Akira YAMAGUCHIProfessor
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Paper
- Protein diffusion inside nanopores
Akira Yamaguchi, Corresponding, Springer Science and Business Media LLC
Analytical Sciences, 22 Jan. 2025, [Reviewed] - Quasielastic neutron scattering study on low-hydrated myoglobin inside silica nanopores
Akira Yamaguchi; Yoshitomo Kojima; Nicolas R. de Souza; Hiroki Iwase; Toshio Kamijo, Lead, Elsevier BV
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Oct. 2024, [Reviewed] - 〔Major achievements〕Albumin Hydrogel–Coated Mesoporous Silica Nanoparticle as a Carrier of Cationic Porphyrin and Ratiometric Fluorescence pH Sensor
Hidetoshi Shinoda; Raiha Higano; Takashi Oizumi; Asako J. Nakamura; Toshio Kamijo; Mio Takahashi; Masaaki Nagaoka; Yusuke Sato; and Akira Yamaguchi, Corresponding
ACS Appl. Bio Mater., Feb. 2024, [Reviewed] - Integration of enzyme-encapsulated mesoporous silica between nanohole array electrode and hydrogel film for flow-type electrochemical biosensor
Daiki Inaba; Akira Yamaguchi, Corresponding
Anal. Sci., Nov. 2022, [Reviewed] - 〔Major achievements〕Influence of ionic strength and temperature on adsorption of tetrakis-N-methylpyridyl porphyrin onto mesoporous silica
Akira Yamaguchi; Ami Ishii; Toshio Kamijo, Lead, In the present study, we examined the effects of ionic strength and temperature for adsorption of tetrakis-N-methylpyridyl porphyrin (TMPyP) on mesoporous silica with 7.0 nm in pore diameter. The adsorption of TMPyP in 10 mM phosphate buffer solutions containing 0–150 mM NaCl showed linear adsorption isotherm plotted as inverse of the adsorption amount of TMPyP versus inverse of the equilibrium solution concentration of TMPyP. From the analysis of the adsorption isotherm by electrostatically modified Langmuir model, decrease in apparent adsorption constant with increasing the ionic strength was ascribed to the surface charge screening by electrolyte ions. In the temperature dependence on the TMPyP adsorption, non-linear van't Hoff plots were analyzed by including heat capacity change during adsorption. The results of the van't Hoff analysis indicated that the TMPyP adsorption at low temperature was exothermic and enthalpy-driven reaction, whereas it became endothermic and entropy-driven reaction with temperature elevation. In addition, the surface diffusivity was suggested as a primary factor to govern the maximum adsorption amount of TMPyP on mesoporous silica.
Colloids Surf. A, Oct. 2022, [Reviewed] - 〔Major achievements〕Protein Condensation at Nanopore Entrances as Studied by Differential Scanning Calorimetry and Small-Angle Neutron Scattering
Mami Aizawa; Hiroki Iwase; Toshio Kamijo; Akira Yamaguchi, Corresponding, The condensation of globular myoglobin (Mb) at the pore entrances of mesoporous silica (MPS) with a series of pore diameters (4.2, 6.4, 7.7, and 9.0 nm) was examined by differential scanning calorimetry (DSC) and contrast-matching small-angle neutron scattering (CM-SANS) experiments. The DSC measurements were performed to estimate the amount of Mb adsorbed at two different adsorption sites, namely, the pore interior and the pore entrance regions. The CM-SANS measurements were conducted to observe condensation of Mb molecules at the pore entrance regions. Notably, the nanopore entrance with a diameter close to twice that of the Mb diameter was found to be the specific cavity to facilitate the condensation of globular Mb. The Mb condensation occurred at the entrances of the 6.4 nm pore during the adsorption uptake from concentrated Mb solutions, whereas the adsorption uptake from diluted Mb solutions induced the condensation of Mb at the entrances of the 7.7 nm pore.
J. Phys. Chem. Lett., Sep. 2022, [Reviewed] - 〔Major achievements〕Giant Carbon Nano-Test Tubes as Versatile Imaging Vessels for High-Resolution and In Situ Observation of Proteins
Tracy T. Chuong; Toshihiko Ogura; Norihito Hiyoshi; Kazuma Takahashi; Sangho Lee; Keita Hiraga; Hiroki Iwase; Akira Yamaguchi; Kiyoto Kamagata; Eriko Mano; Satoshi Hamakawa; Hirotomo Nishihara; Takashi Kyotani*; Galen D. Stucky; and Tetsuji Itoh, Cryogenic electron microscopy is one of the fastest and most robust methods for capturing high-resolution images of proteins, but stringent sample preparation, imaging conditions, and in situ radiation damage inflicted during data acquisition directly affect the resolution and ability to capture dynamic details, thereby limiting its broader utilization and adoption for protein studies. We addressed these drawbacks by introducing synthesized giant carbon nano-test tubes (GCNTTs) as radiation-insulating materials that lessen the irradiation impact on the protein during data acquisition, physical molecular concentrators that localize the proteins within a nanoscale field of view, and vessels that create a microenvironment for solution-phase imaging. High-resolution electron microscopy images of single and aggregated hemoglobin molecules within GCNTTs in both solid and solution states were acquired. Subsequent scanning transmission electron microscopy, small-angle neutron scattering, and fluorescence studies demonstrated that the GCNTT vessel protected the hemoglobin molecules from electron irradiation-, light-, or heat-induced denaturation. To demonstrate the robustness of GCNTT as an imaging platform that could potentially augment the study of proteins, we demonstrated the robustness of the GCNTT technique to image an alternative protein, d-fructose dehydrogenase, after cyclic voltammetry experiments to review encapsulation and binding insights. Given the simplicity of the material synthesis, sample preparation, and imaging technique, GCNTT is a promising imaging companion for high-resolution, single, and dynamic protein studies under electron microscopy.
ACS Appl. Mater. Interfaces, Jun. 2022, [Reviewed] - Solid-State Photophysical Properties of Chiral Perylene Diimide Derivatives: AIEnh-Circularly Polarized Luminescence from Vacuum-Deposited Thin Films
Aoba Kanesaka; Yuki Nishimura; Akira Yamaguchi; Yoshitane Imai; Toshiko Mizokuro; Hiroyuki Nishikawa
Bull. Chem. Soc. Jpn., May 2022, [Reviewed] - Structural Characterization of Proteins Adsorbed at Nanoporous Materials
Akira Yamaguchi; Masahiro Saiga; Daiki Inaba; Mami Aizawa; Yuta Shibuya; Tetsuji Itoh, Lead, A nanoporous material has been applied for the development of functional nanobiomaterials by utilizing its uniform pore structure and large adsorption capacity. The structure and stability of biomacromolecules, such as peptide, oligonucleotide, and protein, are primary factors to govern the performance of nanobiomaterials, so that their direct characterization methodologies are in progress. In this review, we focus on recent topics in the structural characterization of protein molecules adsorbed at a nanoporous material with uniform meso-sized pores. The thermal stabilities of the adsorbed proteins are also summarized to discuss whether the structure of the adsorbed protein molecules can be stabilized or not., SPRINGERNATURE
Anal. Sci., Jan. 2021, [Reviewed] - In-situ Neutron Reflectometry Study on Adsorption of Glucose Oxidase at Mesoporous Aluminum Oxide Film
Akira Yamaguchi; Kazuya Katayama; Stephen A. Holt, Lead
Anal. Sci., Nov. 2020, [Reviewed] - Differential Scanning Calorimetry Study on the Adsorption of Myoglobin at Mesoporous Silicas: Effects of Solution pH and Pore Size
Akira Yamaguchi; Chiharu Kashimura; Mami Aizawa; Yuuta Shibuya, Lead
ACS Omega, Sep. 2020, [Reviewed] - Continuous mesoporous aluminum oxide film with perpendicularly oriented mesopore channels
Yuuta Shibuya; Kazuya Katayama; Kazuhiro Akutsu-Suyama; Akira Yamaguchi, Corresponding
ACS Omega, 18 Oct. 2019, [Reviewed] - Effect of cavity size of mesoporous silica on type I copper site geometry in Pseudoazurin
Akira Yamaguchi; Yurie Edanami; Takahide Yamaguchi; Yuuta Shibuya; Norihisa Fukaya; and Takamitsu Kohzuma, Lead
Bull. Chem. Soc. Jpn., May 2019, [Reviewed] - Effect of Cavity Size of Mesoporous Silica on Short DNA Duplex Stability
Tsubasa Masuda; Yuuta Shibuya; Shota Arai; Sayaka Kobayashi; Sotaro Suzuki; Jun Kijima; Tetsuji Itoh; Yusuke Sato; Seiichi Nishizawa; Akira Yamaguchi, We studied the stabilities of short (4- and 3-bp) DNA duplexes within silica mesopores modified with a positively charged trimethyl aminopropyl (TMAP) monolayer (BJH pore diameter 1.6-7.4 nm). The DNA fragments with fluorescent dye were introduced into the pores, and their fluorescence resonance energy transfer (FRET) response was measured to estimate the structuring energies of the short DNA duplexes under cryogenic conditions (temperature 233-323 K). The results confirmed the enthalpic stability gain of the duplex within size-matched pores (1.6 and 2.3 nm). The hybridization equilibrium constants found for the size-matched pores were 2 orders of magnitude larger than those for large pores (≥3.5 nm), and this size-matching effect for the enhanced duplex stability was explained by a tight electrostatic interaction between the duplex and the surface TMAP groups. These results indicate the requirement of the precise regulation of mesopore size to ensure the stabilization of hydrogen-bonded supramolecular assemblies., American Chemical Society
Langmuir, 15 May 2018, [Reviewed] - Structural characterization of myoglobin molecules adsorbed within mesoporous silica
Jun Kijima; Yuuta Shibuya; Kazuya Katayama; Tetsuji Itoh; Hiroki Iwase; Yoshiaki Fukushima; Minoru Kubo; Akira Yamaguchi, Corresponding, In the present study, we examined the secondary and tertiary structure of myoglobin (Mb) within folded sheets mesoporous material (FSM)- and Santa Barbara amorphous (SBA)-type mesoporous silicas. The Barrett-Joyner-Halenda pore diameters of SBA-type mesoporous silicas were 39, 70, and 75 angstrom, and that of FSM-type mesoporous silica was 40 angstrom. The secondary and tertiary structures of myoglobin were observed by Fourier transform infrared (FTIR) and small-angle neutron scattering (SANS), respectively. The FTIR and SANS results indicated preservation of the secondary and tertiary structures of myoglobin inside the pores of SBA-type mesoporous silicas. Adsorption of myoglobin within FSM-type mesoporous silica, however, resulted in perturbation of the tertiary structure, accompanied by partial unfolding of the secondary structure. Lower structural stability of myoglobin within the FSM-type mesoporous silica was also confirmed. These findings suggest that the Mb structure is more influenced by the inner pore surface characteristics than by geometrical pore size., AMER CHEMICAL SOC
J. Phys. Chem. C, 2018, [Reviewed] - Characterization of Myoglobin Adsorption into Mesoporous Silica Pores by Differential Scanning Calorimetry
Akira Yamaguchi; Kazuhiro Taki; Jun Kijima; Yurie Edanami; Yuuta Shibuya, Lead
Anal. Sci., 2018, [Reviewed] - High-performance bioelectrocatalysts created by immobilization of an enzyme into carbon-coated composite membranes with nano-tailored structures
