　　　　　
北海道大学工学部情報エレクトロニクス学科
2020 - 2022

物理学I　　　　　　　　　　　　　　　
北海道大学全学共通科目
2019 - 2022

Strong Coupling at Meso-Hierarchy
Grants-in-Aid for Scientific Research
Apr. 2023 - Mar. 2028
雲林院 宏, 平井 健二, 五月女 光
Japan Society for the Promotion of Science, Grant-in-Aid for Transformative Research Areas (A), Hokkaido University, 23H04877

自己集合による規則配列を利用した高輝度ポラリトン発光
科学研究費助成事業
Apr. 2024 - Mar. 2027
平井 健二
日本学術振興会, 基盤研究(B), 北海道大学, 24K01447

光共振器を用いた結晶化を誘導する方法の開発　　　　　　　　　　　　　　　
科学研究費助成事業
May 2024 - Mar. 2026
平井健二
日本学術振興会, 挑戦的研究（萌芽）, Principal investigator, 24K21750

Enhancement of ionic conductivity using quantum optical phenomena with optical resonators
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Apr. 2021 - Mar. 2024
平井 健二
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Competitive research funding, ［Internationally co-authored］, 21H01899

多孔性錯体を用いたポラリトンレーザーの開発　　　　　　　　　　　　　　　
住友財団 基礎科学研究助成
Nov. 2022 - Nov. 2023
平井健二

Development of quantum dot lasers using coordination self-assembly
Grants-in-Aid for Scientific Research Challenging Research (Exploratory)
Jul. 2020 - Mar. 2023
平井 健二
Japan Society for the Promotion of Science, Challenging Research (Exploratory), Hokkaido University, Competitive research funding, ［Internationally co-authored］, 20K21200

ラビ分裂による化学反応操作法の確立
Precursory Research for Embryonic Science and Technology
Oct. 2018 - Mar. 2022
平井 健二
Japan Society for the Promotion of Science, Principal investigator, Competitive research funding

Laser Heating for Three-Dimensional Material Synthesis
Grants-in-Aid for Scientific Research
Apr. 2018 - Mar. 2021
Hirai Kenji
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Competitive research funding, ［Internationally co-authored］, 18H01948

Manipulation of Self-Assembly by Vibrational Excitation
Grants-in-Aid for Scientific Research Challenging Research (Exploratory)
Jun. 2018 - Mar. 2020
Hirai Kenji
Japan Society for the Promotion of Science, Challenging Research (Exploratory), Hokkaido University, Competitive research funding, ［Internationally co-authored］, 18K19085

Coordination Polymers as Sacrificial Precursors for Nano- and Micro-structured Inorganic Solids
Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
Apr. 2016 - Mar. 2018
Hirai Kenji
Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Competitive research funding, ［Internationally co-authored］, 16K17875

量子ドットの異方的架橋による２次元規則配列の創出　　　　　　　　　　　　　　　
村田学術振興財団 研究助成
Jun. 2016 - May 2017
平井 健二

CdS/Grapheneコンポジットナノワイヤによる可視光CO2還元　　　　　　　　　　　　　　　
一樹工業技術奨励会 研究助成金
Jun. 2016 - Mar. 2017
平井 健二

錯体結晶を前駆体とした酸化チタンのアニオンドーピング　　　　　　　　　　　　　　　
総合工学振興財団 研究奨励金
Aug. 2015 - Mar. 2016
平井 健二

チタン錯体を前駆体とした酸化チタンへのアニオンドープ法の確立　　　　　　　　　　　　　　　
北海道科学技術振興センター 若手研究人材・ネットワーク育成補助金
Jul. 2015 - Mar. 2016
平井 健二

配位空間を用いたナノ粒子配列の自在制御　　　　　　　　　　　　　　　
海外特別研究員
Apr. 2013 - Oct. 2014
平井 健二
日本学術振興会

多孔性金属錯体を用いた応答性錯体インターフェイスの構築
特別研究員（DC1）
Apr. 2010 - Mar. 2013
平井 健二
金属イオンと有機配位子が自己集合的に組み上がることで構築される多孔性配位高分子(PCP)は、吸蔵材、分離材、触媒材料として高い特性を示すことが明らかになってきており、近年精力的に研究が行われている。本研究課題では電極基板上でPCPを結晶化させ、その規則的なナノ細孔を利用した機能性デバイスの創出を目指している。
最終年度は以下の3項目において成果が得られた。
1.多孔性配位高分子を用いた複合粒子の作成
PCPでは金属イオンや有機配位子を様々に代えることで、細孔特性を自在に設計することが可能である。同形の骨格構造を有するPCPをエピタキシャル成長によって複合化することで、コアシェル型の構造体の作成を行った。コア結晶には蛍光発光を有するPCPを、シェル結晶にはゲスト選択性を有するPCPを用いた。この組み合わせによって得られたコアシェル型PCPは、選択的にゲスト分子を取り込み、蛍光発光を示すことが明らかとなった。センサー粒子としての応用が期待できる。
2.基板上への多孔性配位高分子の固定化
一般に金属酸化物は成型が容易であるため、薄膜化やパターニングが非常に容易である。本課題では酸化アルミニウムと有機配位子を反応させることによって、基板表面でのPCP合成を行った。得られたPCPは酸化アルミニウムの形状を維持しており、電極表面に固定化する方法として非常に有望であることが明らかとなった。
3.多孔性配位高分子を用いたPCPデバイス
重量変化を振動数の変化として検出することが可能な水晶振動子マイクロバランス(QCM)の電極表面上でPCPを薄膜化し、PCP/QCMハイブリッドセンサーを作成した。PCPは蒸気を吸着し、重量が増加するため、PCP/QCMハイブリッドセンサーによって有機分子の存在を検出することが出来る。QCM上のPCP薄膜を複合膜にすると上記選択性が向上する結果も得られており、1の結果と組み合わせることで、高度なセンサーデバイスの作成が可能となった。
日本学術振興会, 特別研究員奨励費, 京都大学, 10J02257