Tetsuji Itoh; Yuuta Shibuya; Akira Yamaguchi; Yasuto Hoshikawa; Osamu Tanaike; Tatsuo Tsunoda; Taka-aki Hanaoka; Satoshi Hamakawa; Fujio Mizukami; Akari Hayashi; Takashi Kyotani; Galen D. Stucky, A large (40 mm phi) composite membrane with mesoporous silica nanotubes (F127MST) was coated with a thin carbon layer (1-2 graphene sheets) by carrying out chemical vapor deposition (CVD) using acetylene, and the obtained carbon-coated F127MST (C/F127MST) was used directly as an electrode. After evaluating the electrical conductivity inside the continuous mesopore network, the enzyme bilirubin oxidase (BOD) was loaded into the mesopores of C/F127MST to form BOD-C/F127MST. Indeed, this loading procedure was effective and achieved direct electron transfer between the enzymes and electrodes. The loading also was found to enhance the stability of stored BOD (it was stable for 15 days) and could be used to control the enzymatic reaction by varying the electric potential. We therefore consider BOD-C/F127MST to be a promising candidate as an effective bioelectrode in various fields., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY A, Oct. 2017, [Reviewed] - Probing structure-function relationships in early events in photosynthesis using a chimeric photocomplex
Kenji V. P. Nagashima; Mai Sasaki; Kanako Hashimoto; Shinichi Takaichi; Sakiko Nagashima; Long-Jiang Yu; Yuto Abe; Kenta Gotou; Tomoaki Kawakami; Mizuki Takenouchi; Yuuta Shibuya; Akira Yamaguchi; Takashi Ohno; Jian-Ren Shen; Kazuhito Inoue; Michael T. Madigan; Yukihiro Kimura; Zheng-Yu Wang-Otomo, The native core light-harvesting complex (LH1) from the thermophilic purple phototrophic bacterium Thermochromatium tepidum requires Ca2+ for its thermal stability and characteristic absorption maximum at 915 nm. To explore the role of specific amino acid residues of the LH1 polypeptides in Ca-binding behavior, we constructed a genetic system for heterologously expressing the Tch. tepidum LH1 complex in an engineered Rhodobacter sphaeroides mutant strain. This system contained a chimeric pufBALM gene cluster (pufBA from Tch. tepidum and pufLM from Rba. sphaeroides) and was subsequently deployed for introducing site-directed mutations on the LH1 polypeptides. All mutant strains were capable of phototrophic (anoxic/light) growth. The heterologously expressed Tch. tepidum wild-type LH1 complex was isolated in a reaction center (RC)-associated form and displayed the characteristic absorption properties of this thermophilic phototroph. Spheroidene (the major carotenoid in Rba. sphaeroides) was incorporated into the Tch. tepidum LH1 complex in place of its native spirilloxanthins with one carotenoid molecule present per alpha beta-subunit. The hybrid LH1-RC complexes expressed in Rba. sphaeroides were characterized using absorption, fluorescence excitation, and resonance Raman spectroscopy. Site-specific mutagenesis combined with spectroscopic measurements revealed that alpha-D49, beta-L46, and a deletion at position 43 of the alpha-polypeptide play critical roles in Ca binding in the Tch. tepidum LH1 complex; in contrast, alpha-N50 does not participate in Ca2+ coordination. These findings build on recent structural data obtained from a high-resolution crystallographic structure of the membrane integrated Tch. tepidum LH1-RC complex and have unambiguously identified the location of Ca2+ within this key antenna complex., NATL ACAD SCIENCES
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Oct. 2017, [Reviewed] - Nanoporous Waveguide Spectroscopy for the Estimation of Enzyme Adsorption on Mesoporous Silica
Hiroyuki Arafune; Kazuhiro Hotta; Tetsuji Itoh; Norio Teramae; Akira Yamaguchi, Mesoporous silica is considered as promising host material for enzymes due to its uniform pore size of enzyme dimensions and tunable surface chemical properties. In this study, we applied nanoporous waveguide (NPWG) spectroscopy to observe adsorption dynamics of heme proteins with different molecular size within mesoporous silica film modified with different surface functional groups. Since NPWG spectroscopy provides kinetic information and rough quantification of adsorption amount, it is useful to study the adsorption process of enzymes within inorganic nanoporous materials., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, Apr. 2017, [Reviewed] - Stability of Hairpin Structure of (CCG)(4) Trinucleotide Repeats inside Amine-functionalized Silica Mesopores
Akira Yamaguchi; Kazuyoshi Nasu; Naruki Wakaume; Yuuta Shibuya; Jun Kijima; Tetsuji Itoh, Thermal stabilities of the hairpin structure of (CCG)(4) trinucleotide repeats were examined in a bulk aqueous solution and inside amine-functionalized silica mesopores (pore diameters: 3.5 and 5.7 nm). The results confirmed that the denaturation temperatures of (CCG)(4) hairpin within TMAP-MPSs were about 10 degrees C lower than those in bulk water. On the basis of enthalpy-entropy compensation, enthalpy change upon denaturation (Delta H) inside the pore was estimated to be 0.8 kcal mol(-1) lower than that for the bulk system., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Dec. 2016, [Reviewed] - Thermodynamics of Complexation between Thiourea-based Receptor and Acetate in Water/Acetonitrile Mixture
Takaya Suzuki; Yuuta Shibuya; Takaya Sato; Seiichi Nishizawa; Itaru Sato; Akira Yamaguchi, A thiourea-based receptor has been extensively studied for selective anion recognition for reasons of its strong hydrogen bond donor ability. In the present study, the thermodynamics of complexation between a thiourea-based receptor and acetate was examined in a water/acetonitrile mixture. The receptor used in this study was N,N'-bis(p-nitrophenyl)thiourea (BNPTU). UV/vis spectroscopic titration and isothermal titration calorimetry (ITC) experiments clearly revealed endothermic and entropy-driven complexation of BNPTU with acetate in water/acetonitrile mixtures. Since the endothermic peaks found in water/acetonitrile mixtures were about three times greater than those in acetonitrile, it appears that preferential hydration of both receptor and acetate was responsible for the endothermic and entropy-driven complexation reaction. The thermodynamic properties found in this study have the potential to contribute to the design of a thiourea-based anion receptor., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, Jul. 2016, [Reviewed] - Collimated microfiber spectroscopy for optical characterization of disordered porous anodic alumina
Yoneda Satoshi; Kimura Saho; Yamaguchi Akira; Kimura Daiki; Ohkoshi Yutaka; Yamanaka Shigeru; Usami Hisanao, Satoshi Yoneda, Saho Kimura, Akira Yamaguchi, Daiki Kimura, Yutaka Ohkoshi, Shigeru Yamanaka, and Hisanao Usami, Institute of Physics
Appl. Phys. Express, 21 Jan. 2016 - Structural stability of light-harvesting protein LH2 adsorbed on mesoporous silica support
Yuuta Shibuya; Tetsuji Itoh; Shun-ichi Matsuura; Akira Yamaguchi, Corresponding, In the present study, we examined the reversible thermal deformation of the membrane protein light-harvesting complex LH2 adsorbed on mesoporous silica (MPS) supports. The LH2 complex from Thermochromatium tepidum cells was conjugated to MPS supports with a series of pore diameter (2.4 to 10.6 nm), and absorption spectra of the resulting LH2/MPS conjugates were observed over a temperature range of 273 - 313 K in order to examine the structure of the LH2 adsorbed on the MPS support. The experimental results confirmed that a slight ellipsoidal deformation of LH2 was induced by adsorption on the MPS supports. On the other hand, the structural stability of LH2 was not perturbed by the adsorption. Since the pore diameter of MPS support did not influence the structural stability of LH2, it could be considered that the spatial confinement of LH2 in size-matches pore did not improve the structural stability of LH2., JAPAN SOC ANALYTICAL CHEMISTRY
Anal. Sci., 2015 - Electrochemical enzymatic biosensor with longterm stability using hybrid mesoporous membrane
Tetsuji Itoh; Takeshi Shimomura; Akari Hayashi; Akira Yamaguchi; Norio Teramae; Masatoshi Ono; Tatuo Tsunoda; Fukio Mizukami Galen D. Stucky; Taka-aki Hanaoka, An acetylcholinesterase-immobilized sensor unit was successfully prepared by encapsulating the enzyme within hybrid mesoporous silica membranes (F127-MST). Through a novel combination with tetracyanoquinodimethane, both acetylcholine and organophosphorus pesticides were successfully detected with high sensitivity. Furthermore, we manufactured the working prototype of an enzyme sensor with this sensor unit for detecting dichlorvos, aldicarb and parathion. At present, the detection limit in this working prototype either equaled or surpassed that of others. Also, we have the advantage of increased stability of the enzyme against the outer environment by encapsulation of the enzymes into a silica nanospace. Consequently, acetylcholinesterase immobilized in F127-MST is a practical sensor with high sensitivity, reusability, and storage stability., ROYAL SOC CHEMISTRY
Analyst, 2014 - Highly sensitive real-time detection of DNA hybridization by using nanoporous waveguide fluorescence spectroscopy
Yong Fan; Kazuhiro Hotta; Akira Yamaguchi; Yu Ding; Yonghong He; Norio Teramae; Shuqing Sun; Hui Ma, In this Letter, we report highly sensitive fluorescence spectroscopy using a nanoporous waveguide (NPWG) comprising a porous anodic alumina (PAA) layer and an Al layer. Simulations show that the TE0 waveguide mode excited in the PAA layer produces an electromagnetic field whose intensity is 40-fold higher than that of the incident light, and which yields enhanced intensity when used to excite fluorophores. We demonstrate the sensing ability of the NPWG by incorporating it into a fluorescent sensor to monitor duplex DNA formation in real-time, with a detection limit as low as 20 pM. (C) 2014 AIP Publishing LLC., AMER INST PHYSICS
Appl. Phys. Lett., 2014 - Trinucleotide duplex formation inside a confined nanospace under supercooled conditions
Hiroyuki Arafune; Akira Yamaguchi; Manato Namekawa; Yusuke Sato; Tetsuji Itoh; Ryoko Yoshida; Norio Teramae, Corresponding, Self-assembly of nucleotides of fewer than three base pairs is often found in protein-nucleotide conjugations, despite their energetic instability, and is regarded as the potential starting point for the creation of artificial hydrogen-bonded supramolecular complexes. Here we report duplex formation of 3-mer DNA fragments confined within silica mesopores modified with a positively charged trimethyl aminopropyl monolayer, and their further stabilization under supercooled conditions (T<273 K). We load 3-mer DNA fragments with donor-or acceptor-dye into modified silica mesopores and examine their hybridization behaviours using FRET measurements. The FRET results clearly reveal that efficient duplex formation through at least two A-T base pairs can be achieved at 233 K. Enthalpy changes for duplex formation are found to be nearly equal between complementary and single-mismatched 3-mer DNA duplexes. These results confirm confined mesoscale cavities to be a novel low-temperature reaction space for hydrogen-bonded supramolecular complexes., NATURE PUBLISHING GROUP
Nature Commun., 2014 - Encapsulation of PEG-modified Myoglobin in Hydrophobic Mesoporous Silica as Studied by Optical Waveguide Spectroscopy
Hiroyuki Arafune; Akira Yamaguchi; Kazuhiro Hotta; Tetsuji Itoh; Norio Teramae, The purpose of this study is to apply optical waveguide (OWG) spectroscopy to characterize the encapsulation behavior of enzymes modified with polyethylene glycol (PEG), i.e. pegylation, in a hydrophobic mesoporous silica film. For that purpose, pegylated myoglobin (PEG-Mb) was introduced into the silica mesopores modified with octadecylsilyl (ODS) groups and studied by OWG spectroscopy. OWG spectroscopy confirmed that the hydrophobic interaction between the PEG group and the surface ODS group promoted the encapsulation of PEG-Mb into the hydrophobic silica mesopores. The surface density of ODS affected the adsorbed amount of PEG-Mb and the higher surface density of the ODS group resulted in the suppression of adsorption and diffusion of PEG-Mb inside the pore. Since the desorption rate of PEG-Mb was found to be much slower than the adsorption rate, the pegylation of an enzyme could be effective for the enzyme encapsulation into the hydrophobic mesoporous silica host., JAPAN SOC ANALYTICAL CHEMISTRY
Anal. Sci., 2013, [Reviewed] - Inclusion Complexation of γ-Cyclodextrin and Coumarin Dye inside Alumina Nanopores Over a Temperature Range of 303 - 223 K
Akira Yamaguchi; Tetsuya Denda, Corresponding, In the present study, we aimed to demonstrate that complexation reactions inside an inorganic water-filled nanopore can be enhanced at below the homogeneous nucleation temperature of bulk water (273 K). Using fluorescence experiments, we examined the inclusion complexation of propylamide coumarin 343 (PAC343) with gamma-cyclodextrin (gamma-CD) inside cylindrical alumina nanopores over a temperature range of 303-233 K. A PAC343-immobilized porous anodic alumina membrane (PAC343-PAA) with a pore diameter of ca. 70 mm was fabricated, and its fluorescence spectra were measured after introduction of 240 aqueous gamma-CD solution into the alumina nanopores. Our results confirmed that the inclusion complexation reaction was gradually enhanced with decreasing temperature, particularly at temperatures between 273 and 233 K. The inclusion complexation reaction was confirmed to be exothermic from van't Hoff analysis of adsorption constants of gamma-CD obtained at temperatures between 288 and 283 K. These results confirm low-temperature (T < 273 K) conditions to be useful for enhancing exothermic complexation reactions that occur inside alumina nanopores filled with, AMER CHEMICAL SOC
J. Phys. Chem. C, 2013, [Reviewed] - Alumina Plate Containing Photosystem I Reaction Center Complex Oriented inside Plate-Penetrating Silica Nanopores
Chihiro Kamidaki; Toru Kondo; Tomoyasu Noji; Tetsuji Itoh; Akira Yamaguchi; Shigeru Itoh, The photosynthetic photosystem I reaction center complex (PSI-RC), which has a molecular diameter of 21 nm with 100 pigments, was incorporated into silica nanopores with a 100-nm diameter that penetrates an alumina plate of 60-mu m thickness to make up an inorganic-biological hybrid photocell. PSI-RCs, purified from a thermophilic cyanobacterium, were stable inside the nanopores and rapidly photoreduced a mediator dye methyl viologen. The reduced dye was more stable inside nanopores suggesting the decrease of dissolved oxygen. The analysis by a cryogenic electron spin paramagnetic resonance indicated the oriented arrangement of RCs inside the 100-nm nanopores, with their surface parallel to the silica wall and perpendicular to the plane of the alumina plate. PSI RC complex in the semicrystalline orientation inside silica nanopores can be a new type of light energy conversion unit to supply strong reducing power selectively to other molecules inside or outside nanopores., AMER CHEMICAL SOC
J. Phys. Chem. B, 2013, [Reviewed] - Nanoporous Waveguide Sensor with Optimized Nanoarchitectures for Highly Sensitive Label-Free Biosensing",ACS Nano,
Kazuhiro Hotta; Akira Yamaguchi; Norio Teramae, Label-free optical biosensors have attracted much attention, and nanoporous metal-oxide membranes with uniform pore structure and diameter are promising candidates for platforms of label-free optical biosensors. However, development of such sensors with high sensitivity still remains challenging. In this paper, we report on the remarkably enhanced sensitivity of a label-free nanoporous optical waveguide (NPWG) sensor composed of a porous anodic alumina (PAA) waveguiding film and an aluminum cladding film. The enhanced sensitivity was achieved by engineering nanostructures and tuning optical properties of the PAA film. Careful tuning of the porosity, pore density, thickness, and refractive index of the PAA film could significantly improve the sensitivity of the NPWG sensor toward adsorption of bovine serum albumin (BSA) onto the PAA surface, and the optimized sensor responded to the adsorption of BSA with an extraordinarily large red shift (>300 nm) of a waveguide mode due to the large adsorption capacity of the PAA film and the inherently high sensitivity of the waveguide mode. The Fresnel calculations suggested that the potential sensitivity of the NPWG sensor was much higher than that of the conventional surface plasmon resonance (SPR) sensors., AMER CHEMICAL SOC
ACS Nano, 2012, [Reviewed] - Enhanced fluorescence in a nanoporous waveguide and its quantitative analysis
Yong Fan; Kazuhiro Hotta; Akira Yamaguchi; Norio Teramae, Fluorescence behavior was examined for fluorophore-labeled protein (BSA-AF) adsorbed on the nanopore surface of a nanoporous waveguiding film. The waveguiding film has a bilayer structure of a porous anodic alumina (PAA) layer on a metallic aluminum (Al) layer, and this structure allows efficient interaction of fluorophores entrapped in the nanoporous waveguiding film with a hotspot of the enhanced electromagnetic field of the waveguide modes. Fluorescence response of BSA-AF depends on the enhanced field within the waveguiding film and the enlarged adsorbed amount in the PAA layer where most of the light is confined. Enhancement of the field in the waveguiding film can be controlled by the refractive index of the PAA layer and enlargement of the pore size efficiently affects the enhancement of the fluorescence response. Compared to the film without a PAA layer, the PAA/Al film exhibits more than 140-fold larger fluorescence response due to the large adsorption capacity of the PAA nanopores and the enhanced field formed by the waveguide modes in the PAA layer with a low refractive index. (c) 2012 Optical Society of America, OPTICAL SOC AMER
Opt. Exp., 2012, [Reviewed] - Microviscosity of supercooled water confined within aminopropyl-modified mesoporous silica as studied by time-resolved fluorescence spectroscopy
Akira Yamaguchi; Manato Namekawa; Tetsuji Itoh; Norio Teramae, Lead, The fluorescence dynamics of rhodamine B (RhB) immobilized on the pore surface of aminopropyl (AP)-modified mesoporous silica (diameter of the silica framework, 3.1 nm) was examined at temperatures between 293 and 193 K to study the microviscosity of supercooled water confined inside the pores. The mesoporous silica specimen with a dense AP layer (2.1 molecules nm(-2)) was prepared, and RhB isothiocyanate was covalently bound to part of the surface AP groups. The fluorescence lifetime of the surface RhB increased with decreasing temperature from 293 to 223 K, indicating that freezing of the confined water did not occur in this temperature range. The microviscosity of the supercooled confined water was evaluated from an analysis of the lifetime data based on a frequency-dependent friction model., JAPAN SOC ANALYTICAL CHEMISTRY
Anal. Sci., 2012, [Reviewed] - Deposition of Polyelectrolyte Multilayer Film on a Nanoporous Alumina Membrane for Stable Label-Free Optical Biosensing
Kazuhiro Hotta; Akira Yamaguchi; Norio Teramae, Corresponding, The stabilization of inorganic nanostructures is a key challenge in developing label-free optical biosensors using inorganic nanoporous films. In the present study, a polyelectrolyte multilayer film (PMF) composed of poly(acrylic acid) and poly(allylamine hydrochloride) was deposited on porous anodic alumina (PAA) film (pore diameter = 40 nm) by the layer-by-layer technique. The characteristics of the PMF as a protective coating layer against dissolution of the PAA film were examined by means of in situ optical waveguide spectroscopy (OWS), ex situ scanning electron microscope/energy-dispersive spectroscopy (SEM/EDS), and infrared reflection-adsorption spectroscopy (IR-RAS). The results obtained by OWS and SEM/EDS indicated the formation of PMF at both the alumina pore surface and the PAA film surfaces. Processing the PMF-deposited PAA (PMF-PAA) film at 180 degrees C to promote thermal cross-linking allowed PMF to act as a strong protective coating layer in aqueous buffer solutions (pH 2.5-8.7) but also in common alumina matrix etchant. Residual amino groups in the cross-linked PMF could also be used to conjugate single-probe DNA at the PMF-PAA film for OWS-based DNA-DNA hybridization assay. From the results obtained in this study, it was concluded that the deposition of PMF followed by thermal cross-linking is potentially useful not only as a protective coating and but also for immobilizing biorecognition elements in the PAA film., AMER CHEMICAL SOC
J. Phys. Chem. C, 2012, [Reviewed] - Transparent nanoporous tin-oxide film electrode fabricated by anodization
Akira Yamaguchi; Teruhiko Iimura; Kazuhiro Hotta; Norio Teramae, A transparent nanoporous tin oxide film electrode was fabricated by anodizing a tin film on a fluorine-doped tin oxide (FTO) film electrode. The resulting anodized nanoporous tin oxide (ANPTO) film has columnar-type pore channels with around 50 nm in diameter and is optically transparent. Electrochemical measurements with Fe(CN)(6)(3-) as a redox probe clearly revealed that the ANPTO film could be used for a working electrode with a large internal surface area. Moreover, it was found that ANPTO film had a wider anodic potential window (> ca. 2.0 V) than conventional metal oxide electrodes, such as FTO and indium tin oxide film electrodes (> ca. 1.3 V). The wide anodic potential window improves applicability of a transparent metal oxide electrode for various electrochemical oxidation reactions, which are often interfered by oxygen evolution in water. These results conclude that the ANPTO film can be used as an advanced transparent nanoporous film electrode. (C) 2010 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
THIN SOLID FILMS, Feb. 2011 - Acid-Base Equilibria inside Amine-Functionalized Mesoporous Silica
Akira Yamaguchi; Manato Namekawa; Toshio Kamijo; Tetsuji Itoh; Norio Teramae, Lead, Acid-base equilibria and effective proton concentration inside a silica mesopore modified with a trimethyl ammonium (TMAP) layer were studied by steady-state fluorescence experiments. The mesoporous silica with a dense TMAP layer (1.4 molecules/nm(2)) was prepared by a post grafting of N-trimethoxysilylpropyl-N,N,N-trimethylammonium at surfactant-templated mesoporous silica (diameter of silica framework =3.1 nm). The resulting TMAP-modified mesoporous silica strongly adsorbed of anionic fluorescence indicator dyes (8-hydroxypyrene-1,3,6-trisulfonate (pyranine), 8-aminopyrene-1,3,6-trisulfonate (APTS), 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid disulfuric acid (TPPS), 2-naphthol-3,6-disulfonate (2NT)) and fluorescence excitation spectra of these dyes within TMAP-modified mesoporous silica were measured by varying the solution pH. The fluorescence experiments revealed that the acid-base equilibrium reactions of all pH indicator dyes within the TMAP-modified silica mesopore were quite different from those in bulk water. From the analysis of the acid-base equilibrium of pyranine, the following relationships between solution pH (pH(bulk)) and the effective proton concentration inside the pore (pH(pore)) were obtained: (1) shift of pH(pore) was 1.8 (Delta pH(pore) = 1.8) for the pH(bulk) change from 2.1 to 9.1 (Delta pH(bulk) = 7.0); (2) PHpore was not simply proportional to pH(bulk); (3) the inside of the TMAP-modified silica mesopore was suggested to be in a weak acidic or neutral condition when pH(bulk) was changed from 2.0 to 9.1. Since these relationships between pH(bulk) and pH(pore) could explain the acid-base equilibria of other pH indicator dyes (APTS, TPPS, 2NT), these relationships were inferred to describe the effective proton concentration inside the TMAP-modified silica mesopore., AMER CHEMICAL SOC
Anal. Chem., 2011 - Functionalization of mesoporous silica membrane with a Schiff-base fluorophore for Cu(II) ion sensing
Xiaotong Chen; Teramae Norio; Akira Yamaguchi; Manato Namekawa; Toshio Kamijo; Aijun Tong, A Schiff base (SB) immobilized hybrid mesoporous silica membrane (SB-HMM) was prepared by immobilizing a Schiff base onto the pore surface of mesoporous silica (pore size = 3.1 nm) embedded in the pores of a porous anodic alumina membrane. In contrast to the non-fluorescent analogous SB molecule in homogeneous solutions, SB-HMM exhibited intense fluorescence due to emission enhancement caused by aggregation of SB groups on the pore surface. The high quantum efficiency of the surface SB groups allows SB-HMM to function as a fluorescent sensor for Cu(II) ions in an aqueous solution with good sensitivity, selectivity and reproducibility. Under the optimal conditions described, the linear ranges of fluorescence intensity for Cu(II) are 1.2-13.8 (M (R(2) = 0.993) and 19.4-60 (R(2) = 0.992) (M. The limit of detection for Cu(II) is 0.8 mu M on basis of the definition by IUPAC (C(LOD) = 3.3S(b)/m). (C) 2011 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Anal. Chim. Acta, 2011 - Mesoporous Silica Hybrid Membranes for Precise Size-Exclusive Separation of Silver Nanoparticles
Moataz M. Mekawy; Akira Yamaguchi; Sherif A. El-Safty; Tetsuji Itoh; Norio Teramae, One-dimensional (1D) nanomaterials have unique applications due to their inherent physical properties. In this study, hexagonally ordered mesoporous silica hybrid anodic alumina membranes (AAM) were synthesized using template-guided synthesis with a number of nonionic n-alkyl-oligo(ethylene oxide), Brij-type (CxEOy), which are surfactants that have different molecular sizes and characteristics. The hexagonal mesoporous silicas are vertically aligned in the AAM channels with a predominantly columnar orientation. The hollow mesostructured silicas had tunable pore diameters varying from 3.7 to 5.1 nm. In this synthesis protocol, the surfactant molecular natures (corona/core features) are important for the controlled generation of ordered structures throughout MM channels. The development of ultrafiltration membranes composed of silica mesostructures could be used effectively in separating silver nanopartides (Ag NPs) in both aqueous and organic solution phases. This would be relevant to the production of well-defined Ag NPs with unique properties. To create a size-exclusive separation system of Ag NPs, we grafted hydrophobic trimethylsilyl (TMS) groups onto the inner pores of the mesoporous silica hybrid MM. The immobilization of the TMS groups allowed the columnar mesoporous silica inside MM to retain this inner pore order without distortion during the separation of solution-phase Ag NPs in organic solvents that may cause tortuous-pore membranes. Mesoporous TMS-silicas inside 1D MM channels were applicable as a size-exclusive separation system to isolate organic solution-phase Ag NPs of uniform morphology and size. (C) 2010 Elsevier Inc. All rights reserved., ACADEMIC PRESS INC ELSEVIER SCIENCE
J. Colloid Interface Sci., 2011 - Grafting of phenylboronic acid on a glassy carbon electrode and its application as a reagentless glucose sensor
Kotaro Morita; Naoki Hirayama; Hisanori Imura; Akira Yamaguchi; Norio Teramae, Phenylboronic acid (PBA) was covalently grafted to the surface of glassy carbon (GC) electrodes using electrochemical reduction of in situ generated diazonium cation. The grafting of GC surfaces was controlled by varying both the concentration of precursor 3-aminophenylboronic acid and the number of potential cycling during the grafting procedure. Cyclic voltammetry (CV) and eletrochemical impedance spectroscopy (EIS) were used to confirm the grafting of the PBA group to the GC surface and formation of multilayer. The barrier properties of the grafted GC electrodes were studied in the presence of a redox probe such as Fe(CN)(6)(3-/4-) by CV. Additionally, the resultant PBA multilayer on the GC electrode was applied for glucose detection utilizing the EIS technique in the presence of a redox probe molecule. Then, the complexation ability of the grafted layers with glucose was also confirmed as an increase of total impedance at non-faradic EIS measurement. (C) 2010 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
J. Electroanal. Chem., 2011 - Assembly of an Artificial Biomembrane by Encapsulation of an Enzyme, formaldehyde dehydrogenase, into the Nanoporous-Walled Silica Nanotube-Inorganic Composite Membrane
Tetsuji Itoh; Takeshi Shimomura; Yasuhisa Hasegawa; Junko Mizuguchi; Taka-aki; Hanaoka; Akari Hayashi; Akira Yamaguchi; Norio Teramae; Masatoshi Ono; Fujio Mizukami, We prepared silica nanotube with nanochannel-wall in the columnar pores of a commercial anodic alumina membrane (F127-MST), and then made up an artificial biomembrane consisting of a hierarchical structure by introducing an enzyme, formaldehyde dehydrogenase, into the silica nanochannels. The formaldehyde dehydrogenase confined in membrane showed a very high activity for the reduction of NAD(+) similar to that of the native, besides much higher electron transfer to the electrode than the native. At the same time, we clarified that the encapsulation of enzymes into the nanochannels enables enzymes to accumulate in high density without aggregation and be arranged regularly. These results indicate that F127-MST can provide a favorable method for enzyme immobilization on the electrode., ROYAL SOC CHEMISTRY
J. Mater. Chem., 2011 - Adsorption and Desorption Dynamics of Sodium Dodecyl Sulfate at the Octadecylsilane Layer on the Pore Surface of a Mesoporous Silica Film Observed In-situ by Optical Waveguide Spectroscopy
Akira Yamaguchi; Hiroyuki Arafune; Kazuhiro Hotta; Tetsuji Itoh; Norio Teramae, Lead, The purpose of this study is to apply optical waveguide (OWG) spectroscopy to observe adsorption and desorption dynamics occurring in a surfactant-templated mesoporous silica film. For that purpose, a mesoporous silica (MS) film with open accessible pores (pore diameter, ca. 6 nm) was formed on an aluminum (Al) layer deposited on a glass substrate, and the pore surface of the MS film was modified with octadecylsilane (ODS). The resulting ODS-modified MS (ODS-MS) and Al multilayer film showed a clear waveguide coupling dip in the reflection spectrum. The position of the waveguide coupling dip was red-shifted as the amount of sodium dodecyl sulfate within the ODS-MS layer increases. These results indicate the usefulness of OWG spectroscopy for the study of adsorption/desorption dynamics occurring in MS materials., JAPAN SOC ANALYTICAL CHEMISTRY
Anal. Sci., 2011, [Reviewed] - Mesoporous Materials toward Nanofabricator and Nanoreactor
Ichizo Yagi; Akari Hayashi; Ken'ichi Kimijima; Hideo Notsu; Narumi Ohta; Akira Yamaguchi, Construction of nanomaterials has been developed from both top-down and bottom-up approaches. In these approaches, surfactant-templated mesoporous materials are promising because of their tunability, uniformity and reproducibility in both the size and shape of produced mesopores. Mesoporous silica materials have been widely and deeply investigated in the early stage, basing on the sol-gel chemistry of silicate. Although insulating mesoporous silica cannot be directly applicable to electrode materials, the mesoporous silica films and their hybrid films are recently applied as hard templates and electrodeposition of metals inside the mesopores realizes the formation of metal nanowire assembly, which has parallel orientation to the electrode surface. Furthermore, the mesoporous silica film with perpendicularly oriented mesochannels are prepared and used as hard-template, resulting in the fabrication of metal nanowire assembly standing on the electrode surface. On the other hand, conductive materials are recently fabricated as mesoporous structure by the surfactant-template method. Mesoporous carbon becomes the most conventional mesoporous conductive material and has been investigated as the electrode material mainly applicable to energy conversion. By introducing catalyst particles and ionomers inside mesochannels, triple phase boundary can be constructed and the application toward cathode electrode in the polymer electrolyte fuel cell (PEFC) has been investigated., ELECTROCHEMICAL SOC JAPAN
ELECTROCHEMISTRY, Feb. 2010, [Reviewed] - Properties of A Metal Clad Waveguide Sensor Based on A Nanoporous/Metal Multilayer Film
Kazuhiro Hotta; Akira Yamaguchi; Norio Teramae, A metal-clad waveguide (MCWG) sensor comprised of a nanoporous waveguiding layer on a metal cladding layer is advantageous in sensing of biomolecules because of a high surface area of nanopores and a sharp dip in the reflection spectrum due to characteristics of the MCWG mode. Here, a porous anodic alumina (PAA)/aluminum (Al) film was fabricated on a glass substrate as a MCWG sensor with the Kretschmann geometry, and the sensor response was examined for both colorless bovine serum albumin (BSA) and colored metal complexes by measurements of reflection spectra and Fresnel calculations. The BSA adsorption on the PAA layer induced a parallel redshift of the waveguide coupling dip in the reflection spectrum. The experimental results were well simulated by the five-phase Fresnel calculations which indicated that the redshift of the dip was linearly dependent on the adsorbed amount of BSA. When the response of a MCWG sensor with a PAA layer was compared with that of a MCWG sensor with a nonporous alumina layer, the former showed larger redshift than the latter, due to a large adsorbed amount of BSA in the PAA layer with high surface area. For the adsorption of colored Ru[Bphen(3)](2+) and Fe[Phen(3)](2+), the effect of both the real and imaginary parts of the complex refractive index on the sensor response was examined. As a result, a redshift of the waveguide coupling dip was observed for both metal complexes irrespective of the wavelength region examined; this could be ascribed to the changes in the real part of the refractive index due to the adsorption of metal complexes on the PAA layer. Meanwhile, an increase in the reflectivity was observed when the coupling wavelength was close to that of the absorption bands of the metal complexes; this could be ascribed to the changes in the imaginary part of the refractive index of the PAA layer. Using the sensor response caused by the changes in the imaginary part, absorption spectral profiles of metal complexes could be reproduced., AMER CHEMICAL SOC
Anal. Chem., 2010 - Organic-Inorganic Mesoporous Silica Nanostrands for Ultrafine Filtration of Spherical Nanoparticles
Sherif A. El-Safty; Moataz Mekawy; Akira Yamaguchi; Ahmed Shahat; Kazuyuki Ogawa; Norio Teramae, We report a protocol for the direct synthesis of hexagonal silica nanostrands inside anodic alumina membranes using cationic surfactants as templates. When coated with layers of trimethylsilyl moieties, the nanostrands were a powerful tool for the ultrafine filtration of noble metal and semiconductor nanoparticles., ROYAL SOC CHEMISTRY
Chem. Commun., 2010 - Characterization of the Inner Space of Mesostructured Silica by Time-Resolved Fluorescence Spectroscopy
Akira Yamaguchi; Toshio Kamijo; Norio Teramae, Time-resolved fluorescence spectroscopy using coumarin dyes as a fluorescent probe provides information on solvation dynamics in the vicinity of the coumarin dyes. In the present study, solvation dynamics occurred inside mesostructured silica With a uniform silica-mesopore diameter was examined by using four kinds of coumarin dyes as a fluorescent probe. In the silica-CTAB nanocomposite composed of CTAB (cetyl trim ethylammonium bromide) micelles and silica-mesopores (pore diameter : 3.4 nm), it was found that coumarin dyes with different functional groups were located at different regions and that the Molecular motions were differently constrained depending on the location of the coumarin dyes. In the silica-mesopores (pore diameter: 3.1 nm) filled with alcohol solvents, relatively small alcohols (ethanol and butanol) exhibited slow solvent relaxation process due to their confinment in the silica-mesopore, whereas such slow relaxation process was not recognized for large alcohols (hexanol and decanol)., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, Jun. 2009, [Reviewed] - Separation of adenine, adenosine-5 '-monophosphate and adenosine-5 '-triphosphate by fluidic chip with nanometre-order diameter columns inside porous anodic alumina using an aqueous mobile phase
Tomohisa Yamashita; Shuji Kodama; Tomoko Kemmei; Mikiya Ohto; Eriko Nakayama; Tatsuya Muramoto; Akira Yamaguchi; Norio Teramae; Nobutaka Takayanagi, Adenine, adenosine-5'-monophosphate and adenosine-5'-triphosphate were separated by fluidic chip with PAA membranes using an aqueous mobile phase., ROYAL SOC CHEMISTRY
LAB ON A CHIP, May 2009, [Reviewed] - Encapsulation of catalase into nanochannels of an inorganic composite membrane
Tetsuji Itoh; Ryo Ishii; Takaaki Hanaoka; Yasuhisa Hasegawa; Junko Mizuguchi; Toru Shiomi; Takeshi Shimomura; Akira Yamaguchi; Hideaki Kaneda; Norio Teramae; Fujio Mizukami, Enzymes, especially those known as membrane proteins existing in plasma membranes, direct important and complicated reactions in living bodies. Thus, attempts have been made to extract such enzymes from living bodies, and immobilize and accumulate them on supports to effectively use their functions for catalysis [M. Hartmann, Chem. Mater. 17 (2005) 4577-4593]. However, enzymes extracted from living bodies tend to aggregate in the absence of detergents or at high concentrations, resulting in a loss of their activities [Y. Urabe, T. Shiomi, T. Itoh, A. Kawai, T. Tsunoda, F. Mizukami, K. Sakaguchi, ChemBioChem 8 (2007) 668-674]. We have, however, succeeded in assembling a highly durable membrane capable of high-density accumulation and providing a regular array of catalase by encapsulating it in mesoporous silica synthesized in the pores of an alumina membrane. The artificial biomembrane showed not only activity similar to that of the native catalase for the decomposition of H(2)O(2) but also much higher stability; the catalase immobilized in the membrane still retained its original activity even after being employed 160 times in decomposing H(2)O(2), whereas the native lost its activity after 40 cycles. (C) 2008 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC, May 2009, [Reviewed] - Solvation dynamics of a surfactant probe in mesostructured silica-surfactant nanocomposites
A. Paul; M. Sarkar; D. C. Khara; T. Kamijo; A. Yamaguchi; N. Teramae; A. Samanta, Steady-state and time-resolved fluorescence behavior of a 4-aminophthalimide-based surfactant probe has been studied in a mesostructured silica-surfactant nanocomposite. While the steady-state measurements indicate the location of the probe in the nanocomposite, the time-resolved study reveals the distinctive features of the solvation dynamics of the probe. Comparison of the present dynamical data with those reported for the parent. uorophore in other organized assemblies suggests the involvement of constrained water molecules near the ionic interface in the observed dynamics. (C) 2008 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
CHEMICAL PHYSICS LETTERS, Feb. 2009, [Reviewed] - Characterization of the inner space of mesostructured silica by time-resolved fluorescence spectroscopy
Akira Yamaguchi; Toshio Kamijo; Norio Teramae, Lead, Time-resolved fluorescence spectroscopy using coumarin dyes as a fluorescent probe provides information on solvation dynamics in the vicinity of the coumarin dyes. In the present study, solvation dynamics occurred inside mesostructured silica with a uniform silica-mesopore diameter was examined by using four kinds of coumarin dyes as a fluorescent probe. In the silica-CTAB nanocomposite composed of CTAB (cetyltrimethylammonium bromide) micelles and silica-mesopores (pore diameter: 3.4 nm), it was found that coumarin dyes with different functional groups were located at different regions and that the molecular motions were differently constrained depending on the location of the coumarin dyes. In the silica-mesopores (pore diameter: 3.1 nm) filled with alcohol solvents, relatively small alcohols (ethanol and butanol) exhibited slow solvent relaxation process due to their confinment in the silica-mesopore, whereas such slow relaxation process was not recognized for large alcohols (hexanol and decanol). ©2009 The Japan Society for Analytical Chemistry.
Bunseki Kagaku, 2009, [Reviewed] - Optical Waveguide Sensor Based on a Porous Anodic Alumina/Aluminum Multilayer Film
Akira Yamaguchi; Kazuhiro Hotta; Norio Teramae, An optical waveguide sensor was fabricated by forming a multilayer film made by porous anodic alumina (PAA) and Al layers on a glass substrate. The fabricated sensor system was based on the monitoring of a waveguide coupling mode, which is sensitive to the change in the refractive index of the PAA layer caused by collection of tar-get molecules into the pores of the PAA layer. The PAA/Al multilayer film was formed by partial anodization of an Al film deposited on the glass substrate, and the waveguide coupling mode was examined by measuring angular spectra (reflectivity dependence on the incident angle of monitoring light; green He-Ne laser, 534.5 nm). A deep and sharp waveguide coupling dip was obtained for the PAA/Al multilayer system where the thicknesses of the PAA and Al layers were 200 and 17 nm, respectively. The optical sensor response of the PAA/Al multilayer system was compared to the responses of a surface plasmon resonance (SPR) sensor made by a Au thin film on a SF10 glass substrate. It was inferred that the optical waveguide sensor made by the PAA/Al multilayer could detect a smaller change in the refractive index of a solution, and it provided higher resolution than the SPR sensor. The sensor response for a change in the complex refractive index of the PAA layer was examined next, and it was found that the optical waveguide sensor was sensitive to the change in the imaginary part of the complex refractive index rather than the change in the real part. This result indicated that the sensitivity of the optical waveguide sensor could be improved by using the light absorption of a target compound., AMER CHEMICAL SOC
ANALYTICAL CHEMISTRY, Jan. 2009, [Reviewed] - Solvation Dynamics of Coumarin 153 in Alcohols Confined in Silica Nanochannels
Toshio Kamijo; Akira Yamaguchi; Shintaro Suzuki; Norio Teramae; Tetsuji Itoh; Takuji Ikeda, Solvation dynamics in alcohols confined in silica nanochannels was examined by time-resolved fluorescence spectroscopy using coumarin 153 (C 153) as a fluorescent probe. Surfactant-templated mesoporous silica was fabricated inside the pores of an anodic alumina membrane. The surfactant was removed by calcination to give mesoporous silica (Cal-NAM) containing one-dimensional (I D) silica nanochannels (diameter. 3.1 nm) whose inner surface was covered with silanol groups. By treating Cal-NAM with trimethylchlorosilane, trimethylsilyl (TMS) groups were formed on the inner surface of the silica nanochannels (TMS-NAM). Fluorescence dynamic Stokes shifts of C 153 were measured in alcohols (ethanol, butanol, hexanol, and decanol) confined in the silica nanochannels of Cal- and TMS-NAMs, and the time-dependent fluorescence decay profiles could be best fitted by a biexponential function. The estimated solvent relaxation times were much larger than those observed in bulk alcohols for both Cal- and TMS-NAMs when ethanol or butanol was used as a solvent, indicating that the mobility of these alcohol molecules was restricted within the silica nanochannels. However. hexanol or decanol in Cal- and TMS-NAMs did not cause a remarkable increase in the solvent relaxation time in contrast to ethanol or butanol. Therefore, it was concluded that a relatively rigid assembly of alcohols (an alcohol chain) was formed within the silica nanochannels by hydrogen bonding interaction and van der Waals force between the surface functional groups of the silica nanochannels and alcohol molecules and by the successive interaction between alcohol molecules when alcohol with a short alkyl chain (ethanol or butanol) was used as a solvent., AMER CHEMICAL SOC
JOURNAL OF PHYSICAL CHEMISTRY A, Nov. 2008, [Reviewed] - Integration of mesostructured silica with bathophenanthroline into a porous alumina membrane by one-pot synthesis method
Logudurai Radhakrishnan; Akira Yamaguchi; Wensheng Fu; Hideaki Kaneda; Norio Teramae, Ail integration of mesostructured silica containing a chelating reagent, bathophenanthroline (Bphen), into a porous alumina membrane by a one-pot synthesis method is demonstrated, and the integrated membrane is applied for detection of Fe(II). The integration is performed by spotting a precursor solution on a porous alumina membrane under moderate aspiration. The precursor solution contains Pluronic F127 as a template surfactant, tetraethoxysilane as a silica source, and Bphen as a chelating reagent. After the integration, columnar mesostructured silica is formed inside the alumina pore, and the pore structure of columnar mesostructured silica is circular or concentric three-layer stacked-doughnuts structure when the concentration of Bphen in the precursor solution is below 15 mM. On the other hand, the distinct pore structure is not obtained when the concentration of Bphen is high (>= 20 mM). The integrated membrane can be used to detect ca. 10 mu M of Fe(II) in an aqueous solution. This indicates that the integration of mesostructured silica containing an organic ligand into a porous alumina membrane is useful for developing a membrane-based analytical chip. (C) 2007 Elsevier Inc. All rights reserved., ELSEVIER SCIENCE BV
MICROPOROUS AND MESOPOROUS MATERIALS, Aug. 2008, [Reviewed] - Electrochemical synthesis of Au/polyaniline-poly(4-styrenesulfonate) hybrid nanoarray for sensitive biosensor design
Meining Zhang; Akira Yamaguchi; Kotaro Morita; Norio Teramae, Au/polyaniline (PANI)-poly(4-styrenesulfonate) (PSS) hybrid nanoarray is fabricated for biomolecular sensing in neutral aqueous solutions. Firstly, an array of one-dimensional Au nanorods (diameter = ca. 200 nm, length = ca. 3 mu m) is formed by a template-electrodeposition method using a porous anodic alumina membrane, and then a thin PANI-PSS composite layer is electropolymerized on the surface of the Au nanorods. The resulting Au/PANI-PSS hybrid nanoarray exhibits a quasi-reversible redox electrochemical process at ca. +0.11 V and electrocatalytic oxidation of reduced beta-nicotinamide adenine dinucleotide (NADH) is attained with a detection limit of 0.3 mu M in a neutral solution. (C) 2008 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE INC
ELECTROCHEMISTRY COMMUNICATIONS, Jul. 2008, [Reviewed] - Structural control of surfactant-templated mesoporous silica formed inside columnar alumina pores
Akira Yamaguchi; Hideaki Kaneda; Wensheng Fu; Norio Teramae, A hybrid mesoporous membrane is developed by forming surfactant-templated mesoporous silica inside columnar alumina pores of an alumina membrane. Predominant formation of onedimensional silica nanochannels (channel diameter = 8 nm) is achieved by controlling the aging time and temperature for preparation of the precursor solution using Pluronic P123 as a template surfactant., WILEY-V C H VERLAG GMBH
ADVANCED MATERIALS, Mar. 2008, [Reviewed] - Diffusion of metal complexes inside of silica-surfactant nanochannels within a porous alumina membrane
Akira Yamaguchi; Moataz M. Mekawy; Yong Chen; Shintaro Suzuki; Kotaro Morita; Norio Teramae, The present paper describes diffusivities of a series of metal complexes inside of silica-surfactant nanochannels (channel diameter = 3.4 nm), which were formed within a porous alumina membrane by a surfactant-templated method using cetyltrimethylammonium bromide (CTAB) as a template surfactant. The metal complexes used in this study were Fe(CN)(6)(3-), Ru(NH3)(6)(3-), ferrocenecarboxylic acid (Fc=COO-), (ferrocenylmethyl)-trimethylammonium (Fc-NMe3+), NN-(dimethylamminomethyl)ferrocene (Fc-NMe2), and ferrocene methanol (Fc-OH). Apparent diffusion coefficients of these metal complexes were estimated by measuring their mass transports through the silica-surfactant nanochannels. The estimated apparent diffusion coefficients were on the order of 10(-1)1 cm(2) s(-1) for Fe(CN)(6)(3-) and Ru(NH3)(6)(3-), and these values were five orders of magnitude smaller than those in a bulk aqueous solution. For the ferrocene derivatives, the apparent diffusion coefficients of charged ferrocene derivatives are almost the same (5.3 x 10(-11) cm(2) s(-1) for Fc-COO- and 5.4 x 10(-11) cm(2) s(-1) for Fc-NMe3+), whereas neutral ferrocene derivatives (Fc-NMe2 and Fc-OH) show faster diffusion than the charged species. In addition, the apparent diffusion coefficient of Fc-NMe2 (27 x 10(-11) cm(2) s(-1)) was about three times larger than that of Fc-OH (10 x 10(-11) cm(2) s(-1)). The difference in these diffusion coefficients is discussed by considering the mesostructure of the silica-surfactant nanochannels, that is, an ionic interface with cationic head groups of CTA and their counteranions, a hydrophobic interior of the micellar phase, and a silica framework. As a result, it is inferred that the slow diffusivities of the charged metal complexes are due to the electrostatic interaction between the charged species and the ionic interface, whereas less interaction between neutral ferrocenes and the ionic interface causes distribution of metal complexes into the hydrophobic micellar phase, which is a less viscous medium compared to the ionic interface, resulting in the faster diffusivities of the neutral species., AMER CHEMICAL SOC
JOURNAL OF PHYSICAL CHEMISTRY B, Feb. 2008, [Reviewed] - Enzyme catalytic membrane based on surfactant-templated mesoporous silica formed within porous anodic alumina membrane
Wensheng Fu; Akira Yamaguchi; Hideaki Kaneda; Norio Teramae, Immobilization of glucose oxidase (GOD) within a hybrid mesoporous membrane with 12 nm pore diameter was successfully achieved, resulting in catalytically high efficiency during flow of a glucose solution across the membrane., ROYAL SOC CHEMISTRY
Chem. Commun., 2008, [Reviewed] - Use of porous anodic alumina membranes as a nanometre-diameter column for high performance liquid chromatography
Tomohisa Yamashita; Shuji Kodama; Mikiya Ohto; Eriko Nakayama; Nobutaka Takayanagi; Tomoko Kemmei; Akira Yamaguchi; Norio Teramae; Yukio Saito, The possibility of using porous anodic alumina membranes as a column for normal-phase high performance liquid chromatography was evaluated using phenol and toluene with mobile phases having different solvent compositions., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, 2007, [Reviewed] - Diffusivities of tris(2,2 '-bipyridyl)ruthenium inside silica-nanochannels modified with alkylsilanes
Akira Yamaguchi; Takashi Yoda; Shintaro Suzuki; Kotaro Morita; Norio Teramae, The apparent diffusion coefficients of tris(2,2'-bipyridyl)ruthenium ([Ru(bpy(3))](2+)) are estimated in silica-nanochannels which are assembled inside columnar alumina pores in an anodic alumina membrane, and are modified with alkylsilanes such as trimethylchlorosilane (C1), butyldimethylchlorosilane (C4), and dodecyldimethylchlorosilane (C12). The estimation is performed by observing the lag-time, which is defined as the time required for [Ru(bpy)(3)](2+) to diffuse through alkylsilane-modified silica-nanochannels in the alumina membrane. When ethanol is used as a solvent, the apparent diffusion coefficients of [Ru(bpy)(3)](2+) are estimated as 2.1 x 10(-10) and 3.2 x 10(-10) cm(2) s(-1) in the C1- and C4-modified silica-nanochannels, respectively. These values are about 10(4) times smaller than that obtained in bulk ethanol. Based on the experimental results on the solvent dependency of the lag-time, the hydrogen-bonding interaction between ethanol molecules is considered to be stronger in the C1- and C4-modified silica-nanochannels than in bulk ethanol, and the hydrogen-bonding interaction plays a critical role for the slow diffusivity in those nanochannels. In contrast, the apparent diffusion coefficient in the C12-modified silica-nanochannel is at least two orders of magnitude larger than those in the C1- and C4-modified silica-nanochannels. This relatively fast diffusion is most likely explained by the presence of a long alkyl chain of C12, which reduces a hindrance effect that is originates in the hydrogen-bonding interaction., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, Dec. 2006, [Reviewed] - Permeation flux of organic molecules through silica-surfactant nanochannels in a porous alumina membrane
Tomohisa Yamashita; Shuji Kodama; Mikiya Ohto; Eriko Nakayama; Sumiyo Hasegawa; Nobutaka Takayanagi; Tornoko Kemmei; Akira Yamaguchi; Norio Teramae; Yukio Saito, The permeation fluxes of phenol, benzene sulfonate (BS) and benzene disulfonate (BDS) through a porous anodic alumina membrane with the perpendicularly oriented silica-surfactant nanochannel assembly membrane (NAM) were measured in water-ethanol mixture media. The permeation flux depended on solute charges and on solvent composition. As the ethanol ratio increased, the fluxes of BS and BDS increased and the flux of phenol decreased. The results of extraction/elution experiments also depended on the solute charges and the solvent composition. Chromatographic experiments in n-hexane showed that dipole and hydrophobic interactions affect the retention of solutes. Permeation of the solute across the NAM in water-ethanol mixture is likely to be determined by various factors such as dipole interaction, hydrophobic interaction, solvation, and anion-exchange efficiencies., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, Dec. 2006, [Reviewed] - Longitudinal diffusion behavior of hemicyanine dyes across phospholipid vesicle membranes as studied by second-harmonic generation and fluorescence spectroscopies
Akira Yamaguchi; Masaki Nakano; Kimihisa Nochi; Tomohisa Yamashita; Kotaro Morita; Norio Teramae, The adsorption and longitudinal diffusion behaviors of a series of hemicyanine dyes to phospholipid vesicle membranes were studied by second-harmonic generation (SHG) and fluorescence spectroscopies. It was observed that the longitudinal diffusion of cationic hemicyanine dyes takes place immediately after the initial adsorption of these dyes to the outer surface of the vesicle membrane. In contrast, hardly any amount of a zwitterionic hemicyanine dye with a sulfonate group diffused across the vesicle membrane within the measurement time (< 2000 s). Based on the difference in the time-course responses of SHG and fluorescence spectroscopies for all of the hemicyanine dyes tested, we propose that hydration of the sulfonate group is mainly responsible for the low diffusivity of the zwitterionic hemicyanine dye., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, Oct. 2006, [Reviewed], [Invited] - Template Synthesis of Arrays of Meso-sized One-Dimensional Gold Nanowires by Electrodeposition
Yong Chen; Akira Yamaguchi; Toshiyuki Atou; Kotaro Morita; Norio Teramae
Chem. Lett., 2006, [Reviewed] - Local environments of Coumarin Dyes within Mesostructured Silica-Surfactant Nanocomposite
Akira Yamaguchi; Yosuke Amino; Kentaro Shima; Shintaro Suzuki; Tomohisa Yamashita; Norio Teramae, Lead, The local environments surrounding dye molecules were studied with use of coumarin dyes in a mesostructured silica-surfactant nanocomposite, which was formed in a porous alumina membrane by a surfactant-templated method and has an average pore diameter of 3.4 nm. Coumarin dyes, such as coumarin 480 (C480), coumarin 343 (C343), and propylamide coumarin 343 (PAC343), were extracted into the silica-surfactant nanocomposite and time-resolved fluorescence spectra of these dyes were examined. C480 and C343 show slow dynamic Stokes shifts and the decay curve can be fitted by a biexponential function. The decay-time constants obtained from the fitting are almost identical for C480 and C343: 0.87 and 7.5 ns for C480, and 0.86 and 7.6 ns for C343. In contrast to these two coumarin dyes, short decay-time constants (0.50 and 4.8 ns) were obtained for PAC343 in the silica-surfactant nanocomposite. These results indicate that the local environments of C480 and C343 are almost identical but different from that of PAC343. By considering the origin of the dynamic Stokes shift and the mesostructure of the silica-surfactant nanocomposite, the location and microenvironment of coumarin dyes within the silica-surfactant nanocomposite are discussed., AMER CHEMICAL SOC
J. Phys. Chem. B, 2006, [Reviewed] - Extraction mechanisms of charged organic dye molecules into silica-surfactant nanochannels in a porous alumina membrane
A Yamaguchi; J Watanabe; MM Mahmoud; R Fujiwara; K Morita; T Yamashita; Y Amino; Y Chen; L Radhakrishnan; N Teramae, Extraction mechanisms of charged organic dye molecules are examined for an assembly of silica-surfactant nanochannels with a channel diameter of 3.4 nm, which is formed inside the pores of an anodic alumina membrane by a surfactant-template method. Experimental results confirm that the extraction mechanism depends on the sign of a charge of the dye molecules. The extraction of the cationic rhodamine 6G is predominantly caused by an ion-pair extraction process, whereas an anion-exchange process is mainly responsible for the extraction of the anionic sulforhodamine B. These extraction mechanisms are discussed by considering the microstructures of the silica-surfactant nanochannels. (c) 2005 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
ANALYTICA CHIMICA ACTA, Jan. 2006, [Reviewed], [Invited] - 表面第二高調波発生分光法を用いる界面吸着ローダミンＢの会合状態解析
山口 央; 内田達也; 伊奈知美; 能智公久; 寺前紀夫, Lead, We have developed an apparatus for the measurement of second harmonic generation (SHG) spectra that provide direct evidence on the electronic structures of interfacial species. By applying the measurement apparatus, we have studied molecular association of rhodamine B (RB) at a heptane/water interface and trimethylchlorosilane (TMS) modified-quartz/water interfaces with a different coverage. The observed SHG spectra at the heptane/water interface showed red-shift of the peak maxima compared to the absorption maximum of monomeric RB in the bulk aqueous phase, and these spectra indicated predominant formation of in-plane associates in which the electronic transition dipoles of each monomer were arranged parallel to one another. At the TMS-modified-quartz/water interface, spectral shape of SHG spectra was almost same with that found in the heptane/water interface when the surface density of TMS was high. In contrast, with decreasing the surface density of TMS, the red-shifted peak due to the in-plane associates become weaker, and other peaks due to a sandwich dimmer appeared. We confirmed that the association form of RB depended on the surface density of TMS., The Japan Society for Analytical Chemistry
分析化学, 2006, [Reviewed], [Invited] - Visualization of DNA hybridization on gold thin film by utilizing the resistance effect of DNA monolayer
T Masuda; A Yamaguchi; M Hayashida; F Asari-Oi; S Matsuo; H Misawa, We propose a novel detection method for a duplex formation of DNA on a solid substrate. In this method, DNA monolayers are prepared on a gold thin film, and then the substrate is treated by an etching process. Since the DNA monolayer can act as a resist layer, the thickness of the gold film in the regions covered by DNA monolayers is larger than that in the region without the monolayer. Furthermore, the difference in the resistance effect of ss- and ds-DNA monolayers induces the difference in the thickness of the gold thin film after the etching. The resistance effect of the ss-probe DNA monolayer increases as a result of the formation of a duplex with the target DNA. The sequence-specific hybridization adsorption of the target DNA can be detected visually by measuring the light transmittance of the gold film, or with the naked eye. Using this method, we succeeded in detecting two base pair mismatches in a 30-base pair nucleotide. (c) 2004 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
SENSORS AND ACTUATORS B-CHEMICAL, Mar. 2005, [Reviewed] - Solvation Dynamics at the Water/Mica Interface as Studied by Time-Resolved Fluorescence Spectroscopy
Tomohisa Yamashita; Yosuke Amino; Akira Yamaguchi; Norio Teramae, Solvation dynamics at the water/mica interface was investigated by time-resolved fluorescence spectroscopy. Time-resolved fluorescence spectra of a coumarin dye immobilized on the mica surface show dynamic Stokes shifts with several hundreds picosecond time scale. Solvent relaxation time observed at the water/mica interface was remarkably longer than that observed in a bulk solution, suggesting existence of a rigid water layer on the mica surface, that is, hydrogen-bonding network is strongly formed at the mica surface., CHEMICAL SOC JAPAN
Chem. Lett., 2005, [Reviewed] - High Sensitivity and Large Dynamic Range Surface Plasmon Resonance Sensing for DNA Hybridization Using Au-Nanoparticle Attached Probe DNA
Masayuki Hayashida; Akira Yamaguchi; Hiroaki Misawa, In this study, we demonstrate the use of surface plasmon interaction between Au nanoparticles (GPs) and a Au thin film for enhancement of surface plasmon resonance (SPR) spectroscopy sensing for DNA hybridization. In situ DNA hybridization with a Au-nanoparticle-attached probe DNA (DNA-GP) monolayer is monitored by SPR spectroscopy, and the results reveal that the DNA-GP allows detection of unlabeled target DNA with the large dynamic range of 1 pM to 10 mu M., INST PURE APPLIED PHYSICS
Jpn. J. Appl. Phys., 2005, [Reviewed] - Adsorption behavior of lauric acid at heptane/water interface as studied by second harmonic generation spectroscopy and interfacial tensiometry
A Yamaguchi; T Uchida; K Nochi; T Yamashita; N Teramae, Interfacial tensiometry and second harmonic generation (SHG) spectroscopy were applied to examine the adsorption behavior of lauric acid (LA) at a heptane/water interface. From interfacial tensiometry measurements, the adsorption kinetics of LA was revealed to be diffusion-controlled, and the adsorption constant of LA was estimated to be 9.6 x 10(4) M-1. The adsorption isotherms obtained by SHG measurements were analyzed by taking account of both the molecular orientation of LA at the interface and a surface electric field generated by the adsorbed LA layer. It was confirmed that the carboxylic groups of adsorbed LA molecules were well ordered at the heptane/water interface and the orientation of the carboxylate group was invariant during the adsorption process., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, Nov. 2004, [Reviewed] - Self-assembly of a silica-surfactant nanocomposite in a porous alumina membrane
A Yamaguchi; F Uejo; T Yoda; T Uchida; Y Tanamura; T Yamashita; N Teramae, A mesoporous membrane composed of nanochannels with a uniform diameter has a potential use for precise size-exclusive separation of molecules. Here, we report a novel method to form a hybrid membrane composed of silica-surfactant nanocomposite and a porous alumina membrane, by which size-selective transport of molecules across the membrane becomes possible. The nanocomposite formed inside each columnar alumina pore was an assembly of surfactant-templated silica-nanochannels with a channel diameter of 3.4 nm; the channel direction being predominantly oriented along the wall of the columnar alumina pore. Molecules could be transported across the membrane including the silica-surfactant nanocomposite with a capability of nanometre-order size-exclusive separation. Our proposed membrane system has a potential use not only for separation science, but also catalysis and chip technologies., NATURE PUBLISHING GROUP
NATURE MATERIALS, May 2004, [Reviewed] - Electrochemical modification of benzo-15-crown-5 ether on a glassy carbon electrode for alkali metal cation recognition
K Morita; A Yamaguchi; N Teramae, Benzo-15-crown-5 (B15C5) was covalently immobilized on a glassy carbon (GC) electrode and its complexation ability with alkali metal cations was studied. A mixture of 4'-aminobenzo-15-crown-5 and NaNO2 was prepared to generate diazotized B15C5, and a GC electrode was immersed in the mixture. By potential cycling between 0.0 and -0.8 V, the diazotized B15C5 was reduced electrochemically and reacted with the carbon atoms at the electrode surface to form the B15C5 layer on the GC electrode. Cyclic voltammetry and scanning tunneling microscopy were used to characterize the B15C5 layer. The surface amount of B15C5 groups increased by repeating the potential cycles, and reached a saturated value within 20 cycles. STM observation reveals that a monolayer or sub-monolayer of B15C5 was formed. The adsorption behavior of alkali metal cations to the B15C5 layer on GC electrode was examined by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The order of adsorption constants was K+ > Na+ > Rb+ > Li+ > Cs+, indicating cooperative association between K+ and B15C5 groups at the modified electrode surface. (C) 2003 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE SA
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, Mar. 2004, [Reviewed] - Construction of DNA-Au Nanoparticles Multilayer and Its Application for Detection of DNA Hybridization
Hongchun Liu; Akira Yamaguchi; Masayuki Hayashida; Shigeki Matsuo; Hiroaki Misawa, We have developed a sensitive detection system for DNA hybridization containing DNA-Au nanoparticles (DNA-GPs) multilayer which leads to the enhancement of the detection sensitivity of surface plasmon resonance (SPR) signals. The SPR angular shift, which is the difference in the SPR angles before and after hybridization, becomes amplified with increasing number of layers of the DNA-GPs. A similar increase in SPR angular shift was obtained for the target DNA with low concentration. The reason for the enhancement is attributed to the interaction between Au nanoparticles and the Au film, as well as the increase in immobilized probe DNA content on the substrate., INST PURE APPLIED PHYSICS
Jpn. J. Appl. Phys., 2004, [Reviewed] - Anion Recognition at the Solid/Liquid Interface as Studied by Second Harmonic Generation Spectroscopy
Akira Yamaguchi; Ryo Kato; Seiichi Nishizawa; Norio Teramae, Lead
Chem. Lett., Sep. 2003, [Reviewed] - Rapid fabrication of electrochemical enzyme sensor chip using polydimethylsiloxane microfluidic channel
Akira Yamaguchi; Peng Jin; Hiroshi Tsuchiyama; Takao Masuda; Kai Sun; Shigeki Matsuo; Hiroaki Misawa, Elsevier BV
Analytica Chimica Acta, Sep. 2002, [Reviewed] - Flexural Rigidity of a Single Microtubule
Toru Takasone; Saulius Juodkazis; Yuji Kawagishi; Akira Yamaguchi; Shigeki Matsuo; Hitoshi Sakakibara; Haruto Nakayama; Hiroaki Misawa, IOP Publishing
Japanese Journal of Applied Physics, 15 May 2002, [Reviewed] - A heater-integrated transparent microchannel chip for continuous-flow PCR
Kai Sun; Akira Yamaguchi; Yutaka Ishida; Shigeki Matsuo; Hiroaki Misawa, Elsevier BV
Sensors and Actuators B: Chemical, May 2002, [Reviewed] - Enhancement of Surface Plasmon Resonance Sensing for DNA Hybridization Using Colloidal Au Attached Probe DNA
Akira Yamaguchi; Saulius Juodkazis; Shigeki Matsuo; Hiroaki Misawa, Abstract
In this study, we demonstrate that the Au particle modified probe DNA monolayer can enhance the surface plasmon resonance (SPR) signal for measuring hybridization of unlabeled DNA molecules. The Au particles adsorbed on single stranded (ss)- and double stranded (ds)-DNA monolayers have different optical interaction with surface of Au thin film, and this difference induces the enhancement of the SPR signal., Oxford University Press (OUP)
Chemistry Letters, 01 Feb. 2002, [Reviewed] - Photo-electrochemical Deposition of Platinum on TiO2 with Resolution of Twenty Nanometers using a Mask Elaborated with Electron-Beam Lithography
Saulius Juodkazis; Akira Yamaguchi; Hidekazu Ishii; Shigeki Matsuo; Hitoshi Takagi; Hiroaki Misawa, We report the patterning of Pt on a TiO2-rutile single crystal (the fundamental absorption band starts at 396 nm) by direct deposition from a water solution of H2PtCl6 (10–20 mmol/dm3) using laser beam writing at 390–396 nm, or by Hg-lamp illumination (i-line at 365 nm). Pt deposition was corroborated by microchemical analysis. A resolution of the Pt patterning down to 20-30 nm was achieved. To create a Pt pattern with resolution of twenty nanometers, we employed a mask elaborated with electron-beam (EB) drawing lithography. The mask was transparent to the writing illumination. The Pt was reduced from the solution by laser beam scanning over resist-covered regions, while the pattern was formed in the openings of the resist. Separation of the growth and illumination regions, typically, by 0.5–2 µm, facilitates the deposition of reproducible, high-aspect-ratio patterns. It is demonstrated that Pt was deposited through a process of diffusion of the light-excited carriers. The possibility of fabrication of a three-dimensional Pt pattern by the overgrowth of the resist is discussed., IOP Publishing
Japanese Journal of Applied Physics, 01 Jun. 2001, [Reviewed] - Glucose sensing based on interdigitated array microelectrode
Peng Jin; Akira Yamaguchi; Fumika Asari Oi; Shigeki Matsuo; Jiubin Tan; Hiroaki Misawa, A micro glucose sensor consisting of an interdigitated array gold microelectrode was developed. The interdigitated array structure, which has 10 μm band width and 10 μm band gap, was fabricated in a small region (2.5 × 5 mm2) on a quartz substrate. Glucose oxidase was chemically fixed onto the electrode surface through self-assembled monolayer of 11-mercaptoundecanoic acid
ferroceneacetic acid was used as electron mediator. Electrochemical properties of the glucose oxidase-immobilized microelectrode were investigated by cyclic voltammogram measurements. Results confirmed that the reductive ferroceneacetic acid generated at counter electrode diffuses through a narrow band gap (10 μm) and can reach the working electrode surface.
Analytical Sciences, 2001, [Reviewed] - Reversible phase transitions in polymer gels induced by radiation forces
Saulius Juodkazis; Naoki Mukai; Ryosuke Wakaki; Akira Yamaguchi; Shigeki Matsuo; Hiroaki Misawa, Springer Science and Business Media LLC
Nature, Nov. 2000, [Reviewed] - Observation of Molecular Association at Liquid / Liquid and Solid / Liquid Interfaces by Second Harmonic Generation Spectroscopy
Tatsuya Uchida; Akira Yamaguchi; Tomomi Ina; Norio Teramae
J. Phys. Chem. B, 2000, [Reviewed] - Resonant Second Harminic Spectroscopy of Rhodamine B Adsorbed onto Fused Silica
Akira Yamaguchi; Tatsuya Uchida; Norio Teramae; Hideaki Kaneta, Lead
Anal. Sci., 1997, [Reviewed]
MISC
- High-Performance Bio-Sensor with Enzymes Immobilized on Mesoporous Membranes: Nanosized Pores Just Corresponding to the Size of an Enzyme Improve the Stability of the Sensor Drastically
Tetsuji Itoh; Akira Yamaguchi; Takashi Kyotani; Taka-aki Hanaoka; Fujio Mizukami
Adv. Porous Mater, Apr. 2016 - メソポーラスシリカ細孔構造制御と細孔内環境の評価
山口央; 渋屋祐太; 成澤淳; 滑川真人; 菅原大輝; 荒船博之; 寺前紀夫
分析化学, 2013, [Reviewed]
Corresponding - Adsorption and desorption dynamics of sodium dodecyl sulfate in a hydrophobized mesoporous silica film observed in-situ by optical waveguide spectroscopy
Akira. Yamaguchi; Hiroyuki Arafune; Kazuhiro. Hotta; Tetsuji. Itoh; Norio Teramae
Anal. Sci., 2011 - シクロデキストリン修飾メソポーラスシリカ膜の作製とD,L‐トリプトファンの膜透過挙動観察
吉川昭平; 荒船博之; 山口央; 寺前紀夫
化学系学協会東北大会プログラムおよび講演予稿集, 25 Sep. 2010 - Characteristics of optical waveguide mode within mesoporous silica film fabricated on the aluminum thin film
荒船博之; 堀田一海; 山口央; 寺前紀夫
日本化学会講演予稿集, 13 Mar. 2009 - Utilization of nanometre-order diameter columns inside porous anodic alumina for chromatography chip system
Tomohisa Yamashita; Shuji Kodama; Mikiya Ohto; Eriko Nakayama; Tomoko Kemmei; Tatsuya Muramoto; Akira Yamaguchi; Norio Teramae; Nobutaka Takayanagi
Chem. Lett., 2008 - Fabrication and analytical applications of hybrid mesoporous membranes
Akira Yamaguchi; Norio Teramae
Anal. Sci., 2008 - Analytical Applications of Metallic and Metal Oxide Nanoporous Films
YAMAGUCHI Akira; KAMIJO Toshio; TERAMAE Norio
ぶんせき, 05 Aug. 2007 - 微細孔を利用した金属ナノ材料
山口 央; 寺前紀夫
化学, 2007 - 陽極酸化アルミナ膜を利用したナノチャンネル形成
山口央; 寺前紀夫
金属, 2004 - Laser manipulation of bio-/biomimetic materials
Toru Takasone; Saulius Juodkazis; Shigeki Matsuo; Akira Yamaguchi; Keiji Sasaki; Jun Ichi Hotta; Hiroaki Misawa
Proceedings of SPIE - The International Society for Optical Engineering, 01 Dec. 2002 - Surface plasmon resonance imaging of Au nano-partifcle modified DNA monolayers
Akira Yamaguchi; Masayuki Hayashida; Saulius Juodkazis; Yoichiro Hara; Shigeki Matsuo; Hiroaki Misawa
Proceedings of SPIE - The International Society for Optical Engineering, 01 Jan. 2002
Books and other publications
- 顕微赤外・顕微ラマン分光法の基礎と応用：第6章3 金属ナノ構造の顕微ラマン測定
山口 央; 寺前 紀夫, Joint work
技術情報協会, 2008 - 先端材料開発における振動分光分析法の応用：第5章４ 金属ナノ構造と表面増強ラマン
山口央; 寺前紀夫, Joint work
シーエムシー出版, 2007 - レーザーハンドブック：第４０章遺伝子解析
山口央; 三澤弘明, Joint work
オーム社, 2005 - Interfacial Nanochemistry: Molecular Science and Engineering at Liquid-Liquid Interfaces, Chapter 11. Molecular Recognition of Ions at Liquid/Liquid Interfaces.
N. Teramae; S. Nishizawa; A. Yamaguchi; T. Uchida, Joint work
Kluwar Academic/Plenum Publishers, 2005 - 機器分析実験：実験２・３ ローダミンＢ色素の会合定数の決定
山口 央, Joint work
東京化学同人, 2002 - 機器分析実験：実験９・８ 石英／水界面におけるアゾ色素の配向性評価
山口 央, Joint work
東京化学同人, 2002 - 界面ハンドブック：非線形レーザー分光法（固／液）
山口央; 内田達也; 寺前紀夫, Joint work
57-60, 2001
Lectures, oral presentations, etc.
- ナノ気液界面を利用したエタノールガスの直接電気科学計測
河合美帆; 山口央
第18回茨城地区分析技術交流会, 13 Dec. 2024 - ホウ素ドープメソポーラスシリカナノ粒子の合成と評価
大橋瑞樹; 山口央
第18回茨城地区分析技術交流会, 13 Dec. 2024 - 交流インピーダンス法を利用した気/氷界面の融解現象の観察
山田侑奈; 山口央
第18回茨城地区分析技術交流会, 13 Dec. 2024 - Pore size effects for biomacromolecules inside nanopores
Akira Yamaguchi
26 Sep. 2024, [Invited] - 中性子非弾性散乱によるナノ細孔内水単分子層のダイナミクス測定
小島吉智; Nicolas de Sauza; Dehong Yu; Pablo Galaviz; 山口央
日本分析化学会第73年会
20240911, 20240913 - 尿素を結合したアクリジンの固液界面における互変異性とアニオン認識挙動
木村奨; 山口央
日本分析化学会第73年会
20240911, 20240913 - メソポーラスシリカナノ微粒子を用いたセラノティクスシステムの開発
高橋美桜; 日賀野頼巴; 中村麻子; 山口央
第17回茨城地区分析技術交流会, 01 Dec. 2023 - アルミナナノ粒子上へのペリレンジイミド単分子膜の作製と評価
木村奨; 山口央
第17回茨城地区分析技術交流会, 01 Dec. 2023 - メソポーラスホウケイ酸ナノ微粒子の合成
井上敬斗; 山口央
第17回茨城地区分析技術交流会, 01 Dec. 2023 - ナノ細孔内におけるアニオン認識系の構築
吉岡穂香; 山口央
第17回茨城地区分析技術交流会, 01 Dec. 2023 - Neutron scattering for the study of confined proteins
Akira Yamaguchi
8th International Symposium of Quantum Beam Science, [Invited]
20231128, 20231130 - 中性子準弾性散乱を用いたナノ細孔内タンパク質のダイナミクス測定
小島吉智; 山口央; Nicolas de Sauza
日本分析化学会第72年会
20230913, 20230915 - ナノ気液界面での電気化学計測を利用したガスセンシング
仲田遥香; 山口央
日本分析化学会第72年会
20230913, 20230915 - レドックス応答性ペリレンジイミド単分子膜の作製と評価
木村奨; 山口央
日本分析化学会第72年会
20230913, 20230915 - 中性子反射率法を用いたアルミナナノ多孔膜へのタンパク質吸着過程の観察
○山口 央・片山 知哉・Stephen A. Holt
第83回日本分析化学討論会, 21 May 2023
20230520, 20230521 - 〔Major achievements〕BSAゲル被覆メソポーラスシリカナノ粒子を用いたセラノティクスシステムの開発
篠田英駿,山口央
日本分析化学会第71年会, 16 Sep. 2022
20220914, 20220916 - 〔Major achievements〕ナノホール電極での気液界面形成と電気化学ガスセンシング応用
仲田遥香,山口央
日本分析化学会第71年会, 14 Sep. 2022
20220914, 20220916 - 〔Major achievements〕ナノ空間におけるタンパク質凝集のサイズマッチング効果
山口 央
日本分析化学会第82回分析化学討論会, 14 May 2022
20220514, 20220515 - 〔Major achievements〕ITO電極表面に形成したPDI-Fc単分子膜の特性評価
木村奨,雑賀将大,山口央
日本分析化学会第82回分析化学討論会, 14 May 2022
20220514, 20220515 - 中性子を利用したナノチャンネルへのタンパク質物質輸送現象の解明
山口 央
第15回東邦大学複合物性研究センターシンポジウム, 04 Dec. 2021, [Invited]
20211204, 20211204 - 〔Major achievements〕BSAゲル被覆メソポーラスシリカナノ粒子を用いたセラノティクスシステムの開発
篠田 英駿,山口 央
日本分析化学会第70年会, 24 Sep. 2021
20210922, 20210924 - ナノ多孔性材料とタンパク質を複合化した生体触媒材料の開発
山口央
2019年度日本分析化学会東北支部若手交流会, Nov. 2019, [Invited] - 小角中性子散乱を利用したタンパク質/ナノ多孔複合材料の評価
山口央
2018年度量子ビームサイエンスフェスタ, Mar. 2019, [Invited] - 小角中性子散乱と熱分析を利用したナノ空間内タンパク質の構造評価
山口 央
日本分析化学会第67年会, Sep. 2018, [Invited] - メソ空隙に閉じ込められた機能性生体高分子の構造と安定性
山口央
GIC第57回研修セミナー, Jul. 2018, [Invited] - 生体高分子の高次構造と閉じ込め空間サイズの相関
山口 央; 渋屋 祐太
日本分析化学会第66年会, Sep. 2017, [Invited] - Optical Waveguide Spectroscopy for Study of Biological Events inside Inorganic Nanopores
PACIFICHEM2015, 18 Dec. 2015 - Stabilities of DNA secondary structures inside confined nanospace
Akira Yamaguchi; Kazuyoshi Nasu; Ryoko Yoshida; Shigeki Wakaume
2nd Asian Symposium for Analytical Sciences, 10 Sep. 2015 - Stabilities of DNA secondary structures,inside confined nanospace
Akira Yamaguchi; Kazuyoshi Nasu; Ryoko Yoshida; Shigeki Wakaume
2nd Asian Symposium for Analytical Sciences, 10 Sep. 2015 - Encapsulation of an enzyme into nanoporous-walloed silica nanotube-inorganic composite membrane
Akira Yamaguchi; Tetsuji Itoh
2014 International Conference on Artificial Photosynthesis, 26 Nov. 2014 - アルミナナノ細孔を利用したバイオセンサー
第31回金属のアノード酸化皮膜の機能化部会（ARS）足柄コンファレンス, 20 Nov. 2014 - ナノポーラス構造に基づくバイオセンシング
2013年真空・表面科学合同講演会, 26 Nov. 2013 - Fabrication of Hybrid Mesoporous Membrane for Bioanalysis
9th International Workshop on Supramolecular Nanoscience of Chemically Programmed Pigments (SNCOO13), 29 Jun. 2013 - 多孔質ナノ材料の分析化学などへの応用について
富山県衛生研究所合同セミナー, 18 Sep. 2012 - 物質透過型ナノ多孔膜の開発とバイオ分析への応用
茨城県産学官連携成果発表会, 15 Feb. 2012 - 均一メソ多孔体内部の特異環境を利用したバイオセンシング系の構築
第12回機能構造と分析化学シンポジウム, 19 Nov. 2011 - Optical Waveguide Sensor Based on Nanoporous/Metal Multilayer Films
PACIFICHEM 2010, 18 Dec. 2010 - 多孔性陽極酸化膜を利用した分離分析手法の開発
第27回 金属のアノード酸化皮膜の機能化部会（ARS）鎌倉コンファレンス, 18 Nov. 2010 - メソ空間を分子認識場とするセンサー開発
第7回茨城地区分析技術交流会, 29 Oct. 2010 - 円筒状アルミナ細孔内で形成する規則性メソ多孔材料
表面技術協会第121回講演大会, 15 Mar. 2010
Research Themes
